bluuebunny/crossref_metadata_2025 huggingface dataset:
The fine structural localization of some testicular phosphatases
Authors: Tice Lois W. , Barrnett R. J.
Published: February 2005

The distribution of several nonspecific and nucleoside phosphatase activities in rat testis fixed in glutaraldehyde was studied with the electron microscope. Seven apparently discrete distributions of activity were found. Nonspecific phosphatase activity at neutral pH was found in the basement membrane of seminiferous tubules, as well as in pinocytic vesicles in connective tissue cells underlying the tubules. Acid phosphatase activity was associated with the dense bodies of Sertoli cells, and with the Golgi apparatus of all spermatogenic cells. In addition, the Golgi apparatus of spermatogenic cells exhibited activity to both nucleoside di‐ and tri‐phosphates. The Golgi apparatus of the Sertoli cells exhibited both di‐ and triphosphatase activity, but no glycerophosphatase activity.

Triphosphatase activity was also found at the cell surfaces of spermatogenic cells in some stages of development. Spermatogonia and early spermatocytes exhibited activity to both ATP and ITP. Little triphosphatase activity was found at the cell surfaces of secondary spermatocytes or early spermatids, while pronounced activity was seen at the surfaces of late spermatids.
Studies on the fine structure of teleost blood cells. I. Peripheral Blood
Authors: Weinreb Eva Lurie
Published: February 2005

The fine structure of goldfish peripheral blood cells was studied by electron microscopy correlated with light microscopy. Various methods of specimen preparation are described. Optimal preservation for electron micoscopy was attained with fixation in 1% OsO4 in acetate‐veronal buffer (pH 7.3) and embedding in Epon. Electron micrographs of erythrocytes reveal division of nucleoplasm into chromatin and interchromatin material, and continuity between the latter and cytoplasm via nuclear pores. Erythrocyte mitochondria contain longitudinally oriented tubular internal structures. Variations in lymphocyte morphology are noted and the close association between membranes of the nuclear envelope, Golgi apparatus and endoplasmic reticulum is shown. Compound granules, the azure granules of stained blood smears, are described. A distinguishing feature of the granulocytes is their specific granulation. Neutrophilic granules appear to be membrane‐enclosed and contain varying amounts of dense material, the amount depending upon maturation, physiological state or degree of preservation. Specific eosinophilic granules are characterized by a dense matrix enclosing one or more crystalloid bodies. The specific granules of the basophil are large, membrane‐enclosed bodies, demonstrating different degrees of electron density. Similarities between thrombocytes and lymphocytes are evident from light and electron microscope studies. A phylogenetic relationship between vertebrate blood cells in indicated.
Bone development in Japanese quail
Authors: Simmons David J. , Pankovich A. M.
Published: February 2005

The development of the long bones of Japanese Quail was studied histologically and microradiographically at different post‐hatching periods from birth to one year of age. At the level of the mid‐shaft, the woven bone of the neonatal animal becomes thicker by rapid periosteal growth and becomes consolidated by the deposition of bone within large vascular spaces throughout the first month of life. Continued periosteal growth and formation of osteons is most rapid during the second and third month, and the mature architecture of the cortex — primary haversian bone — is established at the end of this period. Osteon formation is more progressive in the tibiotarsus and tibia than in the femur. Replacement osteons are established by remodeling endochondral bone incorporated into the metaphysés near the endosteum, but these deposits delimited by cement lines do not seem to be remodeled to any significant degree. Bizarre resorption cavities attributed to osteolysis were frequently observed in highly mineralized interstitial lamellae.
Comparative anatomical and neurohistological observations on the tongue of the marsupials
Authors: Kubota Kinziro , Kubota Junko , Fukuda Nobumasa , Asakura Shigeharu , Nakagawa Shiro , Masui Mitsuko
Published: February 2005

Macroscopic and neurohistological observations of the red, gray and tree kangaroo and wombat's tongues are described. On the dorsum, three circumvallate papillae, foliate papillae (gland‐duct type), fungiform papillae and filiform papillae are observed. In the wombat, the vallate papillae are shaped like a “lotusnut.” Its summit is broadened, rough, and reaches the level of the dorsal surface. The papillae of the kangaroo are shaped like a “walnut” and are situated below the dorsal surface of the tongue. The vallate papilla is occupied with abundant nerves, thin non‐myelinated and thick myelinated fibers, and ganglion cells, multipolar and unipolar. In the upper area of the wombat's papilla, however, there is a demarcated thin layer of non‐innervated connective tissue. Therefore, taste buds are located in nearly the whole wall of the papilla in the kangaroo, but only in the lateral wall in the wombat, closely associated with the subgemmal nerve plexus. Foliate papillae of gland‐duct type, which connect with the serous glands, have many taste buds innervated with thin fibers from the periductal nerve plexus. Also in this region there are many ganglion cells. This gland‐duct type may be regarded as the primitive form of the common foliate and vallate papillae; i.e., foliate papillae may be developed from a linear gathering of its anlages, vallate ones from a circular gathering and bellshaped vallate form from an atypical type of the circular gathering. Taste buds may serve as a chemoreceptor for gland secretion in the tongue because their position does not exhibit any suitable form to receive the sense of taste. Richly innervated fungiform papillae contain a few taste buds, but poorly innervated ones have none in the upper epithelium. Filiform papillae are of a vascular nature. In the apical region of the tongue Vater‐Pacinian corpuscles of simple type are found.
Vascular networks from explants of human synovialis in vitro
Authors: Bailey J. P. , Cubberley J. B. , Stephens C. A. L. , Stanfield A. B.
Published: February 2005

Explants of human synovialis obtained surgically were cultivated under dialysis membrane in the multipurpose Rose chamber and in Eagle's medium enriched with 20% pooled human cord sera. Within 24 hours monocytes and lymphocytic cells emerged from the majority of explants while spindle and stellate cells appeared later on the second and third days of culture. A monolayer of cells developed in which active mitosis was observed. Between 12 to 15 days, fingerlike projections of cells adjacent to the explants branched out between the cover glass and the monolayer of mesenchymelike growth and by the twenty‐fifth day had developed into anastomosing networks eventually ranging in length from 1.2 to 3.2 mm. Ciné and still phase photomicrographs decumented findings. Vascular networks developed in vitro in 85% of the total 80 Rose chambers examined over an average period of 58 days. Minute vessels, patent for only short distances, were lined with endothelial cells characterized by slender elongated nuclei and with two or three small nucleoli. In contrast, flanking fibroblasts were considerably larger with clear oval nuclei containing conspicuous nucleoli. Differential stains demonstrated reticular fibers and distinct bundles of collagen lying along the vessels, particularly in the area adjacent to the fragment. In the study of rheumatoid arthritis, where vascular lesions are known to occur, it is possible that such preparations may provide favorable test objects.
An electron microscope study of the rat endometrium during delayed implantation
Authors: Warren Robert H. , Enders Allen C.
Published: February 2005

The luminal and glandular epithelia of the rat uterus during delayed implantation have been studied with the electron microscope. The tall columnar cells of the luminal epithelium are characterized by a distinct zonation of organelles. On the free surface there are short microvilli and occasional cytoplasmic extrusions, with terminal bars joining adjacent cells at their apical margins. Beneath the free surface are numerous pinocytotic vesicles and mitochondria. Above the nucleus are a prominent Golgi apparatus with large dilated vacuoles, and numerous dense inclusion bodies. Large clusters of lipid droplets and aggregations of mitochondria occupy the basal zone of the cell.

The apical portion of the gland cell has fewer pinocytotic vesicles and the Golgi is smaller than in the luminal epithelial cells. Dense bodies are numerous above the nucleus. The basal portion of the gland cell is devoid of lipid, but there are often one or more enlarged mitochondria. Although a dense PAS+ substance fills the lumina of the glands, there is no obvious evidence of secretory activity in the glands during delay.

The relationships of the epithelia to the environment of the blastocysts during delay is discussed.
The chondrification of the human ilium
Authors: Laurenson R. D.
Published: February 2005

This report on the early human ilium is based on the Streeter collection, Carnegie Institution of Washington, Department of Embryology, Baltimore. The five phases in chondrogenesis, described by Streeter for the humerus ('49) and the horizons (Streeter, '42) are used in the description of the changes observed in the ilium. From horizon XV (7–8 mm, 30–32 days) to horizon XVIII (14–16 mm, 36–38 days) component cells of the ilium are mesoblasts. In horizon XIX (17–20 mm, 38–40 days) young cartilage cells have appeared. Both phase 1 and phase 2 cells appear in horizon XX (21–23 mm, 40–42 days), the former characterized mainly by the first appearance of intercellular material, the latter by their slender shape and arrangement in tiers. Phase 3 cartilage cells, cuboidal with many vacuoles, appear in horizon XXI (22–24 mm, 42–44 days). Increasing vacuolization of the cytoplasm of cells is noted throughout horizons XXII and XXIII until, in horizon XXIII (28–30 mm, 46–48 days) total disintegration of cells, a feature of phase 5, is evident. Thus the phases of cartilage differentiation described for the humerus are present also in the ilium.
Observations on the ultimobranchial body inRana pipiens
Authors: Robertson Douglas R. , Swartz Gordon E.
Published: February 2005

The ultimobranchial body was investigated in 63 specimens ofRana pipiens.The morphology is described for “typical” (unifollicular) glands and those found in animals in poor physiological (“stressed”) condition. The typical follicular epithelium is of a mixed pseudostratified type and includes “elongate” cells which extend from the basement membrane to the free surface. These contain elongated nuclei, prominent terminal lipid droplets and “deltoid bodies” which are triangular, homogeneously staining structures apical or basal to the nucleus. “Isometric” cells do not extend to the basement membrane. They posses intensely staining nuclei, few lipid droplets and no deltoid bodies. The stressed gland is multifollicular and degenerate. Mitochondria, lipid droplets, deltoid bodies and glycogen have been identified and are located in specific areas of the follicular cells. The secretory products within the lumina of the glands have tentatively been shown to contain acid mucopolysaccharides, carbohydrate‐protein complexes, mucoproteins, lipid droplets and lipid complexes. These secretions may either represent possible precursors to future secretions or a retention of secretions produced during metamorphosis. The ultimobranchial body has shown no indication of degeneration in the adult.

The ultimobranchial body in typicalRanais an active secretory gland which shows no indication of degeneration in normal adult anurans. Furthermore, it responds to fluctuations in environmental conditions as illustrated by its altered structure and varied types of secretion when stressed.
Secretion of protein by the acinar cells of the rat pancreas, as studied by electron microscopic radioautography
Authors: Van Heyningen Huberta E.
Published: February 2005

The secretion of protein by the acinar cells of the pancreas occurs in two steps: the synthesis of the protein from amino acids and its migration through the cell to the acinar lumen. Since very soon (one minute) after the injection of leucine‐H3 the labeled protein is found mainly in the ergastoplasm of the basal half of the cell, protein synthesis is believed to occur in this location. At later intervals the labeled protein is found in the Golgi complex (10 and 30 minutes), and then in the zymogen granules of the apical half of the cell (60 minutes). The newly synthesized protein thus migrates from the ergastoplasm to the Golgi complex, and from there as zymogen granules through the apical half of the cell prior to being released in the acinar lumen.
Measurement of hepatic parenchymal cell and nuclear volume in different classes of vertebrates
Authors: Deb Chandicharan , Boral Mohan Chand , Sarkar Chapala
Published: February 2005

The volumes of parenchymal cells and their nuclei in liver were calculated in white rats, Columba livia (rock pigeon), Calotes versicolor (garden lizard) and Bufo melanostictus (toad); from their optical area and cell thickness. The area was measured from camera lucida drawings. The largest cellular and nuclear volume was observed in rats and smallest in pigeons. The cell volume in toads was similar to that found in rats but they had smaller nuclei. The cellular and nuclear volumes in lizards were smaller than in toads; and in pigeons smaller than lizards. The significant difference, in both cellular and nuclear volumes that has been observed in different classes of vertebrate, cannot be correlated with the evolutionary changes.
Glycogen synthetase in the rabbit tongue and uterus
Authors: Bo Walter J. , Smith Mavis S.
Published: February 2005

UDPG‐glycogen synthetase was studied in the uterus of ovariectomized and ovariectomized‐hormone treated rabbits and in the tongue. Following the biochemical technic of Leloir and Goldenberg it was not possible to demonstrate the enzyme in the uterus of the ovariectomized or ovariectomized treated animals. However, in the tongue the enzyme was present. The data from this study along with previous histochemical studies indicates that the glycogen in the uterine muscle is not synthesized through the UPDG pathway, but is synthesized from G‐1‐P by the action of phosphorylase. Since UDPG‐glycogen synthetase can be demonstrated in the tongue a difference seems to exist in glycogen synthesis between the smooth muscle of the uterus and skeletal muscle of the tongue.
Mast cell distribution in the uterus of cycling and pregnant hamsters
Authors: Harvey Elmer B.
Published: February 2005

In this study the distribution of mast cells in the cephalic, middle, or caudal portions of the uterine horns did not differ. In cross‐sections, however, mast cells were most numerous in the myometrium, intermediate in the tunica vasculare of the endometrium and least in the mucosa. In the endometrium, the mast cells were most numerous in the antimesometrial, least in the mesometrial and intermediate in the lateral quadrants. In the myometrium, however, the relative numbers of mast cells between the quadrants varied according to the day in the estrous cycle.

On days 1 (the day after estrus), 2, 3, and 4, (the day of proestrus) of the estrous cycle, there were respectively 42.7, 21.8, 22.5 and 10.7 mast cells in the endometrium per 12 μ sections. The differences in means between groups was highly significant (P < 0.001). In mated females on 67, 79, 91, 103, 115, and 151 hours after ovulation, there were respectively 9.4, 8.4, 4.7, 5.6, 2.1, and 2.2 mast cells in the endometrium per 12 μ cross‐section. The differences in the means were not significant.

The mean number of mast cells per 12 μ cross‐sections of uteri of ovariectomized females was 20 ± 8. Subcutaneous injections of 0.3 gamma estrogen did not significantly alter the number of mast cells but 0.6 gamma depressed the mean count to 11 ± 7.

It appeared from these studies that the uterine mast cell numbers were related to the cyclic phenomena of estrous, but that the numerical relationship to the time of nidation was not clear.
Ectopic glomeruli in the human and animal kidney
Authors: Moffat D. B. , Fourman Julia
Published: February 2005

Ectopic glomeruli and proximal convoluted tubules were found in the kidneys of the rat, cat, dog, rabbit and ferret and in the human full‐term fetus. They lay in the connective tissue around the main intrarenal vessels and deep to the pelvic mucosa. Their afferent arterioles were long and gave branches to the pelvic mucosal plexus, while their efferents supplied the pelvic mucosa and the medulla, or one or the other of these tissues. In the rabbit the ectopic glomeruli often produced small cysts in the pelvic septum. Degenerating ectopic glomeruli were occasionally found and in the dog the majority of them showed this change. In the adult human kidney, aglomerular arteries supplied both the pelvic mucosa and the medulla and it is suggested that such arteries are the result of degeneration of ectopic glomeruli.
A re‐evaluation of the mastoid region of contemporary and fossil man
Authors: Walensky Norman Aaron
Published: February 2005

This study points out a heretofore unrecognized range of variation in the mastoid area, between modern and ancient man. The mastoid region of modern man was re‐investigated and found to present a very different picture from fossil man. A trend was noted in modern man toward the enlargement of the mastoid process, the eruption of the juxtamastoid process in the digastric fossa and the absence of a pronounced occipitomastoid crest. The conditios were considerably differnt in Neanderthal man. In this group the area consisted of a small mastoid process, a spacious digastric fossa with no intervening juxtamastoid process and an occipitomastoid crest which exceeded or at least equaled, the projection of its mastoid process.

This additional data emphasizes the cranial differences between modern man and Neanderthal man and suggests that the region should be re‐evaluated in light of this new data.
Macrophages in post‐secretory mammary involution in mice
Authors: Mayberry H. E.
Published: February 2005

Vital staining by trypan blue was used to demonstrate macrophages within involuting (post‐secretory), lactating and resting mammae of mice. Involution was produced by removal of the nursing young on the eighth day post‐partum when maximal lactation was present. The number of macrophages in involutin mammae was not significantly greater than that found in the rsting glands of mice receiving comparable injections of dye. Macrophages (coarse, granular accmulations of trypan blue in cytoplasm) in involutin mammae were congregated around and within atrophic alveoli and small ducts, while in lactating and resting mammae they were located primarily in the areolar stroma. Plasma cells, lymphocytes and neutrophils were increased during involution, but the limited leucocytic response did not indicate that a significant inflammatory reaction was active in the process of involution. Difuse parenchymal staining, indicating cellular injury or death, was limited to the epithelium of necroptic ducts and alveoli of involuting glands. Granular deposits of dye, as in macrophages or renal tubular epitelium, were not seen in the resting, lacating or involuting mammary parenchyma.
Histochemical study of monoamine oxidase in central nervous system cultures
Authors: O'Steen W. Keith , Callas Gerald
Published: February 2005

Implants from the midbrain and cerebellum of neonatal rats were cultured in roller tubes for 20 to 30 days. The cultures were incubated in a tryptamine‐tetrazolium solution which demonstrated the enzyme activity of monoamine oxidase (MAO) by the formation of a formazan precipitation. Some cultures were incubated without fixation, while others were fixed in a glutaraldehyde solution prior to incubation. The specificity of the reaction was controlled by withholding the substrate or by treatment of the cultures with an MAO inhibitor. An intracellular localization of the enzyme was observed in small and medium sized neurons, but was absent in the largest neurons. Neuroglial cells, including ependyma, and mesenchymal cells and phagocytes were MAO positive. The formazan granules were scattered throughout cell bodies and into cytoplasmic processes. Glutaraldehyde fixation of cultures prior to incubation for MAO preserved the details of cell structure and enhanced the differentiation of cell types. When fixed and unfixed cultures were compared, glutaraldehyde did not appear to interfere or interact with enzyme localization; however, there was evidence that this aldehyde might be interfering with MAO concentration, since a longer incubation period for prefixed tissue was required to obtain a formazan reaction comparable to that of unfixed cultures.
S35 — liquid — scintillation count analysis of morphogenesis and teratogenesis of the palate in mouse embryos
Authors: Jacobs Richard M.
Published: February 2005

S35‐labeled inorganic sulfate was employed as a precursor of sulfated mucopolysaccharides in a radioassay of embryonic palatine shelves of the offspring of normal and cortisone‐treated mice. Samples, composed of four palatine shelves derived from the same litter, were counted on a liquid scintillation spectrometer. A close correlation has been established between the time of the maximum aggregation of sulfated mucopolysaccharides, as expressed by the relative specific activity of retained S35‐labeled sulfate, and the time of “horizontalization” of palatine shelves in both experimental groups.

The competence of embryological mechanism of palate closure has been related to the developmentally normal relative increase of the concentration of sulfated mucopolysaccharides, viewed as a factor maintaining maximum visco‐elasticity and minimal swelling of palatine shelves.
Effect of age of the donor and recipient on the development of transferred golden hamster ova
Authors: Blaha Gordon C.
Published: February 2005

Ova were removed from donors 63‐68 hours after ovulation and placed in the uteri of pseudopregnant recipients of the same pregnancy age. In transfers of ova from young (2 1/2‐6 month) to old (14–18 month) golden hamsters, only 8.3% developed into term fetuses. From old donors to young recipients, 4.5% of ova developed to term fetuses. In transfers of ova from young donors to young recipients, 49.2% of ova developed into term fetuses. There was no significant difference in percentage of fetal development between the two groups containing old females. The difference between these and the control (young to young) group was highly significant.

There was a significantly lower number of ova recovered from old donors. At time of transfer, over one‐sixth of the ova from old donors consisted of only one to four cells. At seven and one‐half days, embryos developing from ova of old donors in uteri of young recipients were retarded and malformed.

It is concluded that while the uterine environment in old hamsters appears inadequate to foster normal fetal development, there are also fewer ova ovulated in old females and these ova more frequently develop abnormally.
The effect of ovarian and hypophyseal hormones on mammary gland epithelial cell proliferation
Authors: Traurig Harold H. , Morgan Charles F.
Published: February 2005

Castrated and castrated and hypophysectomized female mice (BALB/c) were injected subcutaneously with estradiol‐17β (0.5 μg or 1.0 μg/day) and progesterone (1.0 mg or 3 mg/day) in addition to prolactin (1.0 mg), oxytocin (1.0 IU) or growth hormone (1.0 mg), alone and in combination for 10 or 15 days. Twenty‐four hours after the last hormonal treatment, tritiated thymidine (0.7 μc/gram body weight) was injected intravenously, and the mice sacrificed six hours later. Tissue from the inguinal mammary glands was removed and processed for radioautographic, histological and whole mount study.

Radioautographs of hematoxylin stained sections of mammary tissue from each animal were selected. Under oil immersion, 2,000 epithelial cells were consecutively counted and the number of labeled cells noted. Results are expressed as the per cent of labeled epithelial cells.

All hormonal treatment, except oxytocin alone, caused a significant increase in per cent of labeled cells as compared to castrated, untreated animals. The per cent of labeled cells depended, in general, on the dosage and duration of treatment. Combinations of growth hormone with estradiol‐17β and progesterone did not augment epithelial proliferation. The addition of oxytocin or prolactin to the estradiol‐17β (0.5 μg) — progesterone (1.0 mg) combination significantly increased the per cent of labeled cells.

Prolactin, but not oxytocin, augmented epithelial proliferation in similarly treated castrated and hypophysectomized mice. Combinations of estradiol‐17β (1.0 μg) and progesterone (3.0 mg) with oxytocin or prolactin did not significantly augment epithelial proliferation as compared to ovarian steroid treatment alone.
The fine structure of intercellular substances and rounded cells in the incisor pulp of the guinea pig
Authors: Han Seong S. , Avery James K.
Published: February 2005

The fine structure of intercellular substances and rounded cells of the incisor dental pulp of guinea pigs is described. The extracellular fibrils are of two kinds; collagen with typical cross‐striations, varying from 400–700 Å in diameter, and fine fibrils of 100–120 Å in diameter. In cross section the latter fibrils appeared to be composed of three or four smaller subunits of less than 50 Å in diameter. The collagen fibril in the dental pulp appear singly or in small bundles of about a dozen or more fibrils. The fine fibrils are often aggregated along the cell surface.

The ground substances are finely granular to fibrillar and show localized clumping which is related to fibrillar elements. The ground substances form an incomplete covering of 200 Å or more in thickness surrounuding collagen fibrils. When the collagen fibrils make a bundle, the sheath of grouund substances around one fibril becomes fused with that of adjacent fibrils.

Rounded cells including macrophages, lymphocytes and eosinophils are present in the pulp. The fine structure of these cells is similar to that found in the same types of cells previously observed in other organs.
Analysis of cortical and nuclear lens proteins by a combination of paper and starch gel electrophoresis
Authors: Maisel H. , Goodman M.
Published: February 2005

A comparison of the soluble proteins of lens cortex and nucleus of several adult mammalian lenses, using a combination of paper and starch gel electrophoresis, revealed significant differences in the distribution of alpha and gamma crystallins. At least 2–5 gamma crystallin proteins of different molecular size were not detected in the cortex, but were found in the nucleus. These proteins correspond to the category of embryonic lens protein as defined by Francois and Rabaey ('57). Such a protein is synthesized almost entirely before birth, and thus accumulates mainly in the nucleus of the adult lens. In contrast to the mammalian lens, the adult chick lens contains only one protein which is present in significantly lower concentration in the cortex when compared with the nucleus. This protein is the major beta crystallin component, which is first detected during embryogenesis, at the time of appearance of the primary lens fibers. The reason for the decreased synthesis of these proteins in adult life remains to be elucidated.

Differences were also noted in the relative concentration of alpha crystallin in mammalian lens nucleus and cortex. The smaller of the two alpha crystallin molecules was markedly decreased in the nucleus, probably the result of precipitation with age into insoluble protein (Francois and Rabaey, '57).
Electron microscopic studies on the thyroid gland of a teleost, seriola quinqueradiata
Authors: Fujita Hisao , Machino Mitsuo
Published: February 2005

The thyroid gland of normal specimens of the teleost, Seriola quinqueradiata, about 50–70 cm in length, obtained in April, were studied with the electron microscope. The apical surface of the follicular cell is irregular in outline and has fewer microvilli than that in higher vertebrates. The rough‐surfaced endoplasmic reticulum is well developed throughout the cytoplasm of the follicular cell, as in the higher vertebrates, and free ribosomes are widely distributed in the matrix of the cytoplasm.

In all the follicular cells, there are several less dense or moderately dense droplets which are considered to be derived from Golgi elements. In some droplets occur aggregates of numerous wavy, fine filaments and crystal consisting of groups of thick needle‐like fibrils. Each fibril is 110–120 Å in diameter and composed of three layers comprising a less dense layer 35–40 Å thick, between two layers 35–40 Å in thickness. Dense granules such as those commonly found in the higher vertebrates were not observed in the thyroid cell of this fish, though a few round or oval bodies, which might be lysosomes, containing small vesicles, membranous structures, or wrapped whorled lamellae were noticed.

The fine structure of the pericapillary region is similar to that of the higher vertebrates, though the endothelial pores are not observed.
The extracellular compartment of the cerebral cortex
Authors: Bondareff William
Published: February 2005

Specimens of mouse and rat cerebral cortex, fixed by immersion in osmium tetroxide and by perfusion with formalin‐osmium tetroxide were prepared for electron microscopy. The extracellular compartment, consisting of interendothelial cell spaces, capillary basement membranes and extracellular spaces between adjacent elements of neuropil, formed a morphological continuum with capillary lumina. A delicately fibrillar, extracellular matrix characterized the basement membranes and extracellular spaces of the neuropil. Desmosome‐like junctional complexes occurred between endothelial cells and between adjacent neuroglial cells.

It is suggested that in the cerebral cortex molecular species from blood which pass through the basement membranes are further distributed in the cytoplasm of astrocytes. Astrocytic cytoplasm appears, then, to have assumed the histophysiological function of the connective tissue ground substance in other parts of the body. The relative constancy of the extracellular compartment as determined physiologically may relate to electro‐osmotic phenomena.
The pattern of innervation of the extrinsic ocular muscles and the intra‐orbital ganglia of the albino mouse
Authors: Mahran Zaghloul Y. , Sakla Francois B.
Published: February 2005

The innervation of extra‐ocular muscles of albino mice, aged 1, 10, 20, 30 annd 120 days, was studied in serial sections cut in the three main planes. Some orbits were fixed in Bouin's and others were fixed in a mixture of: 5% potassium dichromate, 5% mercuric chloride and 5% potassium chromate. All sections were stained with Holmes' silver stain. The following nerve endings were described:

(a) Preterminal nerve fibers parallel to the muscle fibers end in 1–3 motor endplates in several muscle fibers and others form several en grappe end‐plates on one muscle fiber. (b) The muscles are rich in muscle spindles which have very thin capsules. Two spindles may lie side by side. (c) One or more nerve fibers form spirals around muscle fibers.

Multipolar nerve cells were found:

(a) Within the sclera, (b) Within the short ciliary nerves, (c) A complete ganglion formed of 20 cells was found along the inferior division of the oculomotor nerve.

Unipolar nerve cells were seen along the nasociliary nerve. Harder's gland was innervated by a peri‐acinar plexus which sent nerve fibers between the cells as nerve endings. The significance of the findings was discussed.
The use of D‐L ethionine in the transplantation of pancreatic tissue in hamsters
Authors: House E. L. , Pansky B. , Jacobs M. S. , Strebel R. , Payan H.
Published: February 2005

In order to eliminate the adverse effects of the secretion of the exocrine tissue on the islets in the pancreatic transplants the hosts were injected with D‐L ethionine. Twenty‐six male hamsters were divided into two groups. All animals received subcutaneously 1 mg per gram of body weight per day of a 5% aqueous solution of ethionine. In addition, each received 3 mg of cortisone (25 mg per ml) two days before transplant and 1 mg on the fifth and twelfth post‐transplant days. In group I, the ethionine was begun seven days before transplant and was continued for six days after neonatal pancreas was placed in the cheek pouches of the hosts. In group II, ethionine was started on the day of transplantation and was continued for 13 days. Growth and differentiation were checked for up to 56 days. Growth in both groups was comparable to that in animals receiving cortisone alone. Histological examination revealed neither cyst formation nor interstitial secretion leakage in any of the ethionine animals. In both groups, the differentiation of islets was far superior to that found in untreated hamsters, with 85% of the hosts in group I and 55% of those in group II showing islets.
The conducting system of the heart of the house sparrow, Passer domesticus indicus
Authors: Yousuf Najma
Published: February 2005

In the heart of Passer the specialized conducting tissue develops earlier than the nervous elements. The sinuatrial and the atrioventricular nodes appear simultaneously at the 15 mm stage and the atrioventricular bundle at the 23 mm stage. During development the sinuatrial node shifts its position due to the gradual absorption of the sinus venosus into the right atrium. The caudal end of the interatrial septum is enlarged to accomodate the compound atrioventricular node. In the adult bird the bundle branches extend through the atrioventricular valves of their sides and reach the other wall of the ventricular cavity. Among the specialized tissues, the sinuatrial region is the first to receive the nerve supply. The atrioventricular nodal and bundle regions are innervated by the ganglia present at the atrioventricular sulcus. The ganglionic cells are bipolar or multipolar. The nerve fibers terminate in “end‐bulbs.” Only the atrioventricular node shows a few fine nerve fibers within its substance. No direct nerve connection is present between the nodes and the bundle. It seems that the nervous elements present in the regions of the specialized tissues are concerned only with the control of the activity of these structures.
Variations in the circle of willis in Macaca mulatta
Authors: Kassell Neal F. , Langfitt Thomas W.
Published: February 2005

The circle of Willis was dissected in 75 Macaca mulatta monkeys, and the anatomy is described and compared with several series of human specimens. The principal difference between monkey and man is the presence of a single distal anterior cerebral artery in the former, and the most common anomaly in the moneky is an anterior communicating artery proximal to the junction of the anterior cerebral arteries.

A large vessel joining the internal carotid arteries and an accessory branch of the anterior cerebral artery, probably communicating with the external carotid circulation, were found in a small number of our specimens. In man the posterior communicating is significantly reduced in diameter far more frequently than the anterior communicating artery, whereas the reverse situation obtains in the monkey.

In general, the intracranial distribution of blood in the moneky is the same as in man, because the similarities in the normal anatomy and variations i the circle of Willis outweight their differences. However, physiological data on collateral cerebral circulation will be more meaningful when it is based on the arterial anatomy in each preparation.
Fine structural observations of the absorption of lipid particles in the small intestine of the rat
Authors: Rostgaard RøRgen , Barrnett Russell J.
Published: February 2005

Globules or particles of material, 50 Å to 1000 Å in diameter, stained with Pb++ to become dense, occurred between, on, or within the microvilli of the absorptive cells of the proximal jejunum of rats which had been fasted for 48 hours and fed corn oil one hour before sacrifice. This material was demonstrable in tissues fixed in glutaraldehyde, osmium tetroxide, or both fixatives providing Pb++ staining occurred. No or very little stainable material was present in fasted rats. These findings were correlated with in vitro studies on negatively stained or Pb++ stained solutions of micelles. The absorption of particulate lipid by the microvilli of the epithelial cells of the small intestine is discussed.
The fine structure of differentiating fibroblasts in the incisor pulp of the guinea pig
Authors: Han Seong S. , Avery James K. , Hale Lawrence E.
Published: February 2005

The differentiation of the fibroblast was followed in the dental pulp of continuously growing incisors of the guinea pig. Based on the ultrastructure, the processes of differentiation of the fibroblasts might be conveniently broken into three stages; Stage I – period of early differentiation, Stage II – period of maturation and functioning, and Stage III – period of regression.

During Stage I the cell had structural characteristics shared by other less differentiated cells. The endoplasmic reticulum was poorly developed, showing vesicular to tubular profiles. The ribosomes were abundant but were mostly distributed in free form. Mitochondria were small and had irregular interiors.

Stage II was characterized by a striking development of the rough‐surfaced endoplasmic reticulum, which appeared in various shapes and sizes. The Golgi complex was enlarged, and contained some fibriller materials in dilated portions of its membraneous elements. Other features described in the cytoplasm of fibroblasts from other sources were confirmed.

Stage III was characterized by the decrease in size and number of various cytoplasmic constituents and was considered to represent cells in the state of regression.
Timing of maturation and fertilization of the sheep egg
Authors: Dziuk P. J.
Published: February 2005

Eggs of sheep were recovered at known intervals before or after controlled ovulation. They were examined for cytoplasmic and nuclear changes. The vesicular nucleus in the follicular egg persists to 15 hours before ovulation when the chromatin becomes more compact and dense. The first metaphase lasts from 13 hours before ovulation to shortly before ovulation. The formation of the first polar body occurs from four hours before ovulation to ovulation. Normally sheep eggs have formed the first polar body by the time of ovulation and are in the seocond metaphase. Cumulus cells and corona cells are present on the egg at ovulation and for a few hours afterwards. Sperm penetration does not begin ordinarily until at least three hours after ovulation. The male pronucleus forms from 3 to 9 hours after ovulation at about the same time as the female pronucleus. Pronuclei fusion occurs 11 to 22 hours after ovulation. The first mitotic division takes place usually 19 to 24 hours after ovulation although 2‐called eggs were seen at earlier times.
Intimal hypertrophy in coronary arteries and considerations of the papillary muscle arteries (man)
Authors: Boucek Robert J. , Takeshita Ruth , Brady Al H.
Published: February 2005

Intimal hypertrophy is located irregularly along the coronary arteries. These irregular formations appear related to areas where accentuated intramural physical forces develop. Intimal hypertrophy develops diffusely around ostia of secondary branches apparently due to its anisotropic expansion with each pulse pressure wave. Discrete intimal hypertrophy occurs near the ostium of branch arteries which are guarded by a circumferential muscle. Diffuse intimal hypertrophy occurs in arteries supplying the posterior papillary muscles, and conversely, a barely detectable intima is seen in the arteries to the anterior papillary muscles or in the branch arteries to the ventricular wall. Intimal hypertrophy may be related to areas where naturally occurring shear or radial forces are accentuated. Regional intimal hypertrophy is present by 12 years of age in man and increases in amount and in its diffuseness with age.
Anatomy of the sinus node, AV node and os cordis of the beef heart
Authors: James Thomas N.
Published: February 2005

The bovine sinus node is in a location similar to that in the human and canine hearts, but it contains no central large artery whereas the sinus node in the other two species is distinctly organized about such an artery. This suggests the bovine sinus node may function as a more primitive structure. The arterial supply of the bovine sinus node originates from the proximal left circumflex artery. The AV node and bundle are similar in all three species in location and internal anatomy. The human and bovine AV node and bundle are supplied by a single artery entering from the posterior wall of the heart, while the dog has an equally large branch to this region from the septal artery.

The os cordis is a large constant bone lying near the junction of the interatrial and interventricular septa of the beef heart and extending anteriorly into the AV valve rings, especially the right. The AV node lies parallel to the os cordis on its right atrial side and the AV bundle courses beneath the bone. Possible functions of the os cordis are considered.
The origin of the lymphocytes in the appendix and tonsil iliaca of the embryonic and neonatal rabbit
Authors: Ackerman G. Adolph
Published: February 2005

The appendices and tonsils iliaca of 198 embryonic and neonatal rabbits between 26 days of gestation and 18 days after birth have been examined. Special cytological and histochemical techniques and light and phase microscopy have been employed in order to determine the origin of the lymphocytes in these lympho‐epithelial organs.

Sequential developmental and cytological changes in the appendices and tonsils iliaca of the embryonic and neonatal rabbit indicate that the first lymphocytes are of small and medium size and appear by the twenty‐ninth day of development, viz., two to three days prior to birth. Lymphoblasts are not evident until a short time after birth when the lymphocytic nature of these organs has been established. The first lymphocytes in the appendix and tonsil iliaca appear to develop in situ by the direct transformation of reticular or mesenchymal cells. Lymphocytes tend to migrate toward the mesenchymal condensation of the so‐called domed elevations of the appendix and tonsil iliaca or remain in the connective tissue beneath these domed structures. In addition, lymphocytes enter the appendix and tonsil iliaca via the blood stream at or immediately after birth. These lymphocytes intermix with other lymphocytes in these organs and undergo proliferation within the lamina propria and developing lymphocytic nodules.

Morphological evidence strongly suggests a dual origin or source of the lymphocytes in the developing appendix and tonsil iliaca of the rabbit; a population of lymphocytes derived originally from reticular cells and a population of lymphocytes derived extra‐appendiceally possibly of thymic (epithelial) origin. Neither the origin of lymphocytes or lymphocytic precursors from appendiceal epithelial cells nor the derivation of lymphocytic nodules from appendiceal crypts could be substantiated in this investigation. The mode of origin of lymphocytes and subsequent manner of lymphocytic development in the appendix and tonsil iliaca of the embryonic and neonatal rabbit differ markedly from that observed in the embryonic thymus and bursa of Fabricius.
Presence of a ‘cell coat’ rich in carbohydrate at the surface of cells in the rat
Authors: Rambourg A. , Neutra Marian , Leblond C. P.
Published: February 2005

To find out whether or not mammalian cells have a surface coat, over 50 cell types were examined in rat tissues stained with the periodic acid‐Schiff technique for glycoproteins or the colloidal iron technique for acidic carbohydrates.

With both techniques, nearly all cells investigated are outlined by a thin, but definite band of stained material, indicating the existence of a surface layer. The surface layer is uniform in leucocytes, fibrocytes and other cells of mesenchymal origin. This is true in neurons too, although associated structures may also be stained. In simple epithelia, the layer appears thicker at apical than at lateral and basal surfaces. (At the basal surface, the layer separates the cell from the basement membrane, which is itself colloidal iron negative and therefore is not part of the cell coat.) Finally, the layer is usually interrupted at the tight junction of terminal bars (where the cell interspace disappears as the plasma membranes of adjacent cells fuse). This finding confirms that the layer is not part of the plasma membrane itself but is a surface ‘cell coat.’

In agreement with biochemical data, the staining properties indicate the presence of glycoprotein(s) and acidic residues in the coat of rat cells.
Glomerular ultrastructure in the kidney of a hibernating animal
Authors: Zimny Marilyn L. , Rigamer Elmore
Published: February 2005

Kidney samples were obtained from ten hibernating and ten control 13‐lined ground squirrels. Citellus tridecemlineatus. The tissue was fixed in cold buffered 2% osmium tetroxide, dehydrated in graded alcohols and embedded in Maraglass. Sections were made with glass knives on a Porter‐Blum microtome and viewed with RCA‐EML and RCA‐EMU 3 electron microscopes. Observations and comparisons were made of the glomerular capillaries in samples from both groups. In comparison with data on other animals reported in the literature, the basement membrane of the renal glomerulus of the control ground squirrel is approximately twice as thick, averaging 2,000–2,500 Å in width. Hibernation results in several structural modifications of the glomerular ultrafilter as follows: (1) the endothelial pores are decreased in number and size; (2) the podocytic foot processes are swollen and the slit pores reduced in size; and (3) the basement membrane thickens, averaging 4,000–5,000 Å in width, and becomes irregular in contour. It is concluded that the porosity of the glomerular ultrafilter decreases during hibernation. This aids in explaining the decrease in the rate of urine formation which occurs during this time of lowered body temperature and metabolic depression.
Initiation of irreversible differentiation in vaginal epithelium
Authors: Barker Thomas E. , Walker Bruce E.
Published: February 2005

Ovariectomized mice were given estrogen and progesterone either independently, or simultaneously, or in sequence. Thymidine‐H3 was also injected, and the tissues were radioautographed. Analysis of modulation and differentiation was based on the morphological changes seen in cell populations identified by the presence or absence of radioactive nuclei. Estrogen induced cells newly formed in the basal layer to differentiate into a stratified squamous, keratinizing epithelium but did not convert the slowly proliferating surface cells. Progesterone accelerated basal cell proliferation, although this effect was expressed about a day later than when estrogen was used. When both hormones were used in succession, neither could do more than modify the appearance of the cells produced under the influence of the other hormone. However, either hormone could cause proliferation, migration and differentiation of cells from the same basal cells that had previously been the source of cells induced to differentiate by the other hormone. Therefore, the same basal cells can give rise to either stratified squamous or mucous epithelium. Shortly after cells leave the basal layer under the influence of one hormone they cannot be induced to follow the opposite path of differentiation by reversal of hormone treatment. That is, estrogen or progesterone can induce true differentiation as cells leave the basal layer, but only modulation above this level. Consequently, the initiation of relatively irreversible differentiation in this system is closely associated with the stage at which a cell is produced by mitosis from a less differentiated cell and does not appear related to obvious cytoplasmic differentiation.