bluuebunny/crossref_metadata_2025 huggingface dataset:
Scanning electron microscopy of microcorrosion casts; intracranial and abdominal microvasculature in domestic animals
Authors: Anderson Bettina G. , Anderson Wesley D.
Published: February 2005

The use of methyl methacrylate corrosion casts prepared from portions of the vascular system has made it possible to examine numerous and extensive areas of microscopic structures on a 3‐dimensional scale with the scanning electron microscope. By this means we have examined the arterial microvasculature of intracranial vessels among three domestic animal species. In addition, these vessels have been compared with the terminal branches of abdominal arteries in the dog. The results of this study suggest that the sphincteric control mechanisms of the vessels in the two regions may be structurally different from one another.

In the case of the intracranial vessels, the terminal portion of the arteriole is continued by a precapillary arteriole composed of a chain‐like series of muscular constrictions. This is most suitably described as a precapillary sphincter area, which terminates at the capillary. In the abdominal vessels, the precapillary arteriole is generally followed by a single precapillary sphincter at the origin of the capillary. These morphological characteristics may account, in part, for the difference in response of vessels in these two regions in hypovolemic shock.
Development of the human optic disc: Light microscopy
Authors: Rhodes Roy H.
Published: February 2005

Human embryonic and fetal optic discs were studied in semithin sections stained with silver and toned with gold, in a series ranging from 7 to 21 weeks of gestation. The observations suggest that Bergmeister's papilla forms by proliferation of glial cells in the optic disc rather than by sequestration of retinal glia by axons growing through the region. A possible stimulus for such a glial proliferation is hypothesized to be traction on the anterior face of the disc exerted through the primary vitreous. The formation of the glial sheath of the hyaloid artery also appears to be a consequence of traction from the primary vitreous.
Developmental correlation between hypothalamic gonadotropin‐releasing hormone and hypophysial luteinizing hormone
Authors: Gross Douglas S. , Baker Burton L.
Published: February 2005

Considerable evidence indicates that the pituitary‐gonadal axis is active in the fetus, but little is known about the relative times in development when the brain begins to secrete gonadotropin‐releasing hormone (GnRH) and the hypophysis begins to secrete gonadotropin. The objective was to correlate the time of appearance of GnRH in the median eminence and organum vasculosum of the lamina terminalis (OVLT) with differentiation of LH‐gonadotropes in the hypophysis of the fetal mouse by means of immunocytochemistry. Mice were studied at 15, 16, 17 and 19 days of gestation with the peroxidase‐antiperoxidase (PAP) method of Sternberger. GnRH was first detected at 17 days of gestation in presumptive axons and axon terminals located adjacent to the superficial portal capillaries near the surface of the median eminence and close to the capillaries of the OVLT. LH‐gonadotropes also were found initially at 17 days of gestation. They were prominent in the ventral half of the pars distalis. Most of these cells were ovoid or slightly angular, and almost all abutted one of the numerous sinusoidal capillaries present at this age in development. The number and staining intensity of both LH‐gonadotropes and GnRH foci increased by 19 days. The close temporal relationship between the developmental appearance of GnRH and its target cell, the gonadotrope, provides further evidence that the potential for neuroendocrine control of gonadotropin secretion exists in the fetal mouse as early as 17 days of gestation.
The maturation of the rabbit fetal lung following maternal administration of pilocarpine
Authors: Smith Dennis M. , Shelley Sue A. , Balis John U.
Published: February 2005

Pilocarpine HCl, a parasympathomimetic drug, was administered to pregnant white rabbits in a daily subcutaneous injection of 5 mg/kg on days 24 through 27 of gestation. Fetuses from these animals and from salineinjected controls were obtained by caesarean section at day 28 of gestation. Light microscopic examination revealed thinner alveolar septa in the lungs of pilocarpine‐treated fetuses and, morphometrically, a significant increase in the number of mature type II cells, both per unit area and per 1,000 lung cells of any kind. Examination by electron microscopy revealed that the alveolar epithelium of pilocarpine‐treated fetuses demonstrated morphologic correlates of increased maturation. These included thinning of type I cells to form blood‐air barriers and substantial reductions in the glycogen content of both epithelial cell types. Type II cells of pilocarpine‐treated fetuses contained (as indicated by morphometric analysis) more and larger lamellar inclusion bodies, as well as more multivesicular bodies than those of controls. Biochemical determination indicated that the glycogen content of fetal lung, but not liver, was reduced significantly in the pilocarpine‐treated group. The findings of this study indicate that maternal administration of pilocarpine results in increased maturation of the fetal alveolar epithelium, thus providing a basis for the autonomic manipulation of fetal lung maturation.
A light microscopic study of the developing human neural retina
Authors: Rhodes Roy H.
Published: February 2005

Human embryonic and fetal eyes from 4 mm to 200 mm crownrump length (26 days to 21 weeks of gestation) were studied in 0.75‐μm sections impregnated with silver and toned with gold. The layer of Chievitz was formed by an inward migration of ganglion‐cell and Müller‐cell nuclei from the outer neuroepithelium and then, after further changes in nuclear location, the layer of Chievitz was cleared of ganglion‐cell nuclei to become the definitive inner plexiform layer. Müller‐cell nuclei later populated all retinal layers in the fetus. The argyrophilic Müller‐cell cytoplasm associated with neuronal development is discussed in relation to glia‐neuron interactions, with emphasis on the particular needs of retinal tissue.
Studies on the trophoblast‐epithelial complex during decidual induction in rats
Authors: Lundkvist Örjan , Nilsson Ove , Bergström Staffan
Published: February 2005

Studies were undertaken to elucidate the role of the complex consisting of the trophoblast and uterine epithelial cells during decidual induction in rats. Animals with estradiol‐induced implantation after an experimental delay were used.

In one experiment the ultrastructural changes of the complex were examined at 4‐hourly intervals from delay of implantation to the appearance of the Pontamine Blue Reaction, 24 hours after estradiol injection (24 h.a.e.). Transmission electron microscopy of the trophoblasts revealed signs of increased synthetic activity from 8 h.a.e. onwards, with formation of polyribosomes and glycogen‐like particles and dilation of the granular endoplasmic reticulum. The epithelial cells displayed signs of endocytosis, but no differences between blastocyst‐free and blastocyst‐containing uterine sites were noted. Occasionally, signs of membrane contacts between the trophoblast and epithelial cells were observed before 12 h.a.e., as revealed by transmission electron microscopy of uterine sites and by scanning electron microscopy of blastocyst surfaces. Later an attachment of the trophoblast onto the epithelial cells became evident. Since previous studies have shown that the stromal cells are influenced by the presence of a blastocyst about 12 h.a.e., the results are in accordance both with a humoral and with a contact‐mediated signal from the blastocyst to the endometrium.

In another experiment attempts were made to ascertain whether a continuous influence of the complex upon the stroma is required for the maintenance of an ongoing decidual differentiation. Blastocysts were flushed out from the uterus 16–18 and 24–26 h.a.e. and on the following day the presence of uterine sites with a decidualizing stroma were sought for. The results suggest that the differentiating stroma is dependent upon the presence of an intact complex 16–18 h.a.e. but not 24–26 h.a.e. A continuous signal release from the complex to the stroma is therefore possible during the initial stages of the decidual reaction.
Surface coats on human lymphocytes: Freeze‐drying and staining with cations
Authors: Billings‐Gagliardi Susan , Pockwinse Shirwin M. , Schneider Gary B.
Published: February 2005

Surface coats can be demonstrated on human peripheral blood lymphocytes by staining with ruthenium red, alcian blue, Thorotrast, and cationized ferritin, which are similar in distribution to a 40‐ to 65‐nm layer of amorphous extracellular material recently reported on fixed, freeze‐dried lymphocytes. Several additional lines of evidence, including X‐ray micro‐analysis, suggest that the latter is not a contaminant added by freeze‐drying. Freeze‐drying may provide the means for a morphological assessment of the lymphocyte surface, including the extracellular coat, which may give additional insight into the immune response.
Anatomy of the renal pelvis in the hamster
Authors: Lacy Eric R. , Schmidt‐Nielsen Bodil
Published: February 2005

The hamster renal pelvis has been studied by means of low‐power light microscopy, scanning electron microscopy and morphometric analyses. The results of this study are highly suggestive that the contact of pelvic urine with the other medulla as well as with the inner medulla may be an important aspect of final urine formation. The outer medulla constituted nearly 50% of the total pelvic surface area, with the inner stripe of the outer medulla more than twice the pelvic surface area of the outer stripe of the outer medulla. The large outer medullary pelvic surface area was accounted for by the elaboration of the upper pelvic walls into peripelvic columns, opercula (“secondary pyramids”), fornices and secondary pouches. A thin simple‐squamous to low cuboidal pelvic epithelium separated pelvic urine from outer medullary parenchyma. The inner medulla which constituted about one quarter of the total pelvic surface area was covered by a cuboidal to columnar pelvic epithelium which appeared morphologically similar to the papillary collecting duct epithelium. Tubules and capillaries of the inner medulla did not appear as closely juxtaposed to the pelvic epithelium as did those of the outer medulla. Cortical tissue comprised only 11.7% of the total pelvic surface area and was covered by transitional epithelium similar to that of ureter and bladder. The previously reported impermeability of this epithelium suggests that pelvic urine contact with the cortex is unimportant in final urine formation. The rich layer of smooth muscle under the transitional epithelium probably functions to move urine into and out of the pelvis during pelvic peristalsis, which has been observed in vivo.
The rostral level of origin of sympathetic neurons in the chick embryo, studied in tissue culture
Authors: Newgreen D. F.
Published: February 2005

Groups of three consecutive somites from the first to the eleventh somite from chick embryos of stages 17–18 were grown in tissue culture for seven days. Sympathetic neurons, identified both by phase contrast microscopy and FIF histochemistry, occurred only in cultures which included the sixth, or more caudal, somites.

If it is assumed that sympathetic precursor cells (neural crest cells) have not undergone a caudal shift prior to stages 17–18, and taking into account the loss of one or two rostral somites, then the anterior sympathetic ganglia are derived from neural crest caudal to the sixth or seventh somite Thus, the vagal zone (level with somites 1–7) contributes little to the sympathetic nervous system.
The clara cell: A comparative ultrastructural study in mammals
Authors: Smith Marilyn N. , Greenberg S. Donald , Spjut Harlan J.
Published: February 2005

Clara cells in the terminal bronchioles of mouse, rat, rabbit, calf and human were compared by light, transmission and scanning microscopy, and species‐differences were clearly present. Mouse Clara cells were most numerous and mouse and rabbit Clara cells had large dense mitochondria. Rabbit and calf had glycogen in Clara cells and rat Clara cells had the most variability in secretory granules, some of which had a crystalline structure. Calf Clara cells had deeply indented nuclei. Human Clara cells had the most prominent nucleoli and lacked smooth endoplasmic reticulum, which was a prominent feature of most other species. No evidence of apical extrusion or apocrine secretion of Clara cell secretory granules was observed.
The isolation of single cells from the avian salt gland
Authors: Thompson Ian G.
Published: February 2005

Collagenase, hyaluronidase, and trypsin were used to isolate single cells from the avian salt gland. Three cell types were distinguishable in the resultant cell suspension: peripheral, intermediate, and principal cells. The fine structure of these cells is described and related to the morphology of the intact gland.
Direct efferent and afferent connections of the hippocampus with the neocortex in the marmoset monkey
Authors: Schwerdtfeger Walter K.
Published: February 2005

Anterograde and retrograde transport was studied following injections of 3H‐proline and/or horseradish peroxidase into hippocampal and neocortical areas of the common marmoset monkey. Reciprocal connections between the frontal and temporal neocortex and the subiculum are prominent; sparse connections exist also with fields CA1 and CA2/3 of Ammon's horn. Entorhinal cortex, parasubiculum and presubiculum are reciprocally connected with frontal and temporal neocortex.
Origin of necklace particles in thymic ciliating cells
Authors: Cordier A. C. , Haumont S.
Published: February 2005

The formation of ciliary necklaces during ciliogenesis in a thymic cyst was observed in freeze‐etched replicas. The necklaces first appear as clusters of particles arranged in concentric circles on a flat area of the cell membrane. As soon as the cilium begins to grow, the particles move to the periphery.
Gap junctions in the myometrium of pelvic‐neurectomized rats with blocked parturition
Authors: Burden Hubert W. , Capps Marilyn L. , Lawrence Irvin E.
Published: February 2005

Pregnant Sprague‐Dawley rats were laparotomized on days 8–10 and sham‐operated (S) or subjected to bilateral section of the pelvic parasympathetic nerves (pelvic neurectomy (PN)). Both S and PN animals were allowed to go to term and the time of delivery was recorded. Eight of ten S animals delivered on the afternoon of day 22 and two delivered on the morning of day 23. Pelvic neurectomy blocked parturition in five rats autopsied on day 24, and five rats autopsied on day 26. On these days the PN animals had full‐term fetuses; live on day 24, but dead on day 26. In a second study, the fine structure of the myometrium of S and PN pregnant rats was examined during the parturient period for the presence of gap junctions. Gap junctions were present between myometrial smooth muscle cells of the S group during delivery and in the PN group on days 23, 24, and 25, in the absence of delivery. There was a significant increase (p < 0.05) in the number of gap junctions on day 23 in the PN animals. There was no difference in the length of gap junctions in the different groups. These observations indicate that the parturition block characteristic of PN animals is not attributable to the failure of gap junction formation between smooth muscle cells. Apparently, the nervi erigentes participate in the orchestration of events terminating in parturition, but their specific role remains an enigma.
A new grouping of intrafusal muscle fibers based on developmental studies of muscle spindles in the cat
Authors: Butler Richard
Published: February 2005

The development of muscle spindles was studied using the tenuissimus muscle of the cat. Observations show that the intrafusal muscle fibers develop as two separate groups: one group represented by a single nuclear bag fiber while the second group comprises the second nuclear bag fiber in association with all the nuclear chain fibers. This grouping is most pronounced in the fetus and is clearly seen in neonatal kittens (i.e., up to 2 weeks of age). As the intrafusal fibers begin to separate from each other, the groupings become less noticeable, although this basic pattern is often retained in the adult. The pattern of intrafusal fiber grouping is most noticeable in the equatorial regions of the spindle and least noticeable in the polar regions. This is not the grouping of fibers which would have been expected from a consideration of existing reports on muscle spindles. The implications for spindle form and function are considered.
Inhomogeneous distribution of filipin‐sterol complexes in the ciliary membrane of rat tracheal epithelium
Authors: Montesano R.
Published: February 2005

Pieces of rat trachea fixed in a glutaraldehyde solution containing 300 m̈M filipin, a sterol‐specific polyene antibiotic (Elias et al., '78), were freeze‐fractured in order to study the distribution of cholesterol within the ciliary membrane. Filipin‐sterol complexes, recognizable as 25–30‐nm protrusions on fracture faces, appeared densely and uniformly distributed over most of the ciliary membrane, but were absent from the region of the ciliary necklace. It is possible, therefore, that the ciliary necklace represents a cholesterol‐poor area of membrane.
Involution of the female mullerian duct of the fetal rat in the organ‐culture assay for the detection of mullerian inhibiting substance
Authors: Price J. Michael , Donahoe Patricia K. , Ito Yasuo
Published: February 2005

The study of Mullerian Inhibiting Substance (MIS) has been made possible because of the organ‐culture bioassay devised by Picon ('69) for detecting MIS in vitro. We have studied the degeneration of the female Mullerian duct of the rat fetus, the target tissue of the assay, with electron microscopy. We have observed that the involution of the female Mullerian duct in the organ‐culture assay follows a pattern of degeneration similar to the normal involution of the male Mullerian duct under the influence of MIS from the fetal testis (Price et al., '77). This involution involves alterations in the duct epithelium subsequent to a response of the mesenchyme surrounding the duct. The degeneration of a specific organ system under the direct influence of a specific factor, Mullerian Inhibiting Substance, represents an example of “programmed cell death”.
Luteinizing hormone and follicle‐stimulating hormone production in the pars tuberalis of hypophysectomized rats
Authors: Gross D. S. , Page R. B.
Published: February 2005

Luteinizing hormone and follicle‐stimulating hormone were identified by immunocytochemistry in the same cells of the pituitary pars tuberalis, following hypophysectomy in the rat. A marked hyperplasia and hypertrophy of these cells occurred in response to hypophysectomy. These findings are discussed in light of the potential for hormone production by pars tuberalis gonadotropes following hypophysectomy performed as part of an experimental protocol, as well as that performed for palliation of human metastatic breast cancer.
Glycoprotein synthesis in the mucous cells of the vascularly perfused rat stomach. I. Surface mucous cells
Authors: Van Huis G. A. , Kramer M. F.
Published: February 2005

We developed a constant‐pressure vascular perfusion system of the isolated rat stomach, utilizing an artificial, fluorocarbon (FC‐75)‐containing medium. Perfusion could be maintained for at least six hours, as demonstrated by the ultrastructure of the mucosal cells and by the constant incorporation of [3H]‐galactose in the surface mucous cells. Moreover all mucous cell types in tissue fixed after six hours of perfusion showed the same histochemical reactions for glycoproteins as in tissue fixed shortly after decapitation of the animal.

The surface mucous cells of the antrum incorporated 30% less [3H]‐galactose, [3H]‐serine and [35S]‐sulphate than those of the fundus. The amount of radioactivity incorporated per cell did not decrease during a subsequent 2 hour chase.
Glycoprotein synthesis in the mucous cells of the vascularly perfused rat stomach. II. Differentiating mucous cells
Authors: Wattel W. , Van Huis G. A. , Kramer M. F. , Geuze J. J.
Published: February 2005

Labeled leucine, serine, galactose, glucosamine and sulphate were administered to rat stomachs in a perfusion system. Sections of the gastric fundus were studied by light microscopic autoradiography. Five categories of mucous cells were distinguished and their glycoprotein synthetic activity was measured in autoradiographs by counting silver grains over each category. During their differentiation, while migrating from the isthmus of the fundic glands to the free luminal surface, the surface mucous cells (SMC) showed an increase in incorporation of all precursors used. Differences between the incorporation patterns of the various precursors, in cells of different ages, suggest that structural development runs ahead of functional activity, and that the latter continues up to the very moment the cell is shed from the surface. Sulphate was incorporated at a considerably lower rate by the SMC of the free surface than by the foveolar SMC, in which by cytochemical staining strongly acidic glycoproteins were shown. Since the mucous neck cells incorporated all precursors at a low rate, these cells apparently do not play an important role in gastric mucus synthesis. They did not incorporate sulphate, which is consistent with histochemical observations.
Retrograde changes in Clarke's column following neonatal hemicerebellectomy in the rat
Authors: Smith Diane E. , Castro Anthony J.
Published: February 2005

Long‐Evans black‐hooded rat pups underwent hemicerebellectomies at various postnatal ages. The animals were killed at 28 days of age and thoracolumbar segments of the spinal cord were removed and processed according to Golgi and Nissl techniques. Hemicerebellectomy at two and three days postnatally produced, in addition to cellular hypotrophy in Clarke's column, dendritic alterations which included a decrease in the number of primary dendrites and a reduction of the remaining dendrites to truncated stubs. Hemicerebellectomy at 21 days postnatally had little effect on either cell size or dendritic arborization. The role of the target nucleus in maintaining cell growth and dendritic arborization during critical developmental periods is discussed.
Development of thymus, parathyroids, and ultimo‐branchial bodies in NMRI and nude mice
Authors: Cordier André C. , Haumont Stanislas M.
Published: February 2005

In the NMRI mouse embryo, the thymus develops from the third endodermal pouch and the third ectodermal cleft. The cervical vesicle, formed not by the closure of the sinus cervicalis but by an invagination of the dorsal segment of the ectoderm between the third and fourth branchial clefts, contributes to the formation of the thymus. The intense proliferation of the ectoderm of the third cleft on the eleventh day covers the endodermal part.

The thymus is thus composed of a central endodermal region and a peripheral ectodermal region. The normal adult thymus, then, has a mixed origin, the cortical cells being ectodermal, and the medullary cells endodermal in origin.

The fourth endodermal pouch gives rise to the ultimo‐branchial body, which becomes entirely incorporated within the thyroid on the fourteenth day. There is no formation of a thymus IV nor of a second pair of parathyroids from the fourth endodermal pouch.

In the Nude mouse embryo, the third branchial pouch and cleft, as well as the cervical vesicle, develop normally for the first 11½ days. From this point on, the ectoderm of the third cleft ceases to develop further. The endoderm is, now, no longer covered by ectoderm and, deprived of its normal inducing agent, ceases to develop further. Thymic dysgenesis is thus ectodermal in origin. The fourth endodermal pouch develops normally. No development of an accessory “thymus‐like” structure from the fourth pouch was observed. The dysgenetic thymus originates entirely from the third branchial pouches and clefts.

In both Nude and NMRI embryos, the parathyroids develop at about 11½ days from a very limited area in the dorsal region of the cranial wall of the third endodermal pouch between the pharyngo‐branchial and ecto‐branchial ducts. Morphometric analysis shows that the volume of the parathyroids is the same in both strains of mice at each stage of development; nor does their microscopic appearance differ. Thus, mutation in the Nude mouse does not affect the development of the parathyroids from the third pouch, even though the first anomalies in the development of the thymus are observed at the precise moment at which the parathyroid primordium appears.
Analysis of ovarian follicular development and thymidine incorporation in the cyclic golden hamster
Authors: Chiras Daniel D. , Greenwald Gilbert S.
Published: February 2005

To quantify thymidine incorporation into DNA in the ovary of the intact, cyclic hamster, hamsters were injected at different times throughout the four‐day estrous cycle (day 1 = day of ovulation; day 4 = proestrus). Animals were killed one hour after injection. One ovary was prepared for liquid scintillation counting of DNA and the other for autoradiographic analysis.

Ovarian thymidine incorporation was elevated on days 1 and 4. The peak of thymidine incorporation on day 1 resulted from uptake by small follicles (12 or fewer layers of follicle cells), and coincided with a peak in serum FSH. Stromal and luteal uptake on day 1 was negligible. The peak of thymidine incorporation on day 4 occurred in the morning and was the result of incorporation into small follicles (seven layers of follicle cells and smaller) and antral follicles. This peak occurs when gonadotropin levels are reported to be low, but circulating levels of estradiol are high.

The mean number of follicles at stages 1 and 2 (2–5 granulosa cells) was relatively constant throughout the estrous cycle. Larger follicles were present only at specific times. Small follicles (stages 1 and 2) were most active in thymidine uptake during the latter half of the cycle; stage‐3 follicles were most active on day 4. Follicles of stages 4 and 5 were present only on days 1 and 2, respectively; no measurements of thymidine incorporation were made. Stage‐6 follicles, present on days 3 and 4, showed virtually no variation in activity, as measured by thymidine uptake.

A wave of follicular development was evidenced in larger follicles. Stage‐3 follicles (6 to 7 layers of follicle cells), present on day 4, had developed to stage 4 (eight or more layers of follicle cells) by day 1; stage‐4 follicles had developed to stage 5 (early antral) by day 2. Stage‐5 follicles had developed to stage 6 (antral follicles) by day 3.

Antral follicles consistently incorporated thymidine label (except at 1600 hours and 2400 hours on day 4), especially in the cumulus oophorus and in the granulosa cells bordering the antrum. Despite sudden changes in serum gonadotropins on day 4, stage‐6 follicles showed no discernible differences in labeling.

Thymidine uptake by the corpus luteum (CL) was low on day 1, but higher on day 2 (after the CL was fully developed). Sinuosoidal endothelial cells in the CL were heavily labeled on day 2, but the reason for the late proliferation of these cells and their fate is unknown.
Degenerative changes in endothelial and smooth muscle cells from aging swine ductus arteriosus and venosus
Authors: Toda T. , Leszczynski D. E. , Kummerow F. A.
Published: February 2005

Degenerative changes in endothelial and smooth muscle cells from fetal, 2‐month‐, and 6‐month‐old swine ductus vasculature were observed. In fetal ductus, a discontinuous internal elastic lamina and increased extracellular mucopolysaccharide deposition were initially noted. At 2 months of age, there was widespread fibromuscular intimal thickening, the appearance of modified smooth muscle cells, increased medial fibrosis, and the occurrence of cell debris and nuclear pyknosis. Early modification of smooth muscle cells was marked by increased occurrence of lysosomes, widely dilated rough endoplasmic reticulum, and Golgi bodies. Abundant aggregates of Weibel‐Palade bodies occurred in early endothelial cell degeneration. At 6 months of age, after complete anatomical closure, there was abundant lipid vacuole production by degenerated medial smooth muscle cells. This study demonstrates that at various stages of occlusion, endothelial and smooth muscle cells from ductus vasculature exhibit morphological changes which are qualitatively similar to atherosclerosis.
Retinofugal projections of an echolocating megachiropteran
Authors: Cotter John R.
Published: February 2005

The projection leading from the eye and the nuclear targets of the projection to the brainstem were identified in an echolocating megachiropteran (Rousettus aegyptiacus) following unilateral intraocular injections of radioactive amino acids. In the hypothalamus, the projection ended bilaterally in suprachiasmatic nuclei. In the ventral thalamus, it ended bilaterally in external and internal divisions of the ventral lateral geniculate nuclei. In the dorsal thalamus, the projection terminated bilaterally in the dorsal lateral geniculate nuclei and contralaterally in the lateral posterior nucleus. Input from the two eyes was segregated to laminae in the lateral division of the dorsal lateral geniculate nucleus. The contralateral projection ended in the dorsolateral and ventral portions of lamina 1, in lamina 2, the ventral portions of lamina 3, and an interlaminar fiber plexus. The ipsilateral projection ended in the dorsomedial portion of lamina 1, the dorsal portion of lamina 3, and the most superficial portion of lamina 1. Contralateral and ipsilateral input to the medial division of the dorsal lateral geniculate nucleus was for the most part segregated. The projection to the pretectum terminated in nuclei of the optic tract, pretectal olivary nuclei, and posterior pretectal nuclei. Although the input to the pretectal nuclei was bilateral, the contralateral projection was greater. The contralateral projection to the superior colliculus terminated throughout the rostral‐caudal extent of the superficial gray layer. The ipsilateral projection to the superior colliculus ended in the superficial gray layer in the middle one‐third of the superior colliculus only. On the contralateral side the projection to the outer portion of the superficial gray layer was especially heavy. The superior fascicle of the accessory optic tract was identified. It was traced to dorsal, lateral, and medial accessory optic nuclei. These results indicate that the visual system of Rousettus is more extensive than that of the echolocating microchiroptera and that it is similar to that described for nonecholocating Pteropus.
Comparative histochemical study of prosimian primate hindlimb muscles. I. Muscle fiber types
Authors: Sickles Dale W. , Pinkstaff Carlin A.
Published: February 2005

The profiles of fiber types in hindlimb muscles from the tree shrew (Tupaia glis), lesser bushbaby (Galago senegalensis), and the slow loris (Nycticebus coucang) were determined using histochemical techniques. Fibers were classified as fast‐twitch oxidative‐glycolytic (FOG), fast‐twitch glycolytic (FG), slow‐twitch oxidative (SO), or fast‐twitch oxidative (FO) according to reactions for alkaline‐stable ATPase, acid‐stable ATPase, á‐glucan phosphorylase, reduced nicotinamide adenine dinucleotide diaphorase, succinate dehydrogenase, mitochondrial á‐glycerophosphate dehydrogenase (MáGPDH), and ß‐hydroxybutyric dehydrogenase, as well as glycogen staining by the periodic acid‐Schiff technique. Prolonged dissection of numerous muscles was carried out on hindlimbs submersed in cold Tyrode's solution; such treatment had no qualitative effect on enzyme staining reactions, but it is not a suitable procedure if one wishes to stain for glycogen. Fast‐twitch oxidative (FO) fibers were seen only rarely, and only in tree‐shrew hindlimb muscles; these fibers are alkaline‐stable ATPase‐positive and possess low MáGPDH enzyme activity. These fibers have not been reported previously in any hindlimb muscles. No muscles of any species studied were homogeneous with respect to fiber type. Slow loris muscles lacked FG fibers. The majority of the muscles of the slow loris contained numerous SO fibers. The relationship between enzyme activities and locomotor pattern is discussed.
Characterization of seasonal changes in prolactin and growth hormone cells in the hypophyses of white‐tailed deer (Odocoileus virginianus borealis) by ultrastructural and immunocytochemical techniques
Authors: Schulte B. A. , Seal U. S. , Plotka E. D. , Verme L. J. , Ozoga J. J. , Parsons J. A.
Published: February 2005

Prolactin and GH cells were identified in thin sections taken from the adenohypophyses of adult male (6) and female (8) white‐tailed deer, collected during all seasons of the year, by locating portions of the same cells in adjacent thick plastic sections immunostained for either PRL or GH. Growth hormone cells were round to ovoid in shape and filled with dense spherical secretory granules which ranged in size from 168 to 682 nm, with a mean diameter of 367 ± 18 nm (x̄ ± SD) in the 14 glands studied. No apparent seasonal changes were evident in the ultrastructural appearance of GH cells. Prolactin cells were small and angular in shape during the winter months and contained only a few small secretory granules. By early summer, they were markedly hypertrophied, round to oval in shape, and densely packed with large spherical secretory granules. The increase in size of PRL secretory granules was most prominent in pregnant females in May, when their mean diameter was approximately double that seen in midwinter. The ultrastructural appearance of PRL cells in September was similar to that of cells studied in March. The size distribution of PRL secretory granules overlapped that of the GH granules, ranging from 114 to 564 nm, and the mean diameter was 246 ± 53 nm, calculated from all 14 individual glands. Our observations suggest that the synthesis and secretion of PRL are closely linked to photoperiodic changes in this species, and they demonstrate the necessity of using specific immunocytochemical techniques in the ultrastructural identification of pituitary acidophils, and of specifying the time of year and location (species photoperiod) in studies concerning PRL physiology, particularly when dealing with wild animal populations.
Comparative histochemical study of alimentary tracts with special reference to the mucous neck cells of the stomach
Authors: Suganuma Tatsuo , Katsuyama Tsutomu , Tsukahara Masanori , Tatematsu Masae , Sakakura Yasunori , Murata Fusayoshi
Published: February 2005

Combinations of recently developed paradoxical concanavalin‐A staining (PCS) and other routine histochemical procedures have made it possible to classify mucosubstances more precisely. By taking advantage of these sequences, the present study was undertaken both to characterize the mucinous contents of alimentary tracts of several animal species, and to compare the variability of epithelial mucosubstances with special reference to the mucous neck cells of the stomach. The alimentary tracts obtained from 7 species of fish, 5 amphibians, 3 reptiles, 4 birds, and 6 mammals were used. Acidity of epithelial mucosubstances was highly variable even among the corresponding mucous cells. On the contrary, concanavalin‐A reactivity seemed to be consistent with each cell and species. The mucous neck cells, which were observed in amphibians, reptiles, and mammals, consistently exhibited a characteristic mucosubstance with stable class‐III reactivity by PCS. Inversely, stable class‐III reactivity was found only in species possessing mucous neck cells, and was widely distributed in the esophageal glands of the frog, snake, and man; in esophageal mucous cells of the frog and skink; in pyloric glands of amphibia, reptiles, and mammals; and in Brunner's glands of mammals. These mucous cells seem to form an unique group with morphological and histochemical similarities. It is likely that the stable class‐III reactivity by PCS is a hallmark of the mucous neck cells and related glands and that, in addition, concanavalin‐A reactivity of mucosubstances is evolutionarily more fundamental characteristic.
Kinetic analysis of epithelial cell migration in the mouse descending colon
Authors: Tsubouchi S.
Published: February 2005

The kinetics of epithelial cell replacement in the descending colon of the mouse were studied using cell counts and other measurements in mice given a single injection of 3H‐thymidine at 10:00 a.m. Cell migration occurs from the base of the crypts in the direction of the colonic lumen. The mean turnover time of epithelial cells as measured after the single injection of 3H‐thymidine has been estimated at 4.85 days. Since this figure is in agreement with published data based on continuous infusion of the labeled precursor, it is concluded that the time selected for the analysis provides an index of proliferation which is representative of the mean proliferative activity of the epithelium.

If each side of a crypt cut along its axis is referred to as a “crypt column,” the mean number of cells per crypt column has been found to be 32.9; after a one‐hour pulse labeling starting at 10:00 a.m., the mean number of labeled cells per column was 2.8; and the overall labeling index of the epithelium, 8.6%. The frequency of labeled cells in each cell position along the crypt column varies according to a Poisson distribution with a peak close to position 3. Presumably then, cell proliferation is taking place in a random manner and is, therefore, asynchronous, despite evidence to the contrary in the literature.

The kinetic analysis supports the view that cell migration occurs along the crypt column in the direction of the colonic lumen at a velocity averaging 0.28 cell position per hour, or 4.48 μm per hour.

The results support the view that vacuolated‐columnar, mucous, and caveolated cells migrate jointly; whereas entero‐endocrine cells migrate separately from these cell lines, except during the initial stages of the migration.
Cell types within the medial forebrain bundle: A golgi study of preoptic and hypothalamic neurons in the rat
Authors: McMullen Nathaniel T. , Almli C. Robert
Published: February 2005

The morphology of lateral preoptic (POL) and lateral hypothalamic (HLA) neurons was studied in 14‐ to 200‐day‐old rats with the chlorate‐formaldehyde modification of the Golgi method. Drawings of 91 POL and HLA neurons revealed three distinct neuronal types within the MFB based on somatic size and shape and dendritic morphology. Class I neurons, which accounted for 75–80% of the neurons in the MFB, had fusiform or multipolar somata averaging 21 × 14 μm and 2–5 sparsely branched dendrites with a moderate number of sticklike spines. The extensive dendritic domains of Class I neurons ranged from 700 to 1,500 μm and were usually oriented perpendicular to the longitudinal fibers of the MFB. Both nonoriented and oriented Class I neurons were encountered. Nonoriented Class I neurons had expansive dendritic arbors which reached nearly all regions of the MFB in the coronal plane. Oriented Class I neurons had dendritic domains which were confined to specific regions (e.g., ventral‐lateral) of the MFB. Class II neurons, which made up approximately 10% of the MFB neurons, had large multipolar somata averaging 30 × 17 μm and 2–5 stout dendrites which were densely covered with hairlike spines. Class II neurons also exhibited spines on their somata and proximal dendritic trunks and had dendritic domains of 700–1,000 μm. Class III neurons had small somata averaging 15 × 12 μm and restricted dendritic arbors of 500–700 μm in diameter. Class III neurons exhibited both spiny and spine‐free dendrites and made up 10% of MFB neurons. Because of the parcellation of chemically coded fiber systems within the MFB, individual POL and HLA neurons may not be homogeneous in the type of afferents they receive from other brain areas.
Glycoprotein synthesis in the mucous cells of the vascularly perfused rat stomach. III. Mucous cells of the antrum and the duodenal glands
Authors: Smits H. L. , Kramer M. F.
Published: February 2005

Labeled leucine, serine, galactose, glucosamine, fucose, and sulfate were administered to rat stomachs in a vasular perfusion system. Sections of gastric fundus and antrum, and of the duodenal glands, were studied by light microscopic autoradiography. The rate of incorporation of radioactive label in the various mucous cell types of the antrum and of the duodenal glands was measured by counting the silver grains over each cell type and comparing this rate with that of the surface mucous cells of the fundus. The following major observations were made: The patterns of incorporation in the mucous cells on the surface and in the pits of the antrum did not differ essentially from those of the surface mucous cells of the fundus. On the contrary, the incorporation patterns of the surface mucous cells of the fundus differed considerably from those of the mucous cells of the antral glands and from the mucous cells of the duodenal glands. The mucous cells of the antral glands showed a lower incorporation rate of amino acids and of (amino) sugars, especially of galactose and glucosamine, but a higher incorporation rate of sulfate. The mucous cells of the duodenal glands showed a considerably higher rate of incorporation for serine, but a lower rate for glucosamine. No differences were seen for leucine, galactose, and sulfate. The relatively low synthetic activity of the mucous cells of antral glands correlates well with the various amounts of RER, Golgi system, and secretory granules, found in these cells, and with the histochemical staining characteristics of their mucous granules. The mucous cells of the duodenal glands are characterized by typical parallel arrays of their numerous RER cisternae and by a low number of small secretory granules.
Osteoclast formation in vitro from bone marrow mononuclear cells in osteoclast‐free bone
Authors: Ko Jea Seung , Bernard George W.
Published: February 2005

Recent evidence points to the fact that osteoclasts are derived from mononuclear cells of hematopoietic bone marrow. In this study we have examined the formation of osteoclasts from mononuclear cells in vitro. The mononuclear cells were isolated after 7 days from cultures of mouse bone marrow cells. The isolated cells were co‐cultured with osteoclast‐free, fetal‐mouse calvaria. After 10 to 14 days of co‐culture, multinucleated cells which have all the characteristics of osteoclasts were found in juxtaposition to seams of woven bone. These data strongly suggest that bone marrow mononuclear cells, when suitably induced, can give rise to osteoclasts in vitro.
Fluoride stimulation of the rat parathyroid gland: An ultrastructural study
Authors: Ream Larry J. , Principato Robert
Published: February 2005

The parathyroid glands of rats given 150 ppm fluoride in the drinking water for 10 weeks are evaluated ultrastructurally and compared to the parathyroid glands of untreated rats. As a result of fluoride ingestion, the majority of the parathyroid cells are dark chief cells, indicating that these cells are in the active stages of the secretory cycle. More significantly, in the fluoride‐treated rats, the cytoplasmic organelles of the dark chief cells are even more developed that those seen in the dark chief cells of untreated rats. The dark cells contain an electron‐dense cytoplasm with abundant lamellar arrays of rough endoplasmic reticulum, spiral aggregations of free ribosomes, multiple dilated Golgi complexes, and increased numbers of secretory granules. The cells are at a minimum dimension with maximum tortuosity of the plasma membranes; and, as a result, large intercellular spaces are often seen between contiguous cells. Based on these observations, it is suggested that, in the fluoride‐treated rat, a type of secondary hyperparathyroidism develops resulting in an increase in the organelles involved in protein synthesis and secretion.
Lens regeneration from the pupillary margin of the eyecup in newt embryos
Authors: Reyer Randall W.
Published: February 2005

Early stages in lens regeneration from the dorsal margin of the pupil, following removal of the young lens from the embryonic eyecup, were studied with transmission electron microscopy in Notophthalmus viridescens. At the stage of operation, the eyecup cells have an undifferentiated, embryonic appearance with numerous free ribosomes and scattered mitochondria. In normal embryonic eyes containing a lens, the iris epithelium differentiates from the edge of the optic cup by growth and flattening of the cells to form a two‐layered cuboidal epithelium. There is extensive melanogenesis in both inner and outer layers. In lentectomized eyes, this flattening does not occur and melanogenesis takes place mainly in the outer layer of epithelium. Mitoses are abundant and a vesicle of unpigmented columnar cells, enclosed by a basal lamina, develops from the dorsal pupillary margin of the eyecup. Macrophages are present and phagocytize some of the melanin but less than during dedifferentiation of pigmented iris epithelium. During this regeneration of a lens vesicle, there is an increase in the number of polyribosomes, granular endoplasmic reticulum, and mitochondria in preparation for synthesis of the lens proteins. Micropinocytosis occurs at the cell surfaces.
Distribution and identity of the earliest proliferating progeny of colony‐forming cells in regenerating murine spleen and bone marrow
Authors: Wolf Norman , Rosse Cornelius
Published: February 2005

A study was made of the sites of development and the types of cells found in very early hemopietic colomes in the mouse spleen. Two, 3, and 4 days after transplantation, the proliferating descendants of transplanted bone‐marrow cells were identified on radioautographs of spleen sections and on spleen and bone‐marrow smears of supralethally irradiated recipient mice which were injected with 3H‐TdR at 12, 6, and 0.5 hours before sacrifice. Surprisingly the spleens of nontransplanted, irradiated mice contained proliferating medium and large lymphocytes in the white pulp which increased in numbers during the observation period. The early descendants of transplanted cells that lodged in the spleen could be clearly distinguished from the labeled indigenous cells because they formed discrete nodules or colonies beneath the splenic capsule or in the vicinity of venules and trabeculae of the red pulp. These cells were identifiable on day 2 as transitional cells or unknown hemopoietic blasts and on day 4 included early erythroid cells and small lymphocytes. There was evidence for the traffic of 3H‐TdR‐labeled cells through the splenic sinusoids.