bluuebunny/crossref_metadata_2025 huggingface dataset:
Electron microscopic autoradiographic analysis of the uptake and intracellular transport of H3‐leucine by the rat submandibular gland acinar cells in tissue slices
Authors: Bogart Bruce Ian
Published: February 2005

Uptake of H3‐leucine into secretory product and its subsequent intracellular transport was analyzed by electron microscopic autoradiographic techniques in the rat submandibular gland acinar cells in vitro. The route and kinetic timetable of intracellular transport was established for the acinar cell secretory product by calculating the percent of silver grains and relative grain density associated with the various organelles on a time sequence basis. Radioactivity was first associated with the rough endoplasmic reticulum; then the convex surface of the Golgi apparatus; the concave surface of the Golgi apparatus; and finally with the secretory granules. Comparison of the kinetics of intracellular transport in the rat submandibular gland acinar cell with other established systems revealed only a difference in the exit of radioactivity from the concave surface of the Golgi apparatus.
The influence of progestin and androgen on the fine structure of the male reproductive tract of the rat. I. General effects and observations on the testis
Authors: Flickinger Charles J.
Published: February 2005

The combination of a progestin and androgen has received attention as a possible male contraceptive. The progestin is thought to reduce gonadotropin release and suppress spermatogenesis, while the sex accessory organs and male characteristics are maintained by the simultaneous administration of testosterone. In the present study, the histology and ultrastructure of parts of the male reproductive tract of rats treated with medroxyprogesterone (Provera, Upjohn) (1 mg/100 g body weight/day) alone and combined with testosterone (15, 30, or 100 μg/100 g/day) were studied following treatment for up to 16 weeks. The testes and epididymides of rats administered Provera alone or Provera and testosterone weighed less than those of control rats. The weights of the accessory glands of rats treated with Provera were greatly reduced; it was possible to maintain them at approximately control levels by simultaneously administering sufficient testosterone (100 μg/100 g body weight/day). The fertility of some of the animals was tested by caging them with female rats, and none of the treated rats tested in this way was fertile.

Similar microscopic alterations were present in the testes of animals administered Provera alone or Provera and different levels of testosterone. Spermato‐gonia, spermatocytes, and early spermatids were abundant in treated rats and did not show ultrastructural changes. However, many degenerating or necrotic spermatids of the cap phase (approximately stages 6–7 ) and later were present. Late spermatids of the acrosome and maturation phases were rare. Some necrotic spermatids were surrounded by Sertoli cells, and parts of spermatids lay within lysosome‐like structures in the cytoplasm of Sertoli cells. Many large lipid droplets were also present in Sertoli cells of treated rats. Leydig cells were smaller in treated animals than in control rats. The results suggest that germ cells can develop up to cap phase spermatids but then undergo degeneration. These alterations in spermatogenesis may be responsible in large part for the antifertility effect of the progestin and androgen combination.

Some rats were permitted to recover following the end of treatment. The microscopic appearance of the testis returned to normal within three to six weeks, although epididymal alterations persisted in some animals six weeks after the end of treatment. By 9 to 12 weeks after the end of treatment the reproductive organs had a normal microscopic appearance in all the rats studied.
Innervation of the rat harderian gland by adrenergic and cholinergic nerve fibres
Authors: Huhtala Antero , Huikuri Kauko T. , Palkama Arto , Tervo Timo
Published: February 2005

The innervation of the rat Harderian gland was studied using histochemical methods for catecholamines and acetylcholinesterase (AChE). Selective denervations were performed to investigate the neural connections of this gland with various ganglia.

Light microscopically the AChE‐positive nerves seemed to run as thick bundles in the intertubular connective tissue. These bundles sent finer branches around the acini. The blood vessels, localized in the connective tissue septa, were surrounded by a dense plexus of AChE‐containing fibres. By electron microscopy, the AChE‐positive fibres were seen to terminate near the myoepithelial cells surrounding secretory cells. These fibres were also observed in contact with the blood vessels and occasionally close to the secretory cells. Fluorescent adrenergic nerves surrounded the blood vessels. Some fibres were also observed in the interlobular tissue.

All the AChE‐containing nerves degenerated after cutting the zygomatic nerve. On the other hand, removal of the ciliary ganglion or the superior cervical ganglion, or stereotactic coagulation of the ophthalmic nerve did not affect these nerves. The fluorescent adrenergic fibres disappeared following both removal of the superior cervical ganglion and coagulation of the ophthalmic nerve. These fibres were intact after removal of the ciliary ganglion.
An autoradiographic study of long‐term follicular development in the cyclic hamster
Authors: Chiras Daniel D. , Greenwald Gilbert S.
Published: February 2005

The time required for ovarian follicular development in the cyclic hamster was determined by marking follicles with [3H]‐thymidine on day 1 of the estrous cycle (day of ovulation) and by following their fate over the next three cycles by autoradiography. A model of follicular development was formulated, based on the total number of follicles and the changing percentage of labelled follicles with time.

It was estimated that 20 days elapsed before a preantral follicle with two to three layers of granulosa cells (stage 1) was able to ovulate. Follicles spent eight days in stage 1 and an additional eight days in stage 2 (4‐5 granulosa layers). Preantral follicles entering stage 3 (6‐7 granulosa layers) and 4 ( 8 layers) on day 1 of the cycle ovulated four days later.

Approximately 30 follicles per ovary entered and left stage 1 each cycle, representing a 50% turnover. Of the follicles leaving stage 1, about 50% were transformed into stage 2 follicles; the remaining ones underwent atresia. Stage 2 follicles also had a 50% turnover each cycle. Half of the stage 2 follicles underwent atresia; the remainder developed into stages 3 and 4 follicles Fifty percent of the stages 3 and 4 follicles present on day 1 of the cycle ovulated at the next estrus with the remainder undergoing atresia.
Cell turnover in the beak of Rana pipiens
Authors: Kaung Hue‐Lee Cheng , Kollros Jerry J.
Published: February 2005

Rana pipiens tadpoles were injected with 3H‐thymidine at different stages to label basal cells of the horny beaks, the keratinized oral specializations of many anuran tadpoles. Cells in the column and sheath of the beak are derived from the basal layer. Movement of the labeled cells in beak columns can be traced, permitting calculation of the rate of cell addition into the columns. With the counts of the total number of column cells and cell addition rate, the rate of apical cell loss from a column throughout the larval stages can also be calculated. The rate of cell addition decreases steadily from stage III through stage XX, in all portions of both beaks. The rate of change of these column cell addition rates is similar among middle and lateral portions of both upper and lower beaks. There is a relatively constant rate of cell loss until stage XII or XIII. It then increases sharply, and the beaks are completely lost at stages XIX or XX. The longer, lower beak columns have a much faster cell loss rate than do the upper beak columns at late larval stages. Life spans for cells that move to the sheath may be about one‐half those for cells that enter the beak columns. It is suggested that thyroid hormone accelerates the rate of column cell loss.
Granule release by polymorphonuclear leukocytes treated with the lonophore A23187
Authors: Sannes Philip L. , Bank Harvey L. , Moore Patrick L. , Spicer Samuel S.
Published: February 2005

Polymorphonuclear leukocytes (PMN's) incubated three to eight minutes at 37°C in medium containing 1 × 10−6M of the ionophore antibiotic A23187 released their cytoplasmic granules into the extracellular medium. Transmission electron microscopy of treated cells showed microfilament bundles extending between adjacent granules within the cytoplasm and between granules and the plasma membrane. Tiny dense projections (beads) 8‐12 nm in diameter were observed along segments of the cytoplasmic surface of the plasma membrane with a periodicity of 20–30 nm. These beads were observed on the plasma membrane only in the vicinity of intra‐ or extracytoplasmic granules. The structural relationships of the beads with the plasma membrane micro‐filaments suggest they play a role in the process of ionophore‐induced granule release from polymorphonuclear leukocytes.
Embryologic origin of various epithelial cell types in the thyroid gland of the rat
Authors: Wollman Seymour H. , Hilfer S. Robert
Published: February 2005

Ventral pharyngeal outpocketings and ultimobranchial out‐pocketings from the 14‐day‐old fetus of the Fischer rat were isolated before they fused to form thyroid glands. The outpocketings were implanted into different kidney capsules of adult male Fischer rats, and were allowed to grow for several months. Transplants were then excised and examined by electron microscopy. The ultimobranchial outpocketing gave rise to two types of follicles. One contained ciliated cells, cells with an abundant agranular reticulum, U cells with basal hemidesmosomes, and two types of cells with secretory vesicles. The other contained C cells separated from the follicular lumen by a single flat fiber‐con‐taining cell. The ventral outpocketing formed typical thyroid epithelium making up the usual thyroid follicles differing from follicles in the thyroid in situ by the absence of C cells. These follicles were functional as determined by autoradio‐graphic studies with 125I but differed from thyroid follicles in situ with respect to size distribution. The results suggest that (1) in the adult thyroid gland the C cell in the usual follicle is an ultimobranchial contribution and (2) the so‐called ultimobranchial follicle is ultimobranchial in origin but that the typical thyroid epithelium in mixed follicles of U cells and typical thyroid epithelium is a ventral contribution. The reason for the absence in the thyroid gland in situ of the variety of other cell types observed in ultimobranchial transplants is unknown.
Contact sites between lymphoid cells of the bursa of fabricius, in vivo and in vitro
Authors: Holbrook Karen A. , Perkins William D. , Glick Bruce
Published: February 2005

Contact sites between lymphocytes and between lymphocytes and macrophages were demonstrated by electron microscopy in the lymphoid follicles of the bursa of Fabricius. When compared with nonspecialized regions of the cell membranes, these contact sites were characterized by a decreased intercellular distance, subplasmalemmal densities and coated pits. Microfilaments, microtubules and coated vesicles of the subjacent cytoplasm were frequently associated with these contact sites. When the same cells were isolated and introduced into culture, they formed cluster‐like assemblies in which cells were closely approximated along broadly contacting surfaces. The morphology of the sites appeared to involve primarily the plasma membrane (including coated pits) and the cell coat. These observations indicated that the same cells of a given lymphoid tissue can form one type of contact site in vivo and another, dissimilar type of contact site, in vitro.
Calcium localization in normal rachitic, and D3‐treated chicken epiphyseal chondrocytes utilizing potassium pyroantimonate‐osmium tetroxide
Authors: Carson Freida L. , Davis W. L. , Matthews J. L. , Martin J. H.
Published: February 2005

Normal, rachitic, and vitamin D3‐replete chicken growth plates were studied utilizing the potassium pyroantimonate‐osmium tetroxide procedure. A marked membrane and mitochondrial calcium was revealed in all specimens in the maturing and early hypertrophic zones which disappeared as heavy matrix mineralization began.

The most significant difference shown in the specimens was in the marked intracellular lipid content of chondrocytes in all zones of the rachitic and D3‐replete growth plates. There was negligible lipid present in normal specimens.

It is suggested that as most of the mechanisms postulated as necessary for calcification are present in rachitic chicks, perhaps the increased intracellular lipid pool results from the formation of abnormal lipids for insertion into the plasma membrane and thus prevents normal calcium transport.

Chains of intracellular vesicles were also visualized in maturing and hypertrophic chondrocytes. These were more often seen in rachitic growth plates and in increased numbers in the early D3‐replete specimens. The etiology is unknown at the present time.
The blood‐testis barrier and its formation relative to spermatocyte maturation in the adult rat: A lanthanum tracer study
Authors: Russell Lonnie D.
Published: February 2005

An electron‐opaque substance, lanthanum, was utilized to determine when germ cells of the rat first cross the blood‐testis barrier in adult spermatogenesis. Intravascularly perfused lanthanum was shown to surround all spermatogonia, preleptotene spermatocytes and early leptotene spermatocytes of Stage IX in the adult rat testis. Lanthanum was excluded from the spaces around more mature cells by newly‐formed tight junctions between adjoining Sertoli processes. These processes had previously intervened between the leptotene cells and the basal lamina. The results are in close agreement with those of a previous study (Russell, '77a) which indicated that leptotene cells are the first cells of adult spermatogenesis to enter the intermediate compartment and to reside beyond a permeability barrier.
Growth, protein content and distribution of early pig embryos
Authors: Anderson L. L.
Published: February 2005

Development of porcine conceptuses included transitions of five stages: blastocysts of spherical, ovoid, and tubular forms containing an embryonic disc and trophoblast, extremely elongated filamentous blastocysts, and stages of embryogenesis between days 9 and 18 after mating. Embryonic survival was reduced by 17% during this period. In this litter‐bearing species, intense alteration in distribution patterns occurred at days 11 and 12, when blastocysts rapidly elongated to filamentous forms. Increased embryo mortality did not result from rapid changes in distribution patterns of conceptuses within the same uterine horn at this time. Filamentous blastocysts quickly reached lengths often exceeding 60 cm, and these conceptuses became regularly spaced with no overlap of tubular membranes from other embryos in that horn. The number of concep‐tuses within a uterine horn ranged from 1 to 13. Protein in individual concep‐tuses was used as an indicator of growth and denoted exponential increase, but at a lower rate for blastocysts of spherical, ovoid, and tubular forms as compared with that found in filamentous blastocysts and embryogenesis stage conceptuses. Growth of a conceptus, based upon its protein content, was independent of the developmental stage or potential loss of those neighbors nearest that conceptus.
Synergistic effects of prolactin and testosterone in the restoration of rat prostatic epithelium following castration
Authors: Thompson Sue Ann , Heidger Paul M.
Published: February 2005

Prolactin is known to enhance the uptake and metabolism of testosterone in male accessory sex organs and to increase the weight of accessory sex organs from castrated rats over those from controls treated with testosterone alone. The present study was directed toward defining fine structural changes detectable with scanning and transmission electron microscopy which might accompany such responses. Accordingly, rat ventral prostrate gland was examined from castrated animals which had received testosterone propionate and ovine prolactin singly or together, or which had received vehicle only. Unoperated ani‐mals served as additional controls. Post‐castration glandular atrophy was not influenced by prolactin treatment alone. Testosterone restored epithelial height, secretory product, Golgi complexes and rough endoplasmic reticulum, such that cellular and tissue morphology was generally indistinguishable from that of unoperated controls. Prostatic tissue from animals given testosterone and prolactin simultaneously exhibited pleomorphic, cytoplasmic apical projections which extended into the acinar lumen. Transmission electron microscopy demonstrated that these blebs were devoid of organelles and microvilli; scanning electron microscopy revealed that the blebs were highly wrinkled and more numerous than were the projections observed in tissue from animals treated with testosterone alone, or in tissue from unoperated controls. It is suggested that such blebbing may reflect enhanced apocrine secretion in prolactin/testosterone stimulated restoration of the prostate gland in castrated rats.
Spatial orientation of microtubules in contractile fibroblasts in vivo
Authors: Rudolph Ross , Woodward Marilyn
Published: February 2005

Contracting fibrous tissues from skin wounds in pigs, and scars around silicone implants in humans, contained fibroblasts that had multiple bundles of 60‐80 Å microfilaments with electron‐dense bodies, features typical of contractile fibroblasts both in vivo (myofibroblasts) and in vitro. These in vivo fibroblasts contained many 220 Å diameter microtubules, which paralleled plasma membranes in the long axis of the cells. The spatial orientation of the microtubules in these myofibroblasts strongly suggests a bracing or scaffolding function.
Surface morphology of mouse and rat thymic lymphocytes: An in situ scanning electron microscopic study
Authors: Bhalla Deepak K. , Karnovsky Morris J.
Published: February 2005

The present paper deals with a scanning electron microscopic investigation which was undertaken in order to make a direct study of geometrical conformations of thymocytes, to determine the effect of external mechanical forces and finally to analyse the relation of the cell surface morphology to the differentiation and release of thymocytes into circulation. Thymocytes in situ revealed a striking polyhedral configuration with distinct edges and angles that permit a close orientation of cells in a minimum space. This conformation is probably acquired under the influence of forces in the microenvironment of the cells. The immature thymocytes in the cortex were smooth surfaced and constituted a homogeneous population with regards to surface morphology except for slight variations in the size and angles of various facets of the polyhedra. A minority of the cell population occupying the medulla, however, exhibited a departure in possessing surface undulations and stubby protuberances. Thymocytes isolated in suspension and those in postcapillary venules of thymus did not show the polyhedral shape characteristic of the cells in thymic tissue. They were always rounded, with their surfaces often exhibiting undulations or microvilli The variations observed in situ are discussed in light of external mechanical forces, cell surface characteristics and the inherent properties of differentiating thymocytes.
Cellular responses to experimental inhibition of collagen degradation in the postpartum rat uterus
Authors: Tansey Terese R. , Padykula Helen A.
Published: February 2005

Rapid collagen breakdown in the postpartum rat uterus is accompanied by rising collagenase activity (Jeffrey and Gross, '70) and a transient infiltration of the stroma by heterophils, eosinophils, monocyte‐macro‐phages, lymphocytes, and plasma cells (Padykula and Campbell, '76), cells usually associated with inflammatory response. This uterine catabolism is initiated soon after birth while blood estrogen and progesterone levels are low. To investigate the hormonal factors involved in regulation of this postpartum stromal differentiation, we analyzed the cytological effects of experimentally elevating progesterone and estradiol levels in the peripartum period by following the protocol of biochemical experiments that have demonstrated inhibition of collagenase activity by progesterone (Koob and Jeffrey, '74) and estradiol (Ryan and Woessner, '74).

Prolonged gestation (progesterone, 10 mg/day starting on day 19 gestation) was used as a condition to prevent the prenatal drop in blood progesterone; this treatment was the most effective in blocking postpartum stromal differentiation. It preserved the state of prepartum uterine differentiation and most importantly it prevented monocytic‐macrophagic conversion. Progesterone (40 mg/day) given at birth delayed but did not block stromal differentiation during the first 48 hours; by 72 hours collagen loss was extensive in both control and progesterone‐treated rats and numerous macrophages were present. Estradiol (100 μg/day) given at birth caused a greater delay in stromal differentiation than progesterone given at birth; for approximately 48 hours the number of eo‐sinophils, heterophils, and macrophages was less than normal. By day 3 the number and distribution of the macrophages resembled that of the day 1 control uteri. Overall these experiments indicate that the low estrogen and progesterone levels at birth are essential for normal stromal regression. Since these transient cells originate from the blood, the temporal pattern of their emigration into the uterus may be under hormonal control. Experimental disturbance of this pattern influences the course of collagen resorption.
A new corrosion casting technique
Authors: Nerantzis C. , Antonakis E. , Avgoustakis D.
Published: February 2005

A technique is described, employing polyester as the injection material, for preparing a casting of all cardiac vessels or of arteries or veins separately. This technique was used in 10 bovine and 40 fresh human hearts.

The technique is simple, rapid, economical and the required equipment is available in the average laboratory. The extent of vascular penetration is controlled by the viscosity of the polyester solutions, some of which at a certain density can penetrate through the net of capillaries with an injection pressure of no more than 220 mm Hg.

Our technique does not require any special handling of the heart and it makes no difference to the quality of the casting whether the blood is drained or flushed from the vessels prior to the perfusion.

There is no noted shrinkage or crumbling of our specimens stored at room temperature. The heart size, configuration and the anatomical relationship of the cardiac vessels are preserved without the need for casting cardiac chambers. The injection materials are cheap, easily transported and can be stored without special care. Injection, solidification and corrosion are carried out at room temperature.
Induction of lipid droplet accumulation in cardiac muscle cells of guinea pigs and mice: An analysis of the effects of reserpine and fasting
Authors: Iacovitti Lorraine , Gershon M. D.
Published: February 2005

Reserpine has been demonstrated in previous studies to induce the accumulation of lipid droplets in ventricular cardiac muscle cells of bats and this effect has been attributed to mediation by the sympathetic nervous system. The present study was done to evaluate the species specificity of this action of the drug. Reserpine caused lipid droplet accumulation in cardiocytes of guinea pigs and mice. However, in contrast to the action of the drug in bats, this action of reserpine in guinea pigs and mice could not be antagonized by chemical sympathectomy with 6‐hydroxydopamine or by treatment of animals with phenoxybenzamine, atropine or hexamethonium. Like reserpine, fasting for as little as 24 hours induced lipid droplet accumulation in cardiocytes of guinea pigs and mice. This effect also could not be prevented by treatment with 6‐hydroxydopamine indicating that the sympathetic nervous system was not involved in its mediation. Force‐feeding guinea pigs given reserpine prevented the accumulation of lipid droplets normally induced by this drug. It is concluded that the lipid droplets accumulation in the hearts of guinea pigs that follows administration of reserpine is not due to a direct cardiotoxicity of the drug but is secondary to the failure of drug‐treated animals to eat. Since the autonomic nervous system appears to mediate reserpine's cardiotoxicity in bats, the species difference revealed by these experiments probably results from an underlying physiological difference in the nervous systems of these animals.
SEM of the proximal tubule of the adult rabbit kidney
Authors: Evan Andrew P. , Hay Don A. , Dail William G.
Published: February 2005

The present study utilizes the scanning electron microscope (SEM) to reveal the surface morphology of proximal tubular cells and the parietal cells of Bowman's capsule of the adult rabbit nephron. To facilitate the examination of the basal surface of these cells, proximal tubules were dissected free and treated with collagenase to remove the basememt membrane. Other blocks of tissue were cryofractured to expose the lateral cell surfaces of the proximal tubules. Our investigation has shown that the lateral and basal surfaces of both the convoluted and straight segments of the proximal tubule have numerous processes. However, the arrangement and degree of branching is distinctly different in the two segments. The convoluted segment has large lateral ridges which form at the base of the microvilli and fan out to divide into lateral‐basal processes. Many of the lateral‐basal processes reach the basement membrane intact, interdigitating with complementary processes from adjacent cells. However, some of the lateral‐basal processes branch into short, knobby projections (basal villi) which may also reach the basement membrane. Patches of basal villi are interspersed between broad regions of interdigitating lateralbasal processes. Therefore, in the convoluted segment, the lateral‐basal processes form the major part of the basal cell surface. In tubular cells of the pars recta, unlike convoluted tubular cells, the majority of the ridges remain unbranched and pass directly to the basal surface where they divide into elaborate basal villi. Thus the basal surface of the pars recta cells is highly complex, appearing leaf‐like, being a composite of numerous basal villi with a few lateral ridges.

The basal surface of some parietal cells of Bowman's capsule have parallel ridges, which results in patches of striations.
Site of lodination in rat mammary gland
Authors: Strum Judy M.
Published: February 2005

The ability of the mammary gland to take up and organically bind radioiodide was studied in non‐pregnant, pregnant, and lactating rats. Autoradiography was used to determine whether duct cells or alveolar cells are responsible for iodination in the rat mammary gland. Iodination was not detected in mammary glands from non‐pregnant rats, but occurred late in the twelfth day of gestation and continued throughout pregnancy and lactation. Protein‐containing vacuoles in alveolar cells and casein‐like proteins in milk were the major sites where iodination occurred within the gland. Milk proteins in the lumens of ductules adjacent to alveoli were also iodinated. In contrast, ducts, myoepithelial cells, fat cells, blood vessels and other histological components of the gland did not show iodinating capability. Cytochemistry was also used to identify endogenous mammary peroxidase activity in the same glands, and it was found that the presence and location of this enzyme was correlated with the ability to iodinate.
Calcium transport and the secretory ameloblast
Authors: Eisenmann Dale R. , Ashrafi Shahid , Neiman Abraham
Published: February 2005

The distribution of calcium in the enamel organ of the rat incisor was investigated using potassium pyroantimonate for ultrastructural localization of calcium. Substantial amounts of precipitate occurred in the intercellular compartment of the enamel organ and modest deposits were observed in specific organelles of the secretory ameloblast. Mitochondria, nuclei, granular endoplasmic reticulum, Golgi vesicles and secretory granules consistently contained small deposits of pyroantimonate. Complexing of calcium by the pyroantimonate was confirmed by EGTA decalcification and scanning electron microscope energy dispersive X‐ray analysis. The observed distribution is discussed in light of potential for an intercellular pathway of calcium transport as well as controlled movement of the ion along the synthetic and secretory route followed by organic components of enamel.
Intramitochondrial rod‐like inclusions in human breast tumors
Authors: Seman Gabriel , Gallager Harry S.
Published: February 2005

Ultrastructural screening of human breast tumor biopsies has revealed, in 43% of the carcinomas, and in 16% of the benign lesions examined, the presence of rod‐like inclusions in mitochondria of epithelial cells. The inclusions are cylindrical in cross section, with a diameter of about 50 nm, and show regular striations in longitudinal sections. They are probably derived from cristae. Mitochondria with inclusions are usually enlarged and are found most frequently in epithelial cells of invasive tumors and near zones of tumor necrosis. Similar although not identical inclusions have been observed by other investigators in the liver of women with hydatidiform mole or choriocarcinoma, of pregnant women, and of women taking oral contraceptives. Identical inclusions have been found in mitochondria of HeLa cells treated with anti‐HeLa serum. Although no clear‐cut correlations were found between the finding of inclusions and parameters such as age of patients, nuclear grade or lymphocytic infiltration of the breast tumors, it is conceivable that the presence of mitochondrial inclusions reflects the effect of hormonal or of immunological factors.
Muscle proteins and the changes in shape of avian oxynticopeptic cells in relation to secretion
Authors: Vial J. D. , Garrido J. , Dabike M. , Koenig C.
Published: February 2005

A combined ultrastructural and biochemical study of the avian oxynticopeptic cell was performed. Scanning electron microscopy demonstrates that this cell undergoes great changes in the shape of its apical pole in relation to secretory activity. These changes are confirmed by transmission electron microscopy and by freeze‐fracture images. The biochemical finding of actin‐ and myosin‐like proteins in high‐speed supernatants of homogenates of these cells as well as the ultrastructural and cytochemical localization of actin‐like filaments in their apical poles suggest a possible participation of these proteins in the above‐mentioned changes. Thus, the study of cytoplasmic matrix elements and of their organization may be highly relevant in the search for a correlation between structure and function in these cells.
Development of T and B cell areas in peripheral lymphoid organs of the rat
Authors: Eikelenboom P. , Levenbach Muriel G. E. , van den Brink H. R. , Streefkerk J. G.
Published: February 2005

In the present study the early development of peripheral lymphoid organs (spleen, popliteal lymph node, mesenteric lymph node and Peyer's patches) is described in terms of homing patterns of T and B cells, demonstrated with immunohistoperoxidatic detection of characteristic membrane antigen in normal rats and with routine histology in neonatally thymectomized rats. In the first days after birth the peripheral lymphoid organs are almost exclusively populated by T cells. After neonatal thymectomy lymphocytes appear in the dome areas of Peyer's patches from four to six days after birth, in mesenteric and popliteal lymph nodes lymphocytes are found in the outer cortex from day 6 and day 8 respectively and in the marginal zone of the spleen from eight days onwards. These lymphocytes showed no membrane staining when reacted for T antigen with immunohistoperoxidatic techniques.

The morphological evidence for considering Peyer's patches of rats as central inductive sites for the generation of B cells is poor. The discrepancy in the order of appearance of T and B cell (sub)populations in spleen compartments in normal ontogenetic development and lethally irradiated, stem cell reconstituted animals is discussed.
The role of epithelial coliagen and proteoglycan in the initiation of osteogenesis by avian neural crest cells
Authors: Bradamante Ž. , Hall B. K.
Published: February 2005

Osteogenesis was inhibited when mandibular processes from 3 1/2‐day‐old embryos were cultured in BUdR, LACA, α, αβ‐Dipyridyl, 4‐Methylumbelliferone, and 4‐Methylumbelliferyl‐β‐D‐glucoside or β‐D‐xyloside. Mandibular processes were then cultured in the test substances for 3 days, enzymatically separated into their epithelial and ectomesenchymal components, combined with mandibular components from untreated embryos, and either organ‐cultured or grafted to chorioallantoic membranes of host embryos. Osteogenesis was inhibited when treated epithelium, but not when treated ectomesenchyme, was present in the tissue recombinations.

Analysis of the known action of these inhibitors indicates that proliferation, hydroxylation of collagen, and synthesis of proteoglycans by epithelial cells are all necessary components of this osteogenic epithelial‐ectomesenchymal interaction.
Sequential development and tissue organization in whole mouse embryos cultured from blastocyst to early somite stage
Authors: Libbus Bisharah L. , Hsu Yu‐Chih
Published: February 2005

The development of mouse embryos in culture from the implantation to the head‐fold stage was sequentially examined. Our goal was to compare the morphology of embryos grown in vitro to those developed in vivo, published in standard texts, and to delineate the stages involved in the process of tissue differentiation and organization. Mouse blastocysts (stage 6) were collected at 3.5 days p.c. and cultured. Attachment of the blastocysts occurred on the second day of culture (stage 8). Following the collapse of the blastocyst endoderm cells began to migrate and to encircle the inner cell mass. At 2 days in culture the embryonic and extra‐embryonic ectoderm became distinguishable and the proamniotic cavity appeared (stage 9). Egg cylinders began to project above the substrate at 2.5 days in culture (stage 10) and to progress through the stages observed in vivo. At 4 days a posterior amniotic fold began to form (stage 11) and was followed at 5 days by the formation of the chorion, the appearance of mesoderm, exocoelom, and head fold (stage 12). At 6 days in culture the embryo had differentiated longitudinally and developed an allantois, blood islands, Reichert's membrane, head process, and primitive streak. At 7 days somites as well as the neural fold and heart were observed (stage 14) and were followed by further differentiation at 8 days (stage 15). These observations indicate that apparently normal embryo development can be maintained in vitro through the early stages of organogenesis, thus providing a unique opportunity for investigating the regulation of early mammalian development.
Orderly particle arrays on the mitochondrial outer membrane in rapidly‐frozen sperm
Authors: Friend Daniel S. , Heuser John E.
Published: February 2005

By deep‐etching and rotary replication of unfixed, non‐cryoprotected tissue frozen on a helium‐cooled copper block, previously undemonstrable organellar surfaces and intramembranous structures can be examined. Among the more remarkable features of mammalian spermatozoa thus prepared are the highly ordered particulate arrays on the surface of the mitochondrial outer membrane. In the midpiece of the sperm, mitochondria curl around dense fibers and the axoneme. The surface of the mitochondrion that faces the plasmalemma carries closely packed rods in haphazard dispersement, composed of two to four 70‐to 80‐Å particles, <20 Å apart, while the concave aspect of the organelle contains rods in stepladder pattern. These ladders are parallel, with their paticles in neighboring rungs apparently in register at a 40–45° angle relative to the mitochondrial axis. This organizational disparity between the convex and concave surfaces of the organelle not only affords evidence of a new mitochondrial substructure, but represents a type of topographical heterogeneity rarely found except within specialized areas of the plasma membrane.

Other novel findings in the sperm cell include the observation of “lipid” tracts flanking intramembranous particle‐strands in the plasmalemma of the cytoplasmic droplet, and a gridiron design on the cytoplasmic faces of the droplet's microcisternae, as well as both within and atop its plasma membrane—a motif consistent with the presence of exocytotic or endocytotic activity in this portion of the cell. Additional recent observations are the differing internal and external periodicities of axonemal microtubules and the subunit structure of rectangles on the tail surface overlying the intramembranous particles of the zipper.
Effects of immunization with Freund's complete adjuvant and isologous spermatozoa on the seminiferous epithelium and blood‐testis barrier in guinea pigs
Authors: Pelletier R.‐M. , Nemirovsky M. S. , Calvert R. , Hugon J. S.
Published: February 2005

In order to gain insight into the earliest pathological changes underlying the development of autoimmune aspermatogenic orchitis (AIAO) the blood‐testis barrier was studied by light and electron microscopy, freeze‐etching, and cytochemical techniques early (from 1 to 8 days after adjuvant treatment or isoimmunization). At later times (16 to 21 days) the study was carried out by light microscopy only. Adult male guinea pigs were used either as controls or immunized with Freund's complete adjuvant alone or together with pertussis vaccine. An additional group comprised animals immunized with a suspension of isologous spermatozoa emulsified in Freund's complete adjuvant and with pertussis vaccine. Ultrastructural studies of the testes of experimental animals showed, at earlier periods, apparently normal Sertoli junctions. However, in the adluminal compartment, distended gaps were seen between the facing membranes of adjacent Sertoli cells. At later periods, a massive destruction of the germinal cells were observed. In freeze‐fracture replicas, the Sertoli junctions of testes belonging to all the experimental groups were characterized by an irregular network of occasionally interrupted strands of particles associated with the P face (PF). Large concavities determined distensions between interconnecting ridges. The gap junctions were increased in number and in surface. Tracer studies using horseradish peroxidase showed that the marker permeated the myoid cells of a greater proportion of tubules than in control animals. Within the seminiferous epithelium there was only a limited passage of the marker towards the lumina of the tubules. Yet the tracer was always excluded from the adluminal compartment by the Sertoli tight junctions.

Our observations suggest the possibility that the FCA causes a loosening of the Sertoli junctions. This condition could enhance exchanges between two antigenically different cellular compartments and, thus, favor occurrence of an autoimmune reaction when cytotoxic factors are experimentally induced, as in iso‐ or autoimmunization.
The ultrastructure of the avian Golgi tendon organ
Authors: Haiden Gerald J. , Awad Essam A.
Published: February 2005

The ultrastructure of the avian Golgi tendon organ (GTO) is described and compared with those of mammals using transverse sections through the myo‐tendinous junctions of wing muscles of adult mallard ducks.

The capsule, which is continuous with the perineural epithelial sheath of the Ib afferent nerve fiber, consists of four to seven flattened cellular lamellae. Two to four muscle fibers attach to large collagen bundles which enter the GTO through a tight collar at the proximal end of the fusiform capsule. These collagen bundles divide into many smaller bundles, which run longitudinally through the lumen in compartments formed by septal cells. The septal cells contain many prominent lipid accumulations. The Ib axon divides several times, and the unmyelinated branch axons weave between the small collagen bundles. Schwann cell processes or basement membrane usually intervene between the axons and collagen bundles. The small collagen bundles regroup into larger bundles, which pass through tight capsular collars and merge with the main muscle tendon. The size of the duck GTOs was measured and found to be smaller than the GTOs of man, cat or rat.
Submandibular glands in mice with muscular dystrophy: Studies with nerve growth factor
Authors: Murphy Richard A. , Watson Ann Y. , McCarthy Mary , Papastavros Mary , Neutra Marian , Forssmann W. George
Published: February 2005

Experiments have been carried out to examine the submandibular glands in mice with hereditary muscular dystrophy. Radioimmunoassay data confirm biological studies which show that submandibular glands in mice with muscular dystrophy contain less nerve growth factor (NGF) than glands of normal animals. Male dystrophics have half as much submandibular NGF as unafflicted mice, while females have only 10% of control levels. Gel filtration and electrophoretic studies detect no differences in the molecular properties of NGF in gland extracts from normal and dystrophic mice. Furthermore, NGF from both sources show equal activity in the sensory ganglion bioassay. Together, these results suggest that NGF deficits in submandibular glands of dystrophic mice are not due to measurement artifacts arising from alterations in the structure of the molecule.

Morphological studies have uncovered a cytological basis for chemical deficits within submandibular glands of dystrophic mice. Stereological analysis of light and electron microscopic sections revealed that growth factor containing granular tubule cells (GTC) take up a smaller portion of the total gland volume, are smaller in size, and contain fewer secretory granules than comparable cells in glands from controls. Furthermore, the ultrastructure of GTC in dystrophic animals suggests that the cells are less active in producing secretory protein than GTC in glands from normal animals. These results are consistent with the idea that growth factor deficits arise from cellular abnormalities in the granular tubule segment of the gland.
A histological study of the Harderian gland of mongolian gerbils, Meriones meridianus
Authors: Sakai Tatsuo , Yohro Takeshi
Published: February 2005

The histological structure of the gerbil Harderian gland was investigated by means of light and transmission electron microscopy. The single excretory duct of the gland is directly continuous with endpieces at the hilus and opens nasally and ventrally to the third eyelid. The excretory duct is accompanied by many acini of small serous glands around it. The gland is composed of tubuloalveoli (tubular alveoli) with wide lumina and is not divided into lobules. There is no branched duct system within the gland. The tubuloalveoli themselves convey the secretory materials to the hilus where the excretory duct begins. The alveolar epithelium is composed of only one type of glandular cell as well as myoepithelial cells. The glandular cells contain many clear secretory vacuoles containing lipids and well‐developed tubular smooth endoplasmic reticulum. The secretory vacuoles are surrounded by a unit membrane and are secreted by exocytosis. The interstices of the gland contain two types of autonomic nerve varicosities and a number of melanocytes. The surface of the gland is covered with the endothelium of the orbital venous sinus.
Morphological changes in the mechanically unloaded myocardial cell
Authors: Tomanek Robert J. , Cooper George
Published: February 2005

The role of stretch and/or tension in maintaining the structural integrity of the myocardial cell was investigated in 16 cats. Right ventricular papillary muscles were studied 1–28 days after transection of the chordae tendinae and compared to adjacent intact papillary muscles. A progressive atrophy, as shown by decreased mean cell cross‐sectional area, occurred; by the 28th day mean cardiocyte area was only 28% of the control value. The earliest ultrastructural changes (one day after surgery) were primarily focal and included disorientation of contractile filaments and loss of Z‐line substance. During the first week, vacuolation, loss of contractile filaments, and infiltration of macrophages and fibroblasts were characteristic. By the second week a massive loss of contractile substance, disappearance of the sarcoplasmic reticulum, and a marked increase in connective tissue occurred. Leptomere structures, membrane alterations, and phagocytosis were the most typical changes between the second and fourth week. Hydroxyproline assays on papillary muscles unloaded for three days showed a 38% increase in connective tissue, indicating an early increase in connective tissue/muscle mass associated with mechanical unloading.

It is concluded that the cardiocyte is extremely dependent upon mechanical loading, i.e., stretch and/or tension. Mechanical unloading (tenotomy) results in rapid and marked cellular degeneration which exceeds that observed in skeletal muscle following either disuse or denervation.
Ontogeny of caudal fourth ventricular tanycytes in the rabbit brain: A Golgi study
Authors: Felten David L. , Cummings John P. , Burnett Bruce T.
Published: February 2005

A Golgi study of the floor of the caudal fourth ventricle in the developing and adult rabbit brain stem revealed the presence of several clusters of tanycytes. These tanycytes possessed ciliated apical surfaces and basal shafts extending into the substance of the medulla and pons where they intermingled with specific neuronal fields. These shafts ended in the serotonergic nuclei raphe obscurus and pallidus, and the noradrenergic locus coeruleus and nucleus intercalatus (group A2). The tanycyte shafts extended into the medullary midline early in ontogeny (day 18 of gestation), following which the neurons of the raphe began to sprout neurites. These shafts then formed the underlying structure for a large medullary dendrite bundle. These shafts developed extensive spines during early neonatal ontogeny, which then diminished in number through adulthood. The tanycyte shafts extending into locus coeruleus and nucleus intercalatus developed later in ontogeny than the midline shafts, just before birth. These shafts also persisted into adulthood in close relationship with the monoamine neurons. We suggest that the tanycytes on the floor of the fourth ventricle may take up substances from the CSF and transport them to the region of the monoamine nuclei where the shafts terminate, in a manner similar to median eminence tanycytes. The early development of shafts from fourth ventricular tanycytes suggests a possible regulatory role for these cells over the neuritic sprouting and maturation of the monoaminergic nuclei.