bluuebunny/crossref_metadata_2025 huggingface dataset:
Studies on the thymus of the mammal. XVI. Lipopigment cells in the cortex of the thymus of the mouse
Authors: Smith Christianna
Published: February 2005

In the thymic cortex of mice, certain distinctive lipid‐rich cells, termed foamy cells, were described by Loewenthal and Smith ('52). The abundant cytoplasmic, sudanophilic inclusions of these cells were autofluorescent and PAS positive; these characteristics and others indicated the presence of chromolipoid. Cytochemical reinvestigation of these cells demonstrated acid phosphatase and esterase activities in the cytoplasm. Ultrastructural study of these cells revealed a polymorphic population of residual bodies, most likely of lysosomal origin. Further evidence suggests that a pigment is present which corresponds to an early stage in the development of lipofuscin as stated by Pearse ('60). The characteristics supporting this conclusion are: (1) natural yellow color, (2) yellow fluorescence, (3) weak basophilia, (4) moderate reducing capacity, (5) positive plasmal and PAS reactions, (6) coloring with oil soluble dyes, and (7) variably acid fast. Because of these cytochemical and ultrastructural properties, it is here proposed that these cells should now be called lipopigment cells. Differences in nuclear pattern indicate that they are both epithelial and mesenchymal in origin. Large lipopigment cells gradually develop from smaller cells and accumulate the distinctive cytoplasmic inclusions. Some of these cells are phagocytic. Evidence suggests that the lipopigment cells are long‐lived. The origin of this pigment and its significance in thymic function are unknown.
Accelerated maturation of chick embryo skin treated with a prostaglandin (PGB1): An electron microscopic study
Authors: Kischer C. Ward
Published: February 2005

One of the fatty acid derivatives called prostaglandins, PGB1, when applied to organ cultures of developing chick skin with feather organ loci, completely blocks feather organ development, but stimulates proliferation and keratinization of the epidermis. Control and PGB1 treated explants were harvested after one, two, and three days in culture and processed for study by electron microscopy.

Fine structural observation of control and treated skins indicate the following. (1) Tonofilaments appear much sooner in treated explants than in controls, and are distributed at all levels of the epidermis. (2) The cristae of mitochondria in epidermal cells of treated skins are long, closely apposed, and oriented parallel to the longest axis of the organelle as contrasted with a transverse orientation for them in control epidermis. (3) There is increased deposition of collagen in the mesenchyme of treated skins as contrasted to that observed in controls. (4) Unusual structures (inclusion bodies) occur throughout the stratified and superficial epidermis of treated skins and are composed of fine filaments and granules measuring about 30 Å in diameter. They are often associated with tonofilaments. (5) Small but numerous vacuoles appear in the epidermal cells of treated skins and seem to develop from cisternae of the Golgi apparatus or endoplasmic reticulum.

The change in orientation of cristae of the mitochondria, vacuolation of the epidermis, and appearance of the inclusion bodies first occurs after two days of treatment with PGB1 in culture. These observations coincide with previous data demonstrating that restitution of feather organ development can be accomplished after one day of treatment with PGB1, but not after two days of treatment.

The observations are consistent with an accelerated maturation process, but may be correlated with a specific and irreversible change in a metabolic event necessary for feather development.
The fine structure of the heart valves in the chicken. I. Mitral valve
Authors: Mitomo Yoshio , Nakao Komei , Angrist Alfred
Published: February 2005

The fine structure of the mitral valve in the chicken heart is described. The chicken has no distinct muscular component within the mitral valve; on the other hand, the tricuspid valve is a muscular fold.

The mitral valve is a thin, membranous, fibrous structure and is composed of three layers: (a) an auricular and ventricular endothelial layer, (b) a zona spongiosa, and (c) a zona fibrosa. The endothelium of the heart valve resembles closely that of vascular channels, but the shape and size of the valvular endothelial cells vary considerably from those of other vascular channels. From the valvular endothelial cells thin villus‐like projections extend into the cardiac lumen. Their cellular junctions frequently have a complicated pattern in the form of interdigitating folds, although some show a long linerar zone of simple overlapping between adjoining cells. A fine filamentous plexus is a feature of the cytoplasm but is less evident than in other vascular channels. The basement membrane varies with its location in the valve; it is distinct on the atrial side but is often scanty and obscure on the ventricular surface. Some elastic tissue is found in the subendothelial tissue.

The zona spongiosa and zona fibrosa are quite similar to those of other species, but the amorphous ground substance in the zona spongiosa is more abundant. Both layes contain elastic fibers and collagen in both fibrils and bundles. Their amount, composition and configuration vary in different locations within the valve.

Avian valvular endothelium is compared with that of lining vascular channels and valves of other species. There are structural differences, some of which may reflect physical conditions and function, such as mobility, extensibility and state of contraction.
Ultrastructural studies on fetal and early postnatal mouse ovaries. II. Cytodifferentiation
Authors: Od́or D. Louise , Blandau Richard J.
Published: February 2005

The ultrastructural details of mouse oögonia, oöcytes and follicular cells from fetal day 12 through postnatal day 3 are presented.

In fetal oögonia and oöcytes cytodifferentiation proceeds slowly. The most notable change involves an increase in the number of mitochondria and in the size of the Golgi complex. Oögonial itoses, nuclear synaptinemal complexes, true intercellular bridges and multinucleated cells were observed.

After the formation of unilaminar follicles with growing oöcytes, cytoplasmic alterations are striking. The Golgi apparatus, previously predominately of vesicular elements, now becomes lamellar in form and occasionally develops complex anastomosing tubules. There may be important functional significance in the relationship established between the Golgi elements and long endoplasmic reticulum cisternae. The membranes of the endoplasmic reticulum cisternae facing the Golgi complex lack ribosomes and exhibit bud‐like evaginations in varying stages of abstriction. Ribosomes are attached to the opposite membrane of the cisternae. Profiles of endoplasmic reticulum are intimately associated with the numerous large mitochondria. Numerous multivesicular and “dense” bodies are present in some oöcytes. Zona pellucida formation is initiated in some of the larger unilaminar follicles.

Cytodiferentiation of follicular cells follows a course different from that of the germinal cells in that their cytoplasmic organelles are well differentiated very early in the fetal period. Similarly they send forth the most delicate cytoplasmic extensions which separate adjacent germinal cells. Postnatally, in unilaminar follicles these same cells constitute a flattened epithelial layer containing only a few cytoplasmic organelles. In contrast when these cells become cuboidal and columnar the numerous organelles, as seen in fetal follicle cells, reappear once again. In addition, when the zona pellucida is formed cell processes from these follicle cells extend into it.
Wallerian degeneration in the optic nerve of a reptile: An electron microscopic study
Authors: Kruger Lawrence , Maxwell David S.
Published: February 2005

Numerous optic nerve fibers persist for a period of up to 20 months following enucleation in reptiles, although it is unlikely that a significant number of efferent fibers are present. After varying survival periods, almost all nerve fibers display distinct morphological changes probably associated with degeneration, but most features previously associated with early stages of degeneration can be seen in long‐survival material except for the early and rapid loss of all non‐myelinated fibers and a honeycomb tubular degeneration associated with the inner and outer myelin layers. Distinct sequential stages of axon and myelin degeneration could not be ascertained despite the slow rate of degeneration in poikilotherms. The varieties of abnormal axon morphology are documented and considered in terms of current light microscopic staining methods.
The villous period of placentogenesis in the baboon (Papio sp.)
Authors: Houston Marshall L.
Published: February 2005

Baboon placentae were studied which ranged in age from 13 to 40 days. Implantation in the baboon is superficial and a single, discoid, villous hemochorial placenta is formed. No chorionic villi develop peripheral to the placenta and there is no decidua capsularis. Trophoblastic tissue within the placenta is of two types, cyto‐ and syncytiotrophoblast. The chorionic villi are short and straight at 13 days but have begun to branch by 16 days. The villi consist of a mesenchymal core surrounded by a single layer of cytotrophoblast which is in turn surrounded by a layer of syncytiotrophoblast. Cytotrophoblastic cells from the distal tips of the villi spread over the maternal surface of the placenta and form a complete cytotrophoblastic shell against the uterine stroma. Maternal blood enters and leaves the intervillous space through clefts in the cytotrophoblastic shell which connect with arteries and expanded venules within the endometrium. A limited decidualization of the uterine stroma takes place.
Morphogenesis of the fetal membranes of the white‐tailed deer
Authors: Sinha Akhouri A. , Seal Ulysses S. , Erickson Albert W. , Mossman Harland W.
Published: February 2005

Morphogenesis of the fetal membranes of the white‐tailed deer was studied throughout pregnancy. In placentomes, the long, branched, fetal villi occupied corresponding maternal crypts. The bases of the villi and the arching areas connecting them (arcades) were covered with high columnar cytotrophoblast, which apparently had phagocytosed material from the adjacent degenerating rims of the crypts. This arcade cytotrophoblast contained much glycogen and occasional mitochondria, free ribosomes, and pigment granules. Elsewhere, the columnar cytotrophoblast cells usually contained three to five rows of rod‐shaped mitochondria and other cytoplasmic organelles. Interspersed among them were numerous binucleate giant cells which usually contained peripheral lace‐like granular endoplasmic reticulum and many complex lipoprotein droplets. Cryptal epithelium, deep to the degenerate rims, was low columnar, had infranuclear osmiophilic lipid droplets, and sparsely distributed cytoplasmic organelles. The microvilli of cryptal and cytotrophoblastic epithelia interdigitated and appeared as a brush border under light microscopy. The microvilli and their PAS‐positive mucopolysaccharide material appeared capable of holding uterine and chorionic epithelia together during pregnancy. The placentomes were epitheliochorial, but showed “intra‐epithelial” capillaries. Interplacenomal uterine and cytotrophoblasitc epithelia resembled those of the placentomes. Their microvill were inundated by endometrial gland secretion (uterine milk). The cytotrophoblast contained pigment granules and much absorbed uterine milk. The amniotic epithelium showed short microvilli, complexly folded lateral plasma membranes, many desmosomes, abundant glycogen granules, foot processes and other cytoplasmic organelles.
Studies of Brunner's glands in the opossum. I. Adult morphology
Authors: Krause William J , Leeson C. Roland
Published: February 2005

The duodenal glands of the adult opossum form a lobed, glandular collar in the submucosa immediately distal to the pyloric sphincter. They empty into funnel‐shaped mucosal depressions. The depressions, which form two or three irregular rows that run parallel to the pyloroduodenal junction, are lined by either pyloric or intestinal epithelium. An individual gland of Brunner has an extensive intralobular duct system which terminates in a single excretory duct just prior to entry into a depression. Histochemical studies indicate that the duodenal glands elaborate a neutral glycoprotein whereas the duct system appears to produce both neutral and acidic elements. Light and electron microscopic studies have shown the duodenal glands to consist of large, pyramidal cells which lie on a distinct basal lamina. Discrete, mottled or pale secretory granules are found in close association both with the apices of the cells and with the Golgi complexes. The ergastoplasm, cisternae of which are dilated and contain amorphous material, is associated with polysomes and, in the supranuclear region, often becomes markedly dilated, forming what appear to be large vacuoles containing fibrillar material. Blebbing of the ergastoplasm results in the formation of several small vesicles, many of which lie in close association with the Golgi network. Direct membrane continuity has been noted between the two elements.
Effects of teratogenic doses of vincristine on mitotic cells in the fetuses of DBA mice
Authors: Ungthavorn S. , Joneja M.
Published: February 2005

The main aim of this study was to determine the effects of vincristine on the dividing cells in mouse fetuses. Teratogenic doses of vincristine sulfate (Oncovin) were given intraperitoneally to pregnant DBA/2J mice on day 9 of pregnancy. Treated mothers were killed and the fetuses recovered at eight different time intervals ranging from one‐half hour to 96 hours after injection. Estimates of mitotic arrests, mitotic irregularities and mitotic index were obtained from Feulgen‐stained paraffin sections of the fetuses. A sevenfold increase in the number of metaphase plates was observed at two hours after vincristine treatment. The incidence of anaphase‐telophase aberrations, such as chromosome bridges and fragments, was slightly higher in the treated fetuses than that in the controls. This study showed that vincristine crossed the placental barrier to produce cellular changes which might play an important role in initiating growth defects.
The ultrastructure of stellate cells in the pars distalis of the salamander pituitary gland
Authors: Cardell Robert R.
Published: February 2005

The ultrastructure of a distinct cell type, termed the stellate cell, in the pars distalis of the salamander (Triturus [Notophthalus, Diemyctylus] viridescens viridescens) pituitary gland is described. The cell has three primary characteristics which distinguish it from other cell types of the pars distalis: (1) a lack or sparsity of specific secretory granules, (2) several cellular processes which are long and sheet‐like and (3) cell body and nucleus which are considerably smaller than the cell bodies and nuclei of the chromophilic cells. The stellate cell often has an angular shaped nucleus, and the cytoplasm is characterized by an abundance of glycogen particles, several lipid droplets, an inconspicuous Golgi complex showing no evidence of forming secretory granules, filaments, microtubules and a sparsity of rough endoplasmic reticulum. The cells occasionally contain unusual mitochondria which exhibit longitudinally oriented cristae.

From the electron micrographic evidence obtained in this study, it was suggested that stellate cells probably contact all secretory cells in the pars distalis; thus they are favorably situated to play a sustentacular role in the piuitary gland. In addition, the processes of the stellate cell frequently terminate on the outer basal lamina of the pericapillary space. Consideration was given also to a possible secretory role for the stellate cells, but little morphological evidence was obtained to suggest such a function. It was noted, however, that the cells occasionally contain dense bodies about 250 mμ in diameter which were interpreted as possible secretory granules.
Distribution of lymphatic vessels in mammary glands of ewes
Authors: Lee C. S. , Lascelles A. K.
Published: February 2005

Six multiparous ewes, three of which were lactating and the remaining three in an advanced stage of mammary involution, were used to study the distribution of lymphatic vessels in the mammary gland. The lymphatic system was distended by ligation of the regional efferent lymphatic ducts and either reconstituted blood or Latex was used to fill the blood vascular system. After fixation, distribution of lymphatic vessels was studied macroscopically and microscopically.

One to three mammary nodes were situated at the postero‐dorsal aspect of each gland. Entering and leaving the nodes were 8 to 12 major afferent and 2 to 4 efferent ducts. Four or five of the afferent ducts accompanied the external pudendal artery and vein and their radicles emerged from the deep parenchyma of the gland. The remaining afferent ducts emerged from the parenchyma of the gland independent of blood vessels and their radicles drained both superficial and deep parenchyma.

Lymphatic vessels were found in the connective tissue between lobes, within lobes and between lobules. Lymphatic capillaries were observed in the connective tissue within lobules and also in areas adjacent to the alveolar epithelium. Lymphatic vessels in the connective tissue between lobes and the larger vessels were supplied with valves and their walls posessed an endothelial cell lining together with smooth muscle and connective tissue layers. Finer lymphatic vessels appeared to consist of only a simple endothelial cell lining and valves were not found.
A comparative study of cranial growth in Homo and Macaca
Authors: Duterloo Herman S. , Enlow Donald H.
Published: February 2005

This study deals with the postnatal growth and remodeling changes that take place in the cranial bone of Macaca mulatta. Multiple ground sections were prepared throughout each component bone from the calvaria and cranial floor of young, rapidly growing specimens having primary or mixed dentition. These sections were then analyzed for (1) the different types of inward‐growing and outward‐growing bone tissues present, and (2) the distribution of resorptive and depository periosteal and endosteal surfaces. Using this information, the remodeling history of each bone was reconstructed and the overall growth pattern of the craninum as a whole was determined. The growth changes that characterize the brain case of the monkey were then compared and contrasted with those in Homo. While a number of distinct similarities were observed in their respective growth and remodeling processes, several marked differences were also found. These occurred largely in certain parts of the cranial floor and they appeared to be associated with corresponding differences in the size, configuration, and disposition of the brain in the two species and also with factors related to body posture and facial prognathism.
Interstitial bodies in the early chick embryo
Authors: Low Frank N.
Published: February 2005

Chick embryos of graded ages, ranging from freshly laid eggs to one week incubation, were prepared for electron microscopy.

Interstitial bodies are expressions of “ground substance” that resemble structureless masses of cytoplasm without enclosing plasmalemma. They measure from 0.1 to ca. 1 μ in diameter. Toward the end of the first day of incubation they are found in the tissue space near to or in contact with the ectodermal boundary (basement) membrane. They seem to contribute to its increasing amorphous component. Microfibrils first appear close to or in contact with the ectodermal boundary membrane and are similarly related to interstitial bodies. At 44 hours interstitial bodies are especially numerous where the neural tube is separating from the ectoderm. Here boundary membranes have become intermittent and interstitial bodies appear to contribute to their repair. By the fourth day interstitial bodies are less numerous. Many appear to break up. Their edges tend to become dispersed into clouds of finely granular material, especially in areas of the tissue space occupied by wisps of microfibrils. The close association of amorphous ground substance and extracellular fibrils persists indefinitely.
Striated muscle in the lung
Authors: Aterman K. , Patel S.
Published: February 2005

The occurrence of striated muscle in an “extralobar pulmonary sequestration,” a typical “accessory lobe,” has been described for the first time in an infant with the respiratory distress syndrome of the newborn. The few published cases of the presence of striated muscle in the lungs have been reviewed. In most instances they were associated with benign or malignant tumor formation. The simultaneous occurrence of a pulmonary sequestration and striated muscle is explained by postulating the displacement of a fragment from the lung bud early in its development. This view eliminates the necessity of invoking an additional pathological happening in the sequestrated lung in the form of a “metaplastic transformation” of either smooth muscle or embryonic connective tissue into striated muscle. While a heteroplastic transformation may occur in instances of malignant tumor formation, striated muscle in the developmental anomaly described here may well form on an entirely different basis.
Lipofuscin pigment in neurons of young mice with a hereditary central nervous system defect
Authors: O'steen W. Keith , Nandy Kalidas
Published: February 2005

Mutant mice are described which have an early developing locomotor difficulty accompanied by definite neuronal changes in the central nervous system. They develop head tremors during the second postnatal week and later action tremors while walking. Seizures occur spontaneously and can be induced by stimulation. By the third or fourth week, they lose the righting reflex. The most apparent neuropathologic sign is the progressive development of nuclear hyperchromasia, especially in the largest neurons of the spinal cord and brain stem. Purkinje cells of the cerebellum are similarly affected. Hyperchromasia occurs in single, isolated neurons scattered throughout the central nervous system, as well as in groups of cells which comprise a brain stem nucelus. Lipofuscin pigment in quantities comparable to that in neurons of 12 months old mice was found in neurons with hyperchromatic nuclei as early as five weeks of age, an observation which suggests that premature aging might be occurring in the mutant's central nervous system.
Electron microscopic observations on fibrinoid and histiotroph in the junctional zone and villi of the human placenta
Authors: Dempsey Edward W. , Lessey Robert A. , Luse Sarah A.
Published: February 2005

The surfacr of syncytiotrophoblast covering primary villi in the early human placenta may be smooth, lacy, exhibit a brush border with highly developed straight or branched microvilli, or display projections. These projections may have microvilli and they may contain granules, vacuoles and mitochondria. By contrast, syncytium of the basal or junctional zone has longer and straighter microvilli and numerous projections often extend as long, recurving streamers which penetrate into and engulf the cytolyzed detritus of decidual cells. These streamers contain granules, vacuoles and microvilli. Granular detritus is evident between the microvilli, adherent to their surfaces and in the bays and superficial vacuoles at or just beneath the surface plasma membrane, indicating that phagocytosis and pinocytosis occur in the basal trophoblast.

In occasional areas in the intervillous space and regularly in the basal junctional zone, clots composed of fibrin fibrils occur. Associated with them are amorphous masses of similar electron density. These represent different degrees of maternal blood clotting, possibly associated with clotting agents released after damage to fetal cells.

Fibrin clots and associated leucocytes adhere to the surface of the syncytium, penetrate into it and between the Langhans' cells, occasionally replacing the trophoblastic layers entirely. In such areas, transudates of maternal blood have direct access to the connective tissues of the fetal villus.
Membrane‐coating granules and membrane modifications in keratinizing epithelia
Authors: Martinez I. Ricardo , Peters Alan
Published: February 2005

Membrane‐coating granules are found in close association with the Golgi apparatus, and their apparent size, shape and internal substructure varies with the plane of section.

After a membrane‐coating granule is discharged into the intercellular space, it dissociates into distinct units, the pentalamellar discs, which are stacked like coins in the intact granule. Subsequently, discs become applied to and appear to fuse with the outer leaflets of the horny cell membranes, resulting in the formation of a nine‐layered membrane‐disc complex. When this complex cleaves at the junction of the thick dense lamella and distal lighter lamella of the disc, a pentalaminar horny‐cell surface membrane results. The more common surface membrane, however, is trilaminar consisting of thickened inner leaflet, lighter middle leaflet, and thickened outer leaflet. The thickened outer leaflet may result from the addition of amorphous intercellular material derived from membrane‐coating granules or from the fusion of two outer leaflets, as in the formation of a tight junction.

The thickened inner leaflet results from the deposition of dense material onto the cytoplasmic face of the inner leaflet; there exists a regional variation in its dimensions. The side of the cell facing the surface of the epithelium has a thickened inner leaflet varying in width between 140 and 180 Å, whereas the side facing the underlying cell is only about 100 Å thick.

Discs and amorphous material derived from membrane‐coating granules coat and thicken the plasma membrane by modifying the outer leaflet, and thus may play a role in the barrier function of the stratum corneum.
Early cellular disruption and phagocytosis in photically‐induced retinal degeneration
Authors: O'Steen W. Keith , Lytle Robert B.
Published: February 2005

Albino rats kept at normal body and room temperature develop a progressive retinal degeneration when exposed to ordinary animal room intensities of fluorescent light. Early changes at the light microscope level include stratification of the inner and outer segments of the receptor cells, followed by rapid fragmentation of these elements. Concurrently, cells not usually seen in control retinas invade the outer plexiform and receptor cell layers. These cells, which are first seen after 60 hours of light exposure, resemble microglia and are apparently phagocytic in function, since cytoplasmic inclusions can be detected. Attempts to mark these cells with intraocular India ink or with intraperitoneal trypan blue were unsuccessful. Removal of cellular debris after degeneration of the receptor cells was followed by gliosis in the area of the retina between the bipolar nuclei and the remnants of the pigment cell layer. The extensive retinal damage occurring after fragmentation and removal of the outer segments was irreversible when animals were removed from continuous light and placed into cyclic lighting.
Changes in the Golgi apparatus during spermiogenesis in the rat
Authors: Susi F. R. , Leblond C. P. , Clermont Y.
Published: February 2005

The fine structure of the Golgi apparatus in rat spermatids at various steps of spermiogenesis was investigated in routinely stained preparations as well as in sections stained with the periodic acid‐silver technique for the demonstration of glycoprotein.

In steps 1–7 spermatids, a layer of cisternae of endoplasmic reticulum envelops the Golgi apparatus. Between this layer and the stack of Golgi saccules, small coated vesicles (500–600 Å) are associated with smooth‐surfaced tubular profiles. These are irregular expansions of the first or outermost Golgi saccule. The next few saccules of the stack are regularly arranged and similar to one another. The last or innermost saccule is thick and produces coated buds, similar to the large coated vesicles (900–1200 Å) which are found nearby. Large smooth vesicles with a dense core, known as proacrosomic vesicles, are also found in this location at steps 1 and 2. These at step 3 fuse into the single acrosomic vesicle, which in turn at step 5 transforms into the head cap (while the dense core of the vesicles becomes the acrosomic granule).

Using the PA‐silver technique on steps 1–7 spermatids, a gradation of staining is observed in Golgi saccules, with the most intense reaction in the innermost saccule, its coated buds and the large coated vesicles nearby. Intense staining is also noted in the head cap, while staining of lesser intensity is observed in the acrosomic granule.

In older spermatids (steps 8–18) the Golgi apparatus gradually loses most of the features just described and appears to consist primarily of stacks of saccules with dilated edges. These are only weakly stained by the PA‐silver technique.

These observations are interpreted as follows. Material produced in the endo‐plasmic reticulum would be transferred by small coated vesicles to the outermost saccule of the Golgi stacks. During saccule migration toward the inner aspect of the stacks, the synthesis of glycoprotein would be completed. The transfer of this glycoprotein via the large coated vesicles would cause the proacrosomic vesicles to grow into the acrosomic vesicle which later would become the head cap.
The auriculotemporal nerve of man
Authors: Baumel Julian J. , Vanderheiden John P. , McElenney James E.
Published: February 2005

The auriculotemporal nerve is commonly misrepresented in both illustrations and textual descriptions. Our 85 dissections of the nerve demonstrate that the roots of the “typical” auriculotemporal nerve do not form a tight “buttonhole” loop around the middle meningeal artery. Instead the roots outline an elongated V‐shaped interval with the roots widely separated from one another. At their junction the roots form a short trunk which immediately breaks up in line with the posterior border of the mandible into a spray of branches. The superficial temporal ramus of the auriculotemporal nerve should not be considered as the main continuation of the nerve, but merely as its largest branch. A substantial portion of the nerve makes up its two communicating rami with the facial nerve; these are the strongest and most consistent of the many peripheral communications between trigeminal and facial nerves. Common variations in configuration, branching, and relationships of the nerve are included.
Split hand and foot anomaly in Macaca mulatta: A report of two cases,
Authors: Morris Laura Newell , Kerr Barbara A.
Published: February 2005

Two cases of split hand and foot anomaly in male Macaca mulatta are described. Radiographs and dissection of the muscular anatomy of the first case showed that the muscular changes could be directly related to the osseous deformities. Comparison of the anatomy of case 1 with that of two other nonhuman primate cases on record suggests that two different developmental patterns and possibly two different genotypes may underlie the anatomical differences observed. The second case of the anomaly has been sent to the University of Washington Medical Lake Breeding Facility where it is hoped future pedigree data may provide information on some of the embryological and genetic questions raised by the existing materials.
The thyrotropic cell of the rat hypophysis as studied with peroxidase‐labeled antibody
Authors: Baker Burton L. , Yu Ya‐Yen
Published: February 2005

Utilizing the peroxidase‐labeled antibody procedure with anti‐serum to human thyrotropin (anti‐TSH), the thyrotropic cell was studied in the rat hypophysis with respect to its cytology, distribution, and reactivity to histochemical stains. The presumptive thyrotropic cells were polygonal and stained with aldehyde fuchsin and the periodic acid‐Schiff procedure. They were usually located centrally in cell cords. In the pars distalis thyrotropic cells were most numerous in the centromedian area of the lateral lobes and beneath the pars intermedia, while being rare in the dorsocephalic region.

Several steps were taken to verify the specificity of the immunochemical procedure. After absorption with either human or bovine thyrotropin, anti‐TSH was completely ineffective; staining was almost completely prevented by prior absorption with either sheep or rat thyrotropin. Cytological alterations in thyrotropic cells generally paralleled the differences in pituitary thyrotropic content associated with sex, thyroid deficiency, thyroxine administration, and with rebound after cessation of treatment with propylthiouracil. Thyrotropic cells were differentiated from growth hormone, prolactin and corticotropic cells, as well as from presumptive luteinizing hormone cells, on the basis of shape, cytology, intraglandular distribution, and by immunochemical double‐staining. In this study they were not distinguished from follicle‐stimulating hormone cells which remain unidentified in this laboratory.

Our observations confirm those of earlier investigators, who used histochemical methods for identification of the thyrotropic cell, with regard to its cytological features, intraglandular distribution and responsivity to altered levels of circulating thyroid hormone.
The fine structure of the monkey submandibular gland with a special reference to intra‐acinar nerve endings
Authors: Kagayama Manabu
Published: February 2005

The secretory terminations of monkey submandibular gland were studied by electron microscopy. The acini are composed of two types of secretory cells which are presumably serous and mucous in type. Myoepithelial cells are present also in the acini. The peri‐acinar connective tissue contains many unmyelinated nerve fibers. In some portions, the axons contain many synaptic vesicles of various types. These nerve endings partially lose their Schwann cell investment and reach the acinar basement membrane. In peri‐acinar connective tissue two types of nerve endings may be recognized. They are thought to be adrenergic and cholinergic in type. On the other hand, only one type of nerve ending (cholinergic) is observed within the acini. The intra‐acinar nerve endings are not surrounded by Schwann cell cytoplasm and make direct contact with plasma membranes of the myoepithelial and mucous cells, with a space about 200 Å wide intervening between the nerve and terminal cell. No nerve endings occur in the interspaces between the serous cells. Also, the ultrastructure of the secretory and myoepithelial cells is described.
Secretory processes in follicular cells of the bat thyroid. II. The occurrence of organelle‐associated intercellular junctions during late hibernation
Authors: Nunez Eladio A.
Published: February 2005

The fine structure of bat thyroid follicular cells was examined throughout the late hibernation period (January 17 to April 1), when thyroid gland function undergoes marked increase. The follicular cells during this period are squamous and possess few microvilli, an inconspicuous Golgi complex, scanty rough‐surfaced endoplasmic reticulum and a small number of mitochondria. The cells also exhibit conspicuous membrane‐limited dense bodies and atypical intercellular contacts. The atypical junctional complexes are characterized by a localized dense thickening of the apposed lateral plasma membranes which run parallel to each other for approximately 1 μ. The two dense membranes are separated by an intercellular space 75 Å wide and there is close apposition of rough‐surfaced endoplasmic reticulum and mitochondria. The occurrence of these unusual junctional complexes during late hibernation is discussed in relation to the known increase in thyroid function which occurs at this time.
Regeneration of rabbit olfactory epithelium
Authors: Mulvaney Bruce D. , Heist Herbert E.
Published: February 2005

Epithelial regeneration was determined with light and electron microscopy after preferential chemical destruction of olfactory epithelium in rabbits. Regeneration of either olfactory epithelium, ciliated columnar epithelium or a mixture of the two occurred. Previously observed interspecies variation in olfactory regenerative capability is therefore also an intraspecies variable. The ducts or glands of Bowman appeared to furnish the cells for either type of epithelial regeneration. Well differentiated olfactory cells re‐appeared as early as eight days after destruction with olfactory regeneration being essentially completed 30 days after destruction.
Influence of bile and pancreatic secretions on the size of the intestinal villi in the rat
Authors: Altmann Gabriel G.
Published: February 2005

Along the rat small intestine, the size of the villi gradually decreases from a maximum in the duodenum to less than half of this size in the terminal ileum. In previous work, various villus enlarging and reducing factors present in the intestinal chyme were found to control villus size. A villus enlarging factor which appeared to reach the intestine through the duodenal papilla was presently investigated.

Transplants of duodenal papilla, together with a small segment of the duodenum, were made to isolated ileal segments and to the lower ileum. At both sites, the transplants elicited a marked villus enlargement within a month. A previous finding was that villus size decreased in isolated duodenal segments unless the duodenal papilla was present.

In the next experiments, the bile‐drainage was diverted from the duodenal papilla by implanting the bile duct into an isolated ileal segment which in turn was joined to the colon. The duodenal papilla which now transmitted only pancreatic secretions was then transplanted to the ileum. The bile caused only moderate villus enlargement in the ileal segments whereas marked villus enlargement took place in the ileum receiving the pancreatic secretions.

It was concluded that a villus enlarging influence reached the intestine through the duodenal papilla. The pancreatic secretions appeared to play a major role in this influence.
A morphological study of the development of the human liver. II. Establishment of liver parenchyma, extrahepatic ducts and associated venous channels
Authors: Severn Charles B.
Published: February 2005

The establishment of liver parenchyma, extrahepatic ducts and associated venous channels were examined in serial sections of 100 human embryos representative of Horizons XI through XVII.

The liver parenchyma first begins to develop from the cephalic end of the hepatic diverticulum in embryos between the 20‐ and 25‐somite stage. The parenchyma develops as cords from the walls of the diverticulum which anastomose around isolated endothelium‐lined spaces (blood islands) in the septum transversum. As growth and anastomoses of the parenchymal cords continue, the isolated endothelium‐lined spaces form an interconnecting capillary bed which interdigitates with the developing parenchymal cords. The larger omphalomesenteric veins develop simultaneously with the parenchyma and are continuous with the smaller venous channels which interdigitate with the parenchymal cords. These larger developing veins become surrounded by the developing parenchymal cords. As the parenchymal cords branch from the cephalic end of the diverticulum, that portion of the diverticulum becomes reduced to a small tubular structure, the common hepatic duct, which is always continuous with the parenchyma. As the cephalic portion of the original diverticulum is reduced in size, there is a localized outgrowth from the ventral wall of the caudal end of the original diverticulum. This localized outgrowth becomes the cystic duct and gallbladder. The remainder of the caudal segment of the diverticulum elongates to become the common bile duct. The ventral pancreas develops as a localized outgrowth from the dorsal wall of the common bile duct.
Electron microscopic observations on the contribution of the ultimobranchial bodies to thyroid histogenesis in the rat
Authors: Calvert R.
Published: February 2005

The fine structure of ultimobranchial bodies in the rat has been studied from the fifteenth to the twentieth day of gestation. At 15 days, the ultimobranchial bodies were still separated from the median thyroid primordium by connective tissue. Their lumina were filled with cellular debris and their thick walls were made up of one type of cell in which rough‐surfaced endoplasmic reticulum was scanty. Early in the sixteenth day, cell cords from the median thyroid primordium came in direct contact with the ultimobranchial bodies; no basal lamina separated them. At 17 days the walls of the ultimobranchial bodies were composed of C cells, glycogen‐rich cells and cells that were poor in rough‐surfaced membranes and glycogen. At 18 days three types of cells were present in cell cords in direct contact with the ultimobranchial bodies: C cells, glycogen‐rich cells and follicular cells. The first two cell types had migrated from the ultimobranchial bodies while the follicular cells had originated from the median primordium. In the same cell cords, follicular cells containing glycogen granules were interpreted as being an intermediate stage between glycogen‐rich cells and true follicular cells. In follicular cells of the isthmus region, which presumably originate from the median primordium alone, glycogen granules were not observed after the fifteenth day of development. It is concluded that C cells and few follicular cells are of ultimobranchial origin.
A fine structural study of the highly active thyroid follicular cell of the African basenji dog
Authors: Nunez Eladio A. , Belshaw Bruce B. , Gershon Michael D.
Published: February 2005

The highly active thyroid gland of the basenji dog has been studied. The follicular cell of the basenji thyroid is unusual in that colloid droplets may be found in the apical cytoplasm of normal cells. Their appearance does not require administration of exogenous thyrotrophin. The colloid droplets appear to have been taken in by invagination of the apical plasma membrane forming a small bay at the cell‐colloid interface. Apparent fusion of adjacent plasma membranes subsequently eliminates the mouth of the bay, completing endocytosis of the droplet. Basenji follicular cells are also distinguished by a dense accumulation of two varieties of lysosomes, basal associations of lip d droplets and mitochondria with unusual cristae and specialized junctions between cells of adjacent follicles. It is suggested that these unique structural modifications reflect adaptations for the perpetually active state of the basenji thyroid.
Regional differences in postweaning growth by choroid plexuses as affected by dietary salt deficiencies
Authors: Quay W. B.
Published: February 2005

A diet low in K and Na given to postweaning rats of the Berkeley S1 strain led in two experiments to a greater than normal relative weight of the choroid plexus of ventricle IV (= C.P. IV) to weight of the whole brain in both sexes. This effect did not occur in the choroid plexuses of ventricles I + II (= C.P. I + II) and III (= C.P. III), which were lower than normal in absolute weights and unchanged in ratios with whole brain weights after the low K and Na diet. Quantitative microscopic tissue analyses of the choroid plexuses following one of the experiments failed to demonstrate significant differences in relative tissue composition or cellular structure after this diet. Other evidence, and data on normal postnatal growth of choroid plexuses, suggests that the unequal apparent responses of the different choroid plexus regions to the diet are related to differences in their durations and rates of growth after weaning rather than to a necessarily specific cellular response in the choroid plexus of ventricle IV to internal consequences of dietary restriction in K and Na.
Comparative studies on the proteolysis of fixed gelatin membranes by mammalian sperm acrosomes
Authors: Gaddum‐Rosse P. , Blandau R. J.
Published: February 2005

The acrosomes of mammalian spermatozoa contain a proteolytic enzyme which may be of importance for fertilization. The release and activity of the enzyme can be visualized directly when the spermatozoa are applied to fixed gelatin membranes. The purpose of this study was to determine the pattern of enzyme release from the spermatozoa of a variety of mammalian species. Thin, transparent membranes of pure gelatin were prepared on microscope slides and fixed in glutaraldehyde. Spermatozoa were applied to the membranes and their proteolytic behavior observed under dark‐medium phase objectives at 37°C. In all the species examined (rabbit, bull, hamster, rat, guinea pig and man) extensive depolymerization of the gelatin substrate occurred around the sperm heads. With the exception of human spermatozoa, the onset of proteolysis was clearly identified with the posterior half of the acrosome. In the case of human spermatozoa, no such distinction could be made. It is suggested that the proteolytic enzyme of most mammalian spermatozoa is located in the posterior segment of the acrosome.
Oxyhemoglobin affinity in the armadillo
Authors: Dementi Patricia L. , Burke Jack D.
Published: February 2005

Oxygen‐hemoglobin affinity curves determined spectrophotometrically at 26± 1° C on phosphate‐buffered hemoglobin solutions of 9 armadillos yielded a mean P50 value of 10.1 mm Hg at pH 7.4 and 18.4 mm Hg at pH 6.8. For the 18 curves determined simultaneously at both pH's the mean calculated magnitude of the Bohr effect was ϕ = − 0.43. These values indicate a moderately low P50 (high oxyhemoglobin affinity) and small Bohr effect, consistent with the low metabolic rate of Dasypus novemcinctus. Indicative of increased tolerance to blood acid by‐products, a small value would be advantageous to the armadillo in its adaptation to intensive anerobic energy production. A major and a more slowly moving minor hemoglobin fraction was confirmed by vertical starch‐gel electrophoresis using borate buffer at pH 8.7 and benzidine staining. Transmission curves on oxyhemoglobin had an α peak at 578 mμ and a β peak at 543 mμ.
Effects of halothane on the ultrastructure of rat liver cells
Authors: Ross William T. , Cardell Robert R.
Published: February 2005

The objective was to study the effects of halothane, a volatile anesthetic, on hepatic metabolism of a second volatile anesthetic, methoxyflurane, and to correlate these biochemical findings with hepatic morphological changes. Microsomal fractions isolated from rats treated with halothane and from control animals were assayed for their capacity to dechlorinate methoxyflurane. Microsomes from halothane‐treated rats demonstrated about 2.6 times the capacity to dechlorinate methoxyflurane as microsomes from control animals. Electron microscopy showed that liver cells from halothane‐treated animals, when compared with hepatocytes from control rats, had increased amounts of smooth endoplasmic reticulum, an increased number of lipid droplets, and more microbodies per cell. Rough endoplasmic reticulum and glycogen were decreased by halothane treatment. We interpret these results to mean that halothane induces the rough endoplasmic reticulum to synthesize enzymes required for the biotransformation of methoxyflurane. It is suggested that these enzymes are placed in membranes of the rough endoplasmic reticulum. This organelle is converted to smooth endoplasmic reticulum and here the biotransforming enzymes function to dechlorinate methoxyflurane.