bluuebunny/crossref_metadata_2025_split huggingface dataset:
Some morphological effects of strychnine on the spinal cord: A light and electron microscopic study
Authors: Yates Jane C. , Yates Robert D. 
Published: February 2005

AbstractAdult rats, given intracardiac injections of strychnine (2.5 mg/kg), were allowed to convulse for periods of 5 or 35 minutes after which they were perfused with osmium tetroxide using a variation of Palay's method.Light and electron microscopic examinations revealed no discernible changes in the size of the soma or appearance of the nuclei or nucleoli of the neurons of the ventral horn. However, light microscopic studies showed that clustering of the basophilic content was not as well defined as in the control cells. The most conspicuous feature of the treated material was the presence of a peripheral network of clear spaces in the cytoplasm of many of the large neurons.An electron microscopic investigation showed that many neurons exhibited obvious and consistent cytoplasmic differences from control cells. These differences consisted of dilated endoplasmic spaces approximately 0.4 μ in diameter dispersed throughout the cytoplasm and devoid of material of appreciable density. The Golgi complex was more conspicuous and vesicles surrounding the complex appeared to be more numerous following the convulsive periods. These cytological changes were more extensive and prominent after 35 minutes than after five minutes. Mitochondria were comparable in appearance to those of control cells and vesicles of the axosomatic and axodendritic endings did not seem to differ structurally or numerically from those of control tissues.
A method for injecting the lymphatics of serous cavities and for demonstrating a mechanism of lymphatic absorption
Authors: Durden Charles , Laslie Michael , Allen Lane 
Published: February 2005

AbstractLymphatic plexuses from certain areas of serous cavities can be injected by a simple procedure which simulates the normal mechanism of absorption. Apparatus consists of a 500 ml filtration flask with side arm attached to a vacuum apparatus. Excised serous membranes are draped over the mouth of the flask and flooded with ink. Vacuum is applied intermittently, resulting in absorption and flow. The method can be applied to frozen and thawed tissue and is suitable for human autopsy material.
Reproductive senescence in the female golden hamster
Authors: Blaha Gordon C. 
Published: February 2005

AbstractThe first statistically significant decline in the mean number of young born to female golden hamsters occurred in the fourth litters. The decreased size of fifth litters was highly significant and few females bore six litters.Hamsters unilaterally ovariectomized at 30 days of age had a significantly lower number of litters containing live young during their lifetime. Despite increased unilateral ovulaton, they bore less than half as many total young per female as intact controls and fetal resorptions and stillbirths occurred at an earlier age.The results of matings during the period of reproductive decline were observed in females from the age of ten months until death or sacrifice at an advanced age. Final litters contained few young, some born dead. One or two subsequent pregnancies were of term length but all conceptuses were resorbed. Few females beyond 15 months of age had implantation sites and most of these resorbed. Regular four day estrous cycles continued until a terminal illness and matings resulted in pseudopregnancy. Blastocysts were found at four and one‐half days of gestation in some old females but not at 6 to 8 days. Failure of implantation appeared to be due to an inadequate uterine decidual reaction in the old animals.It appeared from the above observations that decreasing uterine adaptability limited reproductive capacity in aging hamsters.
Numerical variations in the dentition of some pinnipeds
Authors: Kubota Kinziro , Togawa Shigeru 
Published: February 2005

AbstractThe numerical variations observed in the dentition of the northern sea lions, fur seals and seals are summarized as follows: (1) There is a reappearance of the right maxillary second molar in the northern sea lion dentition and of the first deciduous premolar in the fur seal dentition, which may be interpreted as examples of evolutionary recession towards the full mammalian dentition. (2) There is a complete tooth reduction of the molars in the sea lion dentition. (3) There is the presence of a “Dentes geminati” of the second premolar and the supernumerary tooth in the right upper jaw and of the supernumerary tooth between the second and third premolars in the left upper jaw of an adult fur seal, which may be associated with the division of the second premolar tooth germ. (4) There is an appearance of a pair of supernumerary teeth lying lingually to the root of lower permanent central (second) incisors, being of interest in suggesting that they are either the appearance of the successors of the recent central incisors or the reappearance of the permanent first incisors, in the fur seal dentition. (5) There is a tooth reduction in the permanent dental formula from \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm I}\,\frac{{\rm 3}}{{\rm 2}}{\rm C}\,\frac{{\rm 1}}{{\rm 1}}{\rm P}\,\frac{{\rm 4}}{{\rm 4}}{\rm M}\frac{{\rm 1}}{{\rm 1}}\,{\rm to}\,{\rm I}\,\frac{{\rm 3}}{{\rm 1}}{\rm C}\,\frac{{\rm 1}}{{\rm 1}}{\rm P}\,\frac{{\rm 3}}{{\rm 4}}{\rm M}\frac{{\rm 1}}{{\rm 1}} $\end{document} in the seal, which was associated with a “Dentes confusi” in the same category of the dentition.
Development of islets and acini from the explanted primordium of the rat embryo
Authors: Schweisthal Michael R. , Wells Lemen J. , Céas Maria P. 
Published: February 2005

AbstractIn an embryo of eleven and one‐half to twelve and one‐half days, the stomach, duodenum, liver and primordium of the dorsal pancreas were excised en bloc, placed on a rayon grid supported by a grid of stainless steel and cultivated on a liquid medium of cock serum and extract of chick embryo for 8 or 10 or 12 days. The culture was incubated at 37°C in air supplemented by controlled oxygen and carbon dioxide.One‐hundred‐fifteen cultures were fixed in Bouin's solution and the sections stained with aldehyde fuchsin. Forty‐one cultures were fixed in Zenker's solution and the sections stained with hematoxylin and eosin. The 269 control pancreases were of two kinds: beginning controls taken at the time of the explantation (61 specimens); reference controls taken during the period from day eleven and one‐half postcoitum to day five postpartum (208 specimens).From an explant of a pancreatic primordium too primitive to have either islet or acinus, a culture could give rise to islets with granulated beta cells and acini with zymogen granules. The best‐developed islet in a ten‐day culture of an explant from a donor of eleven and one‐half days had an estimated granulation age of twenty‐one and one‐half days; thus the differentiation in vitro had kept pace with that which occurred in vivo during equal time in days. The best‐developed acinus in a 12‐day culture of a pancreatic primordium from an embryo of 12 and one‐half days had an estimated developmental age of twenty and one‐half days.
The hyoid complex of the palm squirrel, Funambulus
Authors: Sivaram Saraswati , Sharma Dharmvir R. 
Published: February 2005

AbstractThe hyoid apparatus of the squirrel, Funambulus consists of basihyal, the immovably fused posterior cornu represented by thyrohyal and the long slender and flexible anterior cornu which is divisible into hypohyal, caratohyal, stylohyal and tympanostyloid synchrondosis. Since the stylomastoid foramen lies posterolateral to the distal tip of the anterior cornu, the hyoid is of the protrematic type. The hyoid apparatus of Funambulus palmarum differs from that of Funambulus pennanti in minor but well marked characters such as a less arched basihyal with smooth shoulders, a small entoglossal process, a trochanter on the lateral side of thyrohyal, a longer hypohyal and a shorter ceratohyal.All the muscles which originate or insert on the hyoid skeleton and their innervation are described. The muscle digastricus of the squirrels is quite characteristic with a well marked intermediate tendon between the anterior and posterior bellies. The muscle jugulohyoideus originates from the paraoccipital process and is well developed, but the stylohyoideus is slender, foreshadowing the condition in gerbils in which only one of these two muscles, possibly the jugulohyoideus is represented.
Uterine metaplasia and plasma levels of vitamin A
Authors: Reiter Russel J. 
Published: February 2005

AbstractThe relationship between vitamin A deficiency and estrogen as etiological agents of uterine stratified squamous metaplasia (keratinizing metaplasia) was studied using the rat. This is the initial attempt to correlate plasma levels of vitamin A with the uterine lesions. From the results the following conclusions can be drawn. Uterine metaplastic lesions which develop in estrogen‐treated rats are not a result of generalized hypovitaminosis A, since plasma levels of vitamin A are not altered in animals treated with estrogen. Estrogen per se can cause uterine keratinizing metaplasia. The histopathologic lesions occur more frequently in vitamin Adeficient estrogenized rats having decreased plasma vitamin A levels as compared to rats with normal vitamin A intake. The two insults are complementary in producing epithelial metaplasia of the endometrium of the rat.
New details of the ultrastructure of the outer segments and ciliary connectives of the rods of human and macaque retinas
Authors: Cohen Adolph I. 
Published: February 2005

AbstractCritical examination of the fine structure of the outer segments of human rods shows that the membranes of at least some and probably most of the flattened saccules filling the outer segment are neither connected with the cell membrane nor with that of other saccules. The saccules typically possess a scalloped edge. The nine pairs of filaments in the ciliary connective become nine singlets in the base of the outer segment and lose their precise orientation before terminating somewhere in the length of the outer segment. The centriolar base in the inner segment possesses nine triplets of filaments and irregular numbers of club‐like, fibrous satellites. Rarely tubules insert in the satellite bodies and these may connect to the cell membrane.
A histological study of remodeling at the periosteal, haversian canal, cortical endosteal, and trabecular endosteal surfaces in human rib
Authors: Epker Bruce N. , Frost Harold M. 
Published: February 2005

AbstractIn human ribs the per cents of four kinds of bone surfaces (i.e., periosteal, haversian canal, cortical‐endosteal, and trabecular‐endosteal) that showed histological evidence of remodeling were measured. At each surface, (1) formative, (2) resorptive, and (3) neither form of remodeling activity was measured. The measurements were done at 350 X with the light microscope and a Zeiss integrating eyepiece II, on mineralized cross sections.The study showed that trabecular‐endosteal and cortical‐endosteal surfaces are approximately equivalent with respect to amount and type of remodeling activity per unit area at any given age. The periosteal surface showed little, and the haversian canal surface considerable, age dependent changes in amount of remodeling.Considerable variability existed within the age groups studied. An overall 16.8% of all surfaces showed histological evidence of bone formation, and 16.9% of bone resorption.
Antagonism of temporal fascia to masseteric contraction
Authors: Eisenberg Norton Alvin , Brodie Allan G. 
Published: February 2005

AbstractThis study was undertaken to test the hypothesis that the temporal fascia lends significant aid to the zygomatic arch in resisting the tensions of the m. masseter. It consisted of the unilateral removal of the fascia in two adult Cebus monkeys from its attachment on the superior and lateral surfaces of the arch, which were then covered with a plate of 24K 50 gauge gold to prevent re‐attachment. Frontal and lateral cephalometric x‐rays were taken and the animals were given three i.v. injections of lead acetate (4 mg/kg body weight) at two‐week intervals beginning at time of operation and sacrificed two weeks after the last. The arches were removed close to their attachments and prepared for histological study according to modified technique of Scheiman‐Tagger and Brodie ('64).Frontal sections through the right and left arches revealed striking differences between them. The operated side measured approximately 25% less mediolaterally and 16% greater superoinferiorly than the unoperated side. Oriented frontal and basal head x‐rays at 5 ft target distance revealed the operated side to be 4 mm lower and 2 mm closer to the midline. The lead lines showed the extensive internal as well as external remodeling that had taken place. Deposition and resorption areas indicated the drifting of marrow spaces and of the zygomaticotemporal suture in the direction of the unopposed pull of the m. masseter.
Correlation between tetracycline binding and mineralization in dentin and enamel
Authors: Bevelander Gerrit , Nakahara Hiroshi 
Published: February 2005

AbstractExperiments were conducted on the incisor of young rats to show (1) the precise areas and manner in which the tetracycline fluorophore combines with dentin and enamel and (2) the relation between the tetracycline localization and mineralization. For the objectives mentioned above rats were injected with tetracycline and a combination of tetracycline and Ca45. Detailed examination of the teeth of specimens injected with tetracycline show a rapid uptake and localization of fluorophore in areas undergoing mineralization. Areas adjacent to the increments undergoing mineralization also reveal the presence of the fluorophore, but to a lesser extent. Comparison of the same area of the tooth injected with tetracycline and Ca45 show that the fluorophore is localized exclusively in areas undergoing mineralization, and to a lesser extent in adjacent, incompletely mineralized regions.Despite the fact that our observations have demonstrated the avidity tetracycline exhibits for mineralizing and recently mineralized areas of dentin and enamel, we have not been able to exclude the possibility that the fluorophore may combine with the organic matrix of these tissues as well as the mineral component.
The origin of electric organs of Electrophorus electricus
Authors: Szabo Thomas 
Published: February 2005

AbstractThe electric organs (main, Sachs' and Hunter's) of a 23 cm and a 38 cm long Electrophorus electricus were studied by histological methods. The results were compared with 12 cm (Keynes, '61) and 140 cm (Couceiro and Ackermann, '48) specimens. All three electric organs originate from striated muscle fiber as indicated by the presence of a striated structure in the undeveloped electroplates. The three organs do not develop simultaneously but in succession: first Sachs' organ, then the main organ and finally Hunter's organ, with considerable overlap in time. In all three cases, the anterior extremity of the organ develops last. The classical notion that the main organ originates from the lateralis imus muscle is not supported by the present findings.
The fine structure of iridial constrictor pupillae muscle of Alligator mississippiensis
Authors: Reger James F. 
Published: February 2005

AbstractThe iridial constrictor pupillae muscle of Alligator mississippiensis is found to consist of admixed smooth, myoblast‐like, and striated muscle cells. Melanophores, bundles of collagen fibrils, nerve cell processes, and smooth muscle cells, which contain melanin granules, are found scattered in the constrictor pupillae muscle. Protoplasmic bridges are present between myoblast‐like cells and between myoblast‐like and striated muscle cells. Myoblast‐like cells contain agranular reticulum, free ribosomes and randomly scattered, or longitudinally oriented filaments of two sizes (50–100 A and 200–250 A). Free ribosomes are found individually and in clusters of 5 to 10. The agranular reticulum is found as anastomosing tubule‐shaped and cisternal elements. The striated muscle fibers consist of myofibrillae and a poorly organized sarcoplasmic reticulum and T system, such that triads and diads are not precisely ordered, but randomly scattered throughout the muscle fiber.This data is discussed in terms of the differentiation and function of striated muscle. On the basis of the disposition of triads and dyads it is concluded that the striated muscle of the constrictor pupillae muscle of Alligator mississippiensis is a slow‐acting rather than fast‐acting muscle.
Comparative anatomical and neurohistological observations on the tongue of the porcupine (Histrix cristata)
Authors: Kubota Kinziro , Fukuda Nobumasa , Asakura Shigeharu 
Published: February 2005

AbstractTwo circumvallate papillae and well developed foliate papillae are observed with fungiform and filiform papaillae on the dorsum. The vallate and foliate papillae are supplied with abundant plexiform nerves concentrated in the lateral area of the papilla, its thin, non‐cornified lateral wall being furnished with many taste buds. The trench wall lined by a nerve plexus is provided with a few taste buds. The ganglion cells are found between the serous glands plentiful in these regions.Fungiform papillae on the dorsum and inferior surface are covered with highly cornified stratified squamous epithelium. They are richly supplied with nerve fibers from a large, thick‐sheathed nerve plexus in the middle portion of the papilla, but they are furnished with no taste buds. Absence of the taste bud seems to be related with high keratinization of their upper epithelium.Filiform papillae are poor in nerve supply. The tongue has the peculiar structure taking the form of flat, horny plate, which consists of many highly cornified filiform papillae on the anterior part of the dorsum. This finding suggests that the filiform papilla is a basic structure of this peculiar papilla.In the area posterior to the vallate papillae there are many mucous glands deep in the muscles. The duct with a wide orifice has cystic dilatations on its course in the mucosa.
Development of cleft palate induced by 6‐aminonicotinamide late in rat gestation
Authors: Chamberlain Jack G. 
Published: February 2005

AbstractSingle injections (8 mg/kg maternal body weight) of the niacin antimetabolite 6‐aminonicotinamide (6‐AN) given to rats on the morning of the fifteenth day of gestation resulted in 100% palatal abnormalities within 24 to 48 hours. Fasting rats for a period of seven or eight days, more than simulating the weight loss observed in 6‐AN treated animals, resulted in young without palatal abnormalities. Simultaneous injection of an equal dosage of nicotinamide prevented the maternal and embryonic effects of the antimetabolite. Intralitter variability in normal palatal closure, similar to the interlitter variation, was observed in embryos of the same chronological age.Retardation in palatal shelf movement appeared to be the initial underlying morphological mechanism giving rise to the abnormal palates. Twenty‐four hours after 6‐AN injection embryonic and placental weights were significantly reduced; the incidence of full open palate was double that observed in untreated rats. Forty‐eight hours following treatment palatal shelves had moved to the horizontal position dorsal to the tongue; failure of fusion was apparent. Further alterations in the morphogenesis of the abnormal palates were secondary to partial or complete failure of shelf fusion, complicated by a dorsally protruding tongue and underdeveloped mandible.The sensitivity of palatal closure between days 15 to 17 of gestation and the rapidity with which shelf movement can be delayed and modified by metabolic procedure in the rat is noteworthy.
A method of removing the brain
Authors: Laurenson R. D. 
Published: February 2005

AbstractThe common method of demonstrating cranial nerves and cerebral arteries to students during removal of the entire brain in the gross anatomical laboratory is unsatisfactory in that only the actual dissector is able to view clearly the structures at the base of the brain. Therefore, a method of hemispherectomy is described; it has the advantage that dural folds, cranial nerves, and cerebral vessels, are preserved in situ until the student has reviewed the anatomy of the cranial fossae and studied important relationships. It is, however, necessary to sacrifice the hemisphere first by taking horizontal slices down to the corpus callosum and then by removing the remainder piecemeal. The method, therefore, cannot be recommended as routine unless neuroanatomical material is available.
A histological and histochemical study on the effects of adrenal cortical steroids in the fetal and neonatal rat thymus
Authors: Lee Robert E. , Domm L. V. 
Published: February 2005

AbstractThe late fetal and neonatal rat thymus was studied by histological and histochemical techniques following adrenal cortical steriod administration. Albino rats from seventeenth day of gestation through thirtieth postnatal day were sacrificed six, 24, 48 and 96 hours following single or series of cortisone or hydrocortisone injections in pregnant or neonatal rats. Some of gestation periods were prolonged by progesterone injections. Stains included Harris hematoxylin and eosin, May‐Grünwald Giemsa, Gomori's ('52) or Burstone's ('58) method for alkaline phosphatase, and the PAS stain. Autofluorescence was examined in some of the sections.A reduction in distinctness of the cortico‐medullary border of the fetal thymus followed maternal cortical steriod treatment. Similar treatment in neonatals one and two days of age led to pycnosis and phagocytosis of small lymphocytes. No histochemically stainable alkaline phosphatase was observed before sixteenth postnatal day, or following steriod administration on day one or two. However, a precocious increase in alkaline phosphatase followed a single injection on day 12. In the fetal and neonatal thymus PAS‐positive material was present, was more prominent on the sixteenth day, and increased following steriod treatment, particularly on the twelfth day. Autofluorescent cells, present on the sixteenth day, increased following steriod administration. Histochemical and autofluorescent modifications were particularly prominent at the cortico‐medullary border and are thought to represent postnatal maturation about the sixteenth day which changes can be induced precociously by cortical steroids.
Morphogenetic studies of the rabbit XXXVI. Effect of gene and genome interaction on homeotic variation
Authors: Sawin P. B. , Gow Maryann 
Published: February 2005

AbstractStudy of the homeotic shifts of vertebral borders as affected by the Da gene when on two different genetic backgrounds shows that the effects of both gene and genome are distinguishable. The Da in either one or two doses shifts both thoracolumbar and lumbosacral borders forward, particularly the former. The effect of the DA genome is in the same direction, but significantly greater, and the two combined are additive. The effect of the IIIDa genome, by contrast, is in the posterior direction and epistatic. It suppresses and tends to shift the localization of Da effect posteriorly. Significant differences between borders when considered separately and in relation to each other indicate differences of interaction between gene and genome. The fact that the only significant difference in the three way comparisons of border, genotype, and genome is between the Da/ + genotypes of IIIDa and DA as a manifestation of overdominance can be discounted because of the differences in border interaction. As reference points defining the relative size and position of the thoracic and lumbar regions, these borders reveal the activity of gene and genome to be an alteration of the relative size and position of the growth gradients of these two regions rather than a direct gene specific morphology.