bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fine structure of the surfaces of the epithelium and mesenchyme of the newt limb regenerate, separated in salt solution: 14 to 25 days
Authors: Jasch Laura G. 
Published: February 2005

AbstractForelimbs of the newt Notophthalmus (Triturus) viridescens were amputated at the wrist, and at 14 to 25 days, the new limb regenerates were removed by a razor‐blade cut. After incubation of the isolated regenerates in a medium containing only inorganic salts, the epithelium was removed easily from the underlying mesenchyme. The surfaces separated in the salt solution were examined using scanning and transmission electron microscopy to evaluate the completeness of the separation and the extent of tissue damage near the plane of separation. Rarely was an epithelial cell found clinging to the mesenchymal surface, supporting previous light microscopic observations. The most apparent morphological damage was sustained by the basal epithelial cell surfaces, which exhibited blebbing; the formation of vacant vesicles within the cytoplasm near the newly exposed plasma membranes; the structural disruption of some organelles; and the tearing away of fragments of the basal epithelial cell plasma membranes, which remained adherent to the mesenchymal surface during separation procedure. Examination of the structure of the epithelialmesenchymal interface of intact regenerates showed that the plane of epithelialmesenchymal separation was, for the most part, between the basal epithelial cell membrane and its substrate, an extracellular material which remained at the mesenchymal surface after separation. This substrate was in the form of an extracellular material closely adherent to the basal epithelial cell membrane at the distal tips of the regenerates; a developing basal lamina at the periphery of regenerates undergoing blastema accumulation; or a mature basal lamina at the base of digit stage regenerates. The usefulness of these separated tissues for future experimentation and the evaluation of the nature of the epithelial substratum throughout the course of limb regeneration are discussed.
Differences in the development of jejunum and ileum as observed in fetal rat intestinal isografts. Possible implications related to the villus size gradient
Authors: Jolma Vladimira M. , Kendall Kevin , Koldovský Otakar 
Published: February 2005

AbstractPrevious studies have shown that villus size in the small intestine decreases from the duodenum toward the ileum. Villus‐enlarging and villus‐reducing factors have been found in the gastric, pancreatic, and duodenal secretions, and in bile (Altmann and Leblond, ′70; Altmann, ′74). We here explore the role of intrinsic factors present in the individual sections of the small intestine by following the development of villus height in fetal (21‐day old) jejunal and ileal segments implanted under the kidney capsule of syngeneic adult rats. Twenty‐eight and 45 days after implantation, the jejunal villi contained significantly more columnar epithelial cells than did the ileal villi, but the jejunoileal gradient was even greater in small intestine of corresponding ages, developing in situ. Our experiments, thus, show that the jejunoileal gradient is already programmed in rats 1 day before birth, while other factors contribute postnatally to regulation of its magnitude.
The urethral sphincter muscle in the male
Authors: Oelrich Thomas M. 
Published: February 2005

AbstractThe male urethral sphincter is a striated muscle in contact with the urethra from the base of the bladder to the perineal membrane. The individual muscle fibers are 25 to 30% smaller than fibers of associated muscles and are embedded in connective tissue which obscures the visibility of the whole muscle.The muscle primordium is laid down around the urethra prior to the development of the prostate. Subsequently, the prostate develops as a diverticulum of the urethra and grows into the developing sphincter, thinning the overlying musculature. With the onset of puberty, accelerated growth of the prostate displaces the sphincter, with atrophy of the overlying muscle, resulting in what may appear to be isolated segments of the sphincter muscle distributed around the prostate. The prostate overgrows the anterior portion of the urethra and the associated sphincter muscle.There is no distinct superior fascia of the so‐called urogenital diaphragm separating the sphincter muscle from the prostate. The fascia of the sphincter muscle is inseparable from the prostatic sheath, is oriented vertically, and passes through the urogenital hiatus to unite with the fascia of the pudendal canals at the isochiopubic rami. Thus, the sphincter muscle is a component of a bladder‐urethra‐prostate‐sphincter unit which lies within the pelvis, in the urogenital hiatus, and rests upon the perineal membrane. The concept of a urogenital diaphragm is not borne out by this study.
Morphological and cytochemical alterations of the Golgi apparatus and GERL in rat parotid acinar cells during ethionine intoxication and recovery
Authors: Oliver Constance , Auth Regina E. , Hand Arthur R. 
Published: February 2005

AbstractThe present electron microscopic cytochemical investigation was undertaken to characterize the alterations in the Golgi apparatus and GERL of rat parotid acinar cells during ethionine intoxication and recovery. Although the Golgi apparatus and GERL were reduced in size, and some broadening of the Golgi saccules occurred as the result of ethionine treatment, the relative localization of thiamine pyrophosphatase (TPPase) activity in the Golgi saccules, and acid phosphatase activity (AcPase) in GERL, remained unchanged. Shortly after ethionine treatment was stopped, a dramatic redistribution of enzyme activities was noted. Within the first 24 hours of recovery, the Golgi apparatus began to enlarge, and the content of secretory granules increased. By day 3 of recovery, cisternae morphologically identifiable as GERL and forming secretory granules possessed TPPase activity, while AcPase activity was virtually undetectable. After seven days of recovery, the Golgi apparatus and GERL appeared both morphologically and cytochemically normal. The enzyme modulation observed during recovery may be correlated with increased secretory granule production. Furthermore, the presence of TPPase activity in GERL and forming secretory granules lends support to the suggestion that GERL may be derived from the trans Golgi saccule.
Cytodifferentiation of the rat paneth cell: An immunocytochemical investigation in suckling and weanling animals
Authors: Lopez‐Lewellyn Jeannette , Erlandsen Stanley L. 
Published: February 2005

AbstractThe cytodifferentiation of the intestinal Paneth cell was investigated in 2‐ to 50‐day‐old rats by evaluating the phenotypic expression of bacteriolytic lysozyme. Samples of duodenum, jejunum, and ileum were exposed to anti‐lysozyme antiserum and treated by the periodic‐acid Schiff (PAS) technique for the demonstration of carbohydrate moieties. The distribution of the Paneth cell population was then assessed.At days 3‐6, Paneth cells were present in ≤ 1% of intestinal crypts and exhibited (a) location in the bases of crypts, (b) apical granules positive for lysozyme, and (c) a slender truncated shape extending to the crypt lumen. By days 6‐8, Paneth cells had acquired their typical broad, truncated shape and prominent secretory apparatus. Between 1 and 7 weeks postpartum, the frequency of Paneth cellcontaining crypts in duodenum rose from 9% to 79%; in jejunum and ileum the frequency increased through the third week of life and stabilized at 77%–93% thereafter. At all ages, a rostro‐caudal gradient of crypts containing Paneth cells was observed, and greater numbers of paneth cells per crypt were seen caudally. In both suckling and weanling animals, two intermediate cell types were encountered. The first predominated at crypt bases through the fourth week of life and contained lysozyme‐positive supranuclear granules, concomitant with an apical aggregation of PAS‐positive material. The second type, identical to goblet cells in size and shape, predominated along the walls of intestinal crypts and at the bases of villi, and manifested both lysozyme‐positive granules and PAS‐positive mucigen droplets in the apical cytoplasm. This cell type appeared by day 12 and persisted through day 50.The results of this study provide further evidence that Paneth cells differentiate from a subpopulation of multipotent stem cells residing at crypt bases. The observation of Paneth cell‐goblet cell transitional forms supports the view that these two cell types share a common lineage.
Differentiation of myoepithelial cells in the developing rat parotid gland
Authors: Redman Robert S. , Sweney Laura R. , McLaughlin Shirley T. 
Published: February 2005

AbstractParotid glands of rats were prepared for light and electron microscopy and for the histochemical demonstration of myofibrils and alkaline phosphatase (AkPase) activity. Through 18 days in utero, the epithelial cells of the developing gland remain relatively undifferentiated. At 20 days in utero, a few cells in the outer layer of the terminal buds and adjacent segments of ducts acquire a cilium, the initial indication that they are differentiating into myoepithelial cells (MEC). Up until the time of birth, the only additional characteristics of MEC that the outer cells develop are to flatten against the underlying cells, begin to send out processes, and produce a few dilated cisternae of rough endoplasmic reticulum. Myofibrils and AkPase activity are first detected at the light microscopic level at five days after birth, around both the developing acini and intercalated ducts. Progressive increases in AkPase activity and in the size and number of myofibrils continue until the acini and intercalated ducts are invested with well‐differentiated MEC at 15 days. Subsequently, as the acini undergo maturation during the weaning period (18‐25 days), the MEC cease to surround the acini and assume the adult pattern of investing only the intercalated ducts. The pattern of MEC differentiation in the parotid gland differs from those in the sublingual and submandibular glands of the rat in several important respects. They begin to differentiate last, yet mature almost as early as do the MEC of the sublingual gland; they begin to differentiate prior to, rather than simultaneously with, the secretory cells; and their distribution changes as the acinar cells become mature.
Cell turnover in the odontogenic organ of the rat incisor as visualized by graphic reconstructions following a single injection of 3H‐thymidine
Authors: Smith C. E. 
Published: February 2005

AbstractTurnover of cells within the odontogenic organ was studied in three dimensions by preparing serial sections of incisors from young male rats killed at various times following a single intraperitoneal injection of 1 μCi/g body weight of 3H‐thymidine. Radioautographs showed that at 1 hour after injection labeled cells were present in all cell layers throughout the entire depth of the odontogenic organ. They were encountered frequently within the inner dental epithelium and stratum intermedium but appeared less abundant within the stellate reticulum and outer dental epithelium. With time, the frequency of labeled cells in each layer declined progressively, and more rapidly at the anterior and labial side of the odontogenic organ than toward its posterior and lingual side. Hence labeled cells were observed over the longest time interval in regions where cell layers were in closest proximity to the opening of the apical foramen, that is, near the apical and cervical loops. By 32 days after injection, numerous labeled cells could still be identified within the outer dental epithelium and stellate reticulum near the apical loop (bulbous part of the odontogenic organ) and the outer dental epithelium near the cervical loops (“U”‐shaped part of the odontogenic organ). These findings support the hypothesis that cells originate within the bulbous part of the odontogenic organ and migrate anteriorly through the “U”‐shaped and root sheath parts of the odontogenic organ during renewal of the incisor. It appears that individual stem cell compartments may be maintained for surface (outer/inner dental epithelium) and intermediate layers (stellate reticulum/stratum intermedium) in the odontogenic epithelium.
Effects of actinomycin D on dexamethasone induced hepatic glycogen accumulation: Morphological and biochemical observations
Authors: Margolis Ronald N. , Cardell Robert R. 
Published: February 2005

AbstractEffects of inhibition of protein synthesis by actinomycin D (ACT) on the acute stimulation of hepatic gluconeogenesis and glucose‐6‐phosphatase (G6Pase) by the glucocorticoid, dexamethasone (DEX), in adrenalectomized (ADX) rats, were investigated using both morphological and biochemical means. Examination of ultra‐thin sections of liver in the electron microscope revealed that ACT, administered alone or with DEX, resulted in a failure of hepatic glycogen accumulation to occur. Smooth endoplasmic reticulum (SER) appeared similar to that of the ADX‐untreated animals, with occasional suggestions of increased amounts of membrane in ACT‐treated animals. G6Pase activity in homogenates was increased, as was activation of the enzyme under all experimental conditions, when compared with ADX‐untreated controls. The DEX‐induced increase in G6Pase activity in SER failed to occur to any appreciable extent in ACT‐treated animals. Plasma glucose levels increased slightly when ACT and DEX were present simultaneously.It is suggested that ACT countered the inductive effects of DEX on hepatic glycogen synthesis, but only partially suppressed acute stimulation of gluconeogenesis. A possible superinduction of G6Pase enzyme synthesis through increased efficiency of translation of extant mRNA is discussed. It is proposed that ACT inhibited the formation of appropriate SER membranes and/or other components necessary for glycogen accumulation.
Immunocytochemistry of prolactin‐producing human pituitary adenomas
Authors: Duello T. M. , Halmi N. S. 
Published: February 2005

AbstractAmong 92 surgically removed pituitary adenomas immunostained for prolactin and growth hormone, 70 showed positive staining for prolactin. The majority of these (54) was associated with hyperprolactinemia leading to amenorrhea (and often galactorrhea) in women of reproductive age. Similar tumors, asymptomatic or conducive to disturbances of sexual function, were found in six hyperprolactinemic men. Among nine acromegalics, seven had immunostained lactotrophs associated with the somatotrophic adenomas cells, but only two of these had hyperprolactinemia. In all of the remaining tumors that had at least some immunoreactive lactotrophs, mild hyperprolactinemia had been present. This indicates that immunostaining of pituitary tumors for prolactin correlated well with elevated plasma prolactin levels, except in the case of mixed somatolactotrophic adenomas. The patterns of distribution of immunoreactive prolactin in adenoma cells are illustrated. Since only some of the prolactin‐producing adenomas stained with carmoisine–a dye that has been suggested as a marker for prolactin cells–immunocytochemistry is the method of choice for the identification of prolactin‐secreting adenomas.
Immunoreactive adrenocorticotropin in rat brain: A neuroanatomical study using antiserum generated against synthetic ACTH1–39
Authors: Joseph Shirley A. 
Published: February 2005

AbstractIn this study an antiserum generated against synthetic ACTH1–39 is used to provide a neuroanatomical map of ACTH‐immunoreactivity in rat brain. Groups of ACTH‐immunoreactive cell bodies were located in the basal hypothalamus, extending from the retrochiasmatic region to the mammillary nuclei. The fiber distribution indicates a broad innervation of structures in the hypothalamus, which include the medial preoptic region; bed nucleus of the anterior commissure and stria terminalis; perifornical region; periventricular stratum; and paraventricular, dorsomedial, arcuate, and mammillary nuclei. Fibers from the hypothalamus reach the amygdaloid nuclei directly in two separate bundles. A large dorsal ACTH‐immunoreactive bundle emerges from the anterior hypothalamic region, distributes to the periventricular thalamic nuclei, and continues more posteriorly to the midbrain periaquaductal gray. It is speculated that the cell bodies in the ventral tuberal region of the hypothalamus are responsible for the vast innervation of fibers to the forebrain, diencephalon, and brainstem.
Electromyography— dynamic gross anatomy: A review
Authors: Basmajian John V. 
Published: February 2005

Abstract“Electromyography: Dynamic Gross Anatomy” is the first in a series of invited review articles by leaders in fields of current interest.Students often ask if anything really “new” has been discovered in gross anatomy in the last fifty years. The answer is an unqualified “yes,” and electromyography probably has provided more of this new information than any other technique. Not since the pioneering work of Duchenne in 1867 has any one man contributed so much to our knowledge of the function of the musculoskeletal system as Dr. John V. Basmajian, Professor of Medicine and Associate in Anatomy at McMaster University and Director of Rehabilitation and Continuing Care Centres of Chedoke‐McMaster Hospital, Hamilton, Ontario, Canada. Since his initial publication in 1952, he has written over 200 scientific papers on electromyography. He is the author of Muscles Alive: Their Functions Revealed by Electromyography, now in its fourth edition, and the author or co‐author of numerous other books on gross anatomy, kinesiology, therapeutic exercise and clinical electro‐neurography.In 1965, Dr. Basmajian was one of the founders of the International Society of Electromyographic Kinesiology (now the International Society of Electrophysiologic Kinesiology), and he served as its first president. In recognition of his many contributions to the discipline, ISEK dedicated its Sixth International Congress to him. Universally recognized as the undisputed leader in the field, Professor Basmajian is the ideal person to summarize the “state of the art” for the readers ofThe American Journal of Anatomy.
An electron microscopic study on the structural development of the neural lobe in the human fetus
Authors: Okado Nobuo , Yokota Norio 
Published: February 2005

AbstractStructural development of the neural lobe of the hypophysis was studied by light and electron microscopy in five human fetuses ranging from 7.5 to 19 weeks of ovulation age.Clusters of small clear vesicles were found occasionally in axon profiles in a fetus of 7.5 weeks. Granular vesicles in axon profiles first accumulated in a fetus of 8.5 weeks. Concurrently, fenestration of capillary walls and expansion of perivascular spaces were observed.After 8.5 weeks, three type of vesicle‐containing axon profiles were found, which contained predominantly granular vesicles (GP), small clear vesicles (SP), and a mixed population of both granular and small clear vesicles (MX), respectively. Their numbers increased significantly during two periods, 7.5–8.5 weeks and 15.5–19 weeks. Ratios of GP, SP, and MX to the total number of the three types of axon were almost the same in all the fetuses studied, i.e., about 40%, 40%, and 20%, respectively.Developmental changes in the diameter of granular vesicles were examined in GP, SP, and MX of each fetus. Apart from a few exceptions, the mean diameter of granular vesicles was larger in GP than in MX, which was in turn larger than in SP. The diameters increased with development and those in GP reached almost the same value as in the adult by 19 weeks.
Membrane‐bound glycoprotein in the alveolar cells of the caprine lung
Authors: Atwal Onkar S. , Brown Laurie M. 
Published: February 2005

AbstractAn ultramicroscopic analysis of caprine lung glycoproteins, designed to detect plasmalemma‐associated sulfoglycoprotein of alveolar type I and alveolar type II cells, was performed. High‐iron diamine staining demonstrated a layer containing sulfated glycoproteins at the apical plasmamembrane of alveolar type I cells and microvilli of alveolar type II cells. The cytoplasmic vesicles of the alveolar type I cell contained the reaction product on the inner leaflet of the vesicular unit membrane. The vesicles showed a variety of interactions with the apical plasma membrane. High‐iron diamine staining also demonstrated sulfogly‐coproteins in the cytoplasmic granules of the mast cells in the alveolar septum. The present study gives evidence that plasmalemma of the alveolar cells of the goat lung possesses exposed hyaluronic acid groups.
An electron microscopic study of implantation in the cow
Authors: Wathes D. Claire , Wooding F. B. P. 
Published: February 2005

AbstractThe paper describes the changes occuring in the uterine and chorionic epithelia of the cow between days 18 and 28 of gestation, before and during implantation. The irregular uterine epithelium of the non‐pregnant cow was simplified to a tall columnar epithelium before attachment began. Areas of attachment were first observed at day 20 in the region of the embryo. Such sites were characterized by the presence of pale uterine cells containing up to 8 nuclei (“giant cells”) which accounted for nearly 50% of the epithelial area by day 24. Fetal binucleate cells were found in contact with, and partly across, the microvillar junction at all stages examined, and the presence of granules characteristic of binucleate cells within the giant cells suggested that the fetal cells contributed to their formation. Many uterine epithelial cells underwent degenerative changes between 22 and 28 days, and residues equivalent to their pyknotic remnants were found at the microvillar junction and within the mononucleate chorion cells. By day 28 some of the giant cells appeared to be degenerating, and areas of low cuboidal epithelium were present. This epithelium resembled the type found in the mature placenta. There was evidence that binucleate cell migration continued at this time. Nevertheless, the definitive membrane in the mature bovine placenta is epitheliochorial.
Ultrastructural cytochemistry of complex carbohydrates of gastric epithelium in the guinea pig
Authors: Sato Akira , Spicer Samuel S. 
Published: February 2005

AbstractUltrastructural and complex‐carbohydrate cytochemical studies were carried out on guinea pig gastric mucosa to assess the histochemical properties of the secretions of different gastric epithelial cells and to investigate the differentiation, origin, and renewal of certain cell types. The observations disclosed heterogeneity or variability of the secretory granules within individual mucigenic cells and zymogen cells. The cytochemical methods also served in characterizing and distinguishing five cell types in the gastric glands, including the isthmus cell, a mucous cell considered comparable to the mucous neck cell, the chief cell, and forms transitional between the isthmus and mucous cells and the mucous and zymogenic cells. The several cell types differed widely in the cytochemical properties of the secretory granules and the apical plasmalemma, and each had a distinctive distribution in the gastric gland. Cytochemical staining observed here provided evidence on synthesis and intracellular metamorphosis of mucous droplets and on formation of glycocalyx.