bluuebunny/crossref_metadata_2025 huggingface dataset:
Cytology and duration of the cycle of the seminiferous epithelium of the boar; duration of spermatozoan transit through the epididymis
Authors: Swierstra E. E.
Published: February 2005

The cycle of the seminiferous epithelium of the boar was divided into eight stages which are described. The relative frequencies of the stages were determined for ten Yorkshire and ten Lacombe boars approximately 11 months of age. The mean relative frequencies for stages 1 through 8 were 10.8, 14.4, 3.5, 11.6, 8.9, 20.3, 18.5 and 12.0%, respectively. Generally, there was a constancy of the relative frequencies of the stages between breeds, among boars within breeds and between testes within boars.

The absolute duration of the cycle of the seminiferous epithelium and the duration of spermatozoan transit through the epididymis were determined by injecting a single dose of 19 mCi of thymidine‐methyl‐H3 into the marginal ear vein of each of four Yorkshire (15.2 months old) and four Lacombe boars (14.9 months old). Unilateral castrations were performed at 0.2, 11.5, 20.0, 24.0 and 25.0 days after the isotope injection. Two intact and two unilaterally castrated animals were ejaculated for eight and seven weeks, respectively, to determine the interval between the thymidine‐H3 injection and the appearance of the isotope in the ejaculated semen. Autoradiographs were prepared from the testis tissues and the semen smears. The most mature germ cells that incorporated the thymidine‐H3 were the late preleptotene primary spermatocytes. Twenty‐five days after injection the label had progressed from late preleptotene primary spermatocytes to spermatozoa leaving the testes. Epididymal transit times for four boars (ejaculated daily) were 9, 10, 10 and 12 days. The duration of one cycle of the seminiferous epithelium based on 12 estimates was 8.6 ± 0.1 days. The durations of stages 1 through 8 were 0.9, 1.2, 0.3, 1.0, 0.8, 1.7, 1.6 and 1.0 days, respectively. The life span of primary spermatocytes was 12.3 days, of secondary spermatocytes 0.4 days, of spermatids with round nuclei 6.3 days, of spermatids with elongated nuclei 1.5 days, and of spermatozoa 6.2 days.
Sperm maturation in the male reproductive tract: Development of motility
Authors: Gaddum Penelope
Published: February 2005

Rabbit spermatozoa were removed from various levels of the male reproductive tract. They were examined in Hanks' solution at room temperature with a phase contrast microscope and their motility characteristics were recorded cinematographically.

Spermatozoa from the seminiferous tubules and ductuli efferentes show weak, vibratory movements with no forward progress. Little change in motility occurs until the sperm reach the flexure of the caput epididymidis where some are capable of moving more vigorously in a circular fashion. Samples from the distal caput epididymidis show a sudden increase in sperm activity and a consistent pattern of tight, circular movement. As the sperm traverse the corpus epididymidis, increasing numbers show progressive, forward movement with longitudinal rotation. The proportion of such sperm becomes significant only in samples from the upper cauda epididymidis and more distal regions. Sperm from the ductus deferens rarely retain the circular movement.

It is concluded that rabbit spermatozoa undergo a distinct sequence of changes in their swimming movements as they mature in the epididymis. A similar change was noted in epididymal spermatozoa from the rat and guinea pig suggesting that this process is fundamental to sperm maturation in several species.
The jejunal absorptive cell of the newborn pig: An electron microscopic study
Authors: Staley Theodore E. , Jones E. Wynn , Marshall Arvle E.
Published: February 2005

The morphology of the intestinal absorptive cell in the newborn pig is strikingly different from that of the three‐week‐old pig. The former's unusual characteristics are: a poorly developed hirsute layer over the microvilli, an abundance of pinocytotic vacuoles and apical tubules, and a subnuclear location of the Golgi apparatus. In unfed newborn pigs the morphology does not change appreciably by 42 hours. Spinous processes line the apical tubules which may be associated with protein absorption. The retention of the tubular system in the absence of feeding (for 42 hours) and its disappearance with feeding, lends support to the concept that this system is important in the absorption of protein macromolecules in the newborn pig. The position of the Golgi may be instrumental in regulating the ability of the cell to absorb large molecular weight proteins.
Bony trabecular changes in the human mandibular ramus from prenatal period to adulthood
Authors: Herzberg Fred , Dovitch Victor
Published: February 2005

The rami of eight human mandibles ranging in age from six months prenatal to adulthood were studied radiographically and by matte acetate tracings. The characteristic trabecular pattern seen in the adult ramus was not found until the fifth year of life. A disorganization of the pattern occurred at nine years of age, but was re‐established by the twelfth year. The changes in pattern observed appear to be related to the eruption times of the teeth, which probably modify the muscular stresses exerted on the bone in the process of mastication.
Occurrence of fluorescent granules in the Purkinje cells of the cerebellum
Authors: Sarnat Harvey B.
Published: February 2005

When examined in the fluorescence microscope, cells of the central nervous system exhibit intense, yellow, naturally fluorescent granules throughout their cytoplasm. In the mouse, cat and man, the granules are absent at birth and present in adults. A study of the development of these granules in the Purkinje cells of the cerebellum was made in the mouse and cat. There is a rapid increase in the number of fluorescent granules in postnatal life. The granules probably represent lysosomes.
The use of oxone to facilitate specific tissue stainability following osmium fixation
Authors: Sevier A. C. , Munger B. L.
Published: February 2005

The specific stainability of 1–3 μ thick sections of tissue prepared for electron microscopy after glutaraldehyde and osmium fixation and araldite embedding is greatly enhanced after oxidation with Oxone. This monopersulfate has been found to leave tissue section in a suitable condition for applying a trichrome stain as well as a specific silver impregnation. These methods are described in detail. The mode of action of Oxone is poorly understood.
Ultrastructural and histochemical studies on the innervation of the mucous membrane of the mouse colon
Authors: Silva Douglas G. , Farrell K. E. , Smith G. C.
Published: February 2005

Ultrastructural and histochemical studies have revealed that the mouse colonic mucous membrane receives an extensive autonomic innervation. Nerve fibers enter the mucous membrane through the muscularis mucosae and ramify in the lamina propria where they were often seen in close proximity to smooth muscle cells. Other axons were seen accompanying blood vessels or passing along the basal aspect of the epithelium subjacent to the basement membrane; none were seen either entering the epithelium or within it.

Several methods of fixation were employed in order to study their effects on intraaxonal vesicles. It was found that in tissue fixed in either glutaraldehyde in phosphate buffer, or in osmium tetroxide in phosphate buffer, the granular vesicles were better preserved than in tissue fixed in a chrome‐osmium tetroxide mixture. The nerve fibers contained mainly agranular vesicles and large granular vesicles (600–1700 Å). Small granular vesicles (300–600 Å) usually associated with adrenergic nerves and specific green fluorescence indicative of catecholamines were only occasionally seen in the mucous membrane. Reserpine depleted the small granular vesicles and also abolished specific fluorescence.

Ultrastructural studies showed that the large majority of nerve fibers were acetylcholinesterase positive.

These findings indicate that the innervation of the colonic mucous membrane is predominantly cholinergic and that the adrenergic innervation is sparse.
Fertilization and early development in the Chinese hamster, Cricetulus griseus
Authors: Pickworth Stella , Yerganian G. , Chang M. C.
Published: February 2005

Eggs from 79 Chinese hamsters, Cricetulus griseus, were examined at various times from before ovulation on the day of mating (Day 0) to implantation (Days 5–6). The animals were kept under reversed lighting (dark period 8 AM to 8 PM). Ovulation occurred between approximately 4 and 6 PM; mean number of eggs recovered per female was 7.6 ± 0.2. Sperm penetration was almost complete by midnight on Day 0. Of 131 eggs collected on Days 1–4, 102 (78%) were fertilized; (females without fertilized eggs excluded). The midpiece and tail of the fertilizing sperm were found in the cytoplasm of only 9% of pronuclear or cleaved eggs, and remained in the perivitelline space of 74%; in the other 17% eggs the sperm tail and most of the midpiece were outside the zona pellucida or were missing at recovery. No polyspermic eggs were found.

The first three cleavages took place at 20–26 hour intervals after ovulation. Eggs reached the blastocyst stage in the oviduct and entered the uterus more than 96 hours post‐ovulation. Implantation occurred between Days 5 and 6.
Histological, histochemical, and cytological observations on the adrenal gland of the wild white‐footed mouse, Peromyscus leucopus
Authors: Costa Jonathan L.
Published: February 2005

Several cytological features of the adrenal gland of the wild whitefooted mouse, Peromyscus leucopus, are described. Nuclei of cortical cells vary widely in size. Medullary cells may be divided into two populations: one with cytoplasm staining intensely with basic dyes and the other with faintly‐staining cytoplasm. Photometric measurements of the DNA content of Feulgen‐stained cortical nuclei show many nuclei containing 4C and 8C amounts of DNA. The distribution of the polyploid nuclei varies in different adrenal zones. Nuclei in the zona glomerulosa are almost all 2C. A majority of those in the zona fasciculata are 4C and 8C. Those in the zona reticularis fall predominantly into a 2C class, with some 4C and 8C nuclei. Groups of formalin‐fixed medullary cells staining intensely with hematoxylin, toluidine blue O, and azure B correspond in location, arrangement, and morphology to those indicating the presence of epinephrine by several histochemical techniques. The substances responsible for the basophilia may be acidic proteins rich in carboxyl groups, since (1) RNase treatment does not appreciably diminish the basophilia; (2) all medullary cells are only faintly PAS‐positive; and (3) the staining behavior of the more basophilic cells, when exposed to azure B solutions buffered to acid pH's, follows that to be expected when this dye is bound by tissue carboxyl groups.
The effects of phytohemagglutinin on the growth and histochemical properties of mammalian cells in tissue culture
Authors: Caso Louis V.
Published: February 2005

Phytohemagglutinin‐P (PHA‐P) exhibited inhibitory action on the growth of two human epithelioid cell lines, HeLa and L‐132, and on the L‐929 strain of mouse fibroblasts. Growth of stationary cultures was measured spectrophotometrically by DNA production after 96 hours incubation. The mitotic indices of the three cell lines were reduced significantly by PHA‐P after 72 hours incubation.

Histochemical studies demonstrate depressed production of cytoplasmic RNA in 72‐hour HeLa cultures after treatment with PHA‐P, with the appearance of prominent, PAS‐positive, diastase‐fast granules in the cytoplasm. Bound lipid aggregates increased in amount in the cytoplasm of HeLa cells after PHA‐P treatment. The PAS‐positive, diastase‐fast granules were also found in the cytoplasm of the L‐132 and L‐929 cell lines after treatment, but cytoplasmic RNA remained unchanged qualitatively. Alkaline phosphatase was slight in amount in HeLa cells and was reduced to trace amounts after PHA‐P treatment. L‐132 cells showed moderate to heavy concentration of alkaline phosphatase, which remained unchanged qualitatively after PHA‐P treatment. The enzyme could not be demonstrated in the L‐929 fibroblasts.
Fenestrated cisternae in the Golgi apparatus of the epididymis
Authors: Flickinger Charles J.
Published: February 2005

Attention is directed toward the occurrence of fenestrations or pores in Golgi cisternae of rat and mouse epididymis. There is a gradation in the degree of cisternal fenestration within a Golgi complex. Cisternae at the convex pole are highly flattened and contain few pores, but those near the concave side are distended and exhibit a large number of roughly circular fenestrations 300–600 Å in diameter. Cisternae in the middle of a stack often have an unperforated central portion that is surrounded by a fenestrated and expanded peripheral region. The structure of these Golgi complexes is compared with previous descriptions of Golgi cisternae, particularly the fenestrated cisternae reported in plant cells.
The presence of fenestrated capillaries in the papillary layer of the enamel organ
Authors: Garant Philias R. , Gillespie Roberta
Published: February 2005

The capillary network of the papillary layer of the enamel organ was studied with the electron microscope. Mandibular incisor teeth of ten‐day old Swiss albino mice were fixed in formaldehyde‐glutaraldehyde, postfixed in osmium tetroxide and prestained with 0.5% uranyl acetate prior to being embedded in Epon. Examination of ultrathin sections revealed the presence of fenestrations approximately 500 Å to 700 Å in diameter within the most attenuated regions of the capillary walls. In most instances the fenestrations appeared to be closed by diaphragms usually consisting of a thin membrane with a thicker centrally located button of electron opaque material.

The presence of fenestrated capillaries within the papillary region of the enamel organ lends further support to the concept that papillary cells are engaged in transport functions during the maturation of enamel.
Early development of thymic lymphocytes in mice, studied by light and electron microscopy
Authors: Hoshino Takeshi , Takeda Masako , Abe Kazuhiro , Ito Takashi
Published: February 2005

Thymic rudiments from mouse embryos varying in gestational from 10–13 days were examined by light and electron microscopy in an effort to learn the origin of thymic lymphocytes. Lymphocytes were recognized and distinguished from mesenchymal cells and thymic epithelial cells by their round shape, larger nucleoli, and high concentration of cytoplasmic ribosomes and dearth of endoplasmic reticulum. No lymphocytes could be found at the earliest stage of development of the third pharyngeal pouch — at approximately ten days' gestational age. They first appeared in the mesenchyme surrounding the third pouch at a later stage, (approximately 11 days' gestation), but in most cases did not appear in the thymic epithelium until the parathyroid and thymus began to differentiate at approximately 12 days' gestation. No cells were seen that appeared to be transitional between lymphocytes and epithelial or mesenchymal cells and it was concluded that these observations support the hypothesis that lymphocytes first reach the thymic parenchyma by immigration from the surrounding mesenchyme. Most of the lymphoctyes found in the region of the thymus at these stages of development were large lymphocytes. The origin of these early lymphocytes remains unknown.
The significance of intramedullary cancellous bone formation in the repair of bone marrow tissue
Authors: Amsel S. , Maniatis A. , Tavassoli M. , Crosby W. H.
Published: February 2005

The repair of hemopoietic bone marrow following evacuation of the tibial or femoral cavity of the rat was sequentially studied with the light microscope. A stereotyped train of histologic events occurred. These were capillary invasion of the cavity, appearance of primitive mesenchymal cells, osteoblastic proliferation, cancellous bone formation, development of sinusoids, reappearance of hemopoietic tissue and resorption of cancellous bone. The studies suggest that restoration of marrow sinusoids takes place only in the interstices of cancellous bone. Mechanical disruption of the sinusoidal system is one method of triggering cancellous bone formation. The cancellous bone which appeared after injury was thought to be produced by endosteal osteoblasts and osteoblasts derived from cells residing in normal hemopoietic tissue. Localized radiation of the tibia followed by mechanical disruption of hemopoietic tissue demonstrated that cancellous bone production and the repair process were unimpaired by 1,000 r but were completely blocked by 4,000 r. This would imply that the cell which can differentiate into an osteoblast is resistant to 1,000 r.
The trigemincd nerve root with special reference to the central‐peripheral transition zone: An electron microscopic study in the macaque
Authors: Maxwell David S. , Kruger Lawrence , Pineda Anselmo
Published: February 2005

The entry zone of trigeminal sensory root fibers displays a “glial dome” covered by a basal lamina. This zone constitutes the “fibrous cone” of gross descriptions of the root and demarcates a sharp transition from peripheral to central nervous system. The dome consists of closely interwoven astrocyte processes, and appears to be identical to the subpial astrocyte meshwork elsewhere in the central nervous system. In the peripheral portion of the root, axons are surrounded by Schwann cells; those associated with myelin sheaths display distinctive laminar inclusions and pinocytotic vesicles lacking in Schwann cells which surround unmyelinated axons. In the peripheral region, separate and distinct endoneurial and perineurial layers of collagen could not always be identified. In the central part of the root, Schwann cells, fibroblasts, and collagen are absent and from the point of transition, the axons are principally surrounded by astrocytes. Oligodendrocytes are relatively rare in the transitional zone. The axonal transition from central to peripheral, occurs at nodes of Ranvier where the basal lamina of the dome is continuous with the basal lamina of the Schwann cell of the last peripheral internode. Some “islands” of glial tissue are interspersed in the root and ganglion but it was not established if these are completely discontinuous with the central “glial dome.” No ganglion cells have been found in such “islands,” nor in the glial dome.
Spontaneous calcification in hearts of DBA mice
Authors: Nabors Charles E. , Ball Carroll R.
Published: February 2005

Onset, frequency and characteristics of the spontaneous calcification which occurs in hearts of mice of the DBA strain have been studied. Calcified myocardial lesions developed as early as 25 days of age. A limited inflammatory response was associated with the fine mineral granules of early lesions. With age, sites of calcium deposition became larger and agranular. There was no evidence of inflammation at such loci and adjacent connective tissue did not increase significantly. In the oldest animals (older than 90 days), fibrous encapsulation of calcified sites was typical. Calcareous epicarditis appeared by 30 days; was minimal (8%) through 90 days, and then rose sharply in incidence (50%) in older animals. Epicardial calcification was restricted to the right ventricle. In general the calcified lesions increased with age and were not related to sex. Incidence of all lesions was 17% by 30 days of age, 80% within 90 days, and 94% in mice older than 90 days.
The pelvis of the free‐tailed bat: Sexual dimorphism and pregnancy changes
Authors: Crelin E. S. , Newton E. V.
Published: February 2005

There are constant morphological differences between the bony pelves of adult males and females that constitute a sexual dimorphism. A convexity along the caudal border of the ischiopubic ramus and a bony projection bordering the pubic joint are present only in the male. The pubic joint in the male is a typical symphysis, whereas in the female it consists of an interpubic ligament interconnecting the coxal bones. The ligament contains an abundance of elastic fibers interspersed among collagenous fibers. The disparity between the size of the pelvic birth canal of the pregnant bat and the single full‐term fetus is so great that during parturition the interpubic ligament stretches to more than 15 times its original length.
Insertions of intrafusal fibers in muscle spindles of the cat and other mammals
Authors: Bridgman Charles F. , Shumpert Edmond E. , Eldred Earl
Published: February 2005

The manner of insertion of intrafusal (IF) fibers of muscle spindles has been studied in serial histological sections of spindles from hindlimb muscle of the cat, opossum, mouse, rat, bat and gibbon. Four basic types of IF terminations in relation to the capsule were recognized: (A) direct insertion into the capsule; (B) strong lateral attachments to the capsule, though the fiber may continue beyond the capsule; (C) termination in the connective tissue beyond the limits of the capsule; (D) free extension of the fiber beyond the capsule. Bag fibers in all species generally extended beyond the capsule. The pattern of chain fiber insertion, however, varied with the species. Most rat spindles, for example, followed the D pattern, those in the cat pattern A, and the gibbon chiefly A and B. The bearing of these findings upon a postulated mechanism by which spindles may detect intramuscular pressures, as changes in length, is discussed.
Fine structure of the dermal luminescent organs, photophores, in the fish, Porichthys notatus
Authors: Strum Judy May
Published: February 2005

Photophores in Porichthys notatus consist of a cellular lens, an underlying area of photogenic tissue and a deep ensheathing reflector. Lens cells exhibit a dense compacted filamentous cytoplasm. Their processes interdigitate and desmosomes exist along their borders. The photogenic tissue, richly supplied by blood vessels, consists of two main cell types: (1) a presumed “photogenic” cell; and (2) a supportive cell. Photogenic cells are characterized by a highly vesiculated cytoplasm and peripheral microvilli. Frequently, they exhibit lamellar membranous whorls. Some whorls display cytoplasmic cores with vesicles. Many of these vesicles communicate via pores with an extracellular channel that envelops the cells. Supportive cells contain cytoplasmic filaments and extend processes around the photogenic cells. Except for isolated desmosomal contact points, a wide extracellular channel intervenes between supportive and photogenic cells. A prominent basal lamina separates supportive cells from the surrounding connective tissue. The strongly birefringent reflector is composed primarily of cells containing guanine crystals. The crystals lie stacked in groups, each membrane‐bounded crystal being separated from its neighbor by an intervening layer of cytoplasm. Such an arrangement produces constructive interference and accounts for the high reflectivity of this multilayered structure. Possible relationships of the above structural features and the production of light are discussed.
Ultrastructure of the placenta and fetal membranes of the dog I. The placental labyrinth
Authors: Anderson John Walberg
Published: February 2005

The ultrastucture of the canine placental labyrinth has been studied at 40 to 60 days of gestation. Cytotrophoblasts persist in an undifferentiated state throughout gestation, with numerous polyribosomes and little rough endoplasmic reticulum, with expanded cisterns containing flocculent precipitate. Fetal capillaries progressively invade the syncytium, without, however, penetrating the basal lamina. Maternal decidual cells are reported here for the first time in this species. The maternal endothelium is considerably hypertrophied, with many profiles of membranous organelles; but there is consideriable thinning of this endothelium between 50 and 60 days. The interstitial membrane intervenes between trophoblast and maternal endothelium, often forming the thickest part of te barrier at 60 days. the definitive endotheliochorial condition is confirmed; and the thinnest barrier is about 1 μ.
A study of the cardiac innervation in domestic animals: Cattle
Authors: McKibben John Scott , Getty Robert
Published: February 2005

The cardiac innervation of cattle was morphologically dissected and described. Descriptions of the ganglia of origin as well as the course and distribution are presented. Sympathetic nerves arose from the thoracic and cervicothoracic ganglia, but unlike those of the horse, dog and cat did not arise from the more cranial situated cervical ganglia. Most left thoracic and some cervicothoracic cardiac nerves passed through a cardiac ganglion of the left intervascular triangle before being distributed to the heart. Parasympathetic cardiac innervation arose from the vagi, both cranial and caudal to the origin of the recurrent laryngeal nerve, and from the recurrent laryngeal nerves themselves. Left heart nerves primarily supplied the area along the coronary groove caudally and on the right side. This included the area of the coronary sinus and atrioventricular node. Left cardiac nerves also extended along the right coronary artery. Both left and right cardiac nerves passed to the cardiac plexus and also along the descending and circumflex branches of the left coronary artery on the left side. Right cardiac nerves extended primarily between the venae cavae or between the caudal vena cava and left atrium to the area of the sinoatrial node but also into the area of the coronary sinus and atrioventricular node.
Electron microscopic observations on myoid cells of the frog's thymus
Authors: Töró I. , OláH I. , Röhlich P. , Virágh S. Z.
Published: February 2005

Myoid cells of the thymus of hibernating frogs were examined by electron microscopy. This cell type is represented by immature, fully‐developed and degenerating cell forms. The immature forms are mainly located at the surface, whereas the developed ones are found in the inside of the thymus. A peculiar type of immature cell containing no thick filaments, but possessing a rich sarcoplasmic reticulum among the thin filaments is described. The developed myoid cells have a myofibrillar apparatus showing regular cross‐striations. The myofibrils are arranged in concentric layers around the nucleus. The proposed role and origin of myoid cells and their probable connection with myasthenia gravis are discussed.
The nature of the litter size loss in senescent hamsters
Authors: Thorneycroft Ian H. , Soderwall A. L.
Published: February 2005

Young and senescent female hamsters were sacrificed on days 8, 10, 12, 14 and 15 of pregnancy, and the number of viable and resorbing conceptuses was determined. The ovulation rate for each group was also recorded. At each day, there was a reduction in the litter size in senescent animals as compared to the young, but the number of ovulations in each age group was equal. The results indicated that the litter size loss, in senescent hamsters, is not due to a reduction in the ovulation rate, but to a seven fold increase in preimplantation deaths and to a two fold increase in resorption.
Responses of fatty livers of mice to carbon tetrachloride
Authors: Wilson Edward R. , Lane Williams W.
Published: February 2005

Female mice of the Taconic Swiss stock were fed one of the three diets described below then injected subcutaneously with 0.035 cm3CCl4/100 gm body weight in a mineral oil solution. One group was fed an adequate commercial laboratory ration, then mice were killed 12, 24 and 48 hours after CCl4; another a cholinedeficient, high‐fat, low‐protein diet for 14 days, then injected with CCl4, and killed 12, 24 and 48 hours later; and another group, a choline‐supplemented (2 gm choline chloride/100 gm diet), high‐fat, low‐protein diet for 14 days, then injected with CCl4 and killed 24 hours later.

In the group fed the normal diet, the polyhalogen produced within 24 hours the expected centrolobular necrosis and glycogen depletion, involving one‐third to one‐half of the lobular areas. In fatty livers produced by feeding the choline‐deficient diet, necrosis at 24 hours post injection was limited in a majority of instances to a zone one or two cells thick immediately surrounding the central vein. Despite this decreased necrosis in fatty livers centrolobular glycogen depletion still involved one‐third to one‐half of lobules and there was an infiltration of inflammatory cells immediately adjacent to the central vein. The hepatic necrosis at 12 and 48 hours paralleled that in the normal dietary group.

Feeding of the choline‐supplemented, high‐fat, low‐protein diet for two weeks produced an extremely limited parenchymal liposis. In such relatively non‐fatty livers CCl4 produced hepatic necrosis comparable to that in mice receiving normal diets. The extent of protection from the necrogenic actions of CCl4 was clearly associated with extensive intracytoplasmic liposis of hepatic parenchyma.
Temporal and cytological aspects of fertilization and early development in the guinea pig, Cavia porcellus
Authors: Hunter R. H. F. , Hunt D. M. , Chang M. C.
Published: February 2005

A study was made of 174 eggs recovered from 58 guinea pigs killed between the first and sixth days after mating, and the cytological details from the stage of sperm penetration to the pre‐implantation blastocyst described. Eighty‐nine percent of the expected number of eggs were recovered, and 97% of these were fertilized. Embryonic development proceeded from pronuclear and 2‐cell eggs on day 1 to pre‐implantation blastocysts on day 6, the duration of each of the early cleavage stages being of approximately 24 hours. No progressive loss of embryos was found over this period, all the eggs recovered on days 4, 5 and 6 being regarded as developing normally. Passage of embryos from the Fallopian tubes to the uterus commenced on the afternoon of day 3, and the majority of embryos entered the uterus shortly after this time at the stage of 8‐ to 16‐cells. The tail of the fertilizing spermatozoon was detected in the cytoplasm of all eggs examined on day 1, in most of those examined on day 2, and frequently persisted up to the 8‐cell stage. Three dispermic eggs, each containing two distinct cytoplasmic sperm tails, were found: one of these was at the pronuclear stage, the other two being considered of 4‐ and 6‐cells respectively. Properties of adhesiveness were shown by blastocysts recovered shortly before implantation on day 6, but the characteristic “zona processes” were not seen.
Studies on hypoxia V. Effects of anoxia on developing connective tissue cells in rats
Authors: Kim Joon H. , Han Seong S.
Published: February 2005

The effect of anoxia on protein synthesis of developing connective tissue cells was studied by radioautography. Neonatal rats were subjected to anoxia for 20 minutes and were immediately injected with 3 μc/gm body weight of leucine‐H3intraperitoneally. They were sacrificed at different intervals after injection. Control animals were handled identically, except that atmospheric air was made available. The heads of the animals were prepared for radioautography in the standard manner. The number of grains was counted over individual fibrobalsts, osteoblasts and chondrocytes of histologically comparable regions, and the data were statistically evaluated.

The number of grains per cell was significantly lower in experimental animals sacrificed at one hour after the anoxic treatment and leucine‐H3administration. At this time, the average grain number per cell in the experimental animal was less than 50% of the control. The difference was about 20% by four hours and was negligible after 24 hours. The result is interpreted to indicate that the overall protein synthesis in connective tissues is immediately but temporarily suppressed by anoxia and that such suppression might lead to a later functional disturbance among these cells.
Fate of 3H‐ribose in the rat as detected by radioautography
Authors: Gonçlalves R. P. , Bennett G. C. , Leblond C. P.
Published: February 2005

Light and electron microscopic radioautographs of the tissues of young rats which were sacrificed at various times after a single 3H‐ribose injection revealed a wide distribution of the label.

Nuclear reactions were seen over hepatocytes and other cell types. After removal of RNA by treatment with RNAse, most nuclear reactions were absent; they were, therefore, attributed to the incorporation of label into newly‐synthesized RNA. In about 2% of the nuclei, however, labeling persisted after RNAse, but was absent after DNAse treatment, indicating uptake into newly‐synthesized DNA. Hence, ribose may be taken up into nucleic acidsundergoing synthesis.

In cells of liver and cartilage as well as in some muscle fibers, moderate reaction appeared over glycogen areas. Removal of the label by salivary amylase confirmed its uptake into glycogen.

In mucous and other secretory cells, amylase resistant radioautographic reactions appeared over the Golgi region and later over secretion products. Presumably the label was incorporated into the glycoproteinmoieties of these secretions.

Many, if not all, cells in the body appear to be able to utilize free exogenous ribose. It is presumed that ribose is first phosphorylated and then either incorporated into the RNA and DNA being synthesized in the nucleus or converted into the glucose or fructose derivatives used for glycogen and glycoprotein synthesis in the cytoplasm. That these pathways may play a significant physiological role is suggested by the recent finding of free ribose in the blood.
Fine structure of the pancreatic islet cells of normal and alloxan treated bats (Eptesicus fuscus)
Authors: Hinkley Robert E. , Burton Paul R.
Published: February 2005

The pancreas of the bat Eptesicus fuscus was investigated with respect to the normal ultrastructure of the islet cells, and structural alterations induced by alloxan. The ultrastructure of normal active and hibernating bat islet cells was similar. Through serial sections, B granules were shown to be disc‐shaped, and some B granules were observed to consist of up to three component plates. Vesicular configurations found in both A and B cells suggest that the Golgi complex is essential to granule formation.
Enzyme histochemistry of embryonic nasal mucosa
Authors: Shapiro Burton L.
Published: February 2005

The prenatal development of rodent nasal mucous membrane has been examined histochemically (lactate dehydrogenase, succinate dehydrogenase, glucose‐6‐phosphate dehydrogenase, alkaline phosphatase, PAS and PAS with diastase digestion). Localization and intensity of the enzyme systems studied were distinctly different in respiratory and olfactory areas. These differences were demonstrable by at least the second half of gestation in the animals studied. Findings in Jacobson's organs were parallel to those in olfactory areas. Each of the pathways of carbohydrate metabolism examined was present in respiratory epithelium. However, intensity was less, appeared later and was more variable in intracellular localization than that found in olfactory areas. Based on enzyme staining olfactory epithelium seemed metabolically more active than respiratory mucosa. Apical portions of olfactory epithelium stained most intensely for oxidative enzyme systems, particularly the glucose‐6‐phosphate dehydrogenase system. These areas of high activity were thought to represent apices of supporting cells rather than receptor cells. This localization of a pentose phosphate shunt enzyme system was related speculatively to ion transport in these cells. Alkaline phosphatase was relatively slight in respiratory areas during the ages studied. The basal portions of olfactory epithelium stained positively for alkaline phosphatase. Since hydrolytic enzymes have been thought to be important in the mechanism of olfaction, its demonstration in these tissues suggests that this portion of the olfactory mechanism is present by midgestation in the rodents studied.
Gross anatomy of the blood supply and biliary drainage of the canine liver
Authors: Sleight Douglas R. , Thomford Neil R.
Published: February 2005

Necropsy examinations were performed on 100 dogs to study the biliary system, blood supply, and topographic anatomy of the liver. The major ligamentous attachments of the relatively mobile organ are the left triangular and hepatoduodenal ligaments. Considerable fixation is provided by the hepatic veins and the intimate attachment of the liver to the inferior vena cava.

The six lobes of the liver are arranged in three natural divisions. The portal vein, its branches, and their distribution are consistent as are major hepatic veins. The hepatic artery branches and major bile ducts have patterns which may be readily related to the divisional boundaries. The branches of the hepatic artery vary in number from one to five. Three branches were present in 64 of 100 specimens. A single gallbladder and cystic duct were found in each of 100 specimens. The common bile duct is formed from three (64%) or four (36%) major collecting or divisional ducts. When four divisional ducts are present, the right and left divisions of the liver are each drained by a single duct with two ducts draining the central division. The cystic duct may join either the right or left central divisional duct to form the common bile duct.
Observations on the ultrastructure of the ectodermal component during odontogenesis in Helostoma temmincki
Authors: Garant Philias R.
Published: February 2005

The role played by the ectodermal component during lower vertebrate tooth development has been a subject of much speculation. In order to provide new information on this matter the cytostructural changes occuring in the ectodermal part of the tooth buds of a small fresh water fish Helostoma temmincki were investigated.

The cells of the two epithelial layers which form the ectodermal cap of the tooth bud showed little sign of specialization during the early phase of tooth formation. There was no evidence of the synthesis and secretion of enamel matrix. With the onset of the calcification of the dentin specializations indicating an absorptive activity were observed in the cells of the outer epithelial layer. These changes consisted of an elaborate system of canalicular spaces and coated vesicles. Concurrently the cells of the inner layer accumulated large amounts of iron in the form of ferritin particles. The iron was subsequently deposited over the outer layer of the dentin imparting a reddish‐brown coloration to the teeth.

The ultrastructural specialization of the ectodermal component during tooth development are suggestive of transport functions similar to those which are thought to occur in post‐secretory enamel organs during the maturation of enamel.
Histology of the para‐anal sebaceous glandular organs of the bat Eonycteris spelaea (Chiroptera: Pteropidae)
Authors: Quay W. B.
Published: February 2005

Para‐anal organs of nine specimens of the rare, Southeast Asian bat Eonycteris spelaea were studied in serial sections by light microscopy. Parenchymal tissue of the organs consists of solid cords of cells budded from the naked epidermis without association with hair follicles. Cytological characteristics and cytomorphosis of para‐anal gland cells differ markedly from those of typical sebaceous glands in adjacent haired skin, and the phases of growth, differentiation and secretion appear to be segregated in time. Nevertheless, holocrine secretory activity and a sebum‐like secretion occur in this highly specialized sebaceous organ. Although found in both sexes, it is larger in adults, in males as compared with females, and in reproductively more active males as compared with males of the same size but with smaller testes.
The presacral component of the visceral pelvic fascia and its relation to the pelvic splanchnic innervation of the bladder
Authors: Roberts W. H. , Taylor W. Holmes
Published: February 2005

The relation of the autonomic nerve supply of the pelvis to the visceral pelvic fascia and in particular that of the parasympathetic supply to the bladder musculature is of particular consequence in pelvic operations. It is observed that the pelvic splanchnics, including those branches supplying the bladder, are embedded in the peripheral component of the visceral pelvic fascia or presacral fascia throughout a considerable part of their course. Early anatomists made no distinction between the presacral fascia and the fascial sheath of the rectum proper. Consequently their illustrations shown only a single fascial layer which they call the “rectal fascia” or “posterior fibrous sheath of the rectum” separating the middle sacral vessels from the superior rectal vessels which lie in the pararectal fat. While such a distinction has since been made in the surgical literature, most anatomical descriptions are still rather vague in this respect. It is essential to develop the plane of cleavage between the presacral fascia and the fascial sheath of the rectum if injury to the pelvic splanchnic nerves is to be avoided.
Embryonic vertebrate central nervous system: Revised terminology
Authors: Angevine Jay B. , Bodian David , Coulombre Alfred J. , Edds Mac V. , Hamburger Viktor , Jacobson Marcus , Lyser Katherine M. , Prestige Martin C. , Sidman Richard L. , Varon Silvio , Weiss Paul A.
Published: February 2005

The layers and cells of the early developing central nervous system lack direct counterparts in the adult and must be designated by a special terminology. The inconsistent and inaccurate language now in use leads to misunderstanding and a revision is proposed in which the four fundamental zones are termed the ventricular, subventricular, intermediate, and marginal zones. Each is defined according to the form, behavior, and fate of its constituent cells. All neurons and macroglia of the central nervous system can be derived from these developmental zones.
Profile analysis of the oviductal wall in rabbits and cattle
Authors: El‐Banna A. A. , Hafez E. S. E.
Published: February 2005

Twelve nulliparous New Zealand White female rabbits, and eight nulliparous Hereford heifers were used for profile analysis of the oviductal layers after in vivo and in vitro fixation of the oviducts. The unstraightened oviducts were cut into eight segments of about 1 cm starting from the uterotubal junction. Using a projection microscope, the areas of the lumen, mucosa + submucosa, and musculature of cross sections from each segment were measured planimetrically. The lumen of segments 5 and 6 (from the fimbriae) had the smallest surface area at all reproductive stages in both species. At about 72 and 168 hours after ovulation, the surface area of the lumen at these two segments increased by two‐fold compared to the estrous stage. The ampullary‐isthmic junction (AIJ) is probably located at 6/10 to 7/10 of the oviductal length (segment 5 or 6) in both species. The widening of the lumen at the AIJ, 60–70 hours post ovulation, is sufficient to allow the trapped eggs to pass rapidly to the uterus. The whole isthmus and particularly the AIJ seems to function as a sphincter, the closure of which may be coordinated by neuro‐endocrine mechanisms.
Twinning in the common snapping turtle, Chelydra serpentina
Authors: Yntema C. L.
Published: February 2005

Twinning or duplication was observed in 28 eggs of the common snapping turtle, Chelydra serpentina serpentina. The methods of observation made detection of separate blastodiscs relatively certain, that of duplication within a blastodisc less so. Only two of the latter were found. Twins occurred in about 1% of the eggs; 26% of the clutches had one or more abnormal eggs. Twinned blastodiscs developed normally in early stages. When incubated through hatching, 12 out of 12 sets of twins developed unequally so that one was essentially normal, the other was small and not viable. In one case, in which the carapace of the smaller twin was three quarters the length of the larger, both died during hatching. The pigmentation patterns of the carapace of these twins differed; this indicates that they are fraternal rather than identical twins.
Identification of the corticotropin cell in rat hypophyses with peroxidase‐labeled antibody
Authors: Baker Burton L. , Pek Sumer , Midgley A. Rees , Gersten Brian E.
Published: February 2005

Utilization of peroxidase‐labeled antibody to porcine corticotropin permitted the delineation of a distinctive cell in the hypophyseal pars distalis of the rat that appears to be the source of corticotropin. Corticotropin cells were stellate and possessed processes that ended on the walls of sinusoids. Corticotropin cells composed a small percentage of the total cell population, and were distributed throughout the gland except that they were less common posteriorly, superiorly, and immediately alongside the pars intermedia. Alteration in size of corticotropin cells was related directly to change in corticotropin content of the gland as effected by differing physiological conditions. Thus, they were larger in the female than in the male and were enlarged after adrenalectomy of the male; they became much smaller following treatment of the female with cortisol. Some corticotropin cells stained with aldehyde fuchsin and the periodic acid‐Schiff (PAS) reaction. These reactions were more intense if hormone antibody and the gamma‐globulin conjugate had been applied previously. However, the capacity of some corticotropin cells to stain weakly with PAS without prior application of antibody suggests that they may contain mucoprotein.
Determination of growth rates by tetracycline‐labelling in guinea pig maxillas
Authors: Soni Narendar N. , Messer Ken B.
Published: February 2005

A surface planimeter was used to assess tetracycline‐labelled areas of undecalcified sections of the maxillas of 16 male guinea pigs. In three different molar regions studied, highest values were found in the last‐molar region, followed by the first‐molar and second‐molar region. In the 32–42 day old animals the values in the incisal region were higher than in the first‐and‐second‐molar region, but lower than in the last‐molar region. In the age groups of 47–57 and 62–67 days, proportions of labelled bone in the incisal regions were lower than those found in the first‐molar and last‐molar regions, but approached the level of those found in the second‐molar region. There were statistically significant age‐associated differences and varying amounts of labelled bone in different areas.
Alterations in the morphology of rat liver cells influenced by insulin
Authors: Morgan Carl R. , Jersild Ralph A.
Published: February 2005

The electron microscopic observations of liver cells from normal, fasted, diabetic, and insulin‐treated diabetic rats were compared. The most striking electron microscopic features were the sparsity of glycogen particles in fasted and diabetic rat liver cells and the diminution in lamellar formations of rough endoplasmic reticulum in the diabetic animals. Forty‐one hours of insulin treatment of diabetic rats restored the appearance of liver cell structure to normal. These variations in liver cell fine structure were correlated with circulating insulin levels and previously reported enzyme activities.
Fibrinoid and the fetal‐maternal interface of the rat placenta
Authors: Martinek John J.
Published: February 2005

Fetal‐maternal interfaces of rat placentas, obtained from midgestation to term, were examined for their content of electron‐dense fibrinoid. Although increased amounts of interfacial fibrinoid were noted as the time of parturition was approached, at no time did fibrinoid form an intact, electron‐dense barrier between the fetal trophoblast giant cells and the maternal decidual cells of the definitive rat placenta. Large areas of apparently viable fetal trophoblast and viable maternal decidua were intimately juxtaposed throughout the latter half of pregnancy. It is concluded that a poorly discontinuous layer of fibrinoid cannot serve as an effective barrier to a proposed flow of transplantation antigens from the fetoplacental unit to the maternal host.