bluuebunny/crossref_metadata_2025 huggingface dataset:
The transverse‐axial tubular system (tats) of mouse myocardium: Its morphology in the developing and adult animal
Authors: Forbes M. S. , Hawkey L. A. , Sperelakis N.
Published: February 2005

Invaginations of the sarcolemma that generate the transverse‐axial tubular system (TATS) of the ventricular myocardial cells have begun to develop in the mouse by the time of birth. The formation of the TATS appears to be derived from the repetitive generation of caveolae, which forms “beaded tubules”. Beaded tubules are retained in the adult, in which they frequently present a spiraled topography. Development of the TATS progresses so rapidly that complex systems are already present in the cardiac muscle cells of young mice; by 10–14 days of age, the ultrastructure is essentially identical to that of the adult. The mouse myocardial TATS is composed of anastomosed elements that are directed transversely and axially (longitudinally). Many tubules have an oblique orientation, however, and most elements of the TATS are highly pleiomorphic. In this respect the TATS of the mouse heart is relatively primitive in appearance in comparison with the more ordered TATS latticeworks typical of the ventricular cells of other mammals. Stereological analysis of the mouse TATS indicates that the volume fraction (VV) and surface density (SV) are considerably greater than previously reported (3.24% and 0.5028 μm−1, respectively). The most complex ramifications of the TATS are embodied in the subsarcolemmal caveolar system and the deeper tubulovesicular “labyrinths”, both of which can be found in early postnatal and adult ventricular cells. In atrial cells, TATS development is initiated several days later than in the ventricular cells. The TATS of adult atrial myocardial cells is less prominent than the ventricular TATS and consists largely of axial elements; the incidence of the TATS, furthermore, is more pronounced in the left than in the right atrium.
The sensorineural apparatus of the human eyelid
Authors: Munger Bryce L. , Halata Zdenek
Published: February 2005

The present study describes a complex array of sensory nerve terminals in the human eyelid. In many respects this pattern of innervation resembles that previously described in the rhesus monkey, but in other respects it is unique to man. The most prominent nerve terminals are a complex array of lanceolate and circular Ruffini and free nerve endings that envelop the eyelashes. In addition, Merkel cells have not been conclusively identified to date in other nonhuman primate nonsinus hairs. The external root sheath collar contains Merkel cells, and dermal Merkel cells have also been identified close to the collar. The anterior cutaneous surface of the eyelid contains small vellus hairs with typical lanceolate, Ruffini, and free nerve endings resembling those of primate facial skin.

Scattered Meissner and scant simple corpuscles as well as scattered free nerve endings (FNEs) can be identified on the occlusal surface of the eyelid. Intraepithelial as well as dermal FNEs were most easily identified in this region in areas lacking other corpuscular receptors. Corpuscular receptors are especially common at the occlusal/conjunctival angle.

The inner or conjunctival surface of the eyelid appears to be a glandular epithelium, whereas in the rhesus monkey it is stratified squamous epithelium. This epithelium needs additional study.

In summary, the present study confirms the unique sensory neural status of the human eyelid and verifies the presence of Ruffini nerve terminals by light and electron microscopy and of free nerve ending terminals at least by light microscopy, as well as a unique pattern of innervation of the human eyelash.
The microcirculation of cerebral arteries: A morphologic and morphometric examination of the major canine cerebral arteries
Authors: Liszczak Theodore M. , Mc Black Peter L. , Varsos Vassilios G. , Zervas Nicholas T.
Published: February 2005

A morphologic and morphometric examination of the major cerebral blood vessels in the dog was carried out to determine whether there were vasa vasorum in these arteries and what features might be associated with them. True vasa vasorum confined to the media were not seen in any of the vessels examined. Microvessels confined to the adventitia, however, were found in the internal carotid and vertebral arteries but not in the basilar, middle cerebral, or anterior spinal arteries. Animal size, vessel size as determined by adventitial and medial area, and the number of smooth muscle cell lamellae were not associated with the presence of these adventitial vessels; they occurred only in arteries with both an intra‐ and extradural portion. It therefore appears that most canine cerebral arteries do not have vasa vasorum.
The organogenesis of murine striated muscle: A cytoarchitectural study
Authors: Ontell Marcia , Kozeka Kenneth
Published: February 2005

The ultrastructure and the three‐dimensional cytoarchitecture of the developing murine extensor digitorum longus muscle has been studied in spaced, serial, transverse and longitudinal ultrathin sections of the muscles of 12‐, 14‐, 16‐, and 18‐day in utero, newborn, and 5‐day‐old 129 ReJ mice. Despite the fact that in vivo myogenesis is asynchronous (i.e., during most of the fetal period, multiple stages of myogenesis can be seen in a single developing muscle mass), a distinct temporal pattern of development can be seen across the entire width and length of the developing muscle. At 12 days in utero, the developing extensor digitorum longus muscle consists of primary myotubes surrounded by a pleomorphic population of mononucleated cells devoid of myofilaments. At this stage, blood vessels and nerves are found peripheral to but not within the developing muscle mass. A delay of ≥ 2 days occurs between the time of formation of the primary and secondary myotubes. Clusters (consisting of one primary myotube and secondary myotubes), axon bundles, capillaries, and primitive motor endplates are found in the muscle by 16 days in utero. Evidence is presented consistent with the hypothesis that cluster formation and cluster dispersal occur simultaneously in the developing muscle, beginning as early as 16‐days in utero. By 18 days in utero, many of the primary myotubes of the cluster and the independent myotubes (i.e., single myotubes enclosed in their own basal lamina) have begun to acquire the polygonal shape, fascicular arrangement, and ultrastructure characteristic of more mature myofibers. At birth, clusters are infrequently encountered, and intramuscular axons have begun to undergo myelination. At this time, the only undifferentiated, mononucleated cells present in the muscle are myosatellite cells. The first week postnatal was characterized by further maturation of the myofibers.
Dynamic histology of the antral epithelium in the mouse stomach: I. Architecture of antral units
Authors: Lee E. R. , Leblond C. P.
Published: February 2005

The architecture of the pure mucous units of the pyloric antrum was investigated in 3‐ to 4‐month‐old CD1 mice. Units were serially cut in cross section and stained by a method combining the periodic acid‐Schiff sequence, a modified Grimelius's silver nitrate procedure, and Regaud's hematoxylin. A total of 195 units were then reconstructed. Of these, six were cast in polyester resin and 189 were two‐dimensionally reproduced on graph paper.

The reconstructions showed antral units to be divided among three main classes. The first class, which contained 32% of the units, consisted of fingerlike tubules referred to as “singlets.” Three types of singlets were observed. The first or type A, which represented 76% of the singlets, was divisible into three successive portions: a pit (foveola) opening onto the mucosal surface and lined by mucous cells referred to as pit cells, and isthmus continuous with the pit and containing immature proliferative mucous cells, and a gland forming the blind end of the tubule and lined by mucous cells referred to as gland cells. Type B (14% of singlets) was similar to type A except that its gland was forked. Type C (10% of singlets) differed by the absence of a gland. The units of the second class, which contained 53% of the total number, were joined together along part of their length and were named “multiplets.” Most of them (90%) were organized into clusters of two, and 10% into clusters of three. In the joined portion, the epithelial cells of the adjacent units were in contact through junctional complexes and, therefore, were not separated by basement membranes. Otherwise the units showed the same component parts as in singlets. Also, as in singlets, the majority of the units were type A and a few were type B or C. The units of the third class, or “intermediates,” consisted of tubules which exhibited a branching process. This process was of variable length but could include gland, isthmus, and sometimes pit. Thus, the process duplicated a varying proportion of the unit.

In conclusion, the pure mucous units of the antrum exhibit various patterns which have been designated singlet, multiplet, or intermediate. It is proposed that these three patterns are related and represent temporal differences in the duplication and production of new units. Based on this assumption, a model has been elaborated to depict the likely sequence in the proliferation of pure mucous units. It is proposed that this proliferation takes place in the antrum of young adult mice.
Dynamic histology of the antral epithelium in the mouse stomach: II. Ultrastructure and renewal of isthmal cells
Authors: Lee E. R. , Leblond C. P.
Published: February 2005

The isthmus of typical mucous units of the pyloric antrum was investigated in 3‐ to 4‐month‐old CD1 mice using light and electron microscopy as well as 3H‐thymidine radioautography.

On the average, the isthmus measured 25 μm in length and was composed of 36 isthmal cells and two enteroendocrine cells. Isthmal cells generally displayed features found in embryonic cells, such as many free ribosomes, scant organelles, and a large reticulated nucleolus, and were, therefore, at an immature stage of development. Isthmal cells could be devoid of secretory granules (“granule‐free cells,” 2%) or contain a few small, spherical, PA‐Schiffpositive, mucous granules in their apex. The granules in some of the cells had a variegated appearance and a diameter averaging 235 nm (“mottled granule cells,” 39%); in other cells, the granules had a large diameter, 278 nm, with a pale background and a dense core (“core granule cells,” 28%); while in still others they were homogeneously dark and measured 264 nm (“dense granule cells,” 12%). Finally, some cells included a mixture of core and dense granules (“mixed granule cells,” 14%). One hour after a single injection of 3H‐thymidine, 37% of the isthmal cells were labeled. Each of the five isthmal cell types could acquire label and, therefore, divide. After one or more days of continuous 3H‐thymidine infusion, all isthmal cells were labeled. Their turnover time was estimated to be 16.1 hr (t1/2 = 11.2 hr).

The isthmus is thus composed of several cell types which are turning over rapidly. While all are relatively immature, the various types are thought to represent different developmental stages in the life history of an isthmal cell. A model devised on this basis proposes that the granule‐free cells are stem cells, from which mottled granule cells are derived. These in turn evolve into either the dense granule cells of the upper isthmus or the core granule cells of the lower isthmus, or into the mixed granule cells (which are believed to develop eventually into dense granule cells or core granule cells). Maintenance of a steady state requires that the rapid production of isthmal cells be associated with rapid emigration; the dense granule cells presumably going to the pit and the core granule cells to the gland. The turnover of isthmal cells is accordingly described as following a “bidirectional pattern” of renewal.
Dynamic histology of the antral epithelium in the mouse stomach: III. Ultrastructure and renewal of pit cells
Authors: Lee E. R.
Published: February 2005

The pit (foveola) of typical mucous units of the pyloric antrum was investigated in 3‐ to 4‐month‐old CD1 mice, using light and electron microscopy, sometimes combined with 3H‐thuymidine radioautography.

Reconstruction of units from serial sections revealed that, on the average, the pit measured 151 μm in length and was lined by 184 mucus‐containing pit cells. Of these, 164 were located along the wall of the pit, whereas 20 surrounded its opening on the free surface. For ultrastructural examination the pit was divided into equal thirds. The proximal third, located next to the isthmus and referred to as pit base, was composed of cells showing electrondense mucous granules greater in number but similar in density and diameter to those of isthmal dense granule cells. Nucleoli were rather large, irregular, and reticulated; these and other features were indicative of partial differentiation. The appearance of the cells gradually changed with the distance from the isthmus. In the middle third or mid pit, cells had small, fairly rounded nucleoli, while mucous granules were more numerous than in the pit base but similar in appearance and size; these cells were considered to be mature. In the distal third or pit top‐surface, granules became elongated and nucleoli shrank, and lysosomes and vacuoles greatly increased in number, indicating that cells were at a terminal stage. Indeed, some of the cells were extruded into the stomach lumen while others were phagocytosed by adjacent cells. Following a single injection of 3H‐thymidine, labeling was found only in a small cohort of cells in the pit base. At the end of 1 day of continuous infusion, the cohort of labeled cells had reached the mid pit; by 2 days, the pit top; and by 3 days, the free surface, where cells were eventually lost. The renewal time of pit cells was assessed at 2.98 days (t1/2 = 1.8 days), giving a turnover rate of 33.5% per day.

It is estimated that the divisions of pit base cells provide two‐thirds of the cells needed daily for pit‐cell renewal, while the other third is supplied by an influx of dense granule cells from the isthmus. These cells enter the pit and continuously migrate toward the gastric lumen, while differentiating in the pit base, maturing in the mid pit, and reaching a terminal stage at the pit topsurface. The progressive and orderly migration of pit cells is described as a “pipeline pattern” of renewal. It is completed in about 3 days when terminal cells are lost at the pit top‐surface.
Dynamic histology of the antral epithelilum in the mouse stomach: IV. Ultrastructure and renewal of gland cells
Authors: Lee E. R. , Leblond C. P.
Published: February 2005

The renewal of gland cells was investigated by three‐dimensional reconstruction of typical mucous units of the pyloric antrum using electron microscopy and 3H‐thymidine radioautography in 3 to 4 month‐old CD1 mice.

Based on analysis of 42 units, the average gland measured 31 μm in length and was composed of 37 (mucous) gland cells with eight enteroendocrine cells scattered among them. The gland neck cells located close to the isthmus showed the cytoplasmic and nuclear features characteristic of differentiating cells. The mid‐gland cells occupying the central portion of the gland appeared to be at a more advanced stage of development and completing differentiation. The gland base cells comprising the blunt end of the gland were fully mature. To quantify the renewal process, the percent of gland cell nuclei carrying label was determined at several times following 3H‐thymidine administration. The rate of proliferation was found to be greatest in the gland neck, lower in the mid‐gland, and even lower within the gland base. Furthermore, the isthmus contributed to gland‐cell renewal by providing an estimated 12.4 cells per day. Labeled cells migrated toward the blunt end of the gland. The migration rate became progressively slower with their descent, and many cells were lost along the migration pathway, mainly in the gland neck. The loss took place without being preceded by gradual cell degeneration, but occurred as a result of rapid extrusion to the lumen or, less frequently by pyknosis, which could be followed by phagocytosis.

It is concluded that the rapid rate of mitosis within the isthmus and gland neck generates a pressure causing downward migration of the cells toward the blunt end of the gland. The rate of migration, however, gradually diminishes as cells descend into the gland, presumably owing both to decreasing proliferation rate and to cell loss. Thus, while cells migrate down toward the gland base, many are lost before reaching it. This sequence is decribed as “the cascade pattern” of renewal.
Analysis of gland cell behavior: Appendix to the dynamic histology of the antral epithelium in the mouse stomach
Authors: Nadler N. J.
Published: February 2005

The origin, route of migration, and ultimate fate of mucous gland cells in mouse antral units have been described in the preceding article. Three regions of the mucous gland, consisting of gland neck cells, mid‐gland cells, and gland base cells, respectively were defined; and the renewal events in each of these regions were studied. In this article, the data obtained by Lee and Leblond (1985) were subjected to a mathematical analysis to obtain additional information about the rate of loss of cells. Calling each anatomical division a compartment, and utilizing the available histometric knowledge concerning the number of cells and the turnover of labeled cells in each compartment, a set of equations was developed, assuming a steady state, for which solutions yielded the number of cells lost from each compartment per unit time.
Early implantation stages in the marmoset monkey (Callithrix jacchus)
Authors: Moore H. D. M. , Gems Sara , Hearn J. P
Published: February 2005

The morphology of the initial stages of implantation in the marmoset monkey (Callithrix jacchus) was studied by obtaining embryos and associated endometrium at timed intervals after ovulation. Estrus cycles were detected by measuring daily levels of plasma progesterone. Following a short follicular phase, circulating levels of progesterone above 20 ng/ml were taken as representing day 1 after ovulation. On this basis, single, twin, and triplet embryos were recovered from six perfused‐fixed females on days 13, 16, 19, 23, and 29 after ovulation and prepared in resin for light microscopy. Early implantation stages, 13 and 16 days after ovulation, were characterized by the intrusion of syncytial trophoblast between epithelial cells of the endometrium with minimal cellular damage. Some hyperplasia of epithelium at the margin of the implantation site was evident. The consolidation of the initial attachment was achieved by an increase in syncytial trophoblast underlying the inner cell mass of the embryo which rapidly surrounded and breached maternal capillaries. Although initially separate, the chorions of twin or triplet embyros started to fuse by day 19 after ovulation. This process was complete by day 29 such that embryos shared a common uterine exocoelom surrounded by continuous trophoblast. It was concluded that implantation in the marmoset monkey commenced on days 11–12.5 after ovulation and involved an intrusive mechanism. Although trophoblast penetration of endometrium was superficial, maternal capillaries were tapped at an early stage of implantation. The fusion of chorions of twins and triplets first occurred around day 19 after ovulation.
Postnatal development of “Synaptic” ribbons and spherules in the guinea pig pineal gland
Authors: Banks J. C. , Dalgleish A. E. , Vollrath L.
Published: February 2005

Previous studies have shown that the functionally enigmatic pineal “synaptic” ribbons are structurally a heterogeneous group of organelles consisting of rodlike ribbons sensu stricto, spherules, and intermediate forms. As ribbons and spherules react differently under various experimental conditions, these organelles were studied qualitatively and quantitatively during the postnatal period in guinea pigs. It was found that the pinealocytes were highly differentiated at birth and contained all three forms of “synaptic” structures. Ribbons and intermediate forms were more abundant than spherules and exhibited a striking increase in number on postnatal days 1 and 2; this increase was followed by a distinct trough and by a second peak at days 12 and 13, after which their numbers declined to reach adult levels by day 20. The spherules were small in number at birth and did not show the large immediate postnatal increase observed for the ribbons and intermediate forms. Instead there was a steady numerical increase up to day 12 (absolute number) or day 15 (relative numbers), followed by a decrease to adult level by day 20. Whereas during the early postnatal period (days 1 to 3) the majority of pinealocytes were characterized by ribbons and intermediate forms, with increasing age spherule‐bearing pinealocytes increased in number. As ribbons and spherules were usually not found in the same pinealocyte, the present findings are interpreted to mean that ribbons and spherules characterize different types of pinealocytes showing an inverse numerical development postnatally. Developmentally intermediate forms behave like ribbons.
Motor innervation of intrafusal fibers in rat muscle spindles: Incomplete separation of dynamic and static systems
Authors: Walro Jon M. , Kucera Jan
Published: February 2005

Distributions of 53 motor axons to different types of intrafusal fibers were reconstructed from serial 1‐μm‐thick transverse sections of 13 poles of spindles in the rat soleus muscle. The mean number of motor axons that innervated a spindle pole was 4.1. Approximately 60% of motor axons lost their myelination prior to or shortly after entry into the periaxial fluid space of spindles. Motor innervation to the juxtaequatorial portion of nuclear bag fibers (particularly the bag1) consisted of groups of short, synaptic contacts that were terminations of thin, unmyelinated axons. In contrast, motor endings on both the bag1 and bag2 fibers were platelike in the polar intracapsular region. Chain fibers had a single midpolar platelike ending. The ratio of motor axons that innervated the bag1 fiber exclusively to axons that innervated bag2 and/or chain fibers was 1:1. However, one‐fourth of motor axons coinnervated the dynamic bag1 fiber in conjunction with static bag2 and/or chain fibers. Thus the complete separation of motor control of the dynamic bag1 and static bag2 intrafusal systems observed in cat tenuissimus spindles is neither representative of the pattern of motor innervation in all other species of mammals nor essential to normal spindle function.
Implantation in the rhesus monkey: Endometrial responses
Authors: Enders Allen C. , Welsh Alerick O. , Schlafke Sandra
Published: February 2005

In this continuing series of studies of implantation in the rhesus monkey, eight specimens, ranging in gestation age from 9.5 days to 16.5 days after ovulation, were examined with a focus on localized modifications in the endometrium as a response to implantation. Additionally, evidence of continuing changes in early pregnancy was provided by three specimens at the end of the first month of gestation (days 24, 28, and 35). The responses of the endometrium to pregnancy start with a localized accumulation of stromal eosinophils, which is rapidly followed by epithelial plaque formation in the basal cells of the luminal epithelium and gland necks. Plaque cells hypertrophy, develop marginal dense granules, and accumulate glycogen. They form a pad underlying the margins but not the central zone of the implantation site. However, some degenerating plaque cells are found as early as day 15; and little more than a region of leukocytic infiltration remains of the plaque by day 35. Shortly after the plaque response is initiated there is a striking subepithelial edema surrounding the plaque, and the venular capillaries enlarge by engorgement and by endothelial hyperplasia. The endothelial cells subsequently hypertrophy, resulting in a largely columnar endothelium. There is a localized decidual cell response, consisting of an increase in rough endoplasmic reticulum and in filaments, but only a moderate amount of hypertrophy of these cells. Endometrial granular cells become more conspicuous in the area as they accumulate glycogen. Patches of large pale cells appear in the lumen and walls of arterioles subjacent to the implantation site, but the cytology of these cells provided insufficient clues to their origin (cytotrophoblast?). Although the endometrial responses described are impressive and diverse, their advantages to the organism are not obvious. The hypertrophy of the anastomotic capillary bed that accompanies plaque formation may well provide an extensive vascular network available to the developing trophoblastic lacunae. The role of endometrial granular cells, decidual cells, and even plaque cells may be more related to their largely unexplored secretory activity than to their physical contribution to the formation of the basal plate.
Ultrastructural characterization of epithelial cell membranes in normal human conducting airway epithelium: A freeze‐fracture study
Authors: Carson Johnny L. , Collier Albert M. , Knowles Michael R. , Boucher Richard C.
Published: February 2005

Cell membranes of normal human nasal and tracheal epithelium were characterized by means of freeze‐fracture preparations. These investigations illustrated a predictable variability in the distribution of membrane‐associated particles on PF‐faces of different cell types and in different regions of the same cell. Details of the fine structure and variability of tight junctional complexes in different cell types are presented as are ultrastructural perspectives of cell membrane involvement in ciliogenesis and in mucus secretion. Because ciliogenic profiles and nascent tight junctional complexes were observed more frequently in nasal epithelial cells, these features provided markers of cellular differentiation. Based on the frequent appearance of such indicators, these observations suggested that cell turnover may be more rapid in the region of the nasal turbinates than in the trachea. There was no appreciable evidence of ultrastructural variability between the epithelial cell membranes of similar cell types in the upper and lower respiratory tract.
Light‐microscopic stereology for the study of the ventral and dorsal prostates of the syrian hamster: Strategy, techniques, and applications
Authors: Buzzell Gerald R.
Published: February 2005

A stereological approach to studying the architecture of the ventral and dorsal prostates of the Syrian hamster is described. In this approach, the prostate is considered to consist of acinar and interacinar compartments. The acinar compartment is divided into luminal, epithelial, lamina proprial, and muscular stromal compartments. Volume fractions of acini and interacinar tissue are calculated with reference to the volume of the gland; those of the acinar components are calculated with reference to the acinar volume. Volume fractions are determined from point counts. The surface fraction of the secretory epithelium is determined from intercept counts, with reference to the volume of the epithelium. By assuming that the acini are cylindrical, the acinar length fraction is calculated with reference to the volume of the gland. Absolute values for the volumes of different components, epithelial surface area, and acinar length can be determined from the weight of the gland, its specific gravity, and the volume fraction of that component, or epithelial surface fraction, or acinar length fraction, respectively. Finally, from these values and assuming a cylindrical shape for acini, characteristics of the typical acinus, including its radius, the thicknesses of its epithelium, lamina propria, and muscular stroma, and the amount of mucosal folding can be calculated from simple geometrical formulae. This approach is illustrated from a consideration of the ventral and dorsal prostates of 20‐week‐old Syrian hamsters.
An experimental analysis of the developmental capacities of distal parts of avian leg buds
Authors: Brand B. , Christ B. , Jacob H. J.
Published: February 2005

The development, differentiation, and pattern formation of isolated distal parts of avian leg buds that had grown ectopically on the chorioallantoic membrane (CAM) or in the coelomic cavity were studied. The grafts grown on the CAM invariably gave rise to cartilage and soft connective tissue. In some cases muscle tissue was also found. The CAM grafts did not undergo overt morphogenesis and pattern formation. A high percentage of grafts grown in the coelomic cavity showed a close approximation to normal limbs. The presence of proximal structures depended on the stage of development of the donor at the time of the operation, on the size of the grafts, and on the site to which the graft was attached within the coelom. The presence of anteroposterior structures depended on the shape of the graft. The pattern formation of this axis was found to be independent of the presence of the zone of polarizing activity at the proximal posterior border of the bud. The distance from the tip of the bud to the line of most distal colonization by myogenic cells was determined. The speed of migration of the myogenic cells can be considered to be constant. In muscleless legs, tendons developed at the levels of the phalanges and the tarsometatarse. They degenerated, however, in the absence of muscle from day 9 on, from proximal to distal areas. CAM grafts as well as coelomic grafts were well vascularized. The endothelial cells of the blood vessels were of host origin. In coelomic grafts, nerves were present with Schwann cells of host origin. The nerves and blood vessels showed a distribution that resembled that in normal legs.
Three‐dimensional reconstruction and quantitative analysis of rat lung type II cells: A computer‐based study
Authors: Young Stephen L. , Fram Evan K. , Craig Brenda L.
Published: February 2005

The three‐dimensional structure of alveolar epithelial type II cells was imaged using a computer‐based system designed for reconstruction and quantitative analysis of serially sectioned specimens. Six type II cells were reconstructed from serial ultrathin sections of lungs from two Sprague Dawley male rats and the results were compared to standard morphometric estimates of type II cell compoition from five other Sprague Dawley male rats. A minor portion of the type II cell surface was in contact with the alveolar airspace while most of the cell surface was embedded in the alveolar septal interstitium. The type II cells contained multiple Golgi regions located close to the nucleus. Mitochondria formed a few branching filamentous networks extending throughout the cell. The reconstructed cells appeared to represent a homogeneous population having fractional volumes of intracellular organelles very similar to those found by morphometric techniques. The spatial distribution of secretory organelle volume suggests that the organization of this cell type reflects an ordered progression of secretory particle maturation which is consistent with earlier hypotheses of lamellar body assembly.
Long‐term comparative effect of cholecystokinin and gastrin on mouse stomach, antrum, intestine, and exocrine pancreas
Authors: Balas D. , Senegas‐Balas F. , Pradayrol L. , Vayssette J. , Bertrand C. , Ribet A.
Published: February 2005

Mice were injected three times a day for 12 days with 300 μg/kg body weight of gastrin G17 or 37.5 Ivy dog U/kg body weight of CCK or saline. Other mice were also injected four times an hr for 1 hr with 7.5 μ/kg of gastrin, nine Ivy dog U/kg of CCK or saline; 1 hr before killing, they were injected with tritiated thymidine to evaluate the labelling indices in peptic, antral, duodenal, jejunal, and ileal mucosae. Four hours after the first injection of the two peptides, the peptic labelling indices increased while those of intestinal mucosa increased 8 hr after these injections. Long‐term injections of CCK had a trophic effect on secretory cells of the digestive tract: the number of gastric zymogenic cells, Paneth cells, and the mucous cells of Brünner glands were hypertrophied. The pepsin, amylase, chymotrypsin, and lysozyme activities increased in stomach, exocrine pancreas, and intestine, respectively. Neither parietal cells nor intestinal enterocytes and hydrolase activities were affected. The trophic effect of long‐term injections of gastrin is confirmed on parietal cells and exocrine pancreatic parenchyma and is demonstrated in Paneth cells. Confirming cytological results, pancreatic lipase and amylase activities and intestinal lysozyme activity were increased after gastrin. Although CCK and gastrin have a structural analogy, these two peptides did not affect the same cellular types. A specific action of CCK on the main secretory cells of the digestive mucosa is demonstrated.
Effects of 1‐hydroxyethylidene‐1, 1‐bisphosphonate (HEBP) on the formation of dentin and the periodontal attachment apparatus in the mouse
Authors: Beertsen W. , Niehof A. , Everts V.
Published: February 2005

The effects of the bisphosphonate HEBP on dentin formation and the structural relationship between the dentin and the developing periodontal attachment apparatus have been studied in the continuously growing mouse incisor. It was observed that HEBP (in doses ≥ 8 mg P/kg b.w/day) not only inhibited the deposition of mineral crystallites in newly formed dentin matrix, but also entirely prevented the formation of a layer of acellular root cementum. It was further noticed that the drug interfered with the deposition of 3H‐serine‐containing substances at the predentin‐dentin border. This was not always accompanied by an inhibition of dentin mineralization, thereby suggesting that 3H‐serine‐containing proteins (presumably phosphoproteins) do not play a critical role in the deposition of mineral layers onto previously formed ones. The absence of a cementum layer did not prevent the developing periodontal ligament from establishing matrix‐to‐matrix connections with the root‐analogue dentin. Collagen fibrils of the ligament intermingled with those of the mantle dentin, which in contrast to teeth not exposed to the drug were clearly visible and not masked by electron‐dense matrix components. Finally, it was found that the drug had distinct effects on the formation of root‐analogue and crown‐analogue dentin. Whereas during the course of the experiment the odontoblasts along the crown‐analogue aspect of the tooth continued to produce circumpulpal dentin matrix, those along the root‐analogue aspect of the tooth did so only when the mantle dentin layer had been mineralized prior to HEBP administration. This phenomenon is interpreted as being indicative of fundamental differences between the formation of crown and root dentin.
Plasma membrane‐associated vesicles in retinal capillaries of the rat
Authors: Gordon Sheldon R. , Essner Edward
Published: February 2005

The structure and function of abluminal vesicles in endothelial cells of rat retinal capillaries was examined using glutaraldehyde—tannic acid fixation and the hemeproteins—horseradish peroxidase, microperoxidase, and lactoperoxidase—as tracers. Numerous vesicles, delimited by a tannic acid—positive membrane, were distributed along the abluminal front. Other vesicles were arranged in clusters and chains or tubule‐like structures. Such vesicles were not found in the vicinity of the capillary lumen. When the retina was exposed to hemeproteins, either in vitro or after intravitreal injection, the abluminal vesicles became labeled with tracer reaction product. Apparently “free” vesicles and tubules seen in tangential sections through the basal lamina were also labeled, suggesting that they were in continuity with the plasma membrane in another plane of section. No enzyme reaction product was present in the capillary lumen. Peroxidase‐positive multivesicular bodies were observed, suggesting that some protein was endocytosed and directed to lysosomes where it was presumably degraded. The results suggest that abluminal endothelial vesicles represent pits or invaginations of the plasma membrane and, as such, are not involved in the transendothelial transport of protein from the perivascular space to the capillary lumen. Tannic acid treatment revealed a population of similar vesicles associated with the plasma membrane of pericytes. After exposure to hemeproteins, enzyme reaction product was localized in these vesicles and in a few multivesicular bodies. The results suggest that the majority of these vesicles are in continuity with the plasma membrane and are not involved in endocytosis.
The effect of atrophy, hyperplasia, and keratinization accompanying the estrous cycle on Langerhans' cells in mouse vaginal epithelium
Authors: Young William G. , Newcomb Guy M. , Hosking Annette R.
Published: February 2005

The morphology and numbers of Langerhans' cells vary in epithelia with different patterns of hyperplasia and keratinization. Langerhans' cells stained for ATPase were compared at five phases of the estrous cycle in murine vaginal epithelium. The cells were more dendritic and sparsely distributed with hyperplasia and were less dendritic and more densely distributed with atrophy. Greater numbers of the cells did not accompany keratinization at estrus. Ultrastructurally, three types of Langerhans' cells were discriminated. The first type, active in protein synthesis and phagocytosis, was commonest in sloughing and atrophic epithelium. The second type, containing accumulated and dispersed, electron‐dense bodies presumed to be lysosomes, predominated in hyperplastic epithelium. The third, a mature resting cell, was found only after keratinization was complete. This study shows that Langerhans' cells in murine vaginal epithelium vary in morphology and numbers with the epithelial changes of the estrous cycle which may relate to their immunological role, but does not support the contention that their distribution is important for keratinization.
Brain sizes, surfaces, and neuronal sizes of the cortex cerebri: A stereological investigation of man and his variability and a comparison with some mammals (primates, whales, marsupials, insectivores, and one elephant)
Authors: Haug Herbert
Published: February 2005

This study deals with the stereological estimation of macroscopic sizes of brain and cortex, i. e., volume, surface, and folding, and of microscopic neuronal sizes, i. e., density, mean size, size distribution and number of neurons. The results show that the degree of variability in man amounts to about 15%. A decrease in volume of the different gray structures can be observed in man after the age of 65 years. The surface, folding index, and length of convolution do not alter with aging. The comparison with mammals of various sizes allows the conclusion that there is a high correlation to brain size for nearly all macroscopic values. Man and elephant, however, have a cortical surface which is, in comparison with whales, relatively small. In contrast, whales have very small cortices compared with man.

At the cytoarchitectonic level, the neuronal density has a correlation to brain size. Contrary to other mammals, the primates and man have a high fraction of small granular neurons, especially in layer 4. The assumption that the number of cortical neurons beneath a given surface area of cortex is the same in all mammals cannot be verified, especially in those with large brains. The allometric connection between brain size and parameters is not valid for all measurements (e. g., thickness of cortex, mean size of neurons, perikaryal size distribution, and glial density). Yet some other measurements are well correlated.
Properties and purification of a colony‐stimulating factor of granulocytes and macrophages produced by mouse spleen cells
Authors: Chou Robin H. , Chen Thelma A. , Chou Koulin L. , Amenta Peter S.
Published: February 2005

Mouse splenocytes are induced by pokeweed mitogen to secrete a factor that stimulates mouse hemopoetic (spelling per Nomina Histologica in the Nomina Anatomica, 5th edition, 1983, Williams and Wilkins, Baltimore) progenitor cells to undergo proliferation and differentiation into granulocytes and macrophages in a semi‐solid culture system. The granulocyte and macrophage colony‐stimulating factor (GM‐CSF) was purified with a four‐step procedure that includes ultrafiltration, chromatography on DEAE‐agarose, Sephacryl S‐200, and chromatofocusing gel. The isoelectric point (pI) of 4.2 of the GM‐CSF was determined by analytical isoelectrofocusing gel electrophoresis. The sensitivity of the biological activity of GM‐CSF to digestion by trypsin and neuraminidase suggests that GM‐CSF is a glycoprotein with its sugar moieties at the active site. The GM‐CSF is also sensitive to heat denaturation at 60°C or higher suggesting that a three‐dimensional conformation is required for its biological activity. The molecular w eight of GM‐CSF is approximately 57,000 Daltons as determined by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate.
Early development of the facial nerve in the chick embryo with special reference to the development of the chorda tympani
Authors: Kuratani Shigeru , Tanaka Shigenori , Ishikawa Yuji , Zukeran Chosei
Published: February 2005

The development of the facial nerve from Hamburger and Hamilton stage 17 to stage 28 is described in chick embryos by means of a new immunochemical nerve staining method that uses an antineurofilament protein (NFP) antibody. A postspiracular branch and an unknown transient posterior branch beneath the ostocyst were observed at stage 17. At stage 19, the primordia of the r. palatinus were observed. A prespiracular branch appeared at stage 21, and with the postspiracular nerve, it made a loop encircling the spiracle (spiracular loop). The first primordium of the ramus (r) hyoideus and transient rami (rr) dorsales appeared around stage 23. At stage 25, the chorda tympani was first observed to arise from the ventral end of the spiracular loop. At stage 26, a communicating branch, connexus cum nervo glossopharyngeo, was found along with the vena (v) capitis lateralis.

The rr. dorsales seemed to represent the r. supratemporalis in lower animals. The communicating branches around the v. capitis lateralis seemed to correspond to the cutaneous nerve communications between the branchial nerves frequently encountered in Amphibia.

It was found that the chorda tympani becomes a prespiracular nerve for the most part in the chick by the reduction of the postspiracular component of the spiracular loop. Thus, the nerve differs markedly from that in other animals, which is postspiracular. This difference explains the different passage of this nerve in the chick as compared with other amniotes.
The interdependence of the follicular, parafollicular, and mast cells in the mammalian thyroid gland: A review and a synthesis
Authors: Kališnik M. , Vraspir‐Porenta O. , Kham‐Lindtner T. , Logonder‐Mlinšek M. , Pajer Z. , Štiblar‐Martinčič D. , Zorc‐Pleskovič R. , Trobina M.
Published: February 2005

The aim of this paper is to summarize some of our quantitative descriptive and experimental studies, to discuss them in view of the literature data, and to present a synthesis of the topic.

The results of stereological analysis of some tissue components of the rat thyroid gland have been compared with the results of topological studies on the parafollicular cells of various mammalian species. Localization of the parafollicular cells in the central regions of the thyroid gland lobes, where the follicular cell activity seems to be greater than in the periphery of the lobes, has led to the hypothesis that the parafollicular cells regulate (stimulate and/or suppress) the activity of the follicular cells.

Long‐term application and antithyroid drugs to mice and rats has shown that excessive concentrations of thyrotropin provoke hyperplashia of both the follicular cells and the intrathyroid mast cells and, transiently, of the parafollicular cells. This and some of the literature data are congruent with the hypothesis that the parafollicular and mast cells also stimulate the follicular cells by their paracrine secretions.

Long‐term application of antithyroid drugs to mice and rats has shown that excessive concentrations of cular cells but also probably stimulation of the follicular cells, as judged by the stereological measurements.

The biological meaning of the spatial integration of follicular and parafollicular cells seems to be a functional coordination of both epithelial cell lines, supported by intrathyroid mast cells.
Characterization of the morphological, growth, and steroidogenic effect of TPA on mouse Y‐1 adrenal cortical tumor cells in culture
Authors: Murray Sandra A. , Polizotto Sandra
Published: February 2005

The tumor‐promoting agent 12–0‐telradecanoyl‐phorbol‐13‐acetate (TPA) caused a time‐ and dose‐ dependent morphological change in Y‐1 adrenocortical tumor cells. The morphological alteration was apparent 2 hr following addition of 1 μg/ml TPA cell cultures and became more striking with longer treatment times. Smaller doses of TPA took a longer time to produce an effect. Cultures grown in the presence of TPA exhibited more rounding and piling up cells than similar cultures maintained in medium lacking TPA. These TPA‐stimulated morphological changes were reversible, and after 24 hr in TPA‐free media, cultured cells began to flatten. After 96 hr in TPA‐media they resembled the control cultures. The reversibility of the morphological change was also dose dependent: cells treated with 1 μg/ml TPA took a longer time to resume the typical control morphology than cultures treated with 0.01 μg/ml TPA. In addition, TPA treatment resulted in a decrease in cell growth rate, an increase in steroid production, and an increase in localization of free catalytic units of cAMP‐dependent protein kinase in the cytoplasm. The steroidogenic effect of ACTH on the cell population was inhibited cultures maintained in TPA. The results of this study indicate that TPA induces morphological changes the Y‐1 adrenocortical tumor cell population while increasing steroidogenesis and the activation of cAMP‐dependent protein kinase and decreasing cell growth rate.
Changes with senescence in the fine structure of the granular convoluted tubule of the submandibular gland of the mouse
Authors: Gresik Edward W.
Published: February 2005

Cells of the granular convoluted tubules (GCTs) of the submandibular glands of senescent male mice show structural changes indicative of functional decline. In order to define the nature of these age‐related changes more clearly, the fine structure of GCT cells of 12‐ and 28‐month‐old males was compared. In old mice, there was cell‐to‐cell variation in the extent of these changes, with some cells of senescent males appearing no different from those of young adults. In affected cells the most striking alterations were seen in secretion granules and lysosomal elements. Secretion granules varied greatly in size, with some GCT cells having only very fine apical granules. Secondary lysosomes and large lipofuscin granules were frequent in the basal cytoplasm. Very large dense bodies (3‐5 μm) occurred in many cells. These possibly represent intracellular pools of released secretory materials, as they were occasionally seen in continuity with the luminal contents. Structures whose appearance was intermediate between the very large dense bodies and lipofuscin granules were common, suggesting crinophagic activity. There was an apparent decrease in numbers of polysomes and in the extent of the Golgi apparatus. These fine structural changes are consistent with impairments with advanced age in synthesis and posttranslational processing of secretory products by affected GCT cells. In addition to cell‐to‐cell variation in any one male, there was also interanimal variation in the degree and extent of these senescent changes.