bluuebunny/crossref_metadata_2025 huggingface dataset:
Direct action upon avian target organs by the antiandrogen cyproterone acetate
Authors: Wollman Arthur L. , Hamilton James B.
Published: February 2005

At ten days of age, intact male chicks had significantly larger combs than intact female chicks. Castration at four days of age eliminated the sex difference in growth of the comb. Growth of the comb, as a result of the secretion of endogenous androgens by the testes, was inhibited by inunction of the comb with small dosages of cyproterone acetate (Cyp A).

Combs of other chicks were divided surgically into posterior and anterior portions of equal weight, thus providing two separate androgenic target organs in the same animal. The local action of Cyp A was investigated by inunction of this compound on the anterior or the posterior portion of the comb, along with simultaneous application of testosterone propionate to both portions. Small dosages of Cyp A antagonized the effect of androgen on the portion of the comb inuncted with Cyp A without affecting growth of the other target organ in the same animal. It was concluded that Cyp A exerted antiandrogenic actions directly upon target organs and was effective topically in doses too small to act systemically.

The posterior portion of the comb, in comparison with the anterior, was more responsive both to the androgen and to the antiandrogen.
A quantitative study on the Vasa nervorum in the ulnar nerve of cats
Authors: Marcarian Heront Q. , Smith R. Dale
Published: February 2005

The sources of blood supply to the ulnar nerves of 15 cats were determined by latex and Pelikan India Ink injections and a quantitative account was given of the numbers and internal diameters of blood vessels in the nerves. The following conclusions were drawn:

The proximal portion of the ulnar nerve usually receives its blood supply from the brachial artery. Proximal to the olecranon, the nerve is supplied by the ulnar collateral artery whereas immediately distal to the olecranon the nerve is always supplied by the recurrent ulnar artery. The palmar and dorsal cutaneous branches of the ulnar nerve receive their arterial supply from the ulnar artery.

The geatest number of blood vessels is located in the middle portion of the nerve with a mean of 313 blood vessels one centimeter proximal to the olecranon and a mean of 322 vessels one centimeter distal to the olecranon. The smallest number of blood vessels is in the dorsal cutaneous nerve with a mean of 140 vessels.

The internal diameter of the intrinsic vasa nervosa ranged between 2.7 and 51.8 μ. Approximately 92% of the blood vessels have an internal diameter of less than 10 μ.

The ratio of blood vessels to myelinated nerve fibers is fairly constant at about 1:25 for all levels of the ulnar nerve.
Changes in pituitary‐gonadal interrelations during perinatal days in the rat
Authors: Eguchi Yasunobu , Morikawa Yoshio
Published: February 2005

The reciprocal relation between the pituitary and the gonads in perinatal rats was studied by gravimetric or volumetric measurements of gonads and by estimations of the collective volume of Leydig cells by the method of Chalkley ('43).

Hypophysectomy of a 20‐day‐old male fetus by decapitation caused two days later a retardation of the testicular growth and a fall of the collective volume of Leydig cells, these effects being prevented by injected GTH. Testosterone prevented somewhat the retardation but did not prevent the change in Leydig cells. The collective volume of Leydig cells fell sharply just after birth and this fall was overcome with injected GTH. In fetuses unilateral castration caused some enlargement of the remaining testis, but in newborn rats such change did not occur. These observations suggest that the pituitary governs largely the Leydig cells before birth and reduces its LH activity after birth.

The fetal ovaries were not affected by decapitation or decapitation and GTH injection and the newborn ovaries were not modified by injected GTH. In an extra uterine parabiosis of a decapitated male and an intact female fetus, the testes failed to gain weight, although the adrenals grew normally. These observations suggest that the female pituitary during late fetal and early postnatal days has no gonad‐stimulating activity.
Effect of steroids on thymus lymphoid development in vitro
Authors: Sidky Younan A.
Published: February 2005

The effect of some steroids on the lymphoid differentiation of embryonic mouse thymus glands was studied. Most of the adrenal cortex hormones tested could inhibit lymphoid differentiation when applied in low concentrations to prelymphoid 13‐day glands. The most effective was corticosterone. Careful washing of the affected glands allowed them to develop normally into lymphoid organs. The application of a high dose of corticosterone produced an effect not reversed by thorough washing. Such permanently affected glands were restituted to lymphoid organs by fusion with 13 or 15‐day embryonic mouse liver or with 15‐day spleen. Lymphoid glands were much less sensitive to low concentrations of corticosterone than the prelymphoid glands. The same concentration of corticosterone was more toxic to more advanced fetal glands. The sex hormones tested were practically ineffective at comparatively high doses; very high concentrations were toxic however.

Basophilic cells normally found in 12 and 13‐day embryonic thymus glands disappeared after corticosterone treatment even in glands which were still potentially capable of lymphoid differentiation suggesting that these cells are not stem cells.
Quantitative characteristics of phagocytic organs
Authors: Kabisch William T. , De Bruyn Peter P. H. , Pabuwal Satya N.
Published: February 2005

Organ and tissue phagocytosis of intravenously injected cobaltic oxide was studied quantitatively over a wide range of dose levels by means of radioassay of Co260O3 in rats.

There is a single linear relationship between the amount of particulate administered and the amount recovered from liver, spleen, and lung combined. The same is true for the uptake by the liver alone. However, the spleen and lung each has two linear relationships. For the spleen the two different linear trends are related to the dose administered, while for the lung the determining parameter is the weight and (or) age of the animal. Notwithstanding these different linear trends, the uptake by spleen and lung is interdependent.

Although the liver is the main phagocytic organ, per unit weight the phagocytic uptake of the spleen exceeds that of the liver at amounts of cobaltic oxide larger than 40 mg. The reverse is true for amounts less than or equal to 40 mg. The phagocytic uptake by other components of the RES was not sufficient for reliable quantitative estimation.
The fine structure of secretory ameloblasts in rat incisors
Authors: Warshawsky H.
Published: February 2005

The fine structure of the ameloblasts which secrete the inner enamel matrix in rat incisors was described using light and electron microscopy. The tissue was fixed by perfusion with 2.5% glutaraldehyde and gently decalcified in isotonic EDTA.

The ameloblasts are tall cells forming a simple columnar epithelium. The base is adjacent to the stratum intermedium and the apex (Tomes' process) extends into newly‐formed enamel. The infranuclear zone is divided by the basal cell web into a small basal bulge adjacent to the stratum intermedium, and a larger compartment containing most of the cell's mitochondria. The supranuclear zone contains the rough endoplasmic reticulum and the Golgi apparatus. The rough endoplasmic reticulum predominates in the proximal and distal regions of this zone where it occupies most of the cell width. In the intermediate region, the rough endoplasmic reticulum surrounds a central tubule‐shaped Golgi apparatus, the tubule wall being made up of flattened saccules. The Golgi region of ameloblasts is associated with coated vesicles, two types of granules (light and dark) which may be lysosomes, and a characteristic dense content granule shown to be the enamel precursor (0.16 μ diameter).

The supranuclear zone is separated from Tomes' process by the apical cell web. Tomes' process is devoid of endoplasmic reticulum and Golgi material, but contains numerous dense content granules as well as microtubules and coated vesicles. The amorphous dense content granules are the precursors of the highly orientated fibrous enamel matrix. The proximity of the process to the fibrous enamel suggests that it is involved in orientation of these fibrils. Since bundles of fibrils constitute rods, the process would seem also to be involved in enamel rod orientation.
Comparative anatomical and neurohistological observations on the tongue of the northern fur seal (Callorhinus ursinus)
Authors: Kubota Kinziro
Published: February 2005

Five fetal and ten adult fur seal tongue were investigated. The number and shape of the vallate papillae vary from one to five on the different tongues. They are intermediate between the fungiform and circumvallate papillae in their neurohistological features. There are a few taste buds on the upper surface without a trench. They are supplied by large basal nerve plexuses with many argyrophilic and argyrophobic multipolar nerve cells and by abundant mixed glands with widely dilated ducts opening directly on the dorsal surface. The tongues lack foliate papillae. Fungiform papillae are scanty on the dorsum, and they have a nerve supply but no taste buds in the upper surface. Between the musculature three types of sensory nerve terminations are found: One, a nerve bundle consisting of inner longitudinal and outer circular fibers, two, a ramified complex termination and three a knob ending. The latter two are probably receptors of the internal depth‐sense in the tongue. Apical mixed glands are present.
Fine structure of midline epithelium in the developing palate of the mouse
Authors: Smiley Gary R. , Dixon Andrew D.
Published: February 2005

The midline seam of epithelium in the developing secondary palate of C57BL mice was examined with the electron microscope. Fetal heads in which the palatal shelves had fused throughout their length were fixed in paraformaldehyde prior to microdissection of the midline palatal tissue which was post‐fixed in osmium tetroxide. The midline epithelial seam was two to four cells thick in the center, while at the nasal and oral ends of the seam the cells increased in number to form a triangular area. The epithelial cells most closely resembled those of the stratum germinativum of the oral mucosa, except for the absence of hemidesmosomes. The epithelial sheet was delineated on both sides by what appeared to be a typical basal lamina which was interrupted in some locations, with and without epithelial degeneration. Epithelial break‐down and fibroblastic migration across the midline was observed during a later stage in palatal development. A striking feature of the midline epithelium was the presence of different morphological types of relatively large electron dense granules. The role of the basal lamina, epithelial microvilli and electron dense granules is discussed.
Some observations on the cerebral arterial circles of mink (Mustela vison)
Authors: Brown James Oliver
Published: February 2005

With the exception of a brief allusion to an unidentified species of Mustela with regard to cerebral vascular studies by de Vriese ('05), major information concerning the circle of Willis in mink was nonexistent until the present investigation. Brains of mink in which the cerebral arterial circles were injected with latex and subsequently hardened in formalin, revealed the primary cerebral arterial anastomosis to be ring‐like in form; all of the component vessels were patent and well formed, none was attenuated or string‐like.

Some of the more prominent findings included: (1) a predominance of asymmetric divergence of the posterior communicating arteries separating from the bifurcating basilar artery; (2) the presence of a posterior intercommunicating artery in all of the specimens; (3) the occasional doubling of the superior cerebellar and the posterior cerebral arteries; (4) deeply placed internal cerebral loops forming secondary arterial anastomoses between some penetrating vessels in the caudal region of the circle; other loops interconnected other penetrating vessels in the rostral region of the circle; (5) blood channels forming an intercarotid anastomosis traversed the pia mater; (6) the presence of a penetrating artery adjunctive to the recurrent artery of Heubner; (7) anastomoses between the internal and the external ophthalmic arteries, and between the internal and the external olfactory arteries forming collateral channels of communication between the intracranial and the extracranial circulations; (8) the occasional presence of an anterior communicating artery supplementing the commonly occurring azygos anterior cerebral artery which continued as a single vessel throughout its extent; (9) unjoined anterior cerebral arteries in one animal which was exceptional.
Ultrastructure of the ventral horn cell in the albino rat
Authors: Rapoport Alan , Stempak Jerome
Published: February 2005

The ventral horn cell of the lumbar cord of the albino rat was examined with the electron microscope. The tissue was fixed with osmium tetroxide or a formalinosmium tetroxide sequence, dehydrated and embedded in Epon 812.

The nuclear envelope contains numerous pores which are spanned by diaphragms. Nuclear indentations or crypts are seen often, and are considered normal structures.

Mitochondria with various arrangements of cristae are described. These include tubular cristae, simple dilated cristae, dilated cristae enclosing vesicles, and sacs which partially contain double membrane limited bodies.

The Golgi apparatus is scattered throughout the cytoplasm. The apparatus is seen near the nucleus more frequently than peripherally. Single membrane limited bodies such as multivesicular bodies and electron dense bodies are described.

Granular endoplasmic reticulum exists as orderly stacks and as haphazardly scattered cisterns. Serial sections demonstrate that the haphazardly scattered cisterns are extensively interconnected.
Distribution of ACTH in the hypophysis of necturus
Authors: Aplington H. W. , Vernikos‐Danellis Joan
Published: February 2005

The winter Necturus hypophysis both whole and selectively divided was extracted in N/10 HCl (0.25 ml per gland or gland portion). Extracts were diluted with normal saline (1:100 and 1:400) and injected 2 ml/100 gm body weight) into groups of 10 or 12 male, hydrocortisone‐blocked assay rats (method of Hodges and Vernikos ('60). Groups of control hydrocortisone‐blocked male rats received corresponding volumes of a standard ACTH solution. ACTH content of extracts was appraised by measuring the adrenal ascorbic acid depletion induced as compared with control depletions. A 2 + 2 assay design was employed; results and their fiducial limits (P = 0.95) calculated.

The ACTH content of the anterior zone of pars buccalis is that of the entire hypophysis. No ACTH was detected in gland portions consisting of the basophilic bed and transitional zone of pars buccalis plus the neural lobe of pars neuralis. ACTH occurs throughout the anterior zone but is more abundant in its caudal two‐thirds both in milliunits (mU) per milliliter of extract and mU/mg of pituitary tissue. This distribution of corticotrophic activity is coincident with the distribution of anterior zone acidophile cells.

Regional and cellular sources of ACTH in mammals and amphibia are discussed.
Demonstration of mast cells in the postnatal mouse ovary
Authors: Skalko Richard G. , Ruby John R. , Dyer Robert F.
Published: February 2005

Cytologically demonstrable mast cells are present within the ovaries of neonatal mice from two strains (ICR, Ttf/t12). They show a preferential distribution, being observed in the hilum primarily in addition to the ovarian mesentery, bursa and ovary proper. They are most evident in the newborn (0 day) animal and show an apparent decrease during the first postnatal week.
Collagenous growth induced by lambda carrageenan in the rabbit cornea
Authors: Garg Bhagwan Dass , McCandless Esther L.
Published: February 2005

Characteristic collagenous lesions developed in rabbit corneas following intracorneal injection of the algal polysaccharide, lambda carrageenan. No reaction occurred in saline injected control corneas. Carrageenan administration brought about an increase in mucopolysaccharides from the third to the eleventh day, followed by synthesis of collagen which reached a maximum between 19 and 28 days. Infiltration of leucocytes, macrophages, and fibroblasts, cells foreign to the cornea, occurred in that order and before development of a corneal blood supply. The beginnings of vascularization occurred regularly about the fifth day after carrageenan administration, and reached a maximum at 19 and 28 days for peripheral and interstitial vessels, respectively. The vascularization produced in this manner was uniform in its initiation and development. The corneal lesion was found to be in large part reversible, but its regression was accompanied by degeneration of pre‐existing collagen fibers of the stromal matrix and left a scar in the corneal surface.
The structure of tendon organs in the cat: A proposed mechanism for responding to muscle tension
Authors: Bridgman Charles F.
Published: February 2005

By reconstructing tendon organs in detail from serial cross sections, a prediction is made on how these sensors might affect their nerve endings during changes in tension at musculotendinous junctions. Tendon organs are composed of specialized encapsulated fascicles of dense collagen which are offshoots from the primary tendon of origin or insertion of a muscle. Fascicles project into the muscle mass on their way to becoming attached to a bundle of extrafusal muscle fibers. The main spur of dense collagen rapidly divides into fine bundles with septa between. Within this encapsulated region, branches of the entering sensory nerve intertwine among the fine bundles of collagen fibers via the septa. Towards the muscle end of the tendon organ, these fine bundles reorganize again into heavy, dense bundles before insertion of extrafusal muscle fibers.

The hypothesis is presented that the spaces between collagen bundles in a relaxed tendon organ might spread open reducing pressure upon nerve endings lying between; during tension, these bundles would straighten and crowd together, leading to compression of nerve endings. Variable compression of nerve endings would excite electrochemical events in sensory axons; thus, tension information would be coded and transmitted to the central nervous system. The arrangement of a tendon organ in series with muscle fibers would imply that the organ sampled tension primarily of that group of extrafusal muscle fibers attaching to the organ.
Development of order during ciliogenesis
Authors: Frisch Donald , Farbman Albert I.
Published: February 2005

This report consists of an electron microscope study of developing cilia in nasal epithelium of 15–18 day mouse embryos. As soon as recognizable cilia were observed, the typical 9 + 2 pattern of ciliary microtubule pairs was present. However, at this stage the intracellular spatial alignment of adjacent cilia, reflected in the adult by directionally oriented central microtubules, was not observed. In the same stage, differentiated basal feet were randomly arranged on adjacent basal bodies within the same cell. The significance of these findings lies in the observation that the structures differentiate at random prior to and independent of the forces that orient them in a coordinated spatial and temporal relationship.
Microangiographic and histologic studies of vascular anatomy of the femur and tibia distal to femoral and iliac arteriovenous fistulas in dogs
Authors: Kelly Patrick J. , Janes Joseph M.
Published: February 2005

The anatomy of intra‐osseous vessels of bones distal to a femoral or an iliac arteriovenous fistula was studied by histologic and microangiographic methods. The venous and sinusoidal vessels were dilated and heavily filled with contrast medium from 3 to 60 weeks after construction of the fistula. The nutrient artery and its branches are smaller in caliber in bones distal to the fistula at three weeks but appeared to return to approximately normal size later in the experimental period. The anatomic findings appear to provide an important link in a hypothesis to explain the increase in total bone seen distal to an arteriovenous fistula.
Hepatic alterations following experimental tetracycline toxicity in rats
Authors: Zussman William V.
Published: February 2005

Toxic doses of tetracycline were injected intravenously in adult female rats to study the morphologic and cytochemical alterations produced in the liver. Fifty percent of the animals treated died within 48 hours; those surviving were sacrificed at 3, 7, 10 or 14 days later. Histologic sections of the livers from all animals were studied utilizing a specific fluorescence technique to determine tetracycline uptake and storage, and with histochemical procedures for alkaline phosphatase and succinic dehydrogenase activity.

Varying degrees of degeneration were observed in the livers of animals dying acutely. Basophilic lamellated bodies at seven days and focal venous thromboses at 14 days were noted in the surviving animals. Tetracycline fluorescence was visualized initially within bile canaliculi and random hepatic cells, and later within dilated interstitial spaces as well as in the basophilic bodies. By 14 days residual fluorescence was limited to the parenchyma adjacent to thrombosed central veins. Succinic dehydrogenase activity was diminished within areas of tetracycline accumulation and minimally increased where the cytologic damage was greatest. Alkaline phosphatase activity present about the central veins and in areas of tetracycline‐induced fluorescence reflected parenchymal distortion.
The differential effect of hydrocortisone on the short‐lived small lymphocyte
Authors: Esteban Jose N.
Published: February 2005

As previously reported, small lymphocytes of the rat comprise two populations of cells with respect to circulating life span, designated as long‐ and short‐lived. By the appropriate injection schedules of H3‐thymidine and by varying the postinjection interval, it is possible to essentially confine the label to one or the other of the populations. Thus two groups of animals were administered H3‐thymidine so that in one group only long‐lived small lymphocytes were labeled and in the other, short‐lived lymphocytes were labeled. The animals were then injected intraperitoneally with 4 mg doses of hydrocortisone at four‐hour intervals. Controls were administered saline. At intervals after receiving from 1 to 12 hydrocortisone injections, the animals were sacrificed and radioautographs were prepared of the thymus, thoracic duct lymph, mesenteric lymph node, bone marrow and spleen. These are tissues known to show significant differences with respect to the percentage distribution of long‐ and short‐lived lymphocytes.

The results from analyzing the percentages of labeled small lymphocytes present in the respective tissues of the two groups are believed to be conclusive in showing that short‐lived small lymphocytes are more susceptible to the destructive effects of hydrocortisone than are the long‐lived lymphocytes.
Comparative peritoneal cellular content as related to species and sex
Authors: Davis Robert H. , McGowan Larry
Published: February 2005

Cytologic fluid specimens were obtained by aspiration from the abdominal peritoneal cavities of young adult male and female mice, hamsters, guinea pigs, gerbils and rats. Two hundred cells were randomly counted and grouped as mesothelial cells, lymphocytes, polymorphonuclear leukocytes, histiocytes, mast cells, bare nuclei, monocytes and daisy cells. In all mammals studied, regardless of sex, mesothelial cells were the predominate cells in abdominal serous fluid. Relatively high distributions of mast cells were observed in rats and hamsters. Bare nuclei without cytoplasm were found in all animals except male mice. Special attention was given to the daisy cell which occurred in rat peritoneal fluid. It is concluded that species and sex difference markedly influence the cytologic content of abdominal peritoneal fluid.
Histoenzymology of the developing human spinal cord
Authors: Duckett Serge , Pearse A. G. E.
Published: February 2005

In the human fetal spinal cord, enzymatic activity is demonstrated in neurons of the anterior horn a few weeks before it appears in neurons of the posterior horn. This enzymatic activity is present first in the lumbar segment of the spinal cord and with advancing time gradually ascends cephalad. The presence of acetyl‐cholinesterase activity in neuronal cytoplasm in the lumbar segment of the spinal cord coincides with the earliest detectable movement in the lower limbs.
Effect of age on alkaline phosphomonoesterase activity in the adrenals of male mice
Authors: Samorajski T. , Rolsten Carolyn
Published: February 2005

This investigation was undertaken to examine the effects of aging on alkaline phosphomonoesterase (Alk Pase) activity in the adrenals of a highly inbred strain of C57BL/10 male mice. A total of 140 male mice were assigned to seven main groups and sacrificed at 1, 4, 8, 12, 16, 20 and 24 months of age for biochemical and morphologic evaluations of adrenal Alk Pase activity. The biochemical findings indicated that while aging may result in a decrease of serum and liver Alk Pase activity, enzyme activity in the adrenals of male mice increases to a maximum level at approximately eight months of age and subsequently decreases at each successive age level. The histochemical findings revealed that the highest concentrations of enzyme activity occurred in the fascicular and reticular zones of sexually mature male mice. There were no major variations in zonal distribution with advancing age. Electron microscopy showed Alk Pase activity along membranes of cortical cells and within the subendothelial space.

The progressive increase in Alk Pase enzyme activity up to eight months of age, and the subsequent fall in activity during senescence as well as its absence in the adrenals of female mice provides further support for a role of androgen in mobilizing cortical alkaline phosphomonoesterase activity.
Deciduomal response of the golden hamster uterus
Authors: Harper M. J. K.
Published: February 2005

The deciduomal response to uterine trauma in pesudopregnant hamsters has been studied. Trauma was effected in one uterine horn by leaving a sterile silk thread in the lumen, pulling a thread through the lumen, injecting oil or air into the lumen or crushing the horn with a hemostat. At autopsy the traumatized and untraumatized horns were weighed separately and examined histologically for a deciduomal reaction. The day of greatest uterine sensitivity was found to be day 4 of pseudopregnancy, and maximal deciduomal growth (mean uterine weight ± S.E. = 2582 ± 279 mg) occurred by day 8. No significant further increase in uterine weight was seen by day 9, and by day 10 separation of the deciduoma from the myometrium had begun. Leaving a thread in the uterine lumen produced a significantly greater uterine weight by day 8 than with any other stimulus, but good deciduomal responses (uterine weights of 1679 ± 245, 1255 ± 156 and 1192 ± 219 mg) were induced by oil injection, pulling a thead through the uterus and crushing the uterus respectively. A poor reponse was produced by air injection. At no particular time during day 4 of pseudopregnancy was it possible to demonstrate a peak of uterine sensitivity using as a traumatic stimulus either oil injection or pulling a thread through the lumen. In this respect hamsters differ from both rats and mice, which have well defined peaks of maximal uterine sensitivity.
Cholesterol changes in developing testicular interstitial cells of the mouse: Histochemical and biochemical study
Authors: Ichihara Ichiro
Published: February 2005

In combination with biochemical determination of cholesterol in testes, cholesterol was studied histochemically in the testicular interstitial cells of dd strain mice from 5 to 63 days.

Cholesterol is found in interstitial cells at five days and cholesterol positive interstitial cells increase significantly from 7% at 5 days to 47% at 21 days (17% at 7 days, 21% at 10 days and 31% at 14 days) and thereafter gradually to 58% at 63 days (50% at 28 days, 54% at 35 days, 56% at 42 days, 58% at 49 days and 57% at 56 days).

The cholesterol concentration of testes (μg of cholesterol per mg testicular weight) remains at low values before 42 days (1.33 at 5 days, 2.12 at 7 days, 1.89 at 10 days, 2.18 at 14 days, 2.16 at 21 days, 1.63 at 28 days and 2.09 at 35 days) but it increases rapidly at days 42–49 (2.21 at 42 days and 5.16 at 49 days) and then it is almost unchanged (5.47 at 56 days and 5.18 at 63 days).

From these results it is suggested that (1) at five days testicular steroid could be elaborated and (2) the capacity of interstitial cells to produce testicular steroid elevates actively from 42 to 49 days.
Uniformity of structural characteristics throughout the length of skeletal muscle fibers
Authors: Farrell Patricia R. , Fedde M. R.
Published: February 2005

Fresh‐frozen, serial cross–sections of the transversus abdominis muscle of four mature chickens (98 fibers) were examined to determine structural and histochemical characteristics throughout the entire length of skeletal muscle fibers. Fiber diameter and nicotinamide adenine dinucleotide diaphorase (NAD‐D) and myosin adenosine triphosphatase (ATPase) activities were used as criteria to classify fibers as Type I or II. Measurements were made at 10 to 22 locations along the length of the fibers. An unimodal distribution of mean fiber diameters ranging from 48 μ to 86 μ was found. Fibers did not appear larger in the belly of the muscle than near the ends. Although small fluctuations in fiber diameter occurred through the length of a fiber, large and small fibers tended to remain relatively large or small at each location. NAD‐D activity was either consistently high or low throughout the length of a fiber. Likewise, myosin ATPase activity was either high or low for an entire fiber. It is concluded that skeletal muscle fibers maintain rather uniform structural and histochemical characteristics along their entire length.
Lysosomes in uterine involution: Distribution of acid hydrolases in luminal epithelium
Authors: Anton E. , Brandes D. , Barnard S.
Published: February 2005

The distribution of acid hydrolytic activities in rat uterine epithelial cells during post‐partum involution was examined by light and electron microscopic cytochemistry. Acid phosphatase, β‐glucuronidase, N‐acetyl‐β‐glucosaminidase and E600‐resistant esterase (cathepsin) increased during the period of involution and the electron cytochemical preparations revealed the lysosomal nature of the acid hydrolytic positive particles visualized by light microscopy.

The newly formed particles included primary lysosomes, in the form of Golgi vesicles, vacuoles, and secondary lysosomes such as dense bodies and autophagic vacuoles. This apparent increase in lysosomal activity during uterine involution is in agreement with similar patterns observed in the course of tissue regression in general.
The role of the thymus in development of lympho‐hemopoietic tissues. The effect of thymectomy on development of blood cells, bone‐marrow, spleen, and lymph nodes
Authors: Kalpaktsoglou Pitsa K. , Yunis E. J. , Good R. A.
Published: February 2005

The effect of thymectomy at different ages in C3H mice on development of circulating leukocytes and cells of marrow, spleen and lymph nodes has been analyzed. Regardless of the age at which thymectomy is performed depression of numbers of circulating lymphocytes is produced. Thymectomy at birth did not affect significantly the relative number of lymphocytes in the marrow during the first few weeks of life, later they fell to low levels. Thymectomy at four weeks was followed by prompt reduction in relative numbers of lymphocytes in the marrow.

After reaching six weeks of age, neonatally thymectomized mice showed a high proportion of monocytes in the marrow. Neonatal thymectomy and thymectomy at two weeks of age reduced the number of eosinophils in the marrow.

Neonatal thymectomy inhibited development of lymphocytes in the spleen, whereas thymectomy later in life produced only transient depression of lymphocytes in this organ. In addition, neontal thymectomy decreased the relative numbers of small lymphocytes in the lymph nodes. This was associated with drastic depletion of lymphocytes in the deep cortical regions of the nodes.
The phrenic nerve: Its terminal divisions and supply to the crura of the diaphragm
Authors: Thornton Myra Williams , Schweisthal Michael R.
Published: February 2005

A study of the crura of the diaphragm and their innervation from the phrenic nerve was made in 22 fresh specimens and four embalmed specimens. The arrangement of the musculature was found to be essentially the same as that described by Low in 1907. The portions of the crural musculature passing to the right and left of the esophagus did not decussate anterior to the esophagus as these fibers insert into the central tendon. The right and left phrenic nerves divided into three to five divisions at the pericardiodiaphragmatic angle. Most commonly, these divisions are: anterior, posterior and lateral. If there are more than three divisions involved, there is usually a medial division present and/or a subdivision of one of the other divisions. It is the posterior division or its posteromedial branch which contributes to the innervation of the crura. None of the other divisions contributes to the innervation of the crura. Secondary branches of either the posterior division or the posteromedial branch do not cross to the contralateral side.
The effects of fluoride and low calcium on the physical properties of the rat femur
Authors: Beary Dexter F.
Published: February 2005

The effect of fluoride on the physical properties of bone was investigated with the aid of an Instron materials tester. Two groups of weanling female rats, one on an adequate (0.6%) calcium diet and the other on a low (0.1%) diet were given the following dosage levels of fluoride (as NaF) in their deionized drinking water over a fifteen and one‐half week period: 3.4 ppm, 10.0 ppm and 45.0 ppm. In the adequate calcium group a significant increase in flexibility in the rat femur was found only at the 45.0 ppm dosage level. This was not offset by a significant decrease in strength. In the low calcium group a similar significant increase in flexibility appeared at the 10.0 ppm dosage level as well as the 45.0 ppm, but a significant decrease in strength at the two dosage levels was observed. These were in direct relation to the amount of fluoride given.
Hair growth cycles in subcutaneous implants
Authors: Chase H. B. , Sanford Barbara H. , Arsenault Claudette T. , Carroll Sarah B.
Published: February 2005

Skin fragments implanted subcutaneously into syngeneic mice remained viable and showed cyclic hair growth over a period of months. Embryonic skin differentiated into the various layers of epidermis and corium, producing sebaceous glands and hair follicles. Implants from both embryos and newborn displayed normal hair pigmentation with appearance in metanagen of the yellow bands characteristic of the agouti hair for that genotype. Follicles were observed to pass through the various hair growth stages into a resting period and then later to re‐enter the growth cycle. There were departures from normal hair growth, however, with some follicular disorganization, especially in the newborn implants, and with areas showing mixed growth stages instead of the follicular synchronization characteristic of the intact mouse.
Stratified squamous metaplasia of the uterine epithelium in early androgen‐treated rats and its inhibition by light deprivation
Authors: Reiter Russel J.
Published: February 2005

Rats, having been given a single subcutaneous injection of testosterone propionate at four days of age, exhibited polyfollicular ovaries, extensive stratified squamous uterine metaplasia and persistent vaginal cornification (90–95% of the smears contained cornified cells) after adulthood was attained. If early androgentreated rats were blinded at 22 days of age the number of vesicular follicles in the ovaries of adults was greatly diminished, the incidence and extent of stratified squamous metaplastic lesions were suppressed and the number of vaginal smears containing cornified cells was reduced by about 50%. The effects of blinding, however, were negated by pinealectomy illustrating that the suppressive influence of light deprivation on reproduction was mediated by way of the pineal gland.
Nuclear and cytoplasmic annulate lamellae in trophoblast giant cells of rat placenta
Authors: Jollie William P.
Published: February 2005

Single stranded profiles of nuclear annulate lamellae were identified in giant cells of rat trophoblast from the day when the chorioallantoic placenta first becomes vascularized, viz., day 12 post coitum, until the day before term, viz., day 22. Cytoplasmic annulate lamellae were observed only in giant cells from placentas at day 12. Occasionally cytoplasmic annulate lamellae were found in parallel array. Often the lamellar membranes were continuous with both granular and agranular membranes of endoplasmic reticulum; they closely resembled doubled outer nuclear membrane. Nuclear annulate lamellae resembled doubled inner nuclear membrane; and often the two were found in continuity. In addition, at later gestational ages (17 and 22 days), nuclear lamellae often were related anatomically to the variety of nuclear inclusions which characterize giant trophoblast cells during late pregnancy. A possible relationship of annulate lamellae to the synthesis of DNA, RNA and protein is considered.
Structural luteolysis of induced corpora lutea in “androgen‐sterilized” rats
Authors: Malven P. V. , Francis R. P.
Published: February 2005

Five‐day‐old female rats were made anovulatory by injection of 50 μg testosterone propionate. When the animals were at least 120 days old, corpora lutea (CL) were induced by injection of human chorionic gonadotrophin (HCG). Various treatments were initiated 15 days after HCG and the morphological regression of induced CL was examined 30 days after HCG. Structural luteolysis was very slight in control animals, suggesting that prolactin secretion was minimal. Exogenous prolactin hastened the rate of luteal regression. Daily injections of estradiol or reserpine also caused rapid structural luteolysis. Destruction of the arcuate nucleus of the hypothalamus also induced morphological regression at a more rapid rate than in controls. In conclusion, exogenous prolactin or three different treatments known to promote secretion of endogenous prolactin accelerated the rate of luteal regression in induced CL.
Origin of amphibian premelanosomes and their relation to microtubules
Authors: Wise Gary E.
Published: February 2005

In amphibian melanophores, premelanosomes appear to be formed in fenestrated cisternae of the Golgi complex. The premelanosomes may develop within the cisternae or vesicles containing melanoprotein may bud from the cisternae to form premelanosomes. Some micrographs also demonstrate a close association between microtubules and either premelanosomes or melanosomes. The microtubules themselves may originate from electron dense particles in the centrosphere region of the cell.
Osmium binding to the surface coat of intestinal microvilli in the cat under various conditions
Authors: Pratt S. A. , Napolitano L.
Published: February 2005

The appearance of the carbohydrate‐rich surface coat covering the the intestinal epithelium of the cat varies with different methods of fixation for electron microscopy. A fibrillar surface coat covers the external surfaces of the microvilli after fixation in glutaraldehyde and postfixation in phosphate‐buffered OsO4; its density is enhanced by heavy metal staining. In tissue fixed in glutaraldehyde alone or followed by dehydration in acetone and postfixation in OsO4 in carbon tetrachloride, a structureless zone less dense than Epon occurs where the surface coat is usually visualized; heavy metal staining does not impart density to the zone. The absence of structure and low density of the zone are not due to extraction of the surface coat by dehydrating agents or by carbon tetrachloride. The data suggest that osmium binds to the surface coat from phosphate buffer, but not from carbon tetrachloride. Also OsO4 in phosphate buffer, but not OsO4 in carbon tetrachloride, facilitates heavy metal staining of the surface coat. Acidic carbohydrates appear to be important for the differential binding of osmium observed in this study. The need for caution in interpreting low density areas of electron micrographs as extracted structures and high density areas as “osmiophilic” structures is discussed.
Age changes in the cranial base of the rabbit (Oryctolagus cuniculus)
Authors: Moore W. J. , Spence T. F.
Published: February 2005

The growth changes in the cranial base of the rabbit between one and 20 weeks after birth have been investigated. The basicranial axis and its anterior extension completed some 50% of their growth during this period in contrast to the posterior extension which had completed 70% before one week. The sphenoethmoidal angle underwent no statistically significant changes despite a decrease in the spheno‐maxillary angle indicating that the face became disposed below rather than directly anterior to the braincase. The foramino‐basal angle decreased progressively during the period of investigation.

The pattern of growth in the linear dimensions of the rabbit cranial base is essentially similar to that already established in man and subhuman primates. The angular changes, however, differ from those in primates where the spheno‐ethmoidal and foramino‐basal angles follow more closely the developmental patterns of the braincase and facial skeleton.
The structure of the interalveolar septum of the mammalian lung
Authors: Ryan Stephen F. , Dumais Charles , Ciannella Arnold
Published: February 2005

Light and electron microscopic examination of serial transverse sections of interalveolar septa of hamster lung have demonstrated a virtually continuous connective tissue sheet of variable thickness in the interalveolar septum. This central sheet, like connective tissue elsewhere, is composed of ground substance in which are immersed cells, collagen and elastin. A capillary network lies on each surface of this sheet. The capillary basement membrane is continuous with the central sheet but in contrast to it is thin, uniform and devoid of cells, collagen or elastin. Capillaries on one surface frequently anastomose directly through the septum with capillaries on the opposite surface.

The central sheet is shown to be virtually continuous despite frequent thinning. Whenever cells, collagen or elastin occur in the interalveolar septum, it is always in the central sheet. The efficiency of this arrangement in combining optimum gas conductance with adequate mechanical support is pointed out.

The central sheet is also continuous with the perivascular connective tissue cuff and thus may serve as an important route of extracellular fluid transport to the perivascular lymphatics.
The fine structure of the vasa recta and associated nerves in the rabbit kidney
Authors: Gosling John A. , Dixon John S.
Published: February 2005

The fine structure of the vasa recta and associated nerves has been studied in the rabbit. Vasa recta were first identified in groups of two or three and were accompanied by small groups of axons. A number of these axons contained granulated, agranular and dense‐cored vesicles. As the vasa recta subdivided, the muscle coat consisted of a single layer of smooth muscle cells. Additional large axon bundles were observed accompanying this segment of the vasa recta. Some of these axons also contained granulated, agranular and dense‐cored vesicles in varying proportions. Further towards the medulla, smooth muscle cells were replaced by others which had irregular collections of filaments within their cytoplasm. These in turn were replaced by cells having a characteristic band of filaments on their luminal aspects. Nerves were only identified adjacent to those parts of the vasa recta which included smooth muscle cells.
Tissue fluid movement in compact bone
Authors: Seliger William G.
Published: February 2005

Thorotrast (colloidal thorium dioxide) was released into tibial marrow cavities of 12 adult cats and into the tibial nutrient arteries of ten adult cats. Following regular intervals the tibiae were removed, fixed, decalcified in formic acid, and prepared histologically.

The label indicated the general tissue fluid drainage of the tibia is in the perivascular connective tissue of Volkmann's canals from the marrow cavity to the periosteal lymphatic vessels.

The tissue fluid flow appears to pass from the Haversian vessel through the canalicular‐lacunar complex to the peripheral lacunae of the osteone. Its path from this point has not been observed.
Morphology and histochemistry of the oviduct and egg‐jelly layers in the frog, Rana pipiens
Authors: Shivers C. Alex , James Judith M.
Published: February 2005

Morphologically the oviduct of the frog, Rana pipiens, consists of a lining epithelium and tubular jelly‐secreting glands. The oviduct can be divided into six regions (designated R1 anteriorly—R6 posteriorly) based on the differential staining of the jelly glands. The regions measured 1, 5, 6, 3, 20 and 3 cm, respectively. These regions correspond to 6 histochemically distinct layers of jelly (designated J1 nearest the egg through J6 farthest from the egg) which are deposited around the egg during the egg's sojourn in the oviduct. A correlation between lengths of each oviducal region and thickness of individual jelly layers was observed. That is, J5 is the thickest, followed by J3, 2, 6, 4 and J1 which is thinnest.

Histochemical properties of jelly glands and corresponding jelly layers were essentially the same in the tests performed. All regions and layers except R5 and J5 contain a large amount of acid mucopolysaccharide and the mucopolysaccharide in R and J1, 3 and 4 is sulfated. Neutral mucopolysaccharide is present in R2, J2, R5 and J5. Although protein is present in all layers and oviducal regions it was found in higher concentration in R and J1, 3 and 6 and in lowest concentration in R and J2.
Cytomorphometric and biochemical differences between the muscle cells in atria and ventricles of the guinea pig heart
Authors: Plattner H. , Tiefenbrunner F. , Pfaller W.
Published: February 2005

Differences in succinate dehydrogenase and cytochrome oxidase activity and also in the Q for a medium containing pyruvate, glutamate, fumarate and glucose (equimolar) were found using histochemical and manometrical methods, when muscle cells of the atria and the ventricles in the guinea pig heart were compared. Most of the activity values were higher in the ventricles than in the atria. According to cytomorphometric measurements, these differences can be explained by differences in the mitochondrial volume (per unit volume of cytoplasm) rather than by a different ultrastructural organization of the individual mitochondria, since they show the same stereological organization in both the atria and the ventricles. The reduced mitochondrial volume in the atria results in a lower density of “oxidative” (i.e., inner mitochondrial) membranes per unit volume of cytoplasm.