bluuebunny/crossref_metadata_2025 huggingface dataset:
Survival of neurons in homografts of ganglia in adult rats neonatally treated with bone marrow or lymph node cells
Authors: Zalewski Andrew A. , Silvers Willys K.
Published: February 2005

Because of a major (Ag‐B) histoincompatibility, organs transplanted from Lewis (LE) to Brown Norway (BN) rats are acutely rejected. This immunological rejection can be prevented by inoculating BN rats at birth with (BN × LE)F‐1 hybrid cells. However, the source of these cells is important since only those derived from the bone marrow are effective in inducing tolerance of LE skin grafts whereas both marrow derived cells as well as those originating from the lymph nodes can induce tolerance of LE hearts. The present study was undertaken to compare the efficacy of cells derived from the bone marrow and the lymph nodes of (BN × LE)F‐1 rats to induce unresponsiveness to LE neurons in BN recipients. In untreated rats, all neurons in sensory (vagal nodose) and sympathetic (superior cervical) ganglia transplanted from LE rats to the anterior chamber of the eye or implanted into the sternomastoid muscle of BN recipients were rejected within 35 days. However, when neonatal BN rats were inoculated with adult (BN × LE)F‐1 hybrid bone marrow or lymph node cells and challenged as adults with LE ganglia grafts many neurons survived beyond 100 days. This result demonstrates that tolerance of Ag‐B incompatible neurons can be achieved with either bone marrow or lymph node cells. Moreover, since tolerance can be produced in rats exhibiting major or minor histoincompatibilities, this method of immunosuppression offers one way of preventing neuronal rejection which occurs acutely in Ag‐B incompatible and chronically in Ag‐B compatible ganglia homografts.
On the granule‐containing cells in the aortic wall of the young chick
Authors: Kondo Histake
Published: February 2005

The granule‐containing cells in the wall of the arch of the aorta proximal to its union with the ductus arteriosus in young chicks were examined by electron microscopy. These cells contain many electron‐opaque vesicles, about 1500 Å in an average diameter, and show basically similar cytological characteristics to the granule‐containing cells described in autonomic ganglia, around the abdominal aorta, and in the carotid body of mammals. Occasionally the cells are in close apposition to smooth muscle cells, fibroblasts or endothelial cells. Other surfaces of the granule‐containing cells are partly covered by satellite cells. Synapses are rarely found on the granule‐containing cells in the tunica media of the aorta.

A few bundles of elongated cells which enclose several nerve fibers in the cytoplasm penetrate perpendicularly into the tunica media of the aorta. In these bundles are also a few granule‐containing cells. Three types of nerve endings terminate on the granule‐containing cells; that is, endings with small clear synaptic vesicles, with small cored vesicles, and with large cored vesicles. In addition, presumptive afferent nerve endings are found in the bundles. They show a variable diameter along their tortuous courses and contain numerous mitochondria.
Fine structural observations of ruthenium red binding in developing and adult rat lung
Authors: O'Hare Karen Hitchcock
Published: February 2005

The ruthenium red staining technique of Luft ('71b) was utilized in an electron microscopic investigation of developing and adult rat lung. Electron‐dense deposits of ruthenium red‐positive material were observed on all exposed surfaces of the tissue block, regardless of the stage of development. In the more central areas of the block, sites of ruthenium red binding changed with age. In early prenatal lung (days 16 to 20) dense accumulations of ruthenium red‐positive material were found in association with the basement membranes of endodermal epithelial cells. Ruthenium red binding was also observed between adjacent epithelial cells; however, their luminal surfaces were negative. The main intracellular site of ruthenium red binding in intact cells was the lamellar body of the developing type II pulmonary epithelial cells. By day 21 of development, accumulations of granular product were observed in association with most lamellar bodies, as well as on epithelial cell luminal surfaces. Ruthenium red binding in postnatal tissue decreases with increasing age. By the second postnatal week, the predominant site of binding is the luminal surface of the type I and type II pulmonary epithelial cells. When compared to fetal and early neonatal stages, adult rat lung has a still more limited distribution of ruthenium red‐positive material. Changes in the distribution of ruthenium red‐positive material correlate with numerous morphologic and biochemical events in rat lung development.
Cyclical changes in the vaginal epithelium of the rat seen by scanning electron microscopy
Authors: Parakkal Paul F.
Published: February 2005

Keratinization or mucification of the epithelium of the rat vagina is related to the hormonal state of the animal. During the normal cycle and after the administration of exogenous hormones (estrogen and progestin) to spayed animals, the surface characteristics and topography of the vaginal epithelium were studied with the scanning electron microscope. During estrus and under the influence of estrogen, the superficial cells were keratinized, overlap each other like shingles, and are continuously sloughed off. Like the surface of other keratinizing epithelia, theirs has a characteristic microridge pattern. In ovariectomized animals, the apical surface is covered with microvilli instead of microridges, and the cells resemble hexagonally shaped units, tightly bound instead of overlapping each other. At the boundary between the cells, a ridge demarcates the cells. The surface configurations of progestin‐treated, progestin plus estrogen‐treated, and diestrous animals are the same as in spayed animals.
Superficial venous patterns in the cubital region of Indians
Authors: Halim A. , Abdi S. H. M.
Published: February 2005

The patterns of the superficial veins of the cubital region were studied in 536 Indian subjects both living and dead. Three basic pattern types were noted. Type I had a median cubital vein joining the cephalic and basilic veins in the cubital region. Type II had the cephalic vein itself draining into the basilic vein in the cubital region. Type III showed the absence of a direct communication between the cephalic and basilic veins in the cubital region. The median vein of the forearm in these latter cases joined either of the cephalic and the basilic veins (type III A) or after bifurcating into a median cephalic and a median basilic vein joined both these veins (type III B). Type I was found to be the most common pattern (67.5%) followed by type II (19.5%), with types III A and III B accounting for 6% and 6.5% of the cases, respectively. Renaming of the median cubital vein as the oblique cubital vein because of its direction and renaming of the median basilic and lateral basilic veins as medial and lateral cubital veins since they follow the medial and lateral borders of cubital fossa respectively has been suggested.
The postnatal development of blood vessels in the substantia gelatinosa of rat cervical cord — an ultrastructural study
Authors: Hannah Richard S. , Nathaniel E. J. H.
Published: February 2005

Light microscopy of semithin sections revealed an increase in blood vessel profiles between one and three weeks postnatal. Ultrastructurally, at birth, there were few patent vessels, but endothelial cells enclosing a slit‐like lumen were numerous. The endothelial cells contained a high concentration of free ribosomes and pinocytotic vesicles. Pseudopod projections of the endothelial cells into the vascular lumen were often present. The nuclei were very irregular and dense with clumped chromatin. The basal lamina varied in thickness. During the period between one and three weeks the nuclei of endothelial cells became less dense; the lumen became patent and the endothelial wall progressively thinner. The periphery of the vessel became completely surrounded by glial end feet and the basal lamina was regular and prominent. By three weeks, most blood vessels resembled blood vessels observed in a mature animal. Pericytes were present at all stages of development. The extracellular space which was quite conspicuous at birth was greatly reduced by the third week.
An ultrastructural analysis of spontaneous activation of hamster eggs aged in vivo
Authors: Longo Frank J.
Published: February 2005

In an effort to elucidate various aspects involving the initiation of development, the morphogenesis of the spontaneously activated egg of the golden hamster was examined at the light and electron microscopic levels of observation. Spontaneous activation of the unfertilized hamster egg occurs upon prolonged incubation within the oviduct, i.e., aging in vivo, and may include the formation of the second polar body and the development of one or several pronuclei. In many instances the activated egg resembles the inseminated ovum at the pronuclear stage of fertilization. Occasionally the activated egg will divide and yields a structure which is morphologically similar to the two‐cell stage. Development beyond the two‐cell stage was not observed. Even though a number of events exhibited by the aging hamster egg mimic those of the fertilized, many are indicative of cellular degeneration. Such processes include, for example, the aggregation of organelles into fairly homogeneous clusters, the budding of portions of the cortex of the egg containing cortical granules into the perivitelline space, the accumulation of vesicles within the ooplasm and the structural modification of microvilli. All activated eggs, at every period investigated (6 to 66 hours post‐ovulation), contained cortical granules.
Persistence of cell types in monolayer cultures of dispersed cells from the pituitary pars distalis as revealed by immunohistochemistry
Authors: Baker B. L. , Reel J. R. , van Dewark S. D. , Yu Y.‐Y.
Published: February 2005

The objective was to study the fate of specific secretory cell types of the rat hypophysis when grown in primary monolayer cultures for periods ranging up to 32 days. The cells were identified immunohistochemically using peroxidase‐labeled antibody. Early in the culture period TSH‐cells were scarce and by 12 days they could no longer be identified. In most cultures LH‐cells were well stained and common for eight to 12 days, after which they underwent involution. Growth hormone cells were a prominent feature up to six days but by 12 days they were declining in number, size, and stainability; in contrast, prolactin cells proliferated and were large and intensely stained throughout the period of study, ultimately becoming the dominant secretory cell type. Corticotropic cells also continued throughout the period of study without regression. Thus drastic shifts occur with time in the relative proportions of cell types in monolayer cultures of rat pituitary cells.
Distribution of mitotic nuclei in the biceps brachii of the mouse during post‐natal growth
Authors: Aziz‐Ullah  , Goldspink G.
Published: February 2005

Distribution of mitotic nuclei in the biceps brachii of five day old mice has been studied after subcutaneous injection of 1 μCi/gm body weight 3H‐thymidine. Serial transverse sections at 5 μm thickness were cut and the number of labeled nuclei per hundred fibers were determined on every fortieth section starting from the proximal end of the muscle.

The proximal region of the muscle has significantly more labeled nuclei than either the belly region (P < 0.005) or the distal region (P < 0.001) of the muscle. The distal region of the muscle and the belly of the muscle did not differ significantly.

Thus, most of the fiber elongation seems to take place at the proximal region of the muscle. As far as the transverse growth is concerned it appears that either every fiber at this stage is increasing in diameter or else the fibers which are undergoing an increase in diameter are randomly distributed throughout the body of the muscle, as no significant differences have been found in the percentage labeled nuclei in the four transverse areas of the muscle in the belly region.
The role of nerves in the regeneration of minced skeletal muscle in adult anurans
Authors: Hsu L.
Published: February 2005

The course of reinnervation and the effects of denervation and immobilization on muscle development were examined during the regeneration of minced muscle in anurans. Reinnervation occurs in the second week, at the time of myotube formation and differentiation. At the end of thirty days, nerves are plentiful and extensively distributed within the regenerating muscle. Cholinesterase activity within the regenerated muscle cannot be demonstrated at this time. Denervated regenerates develop normally during the first two weeks, but, thereafter, the young muscle fibers exhibit signs of degeneration and retarded growth. Denervated regenerates become fibrotic and contain few muscle fibers at the end of four weeks. Regenerates from muscles denervated prior to mincing show an accelerated appearance of presumptive myoblasts in the first week, but despite this precocious development, these denervated regenerates become regressive. On the other hand, the effect of disuse on muscle regeneration is not detrimental; the fibers of reinnervated but immobilized regenerates develop normally and do not become degenerative. These results suggest that nerves are unnecessary for the early myogenic processes of proliferation and fusion, but are essential to later stages of growth, maturation and maintenance of the regenerated muscle fibers.
Nerve fibers in the sympathetic trunk of Rana pipiens: A quantitative electron microscope study
Authors: Davis Wanda M. , Nunnemacher Rudolph F.
Published: February 2005

The numbers and diameters of nerve fibers were determined for the first time for all interganglionic rami of the sympathetic chain of the frog. The number of myelinated fibers ranged from 57 to 263 and was generally highest in the anterior portion (207) and lowest at the posterior end (57) of the chain. The exception was between the fourth and fifth ganglia where the middle splanchnic nerves arise — the number of myelinated fibers was highest here (263). Unmyelinated fiber counts were similar throughout the chain (417–814) except above and below the first sympathetic ganglion (7325 and 3026, respectively), and at the level where the middle splanchnic nerves arise (3780). Unmyelinated fibers constituted 75–97% of the fibers of the chain. The myelinated fibers ranged in diameter from 0.5 to 9.0 μ, 75% of them measuring between 1.5 and 3.0 μ. The diameter range for unmyelinated fibers was 0.1 to 5.0 μ with 78% being 0.1 to 1.0 μ.
The production of extracellular connective tissue fibrils by chick notochordal epithelium in vitro
Authors: Carlson Edward C. , Upson Rosalyn H. , Evans Darrell K.
Published: February 2005

Fertile hens eggs were incubated 48 hours. Embryos were removed from the shell and the cervical region from each excised and placed in a balanced salt solution containing 1% trypsin for 40 minutes. Notochords were isolated by microdissection and further incubated in vitro 48 or 72 hours. Following trypsinization, unincubated notochords were rod‐shaped and were shown by electron microscopy to be devoid of extracellular materials or contaminating mesenchymal cells. Extracellular materials, ultrastructurally indistinguishable from those in the perinotochordal connective tissue space in vivo, are present on the surfaces of cell clusters at 48 hours of in vitro incubation. Areas of fibrillogenesis, in which microfibrils are separated from the surface of cells by intermittent basement lamina, are common. At 72 hours of in vitro incubation fibrogenic activity is less evident, but occasionally intense concentrations of small and large microfibrils, basement lamina and other extracellular substances are seen adjacent to notochordal cell surfaces. These observations are of special interest in light of the known role of the notochord in embryonic induction and recent demonstrations that surface‐associated substances (specifically collagen) are necessary for normal cytodifferentiation.
Morphological classification of rat incisor ameloblasts
Authors: Warshawsky H. , Smith C. E.
Published: February 2005

Longitudinal sections through the incisors of the rat show a continuous layer of ameloblasts on the labial surface of the tooth. This layer contains the entire sequence of developmental stages in enamel production. Using 1 μm Epon sections from the upper and lower incisors of 100 gm male rats, the ameloblast layer was divided into three main zones which were themselves subdivided into regions: (1) Presecretory zone which includes (a) region of ameloblasts facing pulp, itself comprising a posterior portion (upper 172 ± 35 μm; lower 187 ± 37 μm) and an anterior portion (upper 458 ± 28 μm; lower 503 ± 36 μm); (b) region of ameloblasts facing dentin (upper 1210 ± 81 μm; lower 1381 ± 90 μm). (2) Secretory zone, (a) region of inner enamel secretion (upper 2573 ± 141 μm; lower 4274 ± 160 μm); (b) region of outer enamel secretion (upper 1211 ± 60 μm; lower 868 ± 72 μm). (3) Maturation zone (upper 7335 μm; lower 10615 μm), (a) region of postsecretory transition; (b) region of maturation proper, consisting of portions of ameloblasts with striated border and portions of ameloblasts with unmodified apices; (c) region of pigmentation; (d) region of reduced ameloblasts.

These regions are readily identified using clear cut morphological criteria. Length measurements made on a group of 40 rats established the reproducibility of this classification. Therefore, this classification will be used as a basis for future studies of cell population kinetics.
Localization of muscle spindles in the human Extensor indicis muscle for biopsy purposes
Authors: van Gorp Paul E. , Kennedy William R.
Published: February 2005

The number and spatial relations of muscle spindles in the extensor indicis have been determined. Approximately forty spindles lie adjacent to the motor end plate zone dispersed rather equally through this area of the muscle with a modest increase in density among the distally originating fibers. A study of the entire innervation pattern of this muscle has also been completed.

These findings have greatly facilitated the isolation of spindles for electron microscopic study and attempts to perform in vivo recording from the sensory nerves of muscle spindles in this laboratory. It is now possible, with the aid of suitable magnification and stimulating and recording devices, to more rapidly find muscle spindles relative to the gross innervation and the easily located motor end plate zone.
Action of metabolic hormones on the fine structure of rat liver cells III. Effects of adrenalectomy and administration of cortisone
Authors: Cardell Robert R.
Published: February 2005

Electron microscopic studies were made of hepatocytes from sham‐operated rats, adrenalectomized animals fasted 15 hours, and adrenalectomized rats fasted 15 hours but given a single I.P. injection (10 mg) of cortisone acetate. The objective of this work was to define the earliest morphological response of hepatocytes to injection of a glucocorticoid and to provide additional information on the mechanism of hormone action at the cellular level. Hepatocytes from fasted, adrenalectomized rats contained no glycogen particles and very little smooth endoplasmic reticulum (SER). In addition the rough endoplasmic reticulum was disorganized and showed fewer ribosomes and polysomes than found in liver cells from sham‐operated rats. Two hours after glucocorticoid injection glycogen particles were seen in numerous centrilobular cells and some periportal hepatocytes. Elements of SER were associated with the glycogen particles. By 4 hours after hormone injection abundant glycogen was found in all hepatocytes. Centrilobular cells showed dispersed glycogen with extensive tubules of SER associated with the glycogen particles. Periportal hepatocytes accumulated glycogen as dense masses scattered throughout the cytosome. SER occurred mainly at the edges of the glycogen masses. Midlobular cells showed glycogen patterns intermediate between periportal and centrilobular cells; masses of dispersed glycogen with abundant SER occurred within and around the glycogen areas of the cells. Glucocorticoid stimulation also caused cisternae of RER to align in parallel arrays, and more ribosomes and polysomes appeared on membranes of RER than in similar cells from adrenalectomized rats. The interpretation is offered that the glucocorticoid‐stimulated proliferation of SER is the morphological expression of induced microsomal enzyme synthesis (glucose‐6‐phosphatase) known to occur under these hormonal conditions.
Protein secretion in the rat ventral prostate and the relation of Golgi vesicles, cisternae and vacuoles, as studied by electron microscope radioautography
Authors: Flickinger Charles J.
Published: February 2005

Proteins, including enzymes such as acid phosphatase, are among a variety of substances secreted into semen by the prostate gland. The formation, intracellular transport, and discharge of protein components of prostatic secretion were studied in the rat ventral prostate following an injection of leucine‐3H. Samples were prepared for light and electron microscope radioautography at intervals ranging from four minutes to two hours after the injection. In samples prepared four or ten minutes after administration of the precursor, most of the silver grains overlay the rough endoplasmic reticulum. Beginning 30 minutes after the injection, while label associated with the endoplasmic reticulum was declining, the proportion of grains over the Golgi apparatus began to increase, reaching a maximum in one‐hour samples. Secretory vacuoles at the apical ends of the cells became heavily labeled two hours after administration of the leucine‐3H. Labeling of secretions in the lumen of the prostatic alveoli was observed in samples taken two hours after the injection. These results indicate that secretory proteins in the prostate are synthesized in the rough endoplasmic reticulum, transported to the Golgi apparatus, and packaged into secretory vacuoles, which move to the apical ends of the cells and release their contents to the lumen. Additional analysis of the pattern of labeling of different elements of the Golgi apparatus suggests that some protein is transported sequentially from Golgi vesicles to stacks of cisternae and finally into Golgi vacuoles. Radioactive secretory proteins move through prostatic cells more slowly than through the seminal vesicle epithelium of the same animals. The main mode of protein secretion in the prostate appears to be a merocrine type, since apical protrusions such as have been suggested to participate in an apocrine form of secretion were observed infrequently and did not become heavily labeled.
Selective histochemical staining of cartilage matrix by RivanolR
Authors: Wezeman Frederick H. , Kuettner Klaus E.
Published: February 2005

RivanolR, a fluorescent ethoxy derivative of acridine, interacts at different pH's with both glycosaminoglycans and proteins. The present study utilizes the specific interaction of RivanolR with acidic substances of the ground substance for histochemical studies of the cartilage matrix. This stain was applied to newborn mouse epiphyseal cartilages which were either unextracted or dissociatively extracted by graded concentrations of guanidinium chloride (GuHCl) from 0.5–3.0 M for four days at 25°C. Routinely prepared sections were then stained (0.1% solution) for two minutes at pH's ranging from 2.2–11.2. Stainability of the interterritorial matrix as well as the inner halo zone and outer corona zone of the lacunar matrix varied with pH. Whereas the interterritorial matrix decreased in stainability with rising pH, the halo and corona persisted in stainability up to pH 10.7. Dissociative extractions using GuHCl revealed the unextractable nature of the inner halo zone as well as the extractable nature of the corona above 1.0 M GuHCl concentration. Anionic sites on polyelectrolytes such as glycosaminoglycans are known to stoichiometrically bind many cationic dyes. The precise localization of stain‐reactive glycosaminoglycans or proteoglycans in the region of the perichondrocytic matrix by RivanolR supports prior observations using other cationic stains. Our data demonstrates that RivanolR enables one to visualize the unique perichondrocytic matrix which may be interpreted to be both chemically and morphologically a “matrix within a matrix”.
Functional differentiation of the chick endocrine pancreas: Insulin storage and secretion
Authors: Benzo Camillo A. , Green Tim D.
Published: February 2005

A radioimmunoassay for insulin, together with ultrastructural observations of the endocrine pancreas, were utilized to investigate developmental aspects of insulin storage and secretion in the chick embryo. Immunoreactive insulin was detected from the fifth embryonic day onwards, in both the pancreas and blood plasma. In addition, margination of well‐developed beta granules, and emiocytotic events were observed as early as the fifth embryonic day. The initial appearance of insulin, together with its subsequent developmental profile, correlate well with major metabolic events occurring in the embryonic chick, and are discussed in relation to a functionally responding system, the developing liver. The present data show that the chick endocrine pancreas has the potential for activity very early in development, and that insulin may be secreted at earlier embryonic stages than hitherto accepted.
Ultrastructural demonstration of cilia in the adult human ependyma
Authors: Roy Subimal , Hirano Asao , Zimmerman Harry M.
Published: February 2005

Ependyma from random sites of lateral, third and fourth ventricles including the aqueduct in five adult human brains was examined by transmission electron microscopy. In all the specimens studied, cilia were present in variable numbers in the ependymal cells. Our study thus establishes that there is widespread presence of cilia in the ependymal cells of the ventricular system in the adult human brain.
Some morphological features of the myoneural junctions in certain normal muscles of the rat
Authors: Ip M. C.
Published: February 2005

In frozen sections and whole mount preparations of the normal soleus, diaphragm, or intercostal muscles of the rat, myoneural junctions of different AChE and silver staining intensities were regularly observed. Muscle fibers of different diameters showed end‐plates of varying staining intensities. No correlation was found between a certain staining intensity and diameter of the end‐plates or between muscle fiber diameters and the ratio of pale to strongly stained end‐plates. There was, however, a tendency for the smaller muscle fibers to have end‐plates of smaller mean diameter than those in the larger muscle fibers.
Ultrastructural features of chick embryo skin cultured in a chemically defined medium
Authors: Wong Y. C.
Published: February 2005

Explants of six‐day chick embryo skin, cultivated in a chemically defined medium (Waymouth Medium MB 752/1) for one to eight days were fixed and processed for electron microscopic study. Excellent development and differentiation of chick embryo skin was recorded. The skin cultivated in vitro matured much earlier than in ovo. After one day in vitro the morphology of the skin is similar in the stage of development to that of a 10–12 day embryo skin in ovo. After two or four days in culture, the skins are comparable to those of 12–14 day or 15–16 day in ovo embryos, respectively. The periderm of the epidermis was highly developed and contained a large number of peridermal granules after six days of culture. The skin proper, contained a granular layer, which resembled the skin of a 17‐day embryo. Complete cornification of the epidermis was observed for the first time in vitro after 8 days of incubation. Keratohyalin granules which were claimed to be absent in avian skin, were observed.
Cytochemical demonstration of alkaline phosphatase activity in the ultimobranchial bodies and thyroid parenchyma of the rat
Authors: Calvert R.
Published: February 2005

The localization of alkaline phosphatase activity in the ultimobranchial bodies was studied at the fine structural level in Holtzman rat embryos from the 15th to the 19th day of gestation, and also in four‐week old rats of the same strain. In the embryos, no alkaline phosphatase activity was found before the 17th day of gestation. From that day on, plasma membranes of glycogen‐rich cells show the reaction product regardless of their location in the wall of the ultimobranchial bodies. However, when the same cells are seen on cell cords of the median thyroid, they are negative. In the four‐week old rats, plasma membranes of ultimobranchial cells are strongly reactive. C cells are negative both before and after birth. Small thyroid follicular lumina with positive apical cell membranes are also noted in four‐week old rats. These positive thyroid follicles are not more differentiated than those previously described in 19‐day old rat embryos. It is concluded that new thyroid follicles are formed after birth. These results are discussed in relation to the hypothesis that when ultimobranchial cells are transformed into follicular cells, they undergo the same alkaline phosphatase changes as those observed during the maturation of follicular cells derived from the median thyroid primordium. The cytochemical method used is also criticized.
Stimulation of cell division following unilateral collapse of the lung
Authors: Simnett John D.
Published: February 2005

Collapse of the left lung in adult mice is followed by an increased mitotic incidence (MI) in the right lung which persists for approximately four days after operation. This compensatory increase in MI does not occur if the left thoracic cavity is packed with an implant of cotton wool which prevents hyperinflation of the right lung. The rate of incorporation of labelled thymidine per unit of DNA (RIT) is higher in the right than in the left lung of unoperated animals but after collapse of the left lung there is a reduction in the ratio of right to left in respect of RIT. These differences in RIT do not appear to correspond to changes in the rate at which cells enter DNA synthesis and it is suggested that they are due to differences in vascularisation between the right and left lungs. The compensatory increase in MI which follows unilateral collapse is not due to loss of tissue mass, to tissue damage or to the direct effects of the increased physiological load placed upon the remaining functional tissue. It is suggested that hyperinflation of the right lung causes changes in the rate of blood flow through that part of the organ and that, in consequence, there is a change in the local concentration of metabolites including those whose function is to regulate the mitotic rate.
Postnatal changes in the localization of glucose 6‐phosphatase activity within the liver lobule of the mouse
Authors: Kanamura Shinsuke
Published: February 2005

The change in the localization of glucose 6‐phosphatase activity within the liver lobule of the mouse was studied during development. From one day before birth to three days after birth, a uniform localization of the activity was observed throughout the lobule. This uniform localization of the activity gradually changed to that of the adult type, characterized by a relatively higher activity in periportal areas, between three to ten days of age. This indicates that the postnatal growth of the liver is accompanied by a change in the pattern of the localization of this enzyme activity within the liver lobule. Further, the biochemical results showed that the elevated activity after birth was reduced to the level seen in adult at ten days of age. Thus, the reduction in the level of the enzyme activity during ten days after birth corresponds to a redistribution of the enzyme activity within the liver lobule.
Spatial distribution of rat fungiform papillae
Authors: Miller Inglis J. , Preslar Arthur J.
Published: February 2005

The objective of this study was to determine the spatial distribution of fungiform papillae on the rat's tongue. Since each fungiform papilla in the rat has a single taste bud, the spatial distribution of fungiform papillae is equivalent to the location of taste buds on the anterior tongue. A mean total number of 187 fungiform papillae per tongue were found which were about equally divided between the two lateral halves of the tongue. Over 50% of the total number of fungiform papillae were located on the tongue tip for an average density of 3.4 papillae/mm2, while the dorsal surface of the tongue had an average density of 1.3 papillae/mm2 of tongue surface. Papillae were absent on the dorsal midline, but a paracentral line of papillae running from anterior to posterior was a consistent finding. Though not identical, the distribution of papillae was essentially the same on different tongues. The functional significance of the papilla distribution is not understood, but electrophysiological experiments show evidence of neural interaction of papillae which are clustered together. The distribution of papillae and the distribution of nerve fibers which innervate them must be evaluated together in order to appreciate the significance of the distribution of fungiform papillae and their associated taste bunds.
A comparison of secondary palate development with different in vitro techniques
Authors: Smiley Gary R. , Koch William E.
Published: February 2005

Palatal processes from 14‐day fetal C57BL mice were cultured under varying conditions for 48 hours and prepared for light and electron microscopy. Disruption of the epithelium along the medial border occurred when single palatal processes were explanted onto Millipore filters, plasma clots, or lens paper in subjacent contact with nutrient medium. Paired processes under the same culture conditions demonstrated typical midline epithelial disruption and mesenchymal fusion. Regions of mesenchymal necrosis occurred in processes growth on nutrient agar in a dish or submerged in nutrient medium. In similar cultures medial epithelial disruption did not occur in single processes and mesenchymal fusion of paired processes was either delayed or did not occur. Disruption of the epithelium along the medial border in single palatal processes, and mesenchymal fusion in paired palatal processes, occurred when palates weregrown on nutrient agar supported above but in contact with nutrient medium. The results indicated that responses of palatal epithelium and mesenchyme may be altered by different in vitro procedures. These observations emphasize that many factors must be considered in interpreting developmental changes in palatal processes grown in vitro.
On the development of the lymphoid follicles of the bursa of fabricius
Authors: Edwards Joshua L. , Murphy Robert C. , Cho Yongock
Published: February 2005

The structural features of the development of the bursa of Fabricius in white Leghom chick embryos are depicted at carefully timed intervals during embryogenesis, with emphasis on the sequence of events between the ninth and twelfth days of incubation. The direction and character of the migration of lymphoid cell precursors and granulocytes from the intravascular space to intraepithelial sites, where the formation of the primitive lymphoepithelial nodule takes place, is demonstrated. The mechanism of the mode of migration of these cells through the stromal epithelial interface is described and illustrated with electron micrographs and their role in the development of the primitive lymphoid follicles is described and discussed.
A simple, single‐injection method for inducing long‐term paralysis in embryonic chicks, and preliminary observations on growth of the tibia
Authors: Hall Brian K.
Published: February 2005

A method for inducing paralysis in embryonic chicks is described. This involves single injections of the neuromuscular blocking agents, D‐tubocurarine Chloride or decamethonium iodide, into 10‐day embryos. The dose which optimises survival and paralysis is determined along with the effect of the drugs on embryonic growth. Decamethonium iodide at a dose of 1 mg per embryo gave maximum survival and paralysis to 18 days of incubation. Paralysis was assessed by observation of treated embryos in ovo and by examination of embryos removed from their shells between 11 and 18 days of incubation. Embryos were completely paralysed 24 hours post‐injection and remained paralysed until 18 days of incubation. Paralysed embryos failed to hatch. Development of the leg musculature was severely retarded in paralysed embryos. This method of inducing paralysis has considerable advantages over previous continuous infusion methods. The growth and collagen content of the tibia in the paralysed embryos was reduced and these results, and other applications of the method, are discussed.
The development of the granular convoluted duct in the rat submandibular gland
Authors: Srinivasan R. , Chang W. W. L.
Published: February 2005

The development of the granular convoluted duct in the submandibular gland of male rats, 4 to 12 weeks of age, was investigated. During this period, the average weight of the gland increased from 213 to 526 mg, the total DNA and RNA contents doubled, and the protein content tripled. Radioautographs were prepared from Epon embedded sections of the gland of the rats given 3H‐thymidine and stained with toluidine blue. The glands of 4‐week‐old rats consisted mainly of acinar cells (45%), intercalated ductal cells (20%) and striated ductal cells (16%). A few granular convoluted ductal cells were seen in the striated duct close to the intercalated duct. The frequency (and absolute number) of granular convoluted ductal cells increased linearly from 1% (3 × 106) at four weeks to 26% (68 × 106) at eight weeks, while the calculated number of striated ductal cells remained stationary. The absolute number of acinar cells and intercalated ductal cells nearly doubled between four to eight weeks of age. The proliferative activity of all cell types declined with age but between six and ten weeks of age the rate of proliferation of ductal cells was relatively higher than the rate of proliferation of the acinar cells. Morphologically the size and number of granules in the granular convoluted ductal cells increased with age. Based on the above data it is concluded that the granular convoluted ductal cells developed from that segment of the striated ductal cells which is in close proximity with the intercalated ductal cells. The heterogeneity of the granules in the granular convoluted ductal cells observed from six weeks of age might denote the functional diversity of the cells.
Ultrastructure of the oocytes of the egyptian spiny mouse (Acomys cahirinus)
Authors: Kang Yuan‐Hsu , Anderson Winston A.
Published: February 2005

The oocytes of types 2, 3, 4 and 5 follicles from the normal spiny mouse were examined with the electron microscope. Multiple juxtanuclear Golgi bodies, mitochondria associated with flattened granular endoplasmic reticulum, and large nucleus are the main features of the type 2 follicle oocyte. The numbers of mitochondria and Golgi apparati increase significantly at later stages. Small mitochondrial aggregates lacking “intermitochondrial cement” are seen in the ooplasm of types 3, 4 and 5 follicles. “Lamellar complexes” comprising two to six elongate flattened rough ER cisternae and intercisternal filaments begin to appear in the oocyte of the type 3 follicle. The intercisternal filaments may be observed as punctate‐, dashed‐, and solid‐lines in cross sections. In tangential sections the filaments display a paracrystalline structure. In the type 4 follicle oocytes, the “lamellar complex” becomes more extensive; polysomes and ribosomal fibrils are juxtaposed to the “lamellar complexes.” Bundles of ribosomal fibrils are abundant in the ooplasm of the type 5 follicle. The origin of ribosomal filaments and the functional significance of “lamellar complexes” are discussed.
Scanning electron microscopy of a second type of supraependymal cell in the monkey third ventricle
Authors: Coates Penelope W.
Published: February 2005

The third ventricle of monkeys has been examined with the scanning electron microscope (SEM). Two populations of supraependymal (SE) cells were distinguished on the basis of morphology and location. One type has been previously reported (Coates, '72, '73a,b,c). Another, type 2 SE cell, is now described.

Type 2 SE cells were found in the third ventricle of both sexes and in all age groups although the numbers varied highly from animal to animal. The most common site for type 2 SE cells was the floor and transition zone of the third ventricle. Visualized with SEM, these cells had variable morphology, but may be characterized by a small cell body, few non‐branching processes some of which were flared and surface features such as ruffled membranes. Type 2 SE cells most likely correspond to Kolmer or epiplexus cells originally described in association with the choroid plexus. As such, they are probably phagocytes.
Hyperglycemia in the NZB/NZW F1 hybrid mouse
Authors: Pansky B. , Kessler H. S. , Senitzer D.
Published: February 2005

Both the NZW and NZB mice exhibit an elevated fasting blood sugar level when compared to Swiss white mice. The NZB/NZW F1 hybrid mouse shows still a higher fasting serum glucose level than either of its parental strains. This elevated glucose level is noted very early in the animals' life, long before definitive signs or symptoms of pathology are evident, and remains elevated at least until the fortieth week of life, the last testing period in our series before sacrificing the animals. There are two major peaking periods for the glucose levels, namely at 4–10 weeks of age and then again at 31–40 weeks of age. These age periods correspond to the very young animal and to the animal that is beyond its prime and most likely sick and near the end of its lifespan due to the animals' inherent disease processes. The NZB and NZB/NZW F1 hybrid succumb to their disease processes at approximately 8–10 months of age. The NZW usually lives until 18 months.

The questions are raised: does the altered immunologic state in the NZB and/or the NZB/NZW F1 hybrid produce the elevated blood sugar levels and the pancreatic histopatholgy or is it the early hyperglycemic condition coupled with pancreatic pathology which are in some measure instrumental in producing the lesions discussed and observed, in the beginning of the three to four month period of age, in the various organs? Is there a relationship between the hyperglycemic condition and the immune state or are these independent phenomena in a genetically “mixed up” mouse?
Limitations to the neuroregulation of enzymes in mammalian skeletal muscle
Authors: Yellin Herbert
Published: February 2005

Muscle fibers of the sternomastoid and the tongue of the rat were characterized histochemically according to mitochondrial distribution (succinic dehydrogenase), as well as reactivity for the alkali‐ and acid‐stabile “myofibrillar” adenosine triphosphatases. The principal fiber types of the sternomastoid were the large, “white” AαβM fibers and the smaller, “intermediate” BβD and “red” CαL fibers (figs. 1, 2, 3). The unusual musculature of the tongue was populated by diminutive AαM and CαM fibers, and variants thereof; all with relatively high mitochondrial content (figs. 4, 5, 6).

Reinnervation of the sternomastoid muscle by the hypoglossal nerve caused most fibers of the sternomastoid to assume histochemical profiles reminiscent of those commonly observed in the tongue. However, the BβD fibers of the sternomastoid persisted in near usual numbers and disposition (fig. 17), despite their reinnervation by a nerve normally destined for a muscle lacking that particular fiber type. Thus, there are as yet unrecognized factors, possibly of neural origin, though more likely of muscle origin (genetic), that impose restrictions on the metabolism‐regulating functions of substitute motoneurons.
Postnatal observations on the diurnal rhythm and the light‐responsiveness in the pineal glycogen content in mice
Authors: Kachi Takashi , Matsushima Shoji , Ito Takashi
Published: February 2005

In mice of both sexes ranging in age from five days to two years, the development and time course of diurnal rhythm and light‐related variations in pineal glycogen were systematically studied by a semiquantitative histochemical method. When the animals were maintained under the usual diurnal lighting conditions (12L:12D), the diurnal rhythm and light‐related changes in pineal glycogen appeared first at 22 days of age and persisted until two years. The glycogenic response was most prominent between 60 and 150 days, and declined slightly in mice older than one year.

The glycogenic response and cell size tended to differ in the distal, middle and proximal portions of the body of the pineal. These regional differences changes with the ages of the animals.

When mice were kept in continuous darkness for seven days starting from 15, 23 or 60 days of age, the pineal showed a diurnal rhythm in pineal glycogen.

When mice were kept in altered light regimens such as continuous darkness, continuous lighting or 6L:6D from birth up to 30 days, no diurnal variation in pineal glycogen developed.
Ultrastructural studies on postnatal differentiation of neurons in the substantia gelatinosa of rat cervical spinal cord
Authors: Hannah Richard S. , Nathaniel Edward J. H.
Published: February 2005

Neuroblasts of the substantia gelatinosa at birth were small with large oval nuclei and scanty cytoplasm. The cytoplasm possessed ribosomes and mitochondria. Granular endoplasmic reticulum and Golgi complexes were generally absent or rudimentary. Electron dense bodies were seldom observed. By the end of the first week, the nuclei of several cells demonstrated early nuclear invaginations; cytoplasm exhibited growth cones, a well developed granular endoplasmic reticulum and Golgi complexes. At several points the channels of endoplasmic reticulum became continuous with the perinuclear space. By the end of the second week, differentiation of the neuroblasts was more advanced. More nuclei showed invagination of their contour. The cytoplasm revealed well developed granular endoplasmic reticulum and multiple Golgi complexes. Numerous vesicles and dense bodies were found adjacent to the Golgi complexes. Arrays of agranular endoplasmic reticulum also appeared late in the second week. By the third week, features of neuronal differentiation, such as nuclear invaginations, granular endoplasmic reticulum, agranular membrane configurations, multiple Golgi complexes and dense bodies in the cytoplasm became well established.
Scanning electron microscopy of epithelia prepared by blunt dissection
Authors: Miller Marcia M. , Revel Jean‐Paul
Published: February 2005

Simple dissection techniques of samples to be examined in the scanning electron microscope allow one to visualize easily the three‐dimensional shape of epithelial cells in situ. Such preparations reveal a complex system of ridges and folds on the lateral surface of the cells whose intricacy can best be appreciated with SEM. In many epithelia there is a smooth apical band which corresponds to the region occupied by the junctional complex previously identified with conventional EM techniques. The secretion of chylomicra that result from a fatty meal can be observed. It is possible to study the distribution of concanavalin A binding sites on the lateral surfaces of the cells utilizing hemocyanin as a marker. In the case of the proximal tubule epithelium, the apical cell surface has many more binding sites than the lateral cell surface and there is a sharp demarcation at the level of the apical band. After blunt dissection the relationship of the basal surface of the cells with the basement lamina and the basement membrane can be appreciated as well. Possible physiological meaning of the morphological features observed is briefly discussed.