bluuebunny/crossref_metadata_2025 huggingface dataset:
Muscle growth in selected lines of muscular dystrophic chickens
Authors: Holliday T. A. , Julian L. M. , Asmundson V. S.
Published: February 2005

Growth of four muscles was studied in four lines of homozygous dystrophic chickens selected for high or low fat content of pectoralis muscles, or for early or late onset of disability. The light (“white”) pectoralis, supracoracoideus and biceps brachii and the dark (“red”) adductor muscles were studied. Growth characteristics were compared to a randomly mated dystrophic line and to normal chickens. Significant differences in muscle size occurred between lines but all dystrophic lines underwent the same sequence of events: gross hypertrophy of the white muscles during the first few weeks of life, followed enventually by gross atrophy. The dark adductor muscles did not differ consistently from normal. Hypertrophy was accompanied by increased protein (or fat‐free dry matter) and water content. Atrophy was accompanied by increased fat content. Selected lines exhibited greater uniformity and greater extremes of hypertrophy or atrophy than occurred in the random line.
A circadian susceptibility rhythm in rats to pentobarbital sodium
Authors: Scheving Lawrence E. , Vedral Donald F. , Pauly John E.
Published: February 2005

A colony of adult rats was maintained on a standardized regimen with artifical photoperiods extending from 0600 to 1800 alternating with 12 hours of darkness. Every hour during a 24‐hour period separate subgroups of rats were injected with 35 mg/kg of pentobarbital sodium, and the duration of time each animal remained under anesthesia was recorded.

The rats remained anesthetized for longer periods of time between the hours of 1600 and 2200 than at other times of the day; this indicates that the response to the drug is dependent on he circadian phase system of the animal. When the results were plotted along the 24‐hour time scale, the difference between the crest and trough of the curve was about 100%.

A second colony of rats was maintained in a similar fashion except that the animals were subjected to continuous illumination. The rhythm of their susceptibility to pentobarbital sodium persisted for at least four weeks in a form highly modified from the animals synchronized to a light‐dark cycle.

In a third colony of animals, the rhythm still was present four months after they had been blinded; but it was modified and different from either the light‐dark synchronized animals or from rats subjected to continuous illumination.

The importance of recognizing the time structure of the living organism is discussed.
Distribution of the extracellular space during postnatal maturation of rat cerebral cortex
Authors: Bondareff William , Pysh Joseph J.
Published: February 2005

The cerebral cortices of young adult and immature Sprague‐Dawley rats, 10, 14, and 21 days of age, were rapidly frozen in situ and substituted at –78.5°C with a 1% solution of osmium tetroxide in acetone. In random electron micrographs of each animal, each representing 42 μ2 of cerebral cortical molecular layer, the extracellular space was evaluated stereologically.

In all cases the extracellular space was found to be distributed as large extracellular lakes of variable dimension. Where no extracellular space was apparent adjacent cell processes were joined by 5‐membered complexes, which appeared to represent fusion of immediately adjacent plasma membranes.

In 10‐day old animals an extracellular space of 40.5% was found. This diminished progressively to 31.8% at 14 days and 26.3% at 21 days, which approached the adult value of 21.7%. These data were consonant with measurements of the maturing extracellular space based on uptake studies of tracers, water and electrolyte determinations and impedance measurements. They appear to represent accurately the changing distribution of extracellular water in rapidly maturing cerebral cortex.
Oogenesis and ovarian development in the prenatal pig
Authors: Black J. L. , Erickson B. H.
Published: February 2005

Gametogenesis and ovarian development were examined by means of histologic, cytologic and radioisotopic techniques in porcine ovaries of ages ranging from 13 days post coitum (PC) to birth (114 days PC). Limited observations were made in postnatal ovaries (birth to 130 days post partum).

Primordial germ cells were noted at 18 days PC in the region of the germinal ridge (border of mesonephros) seven days prior to its formation (24–25 days).

Meiosis began as early as day 40 in some cases and was a characteristic of most ovaries by day 50.

Diplotene, the resting stage of porcine oocytes, first appeared at 50 days PC and 99% of all germ cells were at diplotene by 20 days post partum. Both the paucity of oogonia and absence of oogonial mitoses at day 100 PC signaled the end of oogenesis.

The number of germ cells increased dramatically from the 5,000 seen at 20 days PC to a peak of 1,100,000 at 50 days. Subsequently, germinal mitotic activity decreased and necrosis of germ cells concurrently increased, resulting in a population of approximately 500,000 germ cells at birth.

The injection of tritiated thymidine into fetuses of varying ages revealed that in the pig the definitive stock of oocytes arises from the prenatal period prior to day 100 with the 70‐day PC‐period being the major contributor.
A light and electron microscopic study of perineuronal glial cells and processes in the rabbit neocortex
Authors: King James S.
Published: February 2005

The morphology of satellite cells was determined by examining brom formalin fixed tissue stained by the silver carbonate technique, and tissue fixed in gluteraldehyde, post‐fixed in osmium and prepared for electron microscopy.

Light microscopy indicated that oligodendrocytes and astrocytes were the predominant perineuronal cell types. Cells with intermediate morphological characteristics were also observed. The light microscopic criteria for cellular indentification were the comparative size and shape of the cell bodies, and the number and nature of glial processes.

Electron microscopy revealed perineuronal cells with round to oval shaped cell bodies, dense nuclear and cytoplasmic matrices, and a rich compliment of organelles. A second, less numerous, type of satellite cell had a larger, oval, elongate, or somewhat angular cell body, light nuclear and cytoplasmic matrices, and gliofibrils and glycogen. The former correlated well with the light microscopic oligodendrocyte and the latter with the astrocyte. “Dark cells” were not observed in a satellite position with the electron microscope nor were cells observed that conform to Hortega's “spiny microglia” in our silver preparations. Specializations of the plasma membranes of satellite glial cells and neurons were observed, and were interpreted as possible morphological evidence for “transport” between neurons and neuroglia.
The germinal layer of the growing human brain during early fetal life
Authors: Duckett Serge
Published: February 2005

The telencephalic vesicles of the human brain appear during the fifth week of embryonic life. These vesicles are closed containers filled with ventricular fluid until the fifteenth week when it escapes through the newly‐formed foramen of Magendie.

The light and electron microscopic studies reported here support the notion that the germinal layer of the telencephalon has an absorptive role between the eighth and fifteenth weeks of fetal life. This assumption is based on the structure and the arrangement of the cells of the germinal layer, which resemble and are arranged in a manner similar to that of other absorptive units such as the renal proximal tubules, the gallbladder and the intestine. The absorbed material is presumably contained in the ventricular fluid.
An electron microscopic study of the relationship between axon diameter and the initiation of myelin production in the peripheral nervous system
Authors: Matthews Murray A.
Published: February 2005

Mid‐thoracic dorsal and ventral roots from adult rats, cats and cows were prepared for electron microscopy using standard techniques. Axon diameters were measured on photographs of known magnification. Minimal diameters of the unmyelinated fibers in the spinal cords of these animals were measured also. With the exception of a few overlapping diameters unmyelinated fibers were smaller than the smallest myelinated fibers in all the material examined. In the dorsal roots of the cow, the unmyelinated fibers, as a group, were larger than those of the rat and cat, and very few were enclosed by any one Schwann cell. The largest unmyelinated fibers were singly enclosed. In addition, the dorsal root of the cow contains many more small myelinated fibers than those of the other two species. In the ventral roots, a progressive increase in the size and relative numbers of myelinated preganglionic fibers from rat through cat to cow was noted. These facts indicated that myelination is directly dependent on fiber diameter irrespective of age, species or function although less precisely than was indicated by the earlier studies of Duncan ('34). Although the critical diameter for myelination in the peripheral nervous system is about one micron, in the central nervous system it is 0.3 μ or less.
Electron microscopic study of somatotropic and lactotropic pituitary cells of the Syrian hamster
Authors: Dekker Andrew
Published: February 2005

Somatotropic (STH) and lactotropic (LTH) cell types of the Syrian hamster's adenohypophysis are readily identified by electron microscopy. Pituitaries of growing and lactating animals were studied to establish the identity of these cell types. The pituitaries of normal, gonadectomized and thyroidectomized adult male and female hamsters were also examined. Distribution of these cell types was determined by examining all blocks of half the gland in adults and of the whole gland in immature animals. Electron microscopic fields were systematically photographed and cell types counted.

The STH and LTH cells are distinguished by the size of the secretory granules which measure maximally 300 and 700 mμ, respectively. A marked predominance of STH and LTH cells is present in the intact adult female gland. Approximately equal numbers of STH and LTH cells are seen in the female gland, whereas, there are significantly fewer LTH cells in the male adenohypophysis. The proportion of the gland comprising STH cells, however, appears to be constant in both male and female.

Both cell types are distributed throughout the gland with no regional localization.
Stage dependent transfer of systemically injected foreign protein antigen and radiolabel into mouse ovarian follicles
Authors: Glass Laurel E. , Cons Jean M.
Published: February 2005

The appearance of albumin‐like antigen and of radioisotope in mouse ovarian follicles following the systemic injection of 10 mg human serum albumin I131 (HSAI131) was studied by immunohistological and autoradiographic methods.

Both isotope and antigen appeared in granulosa cell cytoplasm, ooplasm and oocyte nuclei in similar (or identical) positions. Qualitative impressions from fluorescent antibody preparations were that follicle stages (I, smallest; IX, largest) differed in relative amounts of detectable albumin‐like antigen. In addition, autoradiographic grain counts over 1421 follicles, compared by Sign Test, demonstrated statistically significant stage differences in amount of isotope detected. Radiolabel (and HSA‐like antigen) in ooplasm was highest at Stages I and VII‐IX and lowest at Stage III. Granulosa cell amounts were highest at Stage III and higher than or equal to ooplasm amounts at every other stage (except, perhaps IX). The relative amount of “label,” antigenic or isotopic, in oocyte nuclei was always less than in ooplasm and increase or decrease occurred one stage later than in ooplasm. The relative amount of radiolabel in ovarian blood vessels always exceeded that in granulosa cells and oocytes.

The data are consistent with the interpretation that: (a) systemically injected foreign protein was transferred without major degradation from the blood to constituent cells of the mouse ovarian follicle; (b) transfer was stage dependent; (c) transfer occurred both before granulosa cells completely surrounded the oocyte and after oocyte microvilli and granulosa cell processes interdigitated; and, (d) transfer followed a concentration gradient.
Role of melanocyte morphology in pigmentation of mouse hair
Authors: Sweet Stephen E. , Quevedo Walter C.
Published: February 2005

The pigmented hair provides a lasting record of the complex interactions of melanocytes and keratinocytes which lead to its formation within the hair follicle. Large clumps of pigment are deposited within the developing hair when follicular melanocytes are uprooted from fixed sites in the hair bulbs. The frequency with which melanocytes are incorporated is in some way related to their morphology. Melanocytes with poorly developed dendrites (nucleopetal melanocytes) are dislodged from hair bulbs more frequently than those with well developed dendrites (nucleofugal melanocytes). A detailed investigation of pigment clumping brought about by action of the light (Blt) and leaden (ln) genes has yielded results consistent with this interpretation. Leaden melanocytes remain nucleopetal in morphology throughout the hair growth cycle whereas light melanocytes, initially nucleofugal, often become nucleopetal. The unexpected absence of pigment clumping in light (Blt/—) mice which are homozygous or heterozygous for the pink‐eyed dilution gene p, is correlated with the persistence of nucleofugal melanocytes. In contrast, the pigment clumping found in the hairs of pink‐eyed leaden mice is associated with the presence of nucleopetal follicular melanocytes. The differing interactions of the p‐locus with the ln and b loci, suggest that the leaden and light genes elicit similar morphological changes in melanocyte morphology via different developmental pathways.
Frequency and size of muscle fibers in athletic body build
Authors: Etemadi A. A. , Hosseini F.
Published: February 2005

In one prototype athletic subject and two persons of more average body build complete mid‐point cross sections of the biceps brachii muscle were made. All three cross‐sections were photomicrographed on overlaping fields, and composite photomicrographs of the complete muscle cross section were made. An individual fiber count on these photomicrographs was carried out.

The number of individual muscle fibers in the athlete and the other two persons amounted to 316,243, 227,233 and 199,240 fibers respectively. Sampling methods were also tried on the sections for the evaluation of different estimation procedures. Fiber size distributions were arrayed in frequency polygons in each case. Six thousand fibers, randomly chosen from different parts of the section were measured in each case by means of an automatic counter. The mean fiber diameters are 42.26 ± 7.616 μ in the athletic subject and 24.1 ± 4.583 μ and 22.54 ± 4.919μ in the other two subjects.
The fine structure of the human peridental ligament
Authors: Bevelander Gerrit , Nakahara Hiroshi
Published: February 2005

An electron microscope study was made of the human peridental ligament of the young adult. Examination of several cells which occur in this site exhibit a marked variation in number and distribution of organelles. The fibrous components made up chiefly, if not entirely, of collagen fibers averaged 600 Å in diameter. These fibers usually referred to as principal fibers show an arrangement both in the peridental space proper and also at the surface of the root of a marked irregularity, more so than can be ascertained at the optical level. Our study shows that the arrangement of the principal fibers is more complex than previously described and further that many of the diverse cells present in the peridental space are in an active functional state indicative of the dynamic potential they possess in reference to fibrilogenesis, cementogenesis and osteogenesis in this area.
The ultrastructure of the parathyroid glands of young cats
Authors: Capen Charles C. , Rowland George N.
Published: February 2005

The fine structure of the parathyroid glands of normal rapidly growing cats (9–22 weeks of age) was described and compared with the findings reported in other species. The predominating active chief cells were relatively electron‐dense and contained well developed organelles and frequent secretory granules. Inactive chief cells were slightly larger and had a more electron‐transparent cytoplasm. Cytoplasmic organelles were less well developed and secretory granules were less frequent than in the active chief cells. Oxyphil cells or transitional forms were not identified in the parathyroid glands of kittens. Occasional cilia were observed in chief cells. They arose near centrioles and protruded from the plasma membrane into the intercellular space.
Ultrastructural changes in liver parenchymal cells of the mouse following postnatal cholecystectomy
Authors: Yamada Kazuyori
Published: February 2005

Ultrastructural changes have been induced in liver parenchymal cells of the mouse by postnatal cholecystectomy. The major changes included frequent occurrence of numerous vesicles, frequent development of extensive forms of copious Golgi apparatus and an increase in number of lysosomes and microbodies in the peribiliary cytoplasm, and dilatation of bile canaliculi. The cytoplasm beyond the peribiliary zone, contained numerous large mitochondria which were often associated with abundant granular endoplasmic reticulum. In view of the known cytophysiological roles played by the cytoplasmic components undergoing such changes, an elevated activity of bile secretion is suggested in the liver cells of cholecystectomized animals. The presumed high activity of bile secretion in the cells can be comprehended in terms of a compensatory adaptation to the loss of bile concentrating capability of the biliary system due to the removal of the gallbladder.
Chloride movements during perfusion fixation with glutaraldehyde
Authors: Van Harreveld A. , Khattab F. I.
Published: February 2005

The cerebral and cerebellar cortices of mice were subjected to a histochemical method for the demonstration of chloride after perfusion fixation with glutaraldehyde. Unfixed, nonasphyxiated cortices subjected to the same chloride method were used as controls. Sections of control material showed a rather uniform chloride distribution in which only the pia and the blood vessels stood out as dark structures containing an appreciable amount of chloride. Sections of glutaraldehyde fixed cerebral cortex showed an accumulation of chloride in apical dendrites. In glutaraldehyde fixed cerebellar cortex the chloride accumulated in the fibers of Bergmann and sometimes in the large dendrites of Purkinje cells. The chloride movement during glutaraldehyde perfusion is in all respects comparable with the movement of chloride caused by asphyxiation of the cerebral and cerebellar cortex.
Alterations in blood vessels in X‐irradiated spinal cords of young rats
Authors: Gilmore Shirley Ann
Published: February 2005

Administration of x‐rays (4000 r) to lumbar spinal cords of three‐day‐old rats caused a loss of neuroglia with an inhibition of myelinogenesis, neuronal damage and necrosis. In contrast, the loss of neuroglia following administration of 2000 r is temporary, with myelinogenesis occurring later than normal. Preliminary observations suggested that differences in vascular responses to these two amounts of x‐rays might account for these differing fates of the spinal cords; therefore, this investigation was designed to study further the reactions of the intramedullary vessels.

Rats, irradiated when three days of age, were killed 1 to 27 days later. Some were killed by perfusion with Monolite Fast Blue BNVSA Paste, a substance retained in the vessels and readily visualized on microscopic examination. The remaining rats were decapitated, and spinal cords were stained by Gomori's method for alkaline phosphatase. The earliest consistent alteration, a decreased number of vessels, was noted seven days following irradiation with either dose. Rats receiving 4000 r had marked losses of blood vessels, vasodilatation and necrosis by 15 days post‐irradiation; whereas, a decreased number of vessels was the only change noted in rats irradiated with 2000 r. Alterations in rats receiving 4000 r remained the same or became more severe throughout the study; spinal cords in rats receiving 2000 r returned to normal. These vascular alterations correlate well with the changes in other spinal cord components described previously by this investigator.
A correlative investigation of the human rectovaginal septum
Authors: Milley Paul S. , Nichols David H.
Published: February 2005

Anatomists and gynecologists have debated the existence of a rectovaginal septum in the human female. In this investigation the connective tissue between the vagina and rectum has been reexamined by both dissection and light microscopy in four specimen types. Specimens studied and compared totaled 143 and represent an age range of from eight fetal weeks to 100 years. Included were specimens from patients with different degrees of parity and both normal and abnormal pelvic visceral support.

It has been shown that a definite rectovaginal septum exists in the human female and it is probably the homologue of the male rectovesical septum. The septum is well formed by the fourteenth fetal week and consists of a thin vertical sheet of dense connective tissue which is translucent in the fresh state. In the coronal plane the septum parallels the sacral curvature. It also curves posterolaterally to become fused with the parietal endopelvic fascia. The septum extends inferiorly from the rectouterine peritoneal pouch to the perineal body. It is usually adherent to the posterior aspect of the vaginal connective tissue, capsule. This adherence, together with the difficulty in identifying it histologically may explain why the existence of the rectovaginal septum has been denied.
Distribution and weights of various cell types in the rat stomach
Authors: McCabe Donald R. , Kent Thomas H. , Hogben C. Adrian M.
Published: February 2005

A line sampling method was used to determine the relative volumes of various cell types in the mucosa of the body of the rat stomach. The technique was simple to perform, reproducible and independent of many variables inherent in previous cell counting techniques. Weights of the various cell types were calculated from stomach weights, relative mucosal volumes and cell concentrations in the mucosa. In the five animals studied, gastric body mucosa average 40% of the stomach weight and 1.8 gm per kg of rat. Parietal cells averaged 40% of the gastric body mucosa weight and 0.7 gm per kg of rat. There was no significant variation in parietal cell concentration throughout the gastric body mucosa of the rat. Chief cells averaged 18% of the gastric body mucosa and 0.3 gm per kg of rat. Up to three‐fold variations in chief cell concentration occurred with highest concentrations near the greater curvature and in proximal areas of the body mucosa. Mucous surface cells, mucous neck cells, and connective tissue made up 22, 9, and 7% of the body mucosa respectively and showed only minor varitions in concentration.
Fine structure of neuromuscular relationships in mouse heart
Authors: Thaemert J. C.
Published: February 2005

Hearts of mice were fixed in osmium tetroxide, embedded in Epon, sectioned for electron miscroscopy and stained with uranyl acetate. Various regions of these hearts were examined for neuromuscular relationships. Unmyelinated nerve bundles with partial Schwann cell investment, frequently are present within the perivascular spaces of capillaries and arterioles in the myocardium of all regions studied. Neuromuscular junctions are located in the myocardium of the right atrium, the inter‐ventricular septum and the outer ventricular walls. Neuromuscular junctions seem to be absent from the myocardium of the apex. Previously reported neuro‐effector relationships within various tissues are discussed in relation to the findings of this study.
Structure and evolutionary implications of the musculi arrectores pilorum in chiroptera
Authors: Quay W. B.
Published: February 2005

Skin samples from 16 genera and 19 species of bats were studied histologically. These and review of the literature revealed musculi arrectores pilorum composed of smooth muscle present only in Megachiroptera and complex cutaneous striated muscle systems best developed in Microchiroptera. Smooth muscle arrectores of the mid‐dorsal neck skin of Hypsignathus monstrosus are described in detail and resemble those of generalized structure in other mammalian Orders. Shoulder pouches of the epaulet bats (Epomophorus and Epomops) contain compound smooth and striated muscle systems for eversion of hair tufts and pouch respectively. An evolutionary trend within the Chiroptera of reduction in smooth muscle arrectores and replacement by integumentary striated muscle fibers is suggested.
Differentiation of growth hormone‐ and prolactin‐containing acidophils with peroxidase‐labeled antibody
Authors: Baker Burton L. , Midgley A. Rees , Gersten Brian E. , Yu Ya‐Yen
Published: February 2005

In order to verify the concept that growth hormone and prolactin are contained in two different populations of acidophils, sections of Bouin‐fixed rat hypophyses were stained immunochemically. For this purpose the histochemical demonstration of peroxidase was utilized after sequential application to the tissue section of rabbit antiserum to human growth hormone (or antiserum to rat prolactin) followed by application of peroxidase‐labeled sheep antiserum to rabbit gamma‐globulin. It was found that growth hormone cells and prolactin cells, when revealed immunochemically, corresponded structurally to cell types that could be differentiated with reasonable certainty in sections stained with the Masson trichrome procedure. When delineated immunochemically, growth hormone cells were larger and more densely arranged in the adult male than in the intact female; they exhibited little change in the female after ovariectomy. In contrast, prolactin cells were large and frequent in the female hypophysis but were small and less frequent in the male and in the female after ovariectomy. By double‐staining, growth hormone and prolactin cells were differentiated in the same section. It was concluded that (a) growth hormone and prolactin are contained in, and presumably secreted by, two different populations of acidophils; and (b) the Masson procedure permits a reasonably accurate differentiation of the two cell types.
The fine structure of autonomic nerves after vital staining with methylene blue
Authors: Richardson K. C.
Published: February 2005

Autonomic nerves in the rat, mouse, guinea‐pig and cat were vitally stained with methylene blue and examined electron‐microscopically after fixation in potassium permanganate. Dense patches in the axoplasm and swelling of mitochondria were found in the stained axons. By controlling the pH and saturating with oxygen, only cholinergic axons were stained at pH 6.5–7.0 whereas at pH 5.0–5.3 both cholinergic and adrenergic axons stained. Similar results were obtained by immersion in a bath at controlled temperature as with close arterial perfusion of dye into pelvic viscera. The intermediate pH at which adrenergic axons begin to stain could not be determined. However, as a means of identifying cholinergic axons, particularly those sectioned at a level where no agranular vesicles occur, M B staining is unreliable because not all cholinergic axons respond. In sympathectomized rat iris lacking adrenergic axons altogether, some of the persisting cholinergic axons remained unstained. Experiments with M B thiocyanate and M B chloride in phosphate‐citrate or succinate‐HCl buffer indicated that purity of dyestuff was less important than pH control. Methods for electron‐microscopical demonstration of acetylcholinesterase are more useful for distinguishing cholinergic axons especially if adrenergic nerve vesicles are I reserved in the same preparation by the initial fixation.
Ultrastructure of schwann and perineural sheaths at the mouse neuromuscular junction
Authors: Saito Atushi , Zacks Sumner I.
Published: February 2005

Intramuscular nerve branches are covered by a complex of epithelial sheaths which decrease in thickness and complexity as the nerves branch to reach ultimate termination of neuromuscular junctions. The outermost layer (epineurium) of intramuscular nerves is composed of thin processes of fibrocytes lacking basement lamina and associated with parallel bundles of collagen. Internal to this layer are two or three layers of interdigitating perineural cells covered with basement lamina. The innermost layer is frequently incompletely covered by basement lamina within the perineural sheath. Schwann cells covered with basement lamina enclose myelinated and unmyelinated axons.

In the region of neuromuscular junctions, the basement lamina of Schwann cell processes merge with the myofiber basement lamina. Thin perineural cell processes form a bell‐shaped covering which does not reach the muscle basement lamina. The relationships of myelin to the axon as the terminal axon emerges from the Schwann cell closely resembles the relationships of these structures in nodes of Ranvier.
Histochemical observation on the phosphatase activities of the differentiating taste bud
Authors: Nada Osami , Iwayama Takashi
Published: February 2005

Adenosine triphosphatase, alkaline phosphatase and acid phosphatase activities of the developing taste buds were observed histochemically in the rat circumvallate papilla.

Adenosine triphosphatase activity was already demonstrable in a cluster of cells in the epithelium of the papilla on the first day of birth, when taste buds could not yet be morphologically identified. The cells with the activity are certainly considered as the differentiating taste bud cells. These cells took the form of a bud similar to the adult one about the fourth day of life.

Alkaline phosphatase activity was demonstrated first on the superficial cell layers of the epithelium of its apical surface as well as on that of the epithelium in the gutter of circumvallate papilla just after birth. The activity in the gutter then rapidly increased, while the activity of the apical surface abruptly decreased and disappeared on the second day of life.

Acid phosphatase was demonstrable only in some cells of the taste bud on the fourth day of life. The final pattern of the activity, which is found in the supranuclear cytoplasm of taste bud cells, was established after the eighth day of life.
The purkinje cell cilium
Authors: Del Cerro Manuel P. , Snider Ray S. , Lou Oster Mary
Published: February 2005

In the course of ultrastructural studies on the cerebellar cortex of young rats a cilium was found in some Purkinje cells. The shaft, which is 1800 to 2000 ÅR thick, has an internal portion inside the cell body and an external one projecting into the neuropile. The basal body is consistently located near the Golgi apparatus. Rootlets with periodic cross‐striations (interperiod distance of 525 ÅR) are attached to the basal body. The size and characteristics of the Purkinje cell cilium and its constituent parts compare with similar structures in the cilia of other cell types of the cerebellar cortex. Whether all or only some of the Purkinje cells have a cilium has not yet been determined. Possible functional roles of these organoids are considered.
The fine structure of the extracellular matrix during epithelio‐mesenchymal interactions in the rabbit embryonic incisor
Authors: Slavkin Harold C. , Bringas P. , Lebaron R. , Cameron J. , Bavetta L. A.
Published: February 2005

The fine structure of the extracellular matrix during epithelio‐mesenchymal interactions in the rabbit embryonic tooth germ is described using light and electron microscopy. Observations are restricted to the labial cervical loop region at the bell stage of development in maxillary and mandibular incisor tooth germs. Histochemical methods demonstrate a PAS‐positive basement membrane between outer enamel epithelial cells and adjacent undifferentiated mesenchymal cells. The metachromatic region circumscribes the dental papilla region, becoming more intense and wider in association with cells illustrative of more advanced stages of differentiation. Ultrastructural observations of the basal lamina associated with outer enamel epithelial cells, cervical proliferating epithelial and mesenchymal cells, and with inner enamel epithelial cells and pre‐odontoblasts are reported. The characteristic mesenchymal filopodia appeared in close proximity to the basal lamina. Microfibrils are seen as depositions on the basal lamina and in association with filopodia. The concentration of intercellular microfibrils is increased when in association with epithelia showing advanced differentiation. Collagen fibrils are frequently noted in peripheral association with mesenchymal cells but not adherent to the basal lamina. Numerous homotypic and heterotypic cell junctions are seen. An understanding of intercellular communication between heterotypic cells may be enhanced by postulating a dual developmental origin for the microfibrils associated with the basal lamina. The under surface of the basal lamina facing the extended mesenchymal filopodia appears to be a significant factor during epithelio‐mesenchymal interactions, subsequent extracellular matrix formation, and morphogenesis.
Ultrastructural organization and histochemical profile of adult fowl choroid plexus epithelium
Authors: Doolin Paul F. , Birge Wesley J.
Published: February 2005

The choroid plexus epithelial cell of adult fowl is columnar with an irregular apical border of smooth‐surfaced microvilli and cilia. Bi‐nucleate cells occur frequently. Coated plasmalemma pits and vesicles (∼ 1000 Å) are present at all margins of the cell. Smaller coated vesicles (600–700 Å), found in variable numbers throughout the apical zone, tend to be concentrated in the Golgi region. Sparse to profuse amounts of granular endoplasmic reticulum (RER) are found throughout the cell with tubular whorled configurations occasionally noted in the subnuclear cytoplasm. Parallel arrays of RER extend from the cell base, around the nucleus, to the Golgi zone. Oval, fine granular masses occur in the subnuclear area. Free ribosomes are distributed throughout the cell. An array of diverse dense bodies and a few multi‐vesicular bodies lie near the Golgi complex. Variable amounts of smooth ER are present in the supra‐nuclear region. Toluidine blue, pH 4.0, demonstrates a heavy subnuclear condensation of cytoplasmic RNA. After sulfation, the apical margin and basement membrane are made metachromatic by Toluidine blue. A diastase‐resistant, strong PAS positive reaction occurs in the apical border and basement membrane. Lateral cell margins are lightly stained with PAS. Alcian blue and colloidal iron intensely color the microvillous border. Bromphenol blue and bromsulfalein heavily stain the apical and basal zones of all cells.
Leucocytic infiltration into the hypoglossal nucleus following injury to the hypoglossal nerve
Authors: Adrian E. K. , Smothermon R. D.
Published: February 2005

Tritiated thymidine was injected into adult female A/J mice at 24, 20, and 16 hours before transection of the left hypoglossal nerve. These animals and uninjured controls that received the same sequence of tritiated thymidine injections were sacrificed by perfusion fixation at either 4, 8, 16 or 35 days after the time of the injury. At all time intervals after injury there were several times more labeled cells in the nucleus of the injured nerve than were found in the right hypoglossal nucleus of the same animals. However, the right hypoglossal nucleus of the injured animals had significantly more labeled cells than were found in the hypoglossal nuclei of the uninjured control animals. Labeled mitotic figures were present in the nucleus of the injured nerve on the fourth day after injury. Since no tritiated thymidine should have been available at the time of injury or afterward to label cells that proliferated in response to the injury, the difference in the number of labeled cells between the injured animals and the controls is attributed to an infiltration of labeled mononuclear leucocytes.
Observations on the histochemical and chemical distribution of glycogen in the chick heart
Authors: Czarnecki Caroline M. , Carpenter Anna‐Mary
Published: February 2005

The distribution of glycogen in chick hearts was studied during incubation and one week following hatching. Concurrent histochemical and chemical studies revealed a gradual increase in the deposition of glycogen during the first half of incubation. During the latter half of incubation the average content of chemically extractable glycogen remained relatively stable until day 19 when a significant decline (p < 0.001) was noted. This decrease was attributed chiefly to the decline in the acid‐soluble fraction.

Throughout the incubation period significantly greater (p = 0.05) amounts of chemically extractable glycogen were present in the left chambers and interventricular septum than in the right chambers. These differences were not evident in the post‐hatched chick.

Histochemically, glycogen was demonstrated in the chick hearts throughout the incubation period, but no appreciable amount was detected in the hearts one week after hatching. Chemical analysis of the latter revealed that the glycogen content was below the threshold thought to be necessary for its histochemical demonstration.

Parallel decreases noted in both the depth of stain intensity and the acid‐soluble fraction serve as further evidence that the acid‐soluble fraction is primarily responsible for the histochemical reaction observed with glycogen stains.
A comparative study of sebaceous gland ultrastructure in subhuman primates. I. Galago crassicaudatus, G. senegalensis and G. demidovii
Authors: Bell Mary
Published: February 2005

The differentiating sebaceous cells in three species of galagos have different structural configurations of cytoplasmic membranes. The type unique to G. senegalensis consists of groups of six tubules, which intersect at common centers. The tubules of this configuration probably represent a specialized form of agranular endoplasmic reticulum. A second specialized form of agranular endoplasmic reticulum is found in all three species of galagos; this configuration consists of grids of intersecting tubules that are ∼400 Å in diameter. Individual tubules of agranular endoplasmic reticulum are also abundant in the cells.

Another disposition of cytopalsmic membranes, found only in G. crassicaudatus, is significantly different from the others. In this structure, membranes intersect in three planes to form hexagrams. All of these configurations are closely associated with single, dispersed profiles of predominantly agranular endoplasmic reticulum and sebum vesicles.
Effects of ACTH on membranous whorls in the adrenal gland of the Mongolian gerbil
Authors: Nickerson Peter A.
Published: February 2005

The ultrastructure of whorls of rough endoplasmic reticulum in the adrenal gland of the Mongolian gerbil (Meriones unguiculatus) was examined during and after treatment with ACTH. Whorls were loosely wound after treatment for one day and consisted of only a few paired membranes. Focal areas of increased tubular smooth endoplasmic reticulum were seen throughout the cytoplasm of the cells. Whorls disappeared altogether after three days of ACTH treatment. The structures reappeared one day after stopping the ACTH injections and seemed to enlarge progressively by addition of membranes to the periphery of the structures. Numerous vesicles and sometimes parallel cisternae of rough endoplasmic reticulum were observed in the cytoplasm of adrenocortical cells containing newly forming whorls. The whorls apparently serve as a readily available reserve of rough endoplasmic reticulum, which can transform into smooth reticulum upon stimulation with ACTH.
The development of the human wrist joint during the fetal period
Authors: Lewis O. J.
Published: February 2005

Recent morphological studies have revealed that the hominoid ulna has become progressively excluded from direct articulation with the carpus by the elaboration of an intervening intra‐articular meniscus, which in gibbons contains a bony lunula. In man this meniscus has merged with the triangular articular disk, forming a confluent proximal articular surface and constricting off a diverticulum of the synovial radiocarpal cavity, the prestyloid recess, which may lodge the ulnar styloid process. The present study reassesses the development of the human fetal joint in the light of these findings. Initially separate radioscaphoid, radiolunate and ulnotriquetral synovial cavities communicate to form a single continuous wrist joint cavity; the pisotriquetral cavity, at first independent, frequently establishes continuity with the wrist joint cavity, the normal condition in most Primates. After the 60 mm C. R. stage the ulna withdraws from the carpus and an intervening meniscus and prestyloid recess are elaborated. In a number of specimens a cartilaginous nodule, the so‐called intermedium antebrachii, has been observed adjacent to the ulnar styloid process. There is little doubt that this nodule, which may ossify, is homologous with the gibbon lunula.
Effects of age and exercise on the extent of the myocardial capillary bed
Authors: Tomanek Robert J.
Published: February 2005

The age‐related response of the ventricular capillary bed to enhanced work loads was investigated in male albino rats. During the 12‐week experimental period young, adult and old animals were trained on a motor‐driven treadmill. Resting bradycardia was found to occur after 8–12 weeks of training. Demonstration of the ventricular capillary bed was accomplished by injecting Pelikan biological ink retrograde into the ascending aorta of a beating heart. Capillary/muscle fiber ratios were slightly (6.5–9.5% ), but significantly, increased in all trained groups. The number of capillaries/mm2 decreased with age but was higher in trained animals. Thus while aging is associated with a decrease in the concentration of ventricular capillaries, chronic exercise provides some mechanism which enhances the extent of the capillary bed.
Continuous trophic influence of chromatolysed gustatory neurons on taste buds
Authors: Zalewski Andrew A.
Published: February 2005

Taste buds are believed to be morphologically dependent on a neurohumor that is supplied by the intact gustatory nerve because after nerve transection the buds disappear. Since taste buds regenerate after reinnervation by peripheral or central fibers of the nodose ganglion, the present experiment was performed to determine whether chromatolysed gustatory neurons could support taste buds. The denervated vallate papillae of adult rats was reinnervated by the central fibers of the nodose ganglion and, after a time sufficient to allow for nerve and bud regeneration, the peripheral fibers of the ganglion were cut. Despite undergoing the typical chromatolytic reaction, the gustatory neurons still maintained the taste buds. The number and appearance of the buds found was similar to that seen in control centrally reinnervated papillae, Transection of the central fibers did, however, cause the disappearance of the buds. The results demonstrate that chromatolysed gustatory neurons can support taste buds, and it is concluded that the metabolic changes which occur in chromatolysed gustatory neurons do not interfere with their trophic function.
Laminated cytoplasmic bodies and annulate lamellae in the cat ventrobasal and posterior thalamus
Authors: Herman Mary M. , Ralston Henry J.
Published: February 2005

Large and small laminated cytoplasmic bodies are reported in neurons and dendrites of the ventrobasal and posterior (PO) nuclear groups of the thalamus of the cat. The bodies are more frequently seen in dendritic profiles than in nerve cell bodies. They differ in size, as well as in number and complexity of orientation of the constituent tubules. Their topographic relationship to endoplasmic reticulum, synapses and adhesion plaques is noted and their possible evolution is discussed.

A single collection of annulate lamellae is described in the perinuclear soma of one neuron.
Plasmacytopoiesis in the pronephros of the carp (Cyprinus carpio)
Authors: Smith A. Mason , Wivel Nelson A. , Potter Michael
Published: February 2005

A light and electron microscopy study of the structure of the pronephros of the carp, Cyprinus carpio, revealed lymphocytopoiesis, plasmacytopoiesis and erythrocytopoiesis. In addition to the lymphocytes of various sizes, there were transitional cells which had characteristics of both lymphocytes and plasma cells. Some of the plasmacytoid cells had a configuration of cytoplasmic granules suggestive of the Russell body formation described in higher mammalian forms. When India ink particles were injected into the fish intraperitoneally, macrophages containing this marker could be found in the pronephros. The highly vascular structure of this organ emphasized the close association of the cellular elements with the circulating blood. In view of the cell population of the pronephros and its role as a major source of cells producing antibody, it may well represent a primitive prototype of the more advanced mammalian lymph node.
The origin of the trabeculated ventricular septum in the chick embryo as determined by radioautographic mapping
Authors: Rosenquist Glenn C.
Published: February 2005

The origin of the presumptive ventricular septum (PVS) in the chick embryo was traced by radioautographic analysis of the movements of tritiated thymidine‐labeled grafts excised from medium streak (MS) to three somite (3S) stage embryos and transplanted to the primitive streak and endoderm‐mesoderm layer of similarly staged recipient embryos. The migration of the PVS was traced from the streak into the heart of the early limb bud (ELB) stage embryos by combining the pathways of at least three labeled grafts, since none of the 15 embryos reported here developed all the way from the MS to the ELB stage.

At the MS stage the PVS cells are in the primitive streak approximately halfway between the anterior and posterior ends of the streak. Beginning at the late medium streak (LMS) stage, they migrate into the mesoderm of the lateral plate, anterior and lateral to the streak; during the early somite stages they are folded to the midline as part of the splanchnic mesoderm, where they form part of the atrial and ventricular myocardium at the 13S stage; they move into their definitive position at the apex of the ventricle by the ELB stage.
Changes in neurochemistry and neuronal morphology after exposure of the mouse brain to lethal levels of focal irradiation
Authors: Samorajski T. , Rolsten Carolyn , Curtis Howard J.
Published: February 2005

The brains of normal and irradiated C57BL/J6 adult female mice were studied for morphologic and biochemical differences at four and six hours after focal brain irradiation when the animals first experienced seizures and, at the terminal phase just prior to death. Focal irradiation of the brain was performed under stereotaxic conditions with microbeams delivered through a 5.0 × 9.0 mm aperture to the dorsal surface of the brain at an adsorbed surface dose of 50,000 rad.

An analysis of variance did not indicate any difference in brain weight or in DNA, RNA, or protein concentration due to irradiation. There was a significant increase in 5‐HT and NE concentration, and in AChE activity in the brains of the irradiated groups. Histochemical observations failed to show differences in the localization of alkaline and acid phosphatase activity. However, localization of ATPase activity associated with the blood vessels was more diffuse in the irradiated regions of the brain. Biochemical comparisons of ATPase activity indicated that there was a change in the subcellular distribution of ATPase enzyme following irradiation. Light and electron microscopic comparisons revealed a selective damage to astrocytes and dendritic processes in irradiated regions of the cortex.