bluuebunny/crossref_metadata_2025 huggingface dataset:
Studies of cartilage and osteoid arising spontaneously and experimental attempts to induce their formation in ear chambers
Authors: Williams Roy G.
Published: February 2005

Clark and Clark using a rabbit's ear chamber in which the observation space was in direct continuity with perichondrium reported cartilage arising spontaneously in more than 40% of chambers. With a chamber of different design having a very restricted relationship to perichondrium, osteoid, that is, an unmineralized bone‐like tissue, appeared in 5 of 110 animals and in two of the five there were also unrelated islands of cartilage. In one additional animal osteoid developed three months after local application of continuous pressure of minute degree. In the remaining 104 animals no cartilage or osteoid formed irrespective of the experimental usage to which the chambers were put. The results are interpreted to mean that in rabbit's ear chambers cartilage or osteoid may form from precartilaginous cells resident in or derived from perichondrium but not by metaplasia of morphologically similar connective tissue cells. If a special stimulus was necessary to activiate the precartilaginous cells then the only obvious ones were friction and pressure both of very small degree but continuously maintained for long periods.
Plastic mounting of microscopic serial sections
Authors: White Lowell E. , Moberg Gertrude
Published: February 2005

A technique is described for mounting both small and large serial sections on Dupontleader film or pieces of Mylar‐D plastic sheeting. The blocks are processed in the usual fashion and embedded in paraffin or celloidin. Small sections are mounted serially on five‐foot strips of 35 mm film in a gelatine waterbath and allowed to dry. The film strip is placed on a Nikor developing reel, the paraffin dissolved, the tissue hydrated, and the staining carried out in the usual fashion. The sections are cleared and allowed to dry and then covered with Varathane which hardens in 24 hours. The film strips are stored on 35 mm spools. Large paraffin embedded sections are processed separately in a similar fashion, mounted on Mylar‐D sheets, and stored in a loose‐leaf notebook. When celloidin is used it must be removed before mounting. The sections can be studied microscopically by passing the film over the stage of a microscope in a sequential fashion. The advantages of the method are discussed.
A histochemical study of the toad urinary bladder
Authors: Keller Albert R.
Published: February 2005

Histochemical methods for the demonstration of enzyme activities and carbohydrates were applied to the bladder of the toad, Bufo marinus. The three cell types in the mucosa (ordinary epithelial cell, goblet cell, and mitochondria‐rich cell) were found to be distinctive with the methods used. Dehydrogenase enzyme activities were highly concentrated in the mitochondria‐rich cells. Membrane‐associated ATPase activity was found in the basal cell‐membranes of the mucosal cells, where active sodium transport is thought to occur. The potentialities of the various cell types for active electrolyte transport are discussed.
Extrinsic nerves of the chicken's uterus (shell gland)
Authors: Freedman S. L. , Sturkie P. D.
Published: February 2005

Eighty‐six White Leghorn chickens were examined in a study of the neural components of the hen's uterus (shell gland). All nerves supplying the uterus were found to originate from only the left side of the body.

Contributions from the sympathetic nervous system were supplied by the hypogastric nerve, which is the direct continuation of the aortic plexus, coursing along the hypogastric artery to the uterus. The parasympathetic pelvic nerves originate from the pelvic visceral rami of spinal nerves 30 — 33. The several ganglia and numerous nerves situated along the left pelvic nerve compose the left pelvic plexus. Nerves emanating from the left pelvic plexus course along the middle uterine and posterior uterine arteries to their termination on the uterus. The ganglia situated on the right pelvic nerve are not considered to constitute a right pelvic plexus, as they make no direct contribution to the reproductive system.
Studies on the innervation of the stapedius muscle of the cat
Authors: Blevins Charles E.
Published: February 2005

A study of nerve‐muscle relations and fine innervation patterns is reported for the stapedius muscle of the cat. Gross relations of the muscle to its associated nerves and other middle ear structures are shown by illustrations. Histologic features of innervation are studied with the Bodian silver method. the thiocholine technique, and iron hematoxylin and osmic acid stains.

The muscle is richly supplied by 3 to 4 facial nerve branches in which no axons are found above 8 μ and the majority are unimodally grouped at 2–4 μ. The auricular nerve of the vagus does not penetrate the muscle. Three to four distinct zone is of fasciculi are found whose muscle fibers are 14–20 μ in diameter. Each zone is supplied by primary nerves whose branches do not exhibit terminal overlap or multiple innervation of muscle fibers. Short terminal axons lead to motor and plates from all intramuscular nerve branches. Nerve branches and motor end plates are confined to the basal third of the muscle. Sensory endings are not detected within the muscle or its tendon. It is estimated that each motor neuron supplies no more than five muscle fibers but more probably three or less.
The diameters of the cerebral arteries of the human fetus
Authors: Seydel H. Gunter
Published: February 2005

Ninety‐eight fetal specimens of the circulus arteriosus cerebri and adjacent arteries were injected with a mixture of latex and barium sulphate and dissected after fixation in formalin. Measurements of the intracranial part of the internal carotid artery were carried out and the measured diameters were compared to those of the other arteries at the base of the fetal brain. The diameters of the internal carotid artery were symmetrical and increased approximately linearly with fetal size from 0.7 mm for a fetus of 15.5 cm crown rump length to 2 mm in a specimen with 37.2 cm crown rump length. In one specimen, the intracranial part of the right internal carotid artery was smaller than the left. This was associated with an anomaly of the arterial circle. Twenty‐one circles were symmetrical and complete. The most significant differences between adult and fetal diameters were in the posterior part of the circle, the circular part of the posterior cerebral artery showing a relatively smaller average diameter (0.34 of the diameter of the internal carotid artery) than that described for adult specimens (0.47) while the posterior communicating arteries were of similar diameter (approximately 0.27) in both adults and fetuses. In three cases one posterior communicating artery was absent. No berry aneurysms were found upon inspection with a hand lens.
Studies on the fate of lymphocytes II. Intravenous injection of labeled thymic lymphocytes into homologous rats and isologous mice
Authors: Murray Raymond G. , Murray Assia
Published: February 2005

Suspensions of thymic lymphocytes, 60–80% of which had been labeled in vivo with H3‐thymidine, were injected intravenously into 54 homologous rats and 22 isologous mice. Radioautographs2 of blood and of tissues were analyzed. The cells rapidly disappeared from the blood, although less rapidly in the isologous than in the homologous systems. A large fraction was still present in the tissues during the first post‐injection day. In the first hour many were arrested in the lung, some of which were later redistributed to other organs. At later intervals the spleen contained the greatest concentration, followed by lymph nodes and bone marrow. Cells were found occasionally in the duodenal mucosa, in mice only, and in no case did they reach the thymus. A few survived in both rats and mice for as long as seven days.

Only one labeled cell was seen in mitosis. There was evidence of transformation to erythroblasts in the liver, spleen and bone marrow; to myelocytes in the bone marrow; and to macrophages in the spleen. Label from some of the cells dying in the liver apparently was reutilized by the Kupffer cells.
Analysis of the influence of thyroid hormone on prenatal and postnatal maturation of the rat
Authors: Hamburgh Max , Lynn Edward , Weiss Earl P.
Published: February 2005

The effects of hyper‐ and hypothyroidism on fetal development and on the postnatal maturation of the central nervous system was studied in the rat. Our observations indicated that the development of the rat fetus, as measured by birthweight and skeletal maturation of the newborn animal is not markedly influenced by presence or absence of thyroid hormone during the prenatal stage.

Availability of thyroid hormone is a more critical factor with respect to maturation of the nervous system taking place in the postnatal animal.

Delay in cerebellar maturation and delay in increase in dry weight of cerebrum and cerebellum were noted in hypothyroid rats. A transitory acceleration of oxygen consumption of these structures during their maturation was also noted in hyperthyroid litters.

A more permanent suppression of learning behavior and of the thermoregulating mechanism was observed in young hypothyroid rats deprived of thyroid hormone since birth.

It is concluded that requirements for thyroid hormone during development of the rat are limited to a critical period coinciding with the first two to three weeks of postnatal age.
Calculation of cranial capacity from linear dimensions
Authors: Dekaban Anatole , Lieberman J. E.
Published: February 2005

Physical anthropological and x‐ray linear measurements of length, breadth and height of 28 dried skulls were made. The means and variances of these measurements were calculated and are given in tables. Next, the cranial capacity of these skulls was measured with mustard seeds (this method was validated using water measured skull) and the means and variances are given separately for males and females. Two formulae: (1) Lee's ‐ Males, 0.365 (L × B × H) + 359.34; Females, 0.375 (L × B × H) + 296.40. (2) Spheroid‐π/6 (L × B × H) were applied to calculate cranial capacity (in milliliters) from the linear anthropological and radiological dimensions (in centimeters). The results of the volumes thus obtained were compared to each other and to the control volume of the respective skulls. It was concluded that both the Lee's and Spheroid formulas for calculating the volume showed acceptably small difference from the respective control values. However, the Lee's method gave closer to control volumes for anthropological measurements whereas the Spheroid method gave closer to control volumes for x‐ray measurements.
The renewal areas of the common bile duct epithelium in the rat
Authors: Cohen P. J.
Published: February 2005

The common bile duct epithelium has been studied in common bile duct‐ligated and sham‐operated rats treated with colchicine, and numerous colchicinemitoses have been observed largely localized in the biliary or tubular “glands.” This finding suggests that the “glands” serve as the centers of cell division, i.e., the “renewal areas,” within the duct epithelium. Evidence has also been found that the duct epithelial cells are shed from the surface (luminal) epithelium into the lumen.

In these cytological features, the common bile duct epithelium resembles the small intestinal epithelium, and this suggests the possibility that the pattern of cell renewal and replacement in the common bile duct epithelium is similar to that in the small intestinal epithelium, i.e., the “gland” cells constantly divide and replace the cells which are lost from the surface epithelium.
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

Adult 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

Lymphatic 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

The 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

The 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

In 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

The 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.
Commissures of autonomic fibers in the pelvic organs of rats
Authors: Langworthy Orthello R.
Published: February 2005

A group of autonomic fibers cross the midline over the ventral surface of the cervix of the uterus in the female rat and around the dorsal edge of the prostate and between the spermatic ducts in the male. There is no clear explanation for these decussations.
Uterine metaplasia and plasma levels of vitamin A
Authors: Reiter Russel J.
Published: February 2005

The 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

Critical 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

In 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

This 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

Experiments 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

The 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

The 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

Two 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

Single 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

The 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

The 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

Study 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.
Bony pelvic sexual dimorphism in the rat
Authors: Bernstein P. , Crelin E. S.
Published: February 2005

Normal pelvic dimorphism is the result of the male pelvis acquiring morphological features during postnatal development that differ from those of the female. The first dimorphic features appear at 32 days of age. At 76 days of age the male pelvis has eleven dimorphic features that constitute the dimorphism of the normal adult. The development of five of the 11 features is dependent on the presence of the testes, whereas, the other six develop independently of the testes. The testes‐dependent features develop in males castrated at birth and treated with testosterone. The postnatal development of the female‐type pelvis in the normal female is not dependent on the presence of the ovaries.
The projection of optic nerve fibers in the frog Rana catesbeiana as studied by radioautography
Authors: Goldberg Stephen , Kotani Minoru
Published: February 2005

Tritiated leucine was unilaterally introduced into the vitreous chambers of metamorphosing bullfrog tadpoles in an attempt to determine whether the optic fibers may be traced by radioautography. After injection, the animals were sacrificed at varying time intervals from 4½ minutes to 32 days. Serial sections of the brain were subjected to radioautography. The optic fibers were thereby traced to their known terminations and to a small thalamic cell cluster to which we found no reference in the literature. Significant differential radioactivity was detectable in the contralateral optic lobe as early as six hours postinjection, suggesting a flow, whether intra‐ or extraaxonal, of at least 10–22 mm/day.

A single postmetamorphic frog underwent excision of the optic chiasm with positioning of the stumps of the optic nerves against the lateral wall of the thalamus. Fifteen weeks were allowed for regeneration. When the same histologic and radioautographic technique as above was used (sacrificing at eight days postinjection), a grain path was found to extend from the optic nerve into the brain. This path divided into two distinct branches, one branch crossing over and one remaining on the same side. These results indicate the practicality of tracing nerve distribution within the CNS by radioautography.
The canine lymphoid system: A study of the effect of surgical excision
Authors: Chretien Paul B. , Behar Raymond J. , Kohn Zev , Moldovanu Graziella , Miller Daniel G. , Lawrence Walter
Published: February 2005

A detailed study of the lymph node anatomy of the dog is presented, and a technique for surgical excision of the thymus, spleen, and all gross lymph nodes is described. The dissections were performed after intravenous administration of pontamine blue to living animals.

Major excision of the lymphoid tissue of the dog led to a modest prolongation of skin allograft survival, but it did not lead to a further increase in the allograft prolongation achieved with 6‐mercaptopurine immunosuppression when these two measures were used simultaneously. Neither did lymphadenectomy alter the leucopenia or toxicity of 6‐mercaptopurine when node excision was performed immediately prior to initiation of drug therapy. The transient nature of both the lymphopenia produced and the alteration of allograft response after lymphadenectomy suggest that there is another major contributor to the circulating lymphocyte pool. It is suggested that this may well be the lymphoid tissue in the intestinal wall.

The surgical preparation described is proposed as a model for the study of lymphoid tissue depletion and regeneration in the dog.
Influence of exercise and tenectomy on the morphology of a muscle nerve
Authors: Tomanek Robert J. , Tipton Charles M.
Published: February 2005

The effects of decreased and increased levels of muscular activity on the morphology of the medial gastrocnemius nerve were investigated in male albino rats assigned to tenectomy, control and exercise groups. Nerve fiber diameter and the number of constituent myelinated fibers were measures obtained from images of transverse sections projected onto drawing paper.

The mean values for the tenectomised animals for nerve fiber diameter (X = 7.41 ± 0.13 μ) and number of nerve fibers (X = 223 ± 5.4) are significantly lower than the means of the control animals (X fiber diameter = 7.96 ± 0.14 μ; X number of fibers = 247 ± 5.2). Associated with these changes is a marked atrophy of the gastrocnemius muscle.

A single bout of exercise (running in an activity cage) did not produce changes in nerve fiber diameter (X = 7.58 ± 0.17 μ) nor in the number of nerve fibers (X = 238 + 5.0). Moreover, an eight‐week exercise program consisting of running on a treadmill had no significant effect on mean nerve fiber diameter (X = 8.04 ± 0.18 μ) nor in the number of nerve fibers (X = 231 ± 6.3).

Correlations between gastrocnemius muscle weight and mean nerve fiber diameter or number of nerve fibers revealed no significant relationships. It was concluded that only the tenectomy data supported the theory of interdependency of muscle and nerve.
Observations on the abdominal lymphaticovenous communications of the squirrel monkey (Saimiri sciureus)
Authors: Roddenberry Harvey , Allen Lane
Published: February 2005

The abdominal lymphaticovenous communications in the squirrel monkey were studied by injection, sections and by microscopic observations in vivo. Caval pressures were measured and correlated with lymphatic pressures.

Lymphaticovenous communications were easily identified by a pulsating reflux of venous blood, which was related more to lymphatic than to venous pressure. The caval venous pressure was constant at 7 cm H2O. Lymph continued to flow until venous pressure reached 14 cm H2O. The first lymphatic valve remained competent at 60 cm H2O. There was no anatomical or physiological evidence of a sphincter mechanism at the lymphaticovenous ostia. With identical criteria, no abdominal lymphaticovenous communications were found in the rat. Except for rare anomalies, abdominal lymphaticovenous communications are species characteristics.
Microradiography of intrapulmonary bronchial veins of the dog
Authors: Reeves John T.
Published: February 2005

Microradiographs of 100‐300 μ slices of dog lungs which had pulmonary veins injected with barium sulphate showed good filling of brochial veins. Bronchial veins joined pulmonary veins at frequent intervals along the longitudinal axis and around the circumference of bronchi. Frequently, pulmonary veins and pulmonary capillaries entered the bronchial venous system, suggesting venous flow from lung to bronchus. Single veins along the margin of small bronchi (1 mm) received both pulmonary venous and bronchial venous blood. Therefore, there was a particularly intimate relationship between pulmonary and bronchial veins. The submucous venous plexus was prominent and was composed of thin‐walled, 50 μ‐diameter veins which had surprisingly direct connections to pulmonary veins. The proximity of a large venous plexus to the airway lumen suggested that oxygen transport could occur, thereby reducing venous admixture of the arterial blood.
Differential collagen stain by an acid fuchsin, iron, flavianic acid mixture. A note on ferrous sulfate hematoxylin
Authors: Lillie R. D. , Gutierrez A. , Palmer R. W.
Published: February 2005

Substitution of flavianic acid (50 mM) or of a stoichiometric mixture of naphthol yellow S and hydrochloric acid, in place of picric acid in Van Gieson type mixtures gives deeper yellow colors to cytoplasm, muscle and erythrocytes. Higher concentrations of acid fuchsin can be used with consequent greater density of collagen fiber staining and improved contrast.

The familiar weakening of hematoxylin nuclear stains by exposure to Van Gieson mixtures can be largely avoided by inclusion of 0.1 M ferric chloride in the Van Gieson mixture. Alum hematoxylin can then be used in place of the unstable iron hematoxylin solutions, and the iron hematoxylin effect is attained by the iron postmordanting in the Van Gieson bath. A ten minute prestain in an alum hematoxylin containing 0.5% hematoxylin is adequate but density can be enhanced by longer staining or by staining at higher temperature; 5–10 min at 60°C is suggested. The iron containing flavianic or picric acid Van Gieson staining baths should be restricted to three minutes; longer exposures gradually weaken nuclear staining.

Substitution of 0.1 M copper sulfate for the iron in the Van Gieson bath also yields dark gray to black nuclei. Aluminum chloride (0.1 M) has an effect similar to the control hydrochloric acid, while the chromium ion seems quite inferior, even to the control HCl mixture.

A ferrous sulfate hematoxylin ripened overnight with a small amount of ferric chloride gives excellent progressive nuclear staining, adequate in 2–5 minutes, and not excessive in 30 minutes. The solution gradually deteriorates in 6–8 weeks.
Morphological studies on the reproductive organs of blinded male hamsters and the effects of pinealectomy or superior cervical ganglionectomy
Authors: Reiter Russel J.
Published: February 2005

The testes, seminal vesicles and coagulating glands of hamsters subjected to bilateral optic enucleation (blinding) involuted within 6–8 weeks. During the first several weeks after blinding there was relatively little change in the weights of the reproductive organs, however, between 4–6 weeks the weights of these organs declined precipitously. Finally, the testes and accessory sex organs of 8‐week blinded hamsters were about one‐tenth and one‐third their normal size, respectively. The atrophic testes exhibited a complete loss of spermatogensis and an apparent diminished secretion of androgens since the seminal vesicles and coagulating glands also regressed significantly. Despite the involution, the testes showed a high degree of deoxyribonucleic acid synthesis as evidenced by the large number of spermatogenic cells which took up tritiated thymidine. These findings indicate that the testes retained a certain level of regenerative capacity even in the presence of advanced tubular damage.

If hamsters blinded for 9 weeks, had either their pineal gland or superior cervical ganglia removed, the involuted testes and accessory organs regenerated and returned to the normal size, and presumed function, within approximately 8 weeks. Regenerated testes were histologically indistinguishable from those of normal animals. Eyeless hamsters killed after 17 weeks still possessed involuted reproductive organs.
Extracellular connective tissue fibrils in the chick embryo
Authors: Low Frank N.
Published: February 2005

An electron microscopic study of extracellular connective tissue fibrils in the chick embryo is reported herein. Primary fibrils (40–45 Å) are first to appear, being present in the primordia of ectodermal boundary (basement) membranes in freshly laid eggs. Free microfibrils (40–150 Å) appear by delamination from boundary membranes from 24 hours incubation onward. The notochord becomes intensely active in forming microfibrils toward the end of the second day. By 72 hours free mesenchymal cells are producing microfibrils. Axial periodicity is acquired relatively slowly by microfibrils in their transition to unit collagen fibrils. At one week's incubation fibrillar diameters and periodic banding still do not match the recognized adult pattern.

The hypothesis that a single developmental line of fibrils leads to all extracellular connective tissue fibrous elements is supported by the ontogeny of fine structure in the chick. Microfibrils first arise in close association with primary fibrils, then from notochordal cells and later, more directly from free mesodermal cells (mesenchyme, fibroblasts). The collagen, reticular and elastic fibers of light microscopy arise from aggregations and alterations of fibrillar material whose line of descent is traceable to the microfibril.