bluuebunny/crossref_metadata_2025 huggingface dataset:
Membranous systems in the “chloride cell” of teleostean fish gill; their modifications in response to the salinity of the environment
Authors: Pisam M.
Published: February 2005

The membranous systems of the “chloride cell” were studied in teleostean fish gills stained in ferrocyanide‐reduced osmium (Karnovsky, '71). Three distinct systems were observed: (1) the tubular system, densely stained with ferrocyanide‐reduced osmium, was made up of anastomosed tubules opening in the latero basal intercellular space; (2) the endoplasmic reticulum, faintly stained, and continuous with the nuclear envelope; (3) the vesiculotubular system, the staining of which was intermediate between those of both previously cited systems, was made up of vesicles and short tubules. These membranous systems underwent modifications according to the salinity of the exterior medium: (1) the tubular system formed a broad and loose network in fresh water adapted fishes; in salt water, the meshes of the network became small, tight, and regular thus increasing the cell surface area. (2) the endoplasmic reticulum, which in fresh water, consisted of dilated cisternae often studded with ribosomes; in salt water, it developed in a network of anastomosed smooth sheets interdigitated with the tubular system. (3) the vesiculotubular system seems to be also more developed in salt water than in fresh water‐adapted fishes.
Observations on the structure of the eumelanosome matrix in melanosomes of the chick retinal pigment epithelium
Authors: Zimmerman J. , Winfrey F. , Good P.
Published: February 2005

Eumelanosomes from the developing chick pigment epithelium have been isolated, solubilized, and the residue collected. Examination of this material in the electron microscope provides evidence for new structural entities in the eumelanosome and information on the organization of the melanosome. This evidence suggests that there are (1) 190‐Å fibers arranged in a zigzag fashion, surrounding 240‐Å–diameter electron‐lucent spaces and (2) an internal gridwork enclosing 40–50‐Å‐diameter spaces. These two structures are probably alternately layered and “rolled‐up.”
Embryonic development of the rat pineal gland
Authors: Calvo J. , Boya J.
Published: February 2005

The embryonic development of the albino rat pineal gland has been studied from day 13 of development until birth. The first pineal anlage appears as a midline evagination of the diencephalic roof, which soon adopts a tubular morphology. At 17 days, the disappearance of the pineal recess begins, along with the transformation of the gland into a solid organ. The latter is mainly achieved by an infolding and thickening of the dorsal recess wall, from which derives most of the future pineal parenchyma. Blood vessels are mainly derived from the vessels found in the dorsal surface of the pineal gland.
A restudy of cardiac conduction pathways by techniques for visualization of cholinesterase reaction
Authors: Copenhaver Wilfred M.
Published: February 2005

Histochemical reactions which demonstrate cholinesterase reactions in tissues were used for slides of serial frozen sections of hearts of pigs, dogs, and rats to determine whether there are special types of modified muscle cells in continuous pathways from the SA (sinoartial) to the AV (atrioventricular) node. There were positive reactions for acetylcholinesterase with less reaction for butyrl cholinesterase in ganglion cells and nerve fibers. No continuous pathways of cholinesterase‐reacting cardiac muscle fibers from the SA to the AV node were identified although the muscle fibers were in intimate relation with the nerve fibers. No cells of Purkinje type were demonstrated in the atria.
Evidence for the site of the superior salivatory nucleus in the guinea pig: A retrograde HRP study
Authors: Way John S.
Published: February 2005

Horseradish peroxidase (HRP) was applied to the proximal end of the severed lingual nerve distal to where it was joined by the chorda tympani nerve in 15 female guinea pigs. Labeled cells were seen in the lateral reticular formation dorsal to the facial nucleus along the medial edge of the spinal nucleus of V. These cells were aligned vertically and partially within the facial nerve fibers which were emerging from the facial nucleus lying ventrally. HRP‐reactive axons were also seen among the facial nerve fibers coursing dorsomedially toward the genu of the facial nerve. These results demonstrated for the first time the locus of the superior salivatory nucleus in the guinea pig and were consistent with anatomical results previously reported in other species. In addition, labeled fibers indicated that superior salivatory nucleus axons became incorporated in the facial nerve immediately dorsal to its origin.
Topography of the deep cortex of the lymph nodes of various mammalian species
Authors: Bélisle C. , Sainte‐Marie G.
Published: February 2005

In preceeding studies, we clarified the histology of the deep cortex of the rat lymph node. It was shown that the deep cortex is made up of basic elements termed “deep cortex units,” some of which are fused to one another into “deep cortex complexes.” Each unit is a semirounded lymphocytic structure, centered on the opening of an afferent lymphatic, contiguous to the peripheral cortex, and bulging into the medulla of a node. Moreover, each unit comprises a “center” and a “periphery,” bearing distinct morphological features. The present work was undertaken to verify whether the histology of the deep cortex of nodes from various species of mammals, currently used for experimental immunology, is comparable to that of the rate. The observations yielded a positive answer to the question.
An electron microscopic radioautographic study of collagen secretion in periodontal ligament fibroblasts of the mouse: I. Normal fibroblasts
Authors: Cho Moon‐Il , Garant Philias R.
Published: February 2005

Analysis of electon microscopic radioautographs revealed a maximum labeling with 3H‐proline of rough endoplasmic reticulum (RER) at 3 minutes, Golgi saccules 1 and 2 at 10 minutes. Golgi saccules type 3 at 20 minutes, and presecretory and secretory granules at 30 minutes. Labeling of the extra‐cellular collagen matrix occurred at 30 minutes and increased with time. These observations suggest that pro‐a‐chains of collagen in periodontal ligament fibroblasts are synthesized in the RER and transported to the Golgi apparatus within 10 minutes. These chains then undergo parallel alignment in Golgi saccules type 2 and form segment‐long‐spacing‐like crystallites in Golgi saccules type 3 between 10 and 20 minutes. The peak labeling of presecretory granules and mature secretory granules in small amounts at 30 minutes and the rapid increase in labeling of extracellular collagen matrix which begins at 30 minutes, indicates that the formation of secretory granules requires approximately 30 minutes and that a rapid system of secretory granule translocation exists in periodontal ligament fibroblasts. This evidence futher supports the previously published morphologic evidence for a microtubuledependent system of collagen secretion in periodontal ligament fibroblasts (Cho and Garant, 1981b).
The ultrastructure of isolated glial (Müller) cells from the turtle retina
Authors: Sarthy P. Vijay , Bunt Ann H.
Published: February 2005

Sarthy and Lam (1978) described a method for isolation of glial (Müller) cells from turtle retina which involves papain treatment, mechanical dissociation of the retinae, and subsequent separation of the dispersed cells by velocity sedimentation at unit gravity. In order to establish the cytologic integrity and the extent of contamination, we have carried out ultrastructural studies on the isolated cells using scanning and transmission electron microscopy. During the course of these studies we have also examined the effect of papain on the morphology of the retina. Scanning electron microscopic studies show that the isolated cells have a free surface with limited extraneous material attached. The basal portion of the cell is organized as end bulbs with a convoluted surface while the apical region is specialized with long microvilli. Transmission electron microscopy shows that the isolated cells have intact plasma membranes with very few interruptions. The cytoplasm is dense and contains the normal complement of smooth endoplasmic reticulum, microtubules, and filaments. The extent of contamination as estimated from serial sections of a single cell is about 10–15% of the total cell volume. These studies indicate that Müller cells isolated by this technique should be useful for metabolic studies and for characterizing the Müller cell surface.
Isolation, culture, and preliminary characterization of mucin‐producing cells from trachea of the domestic fowl
Authors: Douglas W. H. J. , Gustafson A. W. , Aghajanian J. D. , Gustafson E. Y.
Published: February 2005

Primary cell cultures enriched in mucin‐producing cells and basal cells were established from the trachea of the domestic fowl. Epithelial cells were selectively removed from the trachea after incubation in 0.1% pronase/0.1% EDTA in Moscona's saline. The majority of the ciliated cells were removed during the initial 30 minutes of incubation. After 50 minutes of incubation, aggregates of mucin‐producing cells and basal cells were removed in large numbers. The cellular aggregates rapidly attached to a collagen‐coated substratum and the cells spread out on the culture surface. The mucin‐producing cells retained their AB/PAS‐reactive secretory granules. The basal cells replicated and as the culture approached confluency, these cells developed a fine dusting of AB/PAS‐reactive material; later, larger secretory granules appeared in the cells. These observations suggest that mucin‐producing cells are capable of retaining their AB/PAS‐reactive secretory products in primary culture and that basal cells are capable of differentiating into mucin‐producing cells in vitro.
The morphology of canine lymphatic valves
Authors: Albertine Kurt H. , Fox Linda M. , O'Morchoe Charles C. C.
Published: February 2005

The architecture of 60 valves from thoracic ducts and from renal hilar and mesenteric collecting lymph vessels of dogs were studied by scanning electron microscopy as well as by light and transmission electron microscopy. All of the valves seen in hilar and mesenteric lymph vessels and most of those studied in the thoracic duct were bicuspid. An occasional tricuspid and one monocuspid valve was seen in the thoracic duct. The semilunar cusps of the valves extended from the vessel wall, to which they were attached, towards the valve outlet where adjacent cusps fused. Coincident to the area of fusion was the formation of mesenteric‐like folds or buttresses that anchored the cusps to the vessel wall. These folds extended 50–100 μm beyond the cusp margins on the outflow side of the valve. The attachments of the cusps, buttresses, and vessel wall to one another resulted in the formation of postvalvular sinuses, such that raised intraluminal pressure downstream to valve areas would distend the sinuses, causing leaflet apposition and hence valvular closure. The morphology of the valves was such that they were not considered to provide any significant impediment to the antegrade flow of lymph.
Comparison of lens regeneration in adult newts, Triturus viridescens, between light and dark preadapted and non‐preadapted animals
Authors: Chan Frank
Published: February 2005

It is well known that if the original lens is removed from the eyeball in certain Urodeles, a new lens will regenerate from the dorsal iris. Experiments were designed to study the different effects on lens regeneration in the newt, Triturus viridescens, between the light and dark preadapted animals and light and dark non‐preadapted animals. The preadapted animals were preadapted to continuous light or dark for 90 days prior to lentectomy. The newts remained in the same controlled environments postlentectomy for 25 days to test the effect of light preadaptation on lens regeneration. The non‐preadapted animals were placed in the light controlled environment immediately after lentectomy for a 25‐day regeneration period.

The results indicated that there was no difference in the rate of regeneration between continuous light preadapted and non‐preadapted animals. However, the dark non‐preadapted animals regenerated new lenses at a much slower rate than the dark preadapted animals.

The rate of lens regeneration was similar among the controls with 12 hours of light per 24‐hour period, the dark preadapted, the continuous light preadapted, and continuous light non‐preadapted groups.
Intraarterial cushions of the rat uterine artery: A scanning electron microscope evaluation utilizing vascular casts
Authors: Kardon Randy H. , Farley Donna B. , Heidger Paul M. , van Orden Dianna E.
Published: February 2005

The intraarterial cushions present in the rat at the points of branching of the main uterine artery have been studied by means of scanning electron microscopy. Such studies confirmed the three‐dimensional concept of these structures gained from previous light microscopic serial section reconstructions as incomplete, raised, asymmetric ridges which encompass the branch orifice. The examination of methacrylate corrosion casts of the uterine vasculature with the scanning electron microscope provided a means for evaluating the relative protrusion or retraction of the cushion structures within the vessel lumen, and thus for assessing their role in regulating uterine blood flow in various physiologic states. Cushions were studied in this manner at the stages of the estrous cycle, in castrated animals, and in animals receiving pharmacologic doses of an alpha adrenergic agonist, phenylephrine. Evaluation of the relative depth of the impression left upon the vascular casts by cushions permitted the following conclusions. The cushions protruded maximally (and thus impeded flow most effectively) in castrated animals and in animals treated with the vasoconstrictor, phenylephrine. In contrast, the cushions protruded less in animals in proestrus and estrus. These data suggest that the cushions do respond, either actively, by virtue of the contractile state of the smooth muscle within the cushion, or passively, as a function of overall vessel geometry, to alpha adrenergic stimulation. The contrast in cushion protrusion between the castrated state, and proestrus and estrus, suggests that ovarian hormones exert an influence over the functional morphology of the cushions in a manner which promotes maximal uterine perfusion during those periods of the estrous cycle which are documented as periods of uterine hyperemia. These studies thus provide evidence for the dynamic role of intraarterial cushions in the regulation of uterine blood flow.
Correlates of ovarian morphology, estrous behavior, and cyclicity in an inbred strain of miniature swine
Authors: Howard Paul K. , Chakraborty Prabir K. , Camp Jonathan C. , Stuart Leonard D. , Wildt David E.
Published: February 2005

Ovarian morphology and behavioral relationships were studied in a group of nine miniature pigs with a characteristically small litter size (∼5) and an average coefficient of inbreeding of 0.39. The first day of standing estrus was designated as day 0. Laparoscopy was used to evaluate and photograph ovarian activity on days 1, 5, 11, 17, and day 2 of the subsequent estrous cycle. Mean (±SEM) duration of estrus and the estrous cycle was 3.1±0.2 and 22.6±0.3 days, respectively. An average of 9.0±0.4 vesicular follicles developed/estrous period and 96% of the follicles showed morphologic evidence of ovulation resulting in a mean of 8.6±0.3 corpora lutea (CL) per animal. There was no significant correlation between the degree of inbreeding and number of vesicular follicles (r=0.27) or CL (r=0.28) developing/cycle within the experimental group. Mature preovulatory follicle and CL size ranged from 6–12 mm and 8–12 mm in diameter, respectively, and 22.5% of the newly formed CL contained distinct postovulatory stigmata. These data indicated that 1) temporal relationships of sexual behavior and gross ovarian morphology in the miniature pig were similar to descriptions previously reported for the standard pig, and 2) the reduced litter size characteristic to this particular strain is, at least in part, due to decreased number of vesicular follicles developing during the estrous cycle.
Plexus muscularis profundus and associated interstitial cells. II. Ultrastructural studies of mouse small intestine
Authors: Rumessen Jüri Johannes , Thuneberg Lars , Mikkelsen Hanne Birte
Published: February 2005

The ultrastructure of plexus muscularis profundus (PMP) of the mouse small intestine was investigated subsequent to vascular perfusion with ruthenium red‐containing and routine aldehyde fixatives. Four types of nerve terminals were revealed. Type I: numerous 500‐Å agranular vesicles and few 1,000‐Å granular vesicles. Type II: predominantly large (1,000–1,500 Å), granular vesicles and fewer 500‐Å agranular vesicles. Type III: an abundance of mitochondria and many flattened vesicles (300 Å × 700‐1,300 Å). Type IV was identified by abundant smooth cisternae 200 Å in width. Types I‐III formed close (200 Å), synapselike contacts to interstitial cells of Cajal (ICC‐III). Presynaptic densities were frequent in type I endings. A direct innervation of muscle cells via PMP was only very occasionally suggested. ICC‐III possessed a basal lamina and numerous caveolae associated with subsurface SER‐cisternae. Mitochondria were very abundant in ICC‐III‐processes. ICC‐III formed multiple, large gap junctions with outer circular‐muscle cells and with other ICC‐III. Also reflexive gap junctions were observed. Fibroblastlike cells (FLC) were distinguished by their prominent GER, the frequent presence of lipid droplets, and the lack of caveolae and a basal lamina. FLC never participated in synaptic arrangements or gap junctions. Macrophagelike cells were occasionally encountered. It is concluded that possible efferent and afferent nerve terminals in PMP may chiefly, if not exclusively, innervate ICC‐III, the ultrastructure of which is compatible with efferent and/or afferent modulatory actions.
Degranulation of endothelial specific granules of the toad aorta after treatment with compound 48/80
Authors: Fujimoto Sunao
Published: February 2005

Incubation of isolated toad aortas in Ringer solution containing compound 48/80, a Histamine liberator, resulted in marked degranulation of endothelial specific granules.

Since incubation of these vessels in Ringer solution only did not show significant morphologic changes in these granules, these findings suggest that the degranulation was induced by histamine release from the granules, as in the case for mast cell degranulation, and that endothelial specific granules are a storage site of histamine in the toad aorta.

The present morphologic data were supported by preliminary chromatography, which showed appreciable concentrations of histamine in the granule‐containing pellets of subcellular fractions of homogenized toad aortas.
A comparative study of osteoclasts: In situ versus smear specimens Osteoclasts in situ and in smears
Authors: Ries William L. , Gong Joseph K.
Published: February 2005

Osteoclasts residing on rims and walls of bony concavities on remodeling proximal Libia from growing rats were examined by light microscopy following stripping of the periosteal connective tissue layer. Comparison of these cells in situ and after transfer to glass slides revealed the presence of numerous mononucleate osteoclasts, as well as typical multinucleate forms, all exhibiting a ruffled border and acid phosphatase and succinic dehydrogenase activity. Macrophage‐like cells were situated adjacent to osteoclasts in situ. Osteoblasts were relatively inconspicuous. The possibility that the basic functional osteoclast unit is a mononucleate cell is discussed.
Distribution of progesterone in the uterus, broad ligament, and uterine arteries of beef cows
Authors: Pope W. F. , Maurer R. R. , Stormshak F.
Published: February 2005

Samples of uterine horn, broad ligament (mesosalpinx and mesometrium), and uterine artery of ten unilaterally ovulating cows, 12–15 days after mating, were examined for differences in concentration of progesterone. Tissues (mesosalpinx, branches of the uterine artery, anterior uterine horn) adjacent to the ovary bearing the corpus luteum contained significantly greater quantities of progesterone than more distal tissues (mesometrium, uterine artery, posterior uterine horn) on the same side and all tissues on the contralateral side. In tissues on the side ipsilateral to the corpus luteum, a gradient of progesterone existed. Differences in tissue concentrations of progesterone may be the cause of observed differences in uterine physiology in the cow and ewe.
An ultrastructural morphometric comparison of the right and left sides and lobes of the dog lung
Authors: Berendsen Peter B. , De Fouw David O.
Published: February 2005

Regional variations of the components of lobes of the lung have been recognized to result from gravitational effects. Excised and isolated perfused lungs are frequently used as objects for studies of fluid flow. This ultrastructural study considered differences between the right and left sides and lobes of the excised lung. The lungs of three mongrel dogs were fixed by simultaneous endotracheal instillation of glutaraldehyde and immersion in fixative. Stratified random sampling, point‐counting volumetry, and line intercept counts were utilized to determine the volume densities of alveolar space, endothelial vesicles, interstitial cells, fibers, and matrix. Thicknesses of the air‐blood barrier, epithelial, interstitial, and endothelial compartments were measured. Values for the right side were compared to values for the left by t‐test. Values for lobes were compared statistically by a two‐way analysis of variance. There was no statistically significant column effect, no row effect, and no interaction between the mean measurements of the factors computed for the right and left lungs and the lobes within the lungs. It is concluded that stratified random sampling combined with endotracheal and immersion fixation as used in this study equalize regional differences in the alveolar lumen volume and air‐blood barrier thickness. With these conditions there are no significant differences by sides or lobes in the volume densities of the epithelial and endothelial cells and components of the interstitium of the air‐blood barrier.
Secondary myogenesis of normal muscle produces abnormal myotubes
Authors: Ontell Marcia , Hughes Donna , Bourke Dianna
Published: February 2005

The extensor digitorum longus muscles of 2‐, 4‐, and 12‐week‐old 129‐ReJ mice were subjected to homotopic, whole‐muscle transplantation. Subsequent to myofiber necrosis and phagocytosis, a new population of myotubes was produced. The three‐dimensional cytoarchitecture of these newly formed myotubes was determined in spaced, serial, ultrathin sections. Myotubes, which for long distances along their length appeared to be separate and discrete, were found to branch and recombine, forming a complex syncytium.
Inhibition of artificially induced decidual cell reaction by indomethacin in the mature oophorectomized rat
Authors: Miller Marilyn M. , O'Morchoe Charles C. C.
Published: February 2005

Prostaglandin F2α (PGF2α) is capable of inducing a decidual cell reaction (DCR) in the hormonally prepared rat. In the present work indomethacin, a PG synthetase inhibitor, was used to determine whether PGF2α is involved in the DCR induced by artificial stimulation of the endometrium. Thirty‐seven animals were oophorectomized and subsequently given daily injections of progesterone for 6 days and one injection of estradiol 17 β on the fourth day. Later on the fourth day, one of several experimental maneuvers was carried out on the right uterine horn of each animal; these included: 1) introduction of phosphatebuffered saline (PBS) twice into the uterus, 2) intrauterine injection of PGF2α with no subsequent application or manipulation, 3) intrauterine injection of indomethacin followed by subsequent injection of PGF2α, 4) intrauterine injection of indomethacin with subsequent artificial stimulation (scratch), 5) intrauterine injection of PBS with subsequent scratch, 6) scratch followed by injection of PBS, and 7) scratch followed by a second scratch. The extent of the ensuing DCR was assessed 48 h later by measurement of horn weight, by light and electron microscopy, by ranking the DCR, and by the mitotic index. Indomethacin significantly reduced the horn weight in animals treated with scratch but had a much less marked effect on animals treated with PGF2α. Similarly the rank of the DCR and the mitotic index were significantly less in endometria treated by indomethacin with scratch than those treated by indomethacin with PGF2α. From these findings it was concluded that the DCR induced by scratch was inhibited, but not abolished, when preceded by indomethacin. Conversely the DCR induced by PGF2α was not inhibited by indomethacin, thus demonstrating that when local generation of PG is reduced or abolished, PGF2α can sustain the decidual cell response.
A freeze‐fracture study of the maturation of synapses in the anteroventral cochlear nucleus of the developing rat
Authors: Mattox Douglas E. , Neises Gabrielle R. , Gulley Robert L.
Published: February 2005

The freeze‐fracture technique was used to study the maturation of the postsynaptic membrane of spherical cells of the anteroventral cochlear nucleus (AVCN) of the developing rat brain. Observations were made at 2‐day intervals from birth to 16 days of age. At all ages, the external leaflet (E‐face) of the spherical cell membrane has aggregates of particles opposite presynaptic active zones. From birth to 6 days of age, these particle aggregates were found only on dendritic processes, not on the cell body. At 8 days of age, the aggregates were found on small somatic appendages and on the cell body adjacent to somatic appendages. In animals from 10 to 12 days of age, particle aggregates became increasingly common on the cell body. Morphometric analysis demonstrated a decrease in size but not packing density of the particles in the aggregates. These changes in the location and size of the aggregates correspond to the location of asymmetrical synapses seen in thin section material at these same time intervals (Neises et al., 1982). At 14 days the fracture plane no longer followed the postsynaptic membrane at the active zone; instead it shifted to the presynaptic membrane and the postsynaptic specilizations were rarely seen. This fracture pattern is typical of adult animals.
The technique of heart plastination
Authors: Tiedemann K. , Hagens G. V.
Published: February 2005

Plastinated hearts are natural specimens, preserved in a firm of flexible state, which thus can be grasped in the hand. They are fixed in a dilated state. Their tissue water and lipids are replaced by polymerized synthetic resins or elastomers. The final specimens show doubly injected coronary vessels, opened atria and ventricles, thus exhibiting all finer external and internal details. The procedure described consists of the removal of the heart; intermediate storage facilities; dilatation with water under hydrostatic pressure; color injection of the coronary vessels; fixation; dehydration in acetone under hydrostatic pressure; forced impregnation in a vacuum chamber; and hardening with aftercare. Technical variations and pitfalls are discussed, as well as the required equipment.
Recent structure‐function relationships in normal and injured mammalian kidneys
Authors: Bulger Ruth Ellen , Dobyan Dennis C.
Published: February 2005

Recent investigations have been aimed at understanding the ultrastructural‐functional relationships within the kidney at organ, tubule, subcellular, and molecular levels. This has led to a redefinition and more precise segmentation of the renal tubule. For example, the connecting piece between distal tubule and collecting system has now been established.

The use of immunocytochemical techniques, such as fluorescence, ferritin‐ or peroxidase‐labelled immunoglobulin methods, has made it possible to identify proteins in the kidney especially in renal corpuscles. Two major noncollagenous glycoproteins, fibronectin and laminin, have now been identified in the glomerulus. The glycosaminoglycan, heparan sulfate, has been localized to the glomerular basement membrane and is thought to play an important role in charge perm‐selectivity during glomerular filtration. Subtle changes in glomerular podocyte or endothelial cell structure are postulated by some to play a role in the pathogenesis of acute renal failure. The role of the mesangial cell in glomerular function is being studied in situ in homogeneous cell populations. These cells are capable of prostaglandin production and can contract in response to hormonal stimulation.

The intimate positioning of short‐ and long‐looped nephrons in the renal medulla and the unique nature of the pelvic epithelium correlates well with the purported role of urea recycling in the urinary concentrating mechanism. Determination of elemental concentration of soluble substances in various renal cell and extracellular compartments have been made using freeze‐hydrated and freeze‐dried cryosections of kidney tissue.

The medullary and cortical ascending thick limbs of the distal tubule are morphologically and functionally distinct regions. Their response to hormonal stimulation and their enzymatic activities are quite different. Morphological studies of the collecting duct have provided new insight into the role this segment of the uriniferous tubule plays in fluid and electrolyte transport and urinary acidification.
Morphological and morphometric changes in the ovaries of white‐footed mice (Peromyscus leucopus) following exposure to long or short photoperiod
Authors: Spanel‐Borowski Katharina , Petterborg Larry J. , Reiter Russel J.
Published: February 2005

Two experiments were carried out with a total of 36 white‐footed mice (Peromyscus leucopus) exposed to either long (LP) or short (SP) photoperiod for six weeks. Ovaries and uteri were weighed. Serial sections of the ovaries were processed for light microscopy. The total number of the interstitial gland cells, preantral and antral follicles with early and advanced stages of atresia as well as corpora lutea, was determined.

Uteri from LP mice weighed significantly more than those from SP mice in both experiments. In contrast, the weight of ovaries from LP and SP animals only differed significantly in one experiment; this experiment also produced no obvious changes in the total number of corpora lutea. While interstitial gland cells of LP ovaries were hypertrophic and appeared mature, the interstitial gland cells of SP ovaries were of the degenerating cell type. The total number of follicles as well as their mean follicular diameters were higher in LP animals in comparison with SP animals. In addition, the percentage of antral follicles were increased and there were fewer signs of advanced stages of atresia in the LP group. It is suggested that the changes of the interstitial gland cell morphology combined with alterations of follicular growth during LP or SP appear to support intensified follicular growth.
Extracts of rat amniotic fluid contain a potent inducer of intestinal crypt formation
Authors: Calvert R. , Lehoux J.‐G. , Arsenault P. , Ménard D.
Published: February 2005

The effect of acid, basic, and organic extracts from Long Evans rat amniotic fluid (RAF) and from Swiss ICR mouse amniotic fluid (MAF) was studied on 15‐day fetal mouse duodenal mucosa in organ culture. Amniotic fluids (20 ml) were lyophilized and extracted (1) with CHCl3:MeOH and the organic phase was evaporated; then (2), the residue was acidified with a solution of 0.1 N HCl in 10% acetic acid and the liquid phase was lyophilized; finally (3), 0.01 M NH4OH was added to the residue and the liquid phase was lyophilized. The product of each extraction was added to 20 ml of Trowell T8 medium. Acid and basic extracts of RAF and MAF have no effect on the formation of duodenal villi and crypts after 48 hours of culture. With the organic extract of MAF, small villi are present after 48 hours of culture and absorptive cells are poorly differentiated. With the organic extract of RAF, well‐developed villi have differentiated after 48 hours of culture; moreover, crypts are present at the same stage and Paneth cells are identified within these crypts. During the 8–10 hour period, the explants cultured with the Trowell T8 medium supplemented with RAF or MAF organic extracts show a 35% increase in 3H‐thymidine incorporation over the controls cultured with Trowell T8 medium alone. These results indicate that organic extracts from MAF and RAF are able to promote villus formation in undifferentiated explants from 15‐day fetal mouse duodenum in organ culture. Furthermore, RAF organic extract contains a factor that can induce the formation of duodenal crypts and the differentiation of Paneth cells in culture at least 2 days before their normal appearance.
Uterine simple and complex nuclear bodies are separate structural entities
Authors: Padykula Helen A. , Pockwinse Shirwin M.
Published: February 2005

In rat uterine luminal epithelial cells, nuclear bodies occur in the euchromatin in varying numbers in relation to the nuclear concentration of the estrogen receptor (Clark et al., 1978; Padykula et al., 1981, 1982). This functional responsiveness indicates that nuclear bodies may be useful indicators of the degree of cellular estrogenization. Because these filamentous bodies vary in size (200–1200 nm), shape, and composition, quantitative analysis of frequency of their occurrence has been difficult. A fundamental division into 2 categories can be made by the following criteria: 1) simple nuclear bodies (200–500 nm) consisting of a protein mesh of microfilaments, and 2) complex nuclear bodies (200–1200 nm) composed of an outer filamentous protein capsule enclosing a lucent core that may contain granules. Previous quantitative analyses at the electron microscopic level has excluded “simple bodies” because they might actually be ultrathin sections through the filamentous capsule of complex bodies (Le Goascogne and Baulieu, 1977; Clark et al., 1978). To resolve this sampling problem, we have performed serial ultrathin section analysis of nuclear bodies in hyperestrogenized luminal epithelial cells. Ultrastructural evidence presented here demonstrates that simple and complex nuclear bodies are anatomically separate entities. Ultrathin sections through the capsule of complex nuclear bodies will be misidentified as profiles of simple bodies during quantitative analysis. This anatomic distinctness of simple and complex nuclear bodies correlates with their differing responses to estrogenic stimulation and withdrawal (Fitzgerald and Padykula, pp. 131–141, this volume). Thus the existence of these two major categories should be taken into consideration during quantitative analyses.
Differing functional responses of simple and complex nuclear bodies in uterine luminal epithelial cells following estrogenic stimuli
Authors: Fitzgerald Maryellen , Padykula Helen A.
Published: February 2005

A single injection of estradiol or the antiestrogen, nafoxidine, into immature female rats results in a striking divergence in the frequency of observation of nuclear bodies in uterine luminal epithelial cells (Padykula et al., 1981). During the 72 hour period after a single injection of nafoxidine (estrogen antagonist with agonist effects), progressive cellular hypertrophy occurs and is accompanied by a linear increase in the total number of nuclear body profiles (TNB). Conversely, the 72 hour period after a single injection of estradiol is marked by cellular catabolism and a linear decrease in TNB. Our recent demonstration that the population of nuclear bodies consists of two major structural types, simple nuclear bodies (SNB), and complex nuclear bodies (CNB) (Padykula and Pockwinse, pp. 119–130, this volume), permits separation and analysis of the original TNB data in terms of the functional responses of SNB or CNB.

During the 72 hour period after injection of nafoxidine, the luminal epithelial cells remain in an anabolic state because the nuclear concentration of estrogen receptor and RNA polymerase activity are elevated. Separate quantitative analysis of the complex and simple nuclear bodies demonstrates two distinct functional responses: (1) a linear increases in the frequency of CNB, and 2) a relatively constant frequency of SNB. Since the complex bodies do not increase in diameter during this period, the increase in the frequency of TNB may arise from an increase in the actual number of CNB per nucleus during cellular hypertrophy.

Conversely, a single injection of estradiol results in a relatively short elevation of nuclear estrogen receptor concentration and RNA polymerase activity which returns by 24 hour to the control level. This brief estrogenic stimulation is reflected by a linear decrease in the frequency of TNB and a linear decrease in the frequency of SNB. The frequency of CNB decreases suddenly between 4 and 12 hours and levels off thereafter. The steady decrease in the frequency of observation of nuclear bodies during catabolism may represent a decrease in the actual number of SNB and CNB per nucleus rather than a reduction in their size.

This study provides quantitative evidence that simple and complex nuclear bodies are functionally separate entities. Also, some evidence suggests that simple nuclear bodies may be the precursors of complex nuclear bodies.
Vicinal glycol‐staining identifies secondary granules in human normal and chédiak‐higashi neutrophils
Authors: Fittschen Claus , Parmley Richard T. , Austin Ronald L. , Crist William M.
Published: February 2005

Neutrophil secondary granules contain large amounts of glycoprotein. We evaluated periodate‐thiocarbohydrazide‐silver proteinate (PA‐TCH‐SP) staining of these granules after α‐amylase digestion to assess their content of vicinal glycol‐containing glycoconjugates and the usefulness of this stain as a positive stain for secondary granules. Using this method, early stages of secondary granule genesis were observed prior to completion of primary granule genesis in myelocytes. Immature secondary granules appeared round to ovoid, but irregular in outline and demonstrated strong staining of the limiting membrane and matrix material. In mature granules, matrix staining was unaltered; however, membrane staining was decreased. Some immature primary granules in promyelocytes demonstrated strong PA‐TCH‐SP reactivity which was masked in mature primary granules of band and segmented neutrophils. The Golgi apparatus showed progressively increasing PA‐TCH‐SP reactivity toward its mature surface which was often convex in promyelocytes and myelocytes and concave in segmented neutrophils. The Chédiak‐Higashi secondary granules were cytochemically and morphologically similar to those of normal individuals and were not statistically decreased in number when compared to controls. They were only rarely observed contacting or fusing with giant granules which had consumed all primary granules leaving an easily detected population of secondary granules. Thus the α‐amylase‐PA‐TCH‐SP method demonstrates a large amount of unmasked vicinal glycol‐containing glycoconjugates in neutrophil secondary granules, which allows their differentiation from primary granules.
Spermatogenesis in the vasectomized monkey: Quantitative analysis
Authors: Hadley Mark A. , Dym Martin
Published: February 2005

The seminiferous epithelium in mature vasectomized Macaca fascicularis was examined quantitatively to assess spermatogenesis. Monkeys were bilaterally vasectomized and controls were bilaterally sham operated. At postoperative periods of 10 and 18 months, groups of monkeys were castrated and their testes prepared for morphologic analysis. Diameters were measured in 100 cross sections of seminiferous tubules from each animal. Numbers of spermatogonia (Ad and Ap), preleptotene spermatocytes, pachytene spermatocytes, and step 7 spermatids, relative to Sertoli cell nucleoli, were counted in stage VII tubules. Tubule diameter and germ cell numbers per Sertoli cell nucleoli were not altered by vasectomy. Our study demonstrates quantitatively that spermatogenesis in the monkey is not inhibited up to 18 months following vasectomy.
Quantitative assessment of neural development in human premolars
Authors: Johnsen D. C. , Harshbarger J. , Rymer H. D.
Published: February 2005

The number of nerve fibers entering a tooth gives an indication of the tooth's capacity to perform a sensory function. Nerve fiber development was quantitated from cross sections of the apical portions of 49 erupted human premolars at various stages of root development and in subjects up to 71 years of age. Neural development was incomplete in immature teeth, greatly variable in young mature teeth, and complete in older teeth. Myelinated axons changed in number but not in size during tooth development. There were significantly fewer myelinated axons in teeth with open and parallel apical foramina than in older teeth. Unmyelinated axons did not change significantly in number with development but fewer large axons were found in older teeth. The number of unmyelinated axons enclosed in a single boundary lamina tended to be lower in older teeth. As a physiologic correlate, threshold responses to electrical stimulation were also determined prior to premolar removal. Threshold stimulation decreased significantly with apical foramen maturation. A significant negative correlation was found between the threshold stimulus and the number of myelinated axons in fully developed teeth, but not in immature teeth.
Properties of soleus muscle Z‐lines and induced Z‐line analogs revealed by dissection with Ca2+‐activated neutral protease
Authors: Yamaguchi Mamoru , Robson Richard M. , Stromer Marvin H. , Cholvin Neal R. , Izumimoto Masatoshi
Published: February 2005

Rat soleus muscle Z‐lines and Z‐line anomalies induced by neostigmine methyl sulfate (NMS) and cat soleus muscle Z‐line and Z‐line anomalies induced by tentomy were examined by electron microscopy before and after dissection of muscle fibers with Ca2+‐activated neutral protease (CAF) to elucidate structural properties of Z‐lines and related Z‐line‐type structures. In both normal and treated muscles, interdigitation of thin (6–7 nm) filaments, which were continuous with I‐filaments (actin) from adjacent sarcomeres, was observed at the Z‐line in longitudinal section.

Both neostigmine methyl sulfate and tenotomy treatments induced muscle atrophy associated with Z‐line degradation, streaming, and irregular distribution and accumulation of Z‐line material and Z‐rod formation. Tenotomized muscle also was characterized by the presence of N‐line‐like bands and I‐Z‐I brushes. CAF digestion removed the electron‐dense covering material from Z‐rods and revealed a backbone of actin filaments. The origin of Z‐rods, their structural similarity to Z‐lines in longitudinal and cross section, and their susceptibility to CAF indicate that Z‐rods are directly related to native Z‐lines and are probably lateral polymers of a basic Z‐line unit.

The regular square net alignment (22 nm) of I‐filaments (actin) in cross sections of I‐Z‐I brushes which contain no N‐lines suggests that the I‐square net arrangement near the Z‐line is determined by Z‐filament‐actin filament interaction rather than by the N‐line or other factors.

The results suggest that I‐filaments (actin) penetrate the mammalian Z‐line and are Z‐line constituents and that the width of Z‐lines and the length of Z‐rods are determined by the amount of overlap of actin filaments. The perpendicular periodicity of Z‐rods and the zigzag‐oblique arrowheadlike appearance seen in longitudinal section of Z‐lines are attributed to α‐actinin.
Pleiotropic effect of Tabby gene on epidermal growth factor‐containing cells of mouse submandibular gland
Authors: Blecher Stan R. , Debertin Manfred , Murphy Joanne S.
Published: February 2005

The influence of the Tabby gene on the submandibular gland of the mouse was assessed by comparing the mass of the gland, and its content of granular convoluted tubules, in prepubertal, pubertal, and adult Tabby mice and their wild type brother controls. The Tabby mice showed reduction in mass of the adult submandibular gland, delayed development of the granular convoluted tubules, and reduction in relative content of granular convoluted tubules. Epidermal growth factor (EGF) is released from the granular convoluted tubules of the mouse submandibular gland, and it is known to experimentally influence the devlopment of at least some of the structures that are affected by the Tabby gene. Accordingly, the question of a relationship between the Tabby gene and EGF is raised.
Ultrastructural observations on the shell membrane of the North American opossum (Didelphis virginiana)
Authors: Krause William J. , Cutts J. Harry
Published: February 2005

Each developing opossum embryo is surrounded by a shell membrane which completely separates embryonic and maternal tissues. During the eighth and ninth prenatal days, the embryos together with their limiting shell membranes float freely within the uterine lumen, surrounded only by the secretions of the uterus. The shell membrane is transparent, nonelastic, tough, and capable of extreme deformation. It consists of a mat of interwoven fibers which vary in external diameter, are electron dense, and show no apparent substructure. The morphology and arrangement of component fibers are similar throughout the width of the shell membrane.
Endocytosis of cationized ferritin to vesicles in the Golgi region of the glomus cells dissociated from the adult rat carotid body
Authors: Grönblad Mats , Åkerman Karl Erik , Eränkö Olavi
Published: February 2005

Glomus cells were dissociated from the carotid bodies of adult rats by enzymatic digestion with collagenase. The cells were then incubated at 37°C for 30 minutes to 3 hours in the continuous presence of cationized ferritin (CF) as a membrane marker and extracellular tracer to study the intracellular route of endocytosis in this cell type. After 30 minutes of incubation with CF, occasional solitary CF‐containing vesicles were observed at the cell periphery and also in the Golgi region. After 2–3 hours of incubation with CF, cell viability was still preserved and CF‐labeled vesicles were abundant in the Golgi region. CF particles were also seen in some vesicles having a dense core. The core of these labeled vesicles appeared to be less electron‐dense than that of typical secretory granules. It is suggested that the Golgi apparatus is involved in membrane recycling in glomus cells and that the membrane is then possibly further transported to an immature type of storage vesicle for reusage.
Tissue freeze‐drying with a closed drying tube stored in a freezer
Authors: Nelson Stanley R. , Wilkinson Harold L. , Walter Donnal C.
Published: February 2005

A simple method of freeze‐drying tissue is described that does not require a continuously running vacuum pump. After the frozen tissue is positioned a few centimeters from the dessicant in a drying tube, a vacuum pump is attached briefly to lower the pressure in the drying tube. The drying tube is closed at a pressure of 5 × 10 −3 mm Hg or less, and the tube is stored in a freezer set at the desired temperature. Frog kidneys, 300‐400 mg, were dry in about 24 hr at −32°C and 48 hr at −40°C. Since the tissue is dried in individual drying tubes, many tissue samples can be dried at one time.