bluuebunny/crossref_metadata_2025 huggingface dataset:
The fine structure of parasympathetic nerve cells in the otic ganglia of the rabbit
Authors: Dixon John S.
Published: February 2005

The ultrastructure of parasympathetic neurons in the otic ganglia of the rabbit is described with the object of providing a basis for comparisons of parasympathetic with sympathetic nerve cells. The neuronal cytoplasm contains Nissl substance, mitochondria, dense bodies, agranular Golgi membranes, neurofilaments (60 to 100 Å in diameter) and microtubules having diameters about 200 Å and filled with irregularly dense material. Granulated vesicles (about 900 Å in diameter) consisting of a limiting membrane and enclosing a dense spherical droplet of about 500 Å diameter are also present in the cytoplasm and processes of these neurons and in presynaptic terminals, thus disproving the hypothesis put forward by some authors that the presence of granulated vesicles indicates a sympathetic nervous pathway. Long, tubular bodies with a dense central core are described which are possibly peculiar to parasympathetic neurons. The nuclear membrane is double, porous and sometimes exhibits localized, deep invaginations of its surface.

Junctional complexes are described between apposing membranes of neurons and satellite cells which are morphologically similar to zonulae adhaerentes.

Small gaps exist in the cytoplasmic sheath surrounding the neurons. Over these areas only a basement membrane separates the nerve cell from the connective tissue space and the significance of this finding is discussed.
The influence of thyroid and testicular hormones on the epithelium of crypts of Lieberkühn in the rat's intestine
Authors: Carriere Rita M.
Published: February 2005

The growth of duodenal crypts of Lieberkühn was investigated in male Sherman rats subjected to thyroidectomy, and/or castration. Histological sections were studied, counting interphase nuclei and mitoses in 25 longitudinally sectioned crypts per animal. At 49 gm body weight, initial control animals had an average of 65.8 ± 2.4 cells per crypt section, and 80 days later, sham‐operated controls weighed 269 gm and had 91.4 ± 5.1 cells per crypt section. There were only 75.0 ± 3.7 cells per crypt section 80 days after thyroidectomy, while castrates had 97.0 ± 2.6 cells per crypt section. Thyroidectomy combined with castration produced results similar to thyroidectomy alone, 74.0 ± 2.5 cells per crypt section. Treatment of such doubly operated rats with testosterone during the last 42 days of the experiment significantly increased the cell number, to 82.7 ± 2.8 per crypt section, while thyroxine increased it to 100.8 ± 4.3. Thus, in the rat, the number of cells per crypt increases between juvenile and adult stages, and this growth is subject to endocrine regulation, particularly by the thyroid.

The mitotic index of crypt cells increases with age, from 3.9 ± 0.1% at 49 gm body weight, to 5.2 ± 0.3% at 269 gm body weight. Castration did not interfere with this increment, but it was reduced in the absence of thyroid hormone, and was restored by the injection of thyroxine to thyroidectomized castrates.

Finally, from related observations in previously reported and unpublished experiments, it is suggested (1) that the influence of thyroid hormone on crypt cell number may be mediated, at least in part, through an action on growth hormone release from the anterior pituitary and (2) that the rate of change in cell number with age may be determined in some measure by a change in the rate of cell displacement toward the villus tip, in addition to a change in mitotic index.
Hormonal determinants of the development of masculine and feminine behavior in male and female rats
Authors: Whalen Richard E. , Edwards David A.
Published: February 2005

To investigate the role of gonadal hormones during the postnatal period on the development of masculine and feminine behavior 129 male and female rats were hormonally manipulated at birth. Within 24 hours of birth male and female rats were: (a) sham operated, (b) gonadectomized, (c) gonadectomized and given testosterone, or (d) gonadectomized and given estrogen. When adult all animals were given testosterone and tested for the display of male behavior, and then given estrogen and progesterone and tested for female behavior. Male behavior: Males exhibited mounting responses more frequently than females regardless of hormone manipulation at birth. Androgen and estrogen at birth did not facilitate mounting behavior in either sex. Males exhibited more frequent intromission responses than females. Animals treated with androgen at birth showed more frequent intromission behavior than non‐treated animals. Androgen facilitated intromission relatively more in males than in females. Estrogen at birth did not facilitate intromission behavior. Female behavior: Males castrated at birth, normal females, and females ovariectomized at birth showed high levels of receptivity. No other animal exhibited frequent lordosis. The data indicated that behavioral sexual differentiation induced by hormones in in‐fancy is best characterized by an inhibition of the potential to display feminine behavior.
Subcommissural organ, lateral hypothalamus, and dorsal longitudinal fasciculus in water and salt metabolism
Authors: Crow Lowell T.
Published: February 2005

Twenty‐two albino rats were divided into three groups for chronic brain electrode implantation. The effects of subsequent stimulation and ablation of the subcommissural organ (SCO), the bilateral lateral hypothalamic nuclei (LH), and the dorsal longitudinal fasciculus (FLD) on volume of water intake, and on concentration of urinary excretion were observed over twenty‐two hour periods of free access to water both before and after treatments.

It was observed that neither stimulation nor lesion of the SCO resulted in disruption of water intake or of urinary volume and concentration. Similar stimulation of LH potentiated drinking, while similar lesions produced a hypodipsia that necessitated tube feeding. Lesions of LH produced, in addition, marked elevation of urine volume, but no change in urine concentration. Sectioning of the FLD was followed by effects similar to those following lesions of the LH nuclei.
Comparative anatomical and neurohistological observations on the tongues of elephants (Elephas indicus and Loxodonta africana)
Authors: Kubota Kinziro
Published: February 2005

Frozen sections from Indian and African elephant tongues were investigated neurohistologically. On the dorsum there are 3 to 5 vallate papillae. Foliate papillae consisting of 18 to 27 clefts are observed in the posterolateral region of the tongue. Wart‐like papillae are distributed along the lateral border of the tongue from the foliate papillae region to the apex. Vallate and foliate papillae contain serous glands but have no taste buds. They are supplied with abundant lamellated corpuscles of Pacinian type in their upper mucosa. The wart‐like papillae are composed of two or more papillae, each of which has many secondary papillae supplied with plexiform thin and thick nerves. They bear a few taste buds and contain lamellated corpuscles of Pacinian type.

From these neurohistologic characteristics wart‐like papillae should be regarded as a receptive organ for secretion of the lingual glands. Lamellated corpuscles of Pacinian type are widely distributed over the whole surface of the tongue. The histologic location of these two structures is of interest in suggesting that they together play important roles as receptors of taste and tactile sensations during mastication of food. Double motor end plates are found on single muscle fibers. The mixed glands which are plentiful in the inferolateral area of the tongue are in close topographic relation with the wart‐like papillae.
The antiestrogenic and antiandrogenic activities of progesterone in the defense of a normal fetus
Authors: Dorfman Ralph I.
Published: February 2005

The hypothalamic‐anterior pituitary‐gonadal system of the infant rodent is sensitive to sex hormones. In the female, an increase in androgens leads to improper development of an anovulatory ovary. In the male, an increase in estrogens prevents the testis from attaining normal development. These atrophic testes show serious abnormalities of spermatogenesis and androgen biosynthesis. Progesterone, which may function as both an antiestrogen and an antiandrogen, can prevent these abnormal developmental changes.

It is suggested that a function of progesterone, in pregnancy, may be the defense of the fetus against increased concentrations of androgens and/or estrogens.
Erythropoiesis in the bone marrow of the fetal rabbit
Authors: King John E. , Ackerman G. Adolph
Published: February 2005

Although the extravascular origin of erythrocytes from undifferentiated mesenchymal or reticular cells in mammalian bone marrow is generally accepted, the morphological evidence on which this concept is based has not conclusively ruled out the possibility of endothelial cell contributions to erythropoeisis or of the preferential localization of developing erythrocytes within endothelial cell‐lined spaces. Since conventional methods of tissue preparation have produced artifacts which obscure the fine details of marrow architecture, the re‐examination of this problem using newer histological and fixation methods permits a more critical study of the bone marrow in nearly artifact free sections.

Ribs and long bones of 65 rabbits, ranging from 18 days of gestation to the second day after birth were removed, fixed intact with 10% aqueous acrolein, decalcified in 5% aqueous nitric acid and embedded in plexiglass‐methacrylate. Two micron sections stained with toluidine blue were examined with the light microscope. Serial paraffin sections of formal‐Zenker fixed material also were examined.

Morphological studies conclusively indicate that erythrocytes develop extravascularly arising from mesenchymal or reticular cells in the fetal bone marrow. Mature erythrocytes enter the circulation through discontinuities in the sinusoidal walls. Neither endothelial cells or blood‐borne lymphocytes make an apparent contribution to erythropoiesis. The first hemopoietic cells to form in the fetal marrow are determined and develop along the erythrocytic line. These proerythroblasts initially arise randomly in the marrow parenchyma and are not in obvious association with the sinusoids. Subsequent maturation and proliferation of the primitive erythrocytic cells result in the formation of colonies of erythrocytic cells at all stages of development. As these colonies enlarge, the erythrocytic elements come in close association with the sinusoids. In later stages of marrow development, developing erythrocytic and granulocytic cells become intermixed and more randomly associated in the extravascular space of the marrow.
Further observations on resorption in guinea pigs following injections of trypan blue
Authors: Hoar Richard M. , King Theodore J.
Published: February 2005

Pregnant guinea pigs were injected with 2 ml of either 1% saline or 1% trypan blue of the eleventh day of gestation and sacrificed on days 12, 13, 14, 15 or 20 or laparotomized on day 15, examined for implantation sites and sacrificed on days 25, 30 or 35.

Trypan blue increases both the number or pregnancies affected and the number of embryos resorbed within 24 hours after injection. Laparotomy on day 15 augmented the above effects in both saline and trypan blue‐injected females. This increase is superimposed upon the number of resorptions already established for the two groups. Evidence is presented which suggests that resorption of guinea pig embryos can be so complete as to leave no indication of the original presence of the embryo or its placenta. This can occur within as few as five days.
Ultrastructure of the carotid body of the cat as revealed by various fixatives and the use of reserpine
Authors: Duncan Donald , Yates Robert
Published: February 2005

Carotid bodies from 11 cats were prepared for study with the electron microscope. All cats used were initially healthy and weighed from 1.5 to 4.0 Kg. Four cats were given daily doses of reserpine 1.5 mg/Kg for 2, 3, 4 or 12 days; the other cats were untreated. Carotid bodies were fixed by immersion in Dalton's fluid, collidine buffered osmic acid or 3% potassium permanganate in 0.1 M phosphate buffer. Other carotid bodies were fixed by perfusion with buffered formalin or with 3% glutaraldehyde in phosphate buffer. Each fixative produced distinct differences in the appearance of the carotid body, particularly in the size and opacity of the granules within the characteristic vesicles of glomus cells (type I). After Dalton's fixative the granules were faint and inconspicuous whereas after osmic acid fixation the granules were very dense but small in comparison to the size of the enclosing vesicular membrane. Aldehyde fixation resulted in very dense granules that almost completely filled the vesicles but permanganate fixation produced vesicles that were devoid of the dense central cores except for a very few. Carotid bodies from reserpine treated cats that were fixed in osmic acid displayed empty vesicles while those from reserpinized animals fixed by perfusion with glutaraldehyde revealed granules that differed little from normal in numbers, size and density. However, vesicles in the adrenal medulla and in sympathetic nerve endings in the pineal gland from the same animals contained empty vesicles. The results are regarded as evidence of a different degree or method of binding between catecholamines and other components of the vesicles in glomus cells when compared to similar vesicles in sympathetic nerve endings and the adrenal medulla.
Brain abnormalities in early chick embryos infected with influenza‐a virus
Authors: Robertson G. Gordon , DeBandi Harry O. , Williamson Alice P. , Blattner Russell J.
Published: February 2005

Chick embryos were inoculated with influenza‐A virus over the blastoderm at 42–50 hours incubation (37°C). Surviving embryos were harvested 24 hours later, Grossly and microscopically, the developing brain exhibits a type of abnormality in which the neural wall is highly convoluted with folds projecting into the ventricular cavities, suggesting “overgrowth” of the neural tissue.

A comparison of measurements on projection drawings of serial sections of virus inoculated and control embryos at comparable developmental stages indicates that the ventricular surface area, volume of brain tissue and volume of the ventricular cavity are markedly less in the experimental embryos, but average thickness of the brain wall is greater. There are fewer nuclei and mitotic figures in experimental embryos, although average nuclear and mitotic densities and mitotic index are approximately the same as control values.

It is evident that the characteristic neural defect is not due to excessive growth, since the volume of brain tissue and number of cells are consistently less in experimental embryos. It is concluded that the virus infection results in an inhibition of growth of the brain wall, and that the increased thickness and foldings must result from collapse of the brain which in turn may be due to a decrease in the amount of ventricular fluid.
The ultrastructure of the myometrium of the rat with special reference to the innervation
Authors: Silva Douglas G.
Published: February 2005

An ultrastructural study of the rat myometrium revealed the presence of a number of nerve bundles, many of which were associated with either muscle cells or blood vessels. The nerve fibers were found to contain agranular and granular vesicles of widely varying proportions and the spatial relationship between nerve fibers and muscle cells in the myometrium was comparable to that found in smooth muscle generally.

A study of regions of close apposition between muscle cells showed three types of “cellular contacts.” In the first type the opposing muscle cells are separated by a gap of about 200Å with filamentous structures extending across the gap. In the second type the opposing plasma membrane are in direct contact. The third type consists of regions of cytoplasmic continuity between adjacent cells. It is suggested that the “cellular contacts” provide a path for impulse transmission between muscle cells.
Ultrastructural aspects of fibrogenesis and osteogenesis in tissue culture
Authors: Winell M. , Bassett C. A. L. , Wiener J. , Spiro D.
Published: February 2005

This electron microscopic study of 11 day old chick tibiae cultured for 7 and 14 days has demonstrated significant changes in the exposed, cut, cartilaginous surfaces of the explants. Many chondrocytes had degenerated near these surfaces and, in the lacunae of these cells, 640Å‐banded collagen fibrils appeared. The diameters of these fibrils varied widely and, sometimes, exceeded 4,000Å. The non‐banded filaments of the normal, cartilaginous, extracellular matrix were replaced by 640Å‐banded collagen fibrils near the cut surfaces of the explants. These fibrils had a narrower (500Å) and more uniform diameter than those in the lacunae of degenerated chondrocytes. This study also has confirmed the occurrence of osteogenesis in vitro. The collagenapatite and matrix‐cell relationships were similar to fiber (embryonic) bone. Two types of cells resembling osteocytes and osteoblasts were found in the newly mineralized matrix formed in culture. Mineralization in the zone of outgrowth was incomplete and focal. In some regions the hydroxyapatite crystals were larger than usual, measuring 1,000–2,000 Å in length. Longitudinal sections of collagen fibrils in the zone of outgrowth revealed electron‐dense granules along the course of the fibrils. These granules exhibited no preferred orientation with respect to the band or interband regions.
The origin of intra‐arterial cells in the pregnant uterus of the macaque (Macaca mulatta)
Authors: Beck A. J. , Beck F.
Published: February 2005

An investigation into the source of the cells present in the endometrial arteries of the pregnant Macaque is presented. By comparing the levels of sex chromatin found in these cells with those in fetal cytotrophoblast and in maternal endometrial stroma it was possible to determine that they are essentially of fetal origin.
Gross and microscopic observations on the communicating branch of the facial nerve to the lesser petrosal nerve
Authors: Vidić Branislav , Young Paul A.
Published: February 2005

The contents of the facial canal (first and second parts of the facial nerve, and geniculate ganglion), the tympanic plexus, the greater and lesser petrosal nerves, and all intervening connections were dissected in 40 cadavers. This entire nerve complex was removed in 30 cases, and in parts in ten cases, dehydrated, and stained with Sudan Black B or Protargol. A constant communication from the second part of the facial nerve, the geniculate ganglion, or the greater petrosal nerve was observed to pass to the lesser petrosal nerve in all dissections. A review of the literature indicates other points relative to the exchange of autonomic fibers between the facial and glossopharyngeal nerves.
Histologic and physiologic comparisons of the thyroid glands of the wild and domesticated norway rat
Authors: Mosier H. David , Richter Curt P.
Published: February 2005

A comparison of the histological pattern of the thyroid glands of 138 wild and 157 domesticated Norway rats showed that the domesticated rat has smaller epithelial cells, greater uniformity in the size of follicles, larger follicular lamina, and fewer vacuoles in the intrafollicular colloid. These differences are not present at birth but develop gradually with age. Hypophysectomy causes a loss of these differences and results in an identical histologic pattern of atrophy in the two strains of rats. There is greater uniformity of thyroid I131 uptake and labelling of the components of thyroglobulin in the domesticated rat, but the average percent uptake of I131 in the thyroid glands of both strains is the same.

These differences may be accountable partly on the basis of different reactions to the environment conditioned by different temperaments in the two strains, by actual differences in the environment, and by genetic differences.
Congenital malformations induced by alloxan diabetes in mice and rats
Authors: Takano Kiichi , Nishimura Hideo
Published: February 2005

Two separate experiments were carried out. (1) Alloxan was injected subcutaneously into ICR female mice at 200 mg/kg on day 0 (zero) of gestation. In the animals which became persistently diabetic, 27.5% of the conceptuses underwent resorption or death and 7.2% of surviving fetuses showed gross malformations, including exencephaly, spina bifida and cleft palate. In nondiabetic experimental animals there was no increase in fetal mortality or malformation rate. (2) Wistar rats were treated by alloxan intraperitoneally at 160 mg/kg on the seventh day of gestation. Again, only in cases of persistent diabetes were there raised fetal mortality and high incidence of external and internal malformations (50.0% of survivors abnormal), including cataract, hydronephrosis, microphthalmia, exencephaly and cleft palate. When glucose concentration was determined in the embryo and amniotic fluid on the eleventh and thirteenth days of gestation, it was found to be much higher in the diabetic than in the control or the nondiabetic treated animals. The embryonic glucose level was always slightly lower than that of the maternal blood.
Cholinesterase activity in the harderian gland of anas domesticus
Authors: Fourman Julia , Ballantyne Bryan
Published: February 2005

The histochemical localization and quantitative levels of acetylcholinesterase and butyrylcholinesterase have been determined in the Harderian glands of normal ducks and ducks fed with salt to increase their serum sodium concentrations; there was no significant difference between the two groups.

Acetylcholinesterase was present at a mean concentration of 68.2 μM/gm/hour (range 65.5 – 72.7 μM/gm/hour) in the normal animals and 67.6 μM/gm/hour (range 63.8 – 76.4 μM/gm/hour) in the salt‐fed group; the enzyme was present in nerves related to blood vessels. Butyrylcholinesterase was present at a mean concentration of 42.5 μM/gm/hour (range 20.4 – 58.7 μM/gm/hour) in the control animals and 40.2 μM/gm/hour (range 29.3 – 61.3 μM/gm/hour) in the salt‐fed group; the enzyme was present in epithelial cells and in nerves related to blood vessels similar to those containing acetylcholinesterase. There was a close correlation between the subjective assessment of cholinesterase activity based on histochemical techniques and the amount quantitatively measured.

The gland probably secretes mucus and lipids; the epithelial butyrylcholinesterase may play a role in lipid metabolism in the tissue. The nerves may regulate the flow of blood through the gland.
Fiber sizes and capillary to fiber ratios in skeletal muscle of exercised rats
Authors: Carrow R. E. , Brown R. E. , Van Huss W. D.
Published: February 2005

Thirty male rats (Sprague‐Dawley), 25 days of age, were placed in exercise cages for seven days. They were matched into trios on the basis of the last four days total exercise and randomly placed in three groups: sedentary, spontaneous exercise and forced exercise. For the next 35 days, the sedentary group was permitted no exercise other than that allowed by their small individual cages. The spontaneous group remained in activity cages while the forced group in addition to being in activity cages, swam one 30‐minute period each day with weights equal to 20% of the body weight attached to their tails. At the end of the 35‐day activity period, the animals were sacrificed. The hind limbs were injected with India ink, embedded in gelatin and cut on the freezing microtome. The cross‐sectional area of red and white fibers from the gastrocnemius muscles were measured by using the polar planimeter. Ink‐filled capillaries were counted, in conjuction with fiber measurements.

With forced and voluntary exercise programs there was a greater increase in crosssectional area of the red than of the white fibers. Under the same conditions, the increase in the number of capillaries per fiber was greater for white than for red fibers.
The myelinated fibers in the aortic nerve of the swine
Authors: Schmidt E. M. , Stromberg M. W.
Published: February 2005

The aortic nerves of 24 Chester White swine were identified electrophysiologically by the synchronization of the recorded action potentials with the cardiac cycle; and the occurrence of the maximum firing rates observed on the oscilloscope during systole. The aortic nerve, thus identified, was traced to the aortic arch in two preparations. The left aortic nerve was a separate bundle in 15 of 24 (62.5%) swine investigated. In the remaining 37.5% of the swine the nerve was dissected from within the vagus after identification at the level of the nodose ganglion. At this level the aortic nerve leaves the ganglion with the superior laryngeal nerve, runs caudomedially with it a short distance, then loops back laterally into the vagus to run caudally to the arch of the aorta. An aortic nerve was not observed in the right vagus nor in the sympathetic trunk of either side. The myelinated fibers counted from six aortic nerves were less than 10 μ in diameter with the majority in the 2–6 μ range, and averaged 542 in number.
Two cases of intersex in rabbits
Authors: Shaver Evelyn L.
Published: February 2005

A description is given of two intersex rabbits, which appeared to be females and, in the course of an experiment, were injected with chorionic gonadotrophin, and then matted with a male. When the animals were sacrificed six days later, the reproductive system was found to be absent except for testes located in the abdomen. On histological examination of the gonads, large amounts of interstitial tissue were found, together with immature seminiferous tubules. The tubules contained large atypical cells, spermatogonia and Sertoli cells. The chromosome number and karyotype, as determined from bone marrow, were male in each case. The intersex pattern and the morphology of the large cells within the seminiferous tubules are discussed.
The histochemistry of carbohydrate‐rich substances in certain ungulate salivary glands
Authors: Leppi T. John , Spicer S. S.
Published: February 2005

The carbohydrate‐rich secretions of bovine, ovine and porcine submandibular and sublingual glands have been investigated histochemically. The strong PAS staining of mucous acini in all the glands indicates presence of mucin rich in residues with vic‐glycols. This staining correlates well with the neutral sugar (hexose or deoxyhexose) content except in the bovine submandibular gland in which other types of residues as perhaps C‐6 linked or terminal amino sugars with vicinal hydroxyls apparently account for PAS staining. Strong staining with a periodate‐para diamine procedure is observed only in the glands with high hexose or deoxyhexose levels and is absent from those with strong PAS reactivity apparently attributable to amino sugars. Digestion with malt diastase diminishes the PAS staining of a mucous secretion in mucous acini of the sheep glands.

The mucous acini of the submandibular glands form sialomucin uniformly and afford no evidence for the presence of a sulfomucin. The basophilia of this sialomucin in sow and ewe is fully susceptible to sialidase. Sialomucin basophilia in the bovine submandibular gland is only partially digestible, indicating presence of two kinds of neuraminic acid or two sialomucins in this gland.

In the sublingual glands the proportion of sulformucin to sialomucin increases in the order cow‐sow‐ewe. The sialomucin in the bovine and porcine sublingual mucous acini revealed as blue‐stained material with the high iron diamine‐alcian blue sequence largely succumbs to sialidase. Much of that similarly demonstrated in the ovine sublingual gland resists digestion, suggesting presence herein of two sialomucins. The sialomucin in all the mucous acini of the ovine submandibular and some mucous acini of the ovine sublingual glands loses azurophilia and undergoes marked decrease in alcianophilia after digestion with malt diastase.

Prominent seromucous demilunes in the ovine and bovine glands appear to secrete a sulfated mucosaccharide. The secretion in these sites stains well with the PAS method. The seromucous demilunes in the cow afford evidence also of a mucosaccharide‐containing sialic acid.
Reconstruction of the human sinoatrial node
Authors: Truex Raymond Carl , Smythe Martha Q. , Taylor Margaret J.
Published: February 2005

The superior vena cava and adjacent right atrium containing the sinoatrial node in each of five human hearts was studied histologically in serial section. The tissue block of a 41 year old man was reconstructed in four colors to provide a three‐dimensional model of the sinoatrial node, atrial relations, blood supply and nodal configuration. The resulting model demonstrated the curved course of the compact sinoatrial node and the mural relations of its tapered superior and inferior ends.

Microscopic measurements of the boundaries of the five human nodes yielded an epicardial to endocardial mean thickness in the compact body of the node of 1.6 mm, that of the lower node was 0.6 mm. The mean length of the five nodes was 7.3 mm. Such microscopic delineation of the node is more accurate than gross measurements and indicates that the size of this vital mass of pacemaker tissue in man is smaller than the larger measurements usually given in the literature. Small strands of nodal muscle fibers follow longer or shorter courses before they become continuous with the larger more darkly stained atrial cardiac muscle fibers. We found no histologic evidence within the human node, or along its periphery, of continuity between the small nodal fibers and very large atrial fibers.
The fine structure of Brunner's glands in the rabbit
Authors: Leeson C. Roland , Leeson Thomas S.
Published: February 2005

The fine structure of the duodenal glands of Brunner in the rabbit has been examined. The glands, which are concentrated within the submucosa, are composed of tubules that open into the bases of the intestinal glands. Unlike most species, in the rabbit two distinct cell types are present within the tubules. Serous cells, which occur in small groups in the blind endings to the tubules, contain a concentration of ergastoplasm in the basal cytoplasm and the apical cytoplasm is occupied principally by discrete secretory droplets. Intercellular secretory canaliculi occur between opposed serous cells and between serous and mucous cells. The latter cells possess little ergastoplasm but exhibit an extensive development of the Golgi apparatus in the supranuclear region. Secretory droplets are pale and show a tendency to fuse into complexes. No intercellular canaliculi occur between mucous cells.

The cytological features are discussed in relation to previous observations on duodenal glands of other species, where only mucous cells are present. It is apparent that there are species differences with regard to mucous cells. These structural differences may reflect physiological and biochemical differences in the glands. The significance of the presence of serous cells in rabbit duodenal glands is unknown.
An analysis of the growth retarding effects of trypan blue in the albino rats
Authors: Jensh Ronald P. , Brent Robert L.
Published: February 2005

A laparotomy was performed on 74 pregnant Wistar rats after eight days of gestation and injection with trypan blue, normal rabbit serum, or sterile saline. Also, a laparotomy was performed on a control group which received no injections. After 21 days of pregnancy, the rats were sacrificed and the fetuses and their placentae removed, weighed individually, and then fixed in Bouin's fixative. All fetuses were dissected and examined for abnormalities. Several analyses of variances and a paired t‐test were completed to determine if fetal growth was retarded in the abnormal fetuses. Fetuses in each experimental group were also separated into weight classes as determined by Sturge's Law for class intervals. It was shown that in inbred colonies the timing of the pregnancy, litter size, and maternal factors cannot be neglected. The results indicate that: (1) Trypan blue exerts a definite growth retarding effect on rat fetuses; (2) The weights of malformed fetuses are significantly reduced; (3) The mean term fetal weight of the normal fetuses that were exposed to trypan blue is not significantly different from the mean weight of the control normal fetuses; (4) The mean weight of the abnormal fetuses that were exposed to trypan blue is significantly less than that of the control normal fetuses as well as the normal fetuses treated with trypan blue; (5) There is no weight threshold below which all fetuses are abnormal and above which all fetuses are normal.
The effect of Steroids on mitosis and maintenance of pregnancy in spayed rats
Authors: Kim Yong Jim , Foreman Darhl
Published: February 2005

Rats were ovariectomized on the eighth day of pregnancy and either 10 or 20 mg of progesterone, 10 mg of progesterone with 1 μg estradiol benzoate or 1 μg estradiol benzoate alone were administered between the eighth and twelfth day. On the twelfth day tritiated thymidine was injected to study mitoses in the junctional zone cells of the placenta by autoradiography, and tracings of spontaneous uterine contractions were made. Twenty milligrams of progesterone daily sustained pregnancy to the twelfth day in spayed rats as effectively as it was sustained in the untreated normal rats; 10 mg progesterone daily was less effective and 10 mg progesterone with 1 μg estradiol benzoate did not maintain normal pregnancy. Progesterone produced normal rates of mitosis in the placental trophoblast cells of spayed rats. No correlation was found between the maintenance of pregnancy and decreased contractions of the myometrium in this study. The injection of 20 mg progesterone produced patterns of contraction similar to the normal contraction patterns and differing from those found in spayed rats and in rats injected with 10 mg progesterone, progesterone and estradiol benzoate or estradiol benzoate alone. It is concluded that a sufficient supply of progesterone maintains both normal mitotic activity in the trophoblastic cells and normal patterns of contraction by the muscle of the uterus.
Diprosopus and related cephalic malformations in a calf
Authors: Jenkins Thomas W. , Hardy Phillip H.
Published: February 2005

The head of a young calf with diprosopus (two faces) and related cephalic malformations was dissected and grossly studied. The head was removed, preserved with 10% formalin, and the cephalic vessels were doubly injected with latex.

The related outstanding cephalic abnormalities were: four eyes (tetrophthalmus) with the two adjacent eyes and orbits fused into a single median one; a large domeshaped head, characteristic of hydrocephalus; two mouths, each with a tongue, both of which protruded and retracted simultaneously; two cleft palates; duplication of the brain from the rostral end caudally to the mesencephalo‐metencephalic junction with each side of the brain containing a pituitary gland, paired cerebral peduncles, and an aberrant circulus arteriosus (circle of Willis). There were four olfactory bulbs and optic nerves, but only three oculomotor and abducens nerves. The aberrant median third and sixth cranial nerves were interpreted to be a fusion of the two adjacent nerves if duplication had been complete.

Diprosopus is classified as a form of anterior twinning. The anterior brain duplication probably is referable to a doubling of the cephalic end of the neural tube followed by a diverging migration of the two frontal poles so that these areas finally are located at opposite lateral sides of the skull. The degree of neural tube duplication determines the extent of brain duplication.
The intertubular cleft and membranous whorl in the rabbit placenta
Authors: Sinha Akhouri A.
Published: February 2005

The chorio‐allantoic placenta of the rabbit is of the labyrinthine hemodichorial type where the outer trophoblastic layer next to the maternal blood space is syncytial and the inner is cellular. The syncytium has thick and thin areas. It is at the thick areas that the trophoblast from either side of the maternal blood tubule encloses a narrow intertubular cleft which has numerous interdigitating microvilli and desmosomes. Intravenously injected thorotrast (an electron dense particle) and maternal plasma readily enter the intertubular cleft. Along the intertubular cleft numerous caveolae, arrays of rough endoplasmic reticulum and mitochondria are present in the syncytium suggesting that the clefts are areas in which fluid and certain metabolites are absorbed. The agranular membranous whorls are found in the syncytial thick areas. They enclose central or eccentric masses of lipid droplets. Small whorls are found during early pregnancy; smaller and larger ones, however, are found from midpregnancy to term. The whorls progressively increase in size as pregnancy advances. Membranes of the whorl and the rough endoplasmic reticulum are interrelated and contiguous.
A radioautographic comparison of glycerol‐H3 and galactose‐H3 uptake during intestinal glyceride synthesis
Authors: Jersild Ralph A.
Published: February 2005

Radioautography was used to compare the in vivo incorporation of glycerol‐H3 and galactose‐H3 in intestinal absorptive cells in relation to glyceride synthesis. Each labeled compound was injected, either singly or mixed with linoleic acid chyme, directly into ligated segments of rat upper jejunum. The segments were removed at 5 and 20 minutes and prepared for light and electron microscopic radioautography. Following glycerol‐H3 and chyme injections, label is rapidly incorporated in the vicinity of newly formed fat droplets in the apical endoplasmic reticulum. Later, labeled droplets accumulate in dilated Golgi cisternae and intercellular spaces. Galactose label is initially found in the Golgi region and later in the apical cytoplasm. Glycerol labeling is considerably reduced in the cells when the fat is extracted prior to radioautography, or when glycerol alone is absorbed. Galactose labeling is not affected by these procedures. The results indicate a significant incorporation of glvcerol label into newly synthesized glycerides, as previously also shown for glucose label. Galactose label follows a different metabolic pathway not related to glyceride synthesis.
A histochemical study of neuro‐insular complexes in the pancreas of the rat
Authors: Morgan Carl R. , Lobl Richard T.
Published: February 2005

Neuro‐insular complexes (neural elements in juxtaposition to islet cells of the pancreas) were studied in Holtzman albino rats.

Pancreases were stained by either the aldehyde‐fuchsin‐ponceau (A‐F‐P) or the acetylcholinesterase (ACHE) technique. The A‐F‐P stain gave good definition of islet structure. Although some nerve cell bodies were distinguishable with this stain, the AChE technique gave better definition of nerve cells, including interstitial cells of Cajal.

In adult rats every islet examined had a nerve network. In newborns the nerve network was less apparent though some nerve elements were present. A nerve network typical of the adult was found in rats 48 hours after birth.

Following insulin and glucose loading, variation in the localization of AChE was noted. It is suggested that neuro‐insular complexes have a modulatory influence on release of hormones.
Central projections of selected spinal dorsal roots in anuran amphibians
Authors: Joseph Barry S. , Whitlock David G.
Published: February 2005

The total central distribution of single brachial or lumbar dorsal roots has been assessed in toad (Bufo marinus) and in frog (Rana catesbeiana). Two methods were employed to examine the afferent fibers. The uranyl nitrate modification of the Nauta method (Nauta, '66) was used to study degenerating elements resulting from single root transection. A radioautographic tracing technique was also employed to examine the distribution of essentially normal afferent fibers. This latter method involved local injection of small amounts of L‐leucine‐H3 into a single ganglion of otherwise intact nerves and subsequent determination of location of the incorporated label in the CNS. The distribution was ascertained by counting silver grains microscopically in radioautographs of the CNS for standard sized areas. The results obtained by either method essentially were identical. All dorsal root projections are distributed unilaterally within the CNS. Fibers passed into a dorsolateral bundle and into the dorsal column. Collaterals from the dorsal column passed into the dorsal and intermediate gray matter, but no primary afferent fibers distributed within the ventral horn. Both brachial and lumbar roots distributed segmentally over approximately five spinal segments. Root fibers coursed rostrally in a somatotopically organized dorsal column. This pathway ultimately passed into the cerebellum. Some evidence was obtained in support of a dorsal column‐medial lemniscal relay in anuran amphibians.
The variations in length of the pterygoid process as a function of the variations of the sphenoid angle
Authors: Vidić Branislav
Published: February 2005

The variation in the length of the pterygoid process was studied as a function of the sphenoid angle. Three hundred human skulls and ten skulls of certain animals (dog, sheep, pig, ox, horse) were appropriately measured. The length of the pterygoid process (lateral plate), was measured in all instances from the point of junction between the lamina and the greater wing of the sphenoid to the midpoint of the lower margin of the lamina. The average value of this dimension in man was 34.7 mm with variations from 28.0 mm to 44.5 mm.

The average value of the length of the pterygoid process was found separately in male and female skulls; in different age groups; in skulls with narrow versus wide sphenoid angle; in skulls possessing a short versus a long nasion — basion distance. In each instance the values are compared and the standard deviation ascertained. The results of measurements made in man and animals are presented in a table.
The hepatic lobules of Suidae, Tayassuidae, and Hippopotamidae
Authors: Steiner Paul E. , Ratcliffe H. L.
Published: February 2005

The hepatic lobules of the family Suidae are unusually large, completely surrounded by fibrous tissue, and supplied by relatively large branches of the hepatic artery. The interlobular septa carry small branches of the artery, vein and bile ducts of the adjacent portal tracts and may be regarded as attenuated extensions of the portal tracts. The hepatic lobules of Tayassuidae and Hippopotamidae lack these distinctive features.
The geometry of the human cerebellar vermis
Authors: Turner R. S.
Published: February 2005

Some general statements concerning the overall geometry of the cerebellar vermis are presented as a preliminary step in the theoretical analysis of its morphology. From a large number of measurements made on a sample of 30 human cerebella the following relationships may be demonstrated: (1) the mean outline of superimposed sagittal sections through the mid‐vermis fits very closely the curve

(2) the relation of the total circumference (y) of individual lobes or of the entire vermis to a measurement of the outside (visible) perimeter (x) is shown to be fitted almost exactly by the equation y = ax2; (3) the relation of total circumference to outside perimeter in the rat and the cat is found to be constant during development; (4) in the human arbor vitae the relation of the width of the “trunk” to the sum of the widths of bifurcating branches is seen to be linear with a slope, in the midline, of approximately one; (5) no simple relationship could be ascertained in teh arbor vitae between angles of branching and widths of branches or trunks.
A histochemical study of the aryl sulfatases of the rat placenta
Authors: Bulmer D.
Published: February 2005

A histochemical study was made of the nitrocatechol sulfatase activity in the rat placenta and metrial gland by the lead salt technique. Marked deposits of reaction product were demonstrated in the uterine epithelium and the granulated metrial gland cells. Diffuse reactions occurred in the visceral endoderm of the yolk sac and the trophoblastic gint cells in material fixed overnight, but with fixation in formalin for seven days these were replaced by discrete granular deposits. The reactions appear to be due to type II sulfatases. They have a distribution similar to that of β‐glucuronidase and organophosphate‐resistant esterase, except that the metrial gland cell sulfatase activity becomes reduced in late gestation and the early postpartum period. The postcoupling method with 6‐benzol‐2‐naphthyl sulfate, which demonstrates mainly sulfatase C, gives a differing distribution from the lead salt technique, and the reaction is almost completely abolished by prolonged formalin fixation.
The ovary of the sea otter
Authors: Sinha Akhouri A. , Conaway C. H.
Published: February 2005

The ovarian histology of 140 sea otters (4 juvenile and 136 sexually mature) is described. Multilayered germinal epithelium occurs in thickened areas on the ovarian surface and in fissures which are simple or complexly branched. Occasionally an epithelial tube extends from the fissure into the cortex. Typically a single Graafian follicle reaches the prevulatory stage while others become atretic. Interstitial gland cells of theca interna origin are abundant and apparently secretory during estrus. The corpus luteum of preimplantation pregnancy has a medium to large antrum which is obliterated by the time the blastocyst implants. During delayed implantation, the luteal cells progressively hypertrophy and by the time of implantation they are polygonal with a uniformly granular, nonvacuolated cytoplasm. Following implantation, many small secondary cavities or spaces are observed in the corpus. Subsequently, they coalesce to form larger ones. These cavities are strikingly well developed during mid gestation. After parturition, the corpus luteum degenerates rapidly. A corpus albicans persists for at least two years before blending with the stroma.
Early changes in diet‐induced fatty livers of Mice
Authors: Wilson Jack L. , Ashburn Allen D. , Williams W. Lane
Published: February 2005

Mice (Taconic Swiss) were fed a high‐fat (28% lard), low‐protein (8% casein), lipotropic‐deficient diet for 1–90 days. For 21 days parenchymal liposis was greatest in peripheral and outer middle zones of the lobule. During 21–90 days fat increased in central and middle zones and decreased in peripheral zones.

Ceroid pigment developed in Kupffer cells within 12 days. During 31–45 days Kupffer cells coalesced and formed large ceroid globules which increased in size and number during the 46–90 day period. A reticular fibrosis surrounded the masses of ceroid.

As early as seven days stromal distortion consisting chiefly of compression of reticulum by fat laden hepatocytes was prominent in peripheral lobular zones. Sinusoids were also obstructed and dilated by this process. Some became non‐functional and were transformed to fibrous cords. With progressive liposis (after 30 days) irregular stromal changes developed in all zones of lobules.