bluuebunny/crossref_metadata_2025 huggingface dataset:
Early morphological alterations of pressure‐overloaded cat right ventricular myocardium
Authors: Marino Thomas A. , Houser Steven R. , Cooper George
Published: February 2005

Pressure overload of the right ventricle results in an increase in ventricular mass. It also results in abnormal in vitro contractile function in advance of the onset of congestive heart failure as determined in papillary muscles removed from these ventricles. To correlate these functional abnormalities with any early underlying morphological changes, a band was placed around the proximal pulmonary artery of cats. This band restricted the lumen to 20% of normal and was left in place for 2 weeks. At that time, hemodynamic variables were measured to insure that right ventricular pressure overload had been produced. The hearts were then perfusion fixed, and papillary muscles from the right ventricle were prepared for light and transmission electron microscopy. Quantitative morphological data were obtained for the volume density both of several tissue components and of several organelles. It was found that there are significant increases in myocyte cross‐sectional area and diameter in hypertrophied tissue with a concurrent increase in the volume density of interstitial tissue. There are no alterations in the volume density of organelles in the hypertrophied myocytes. We suggest that the substantial increase in the proportion of connective tissue and the decrease in the surface area to volume ratio that accompany pressure overload cardiac hypertrophy may be early underlying structural changes that relate directly to the abnormal contractile function found in this type of hypertrophy.
Ultrastructural distribution of sulfated complex carbohydrates in elastic cartilage of the young rabbit
Authors: Takagi Minoru , Parmley Richard T. , Denys Francis R. , Kageyama Masato , Yagasaki Hiroshi
Published: February 2005

Sulfated glycosaminoglycans are an integral component of elastic cartilage. We have investigated the ultrastructural distribution of sulfated complex carbohydrates (CC)in the mature cartilage and the perichondrium of young rabbit auricles using the high iron diamine‐thiocarbohydrazide‐silver proteinate (HID‐TCH‐SP) and the tannic acid‐ferric chloride (TA‐Fe) methods. In the mature cartilage, HID‐TCH‐SP stained intracellular Golgi saccules of the mature face, secretory granules, and the extracellular matrix granules, but staining was not discernible in collagen fibrils and osmiophilic elastic fibers consisting of only amorphous elastin. The HID and TA‐Fe staining were similarly observed in matrix granules, whereas the elastic fibers and collagen fibrils lacked the staining. The pericellular matrix granules had a diameter of 34 ± 5 nm (mean ± SD; n = 30). Thiéry's periodate‐TCH‐SP (PA‐TCH‐SP) method stained vicinal glycol‐containing CC in collagen fibrils but failed to stain matrix granules and elastic fibers. In the perichondrium, HID‐TCH‐SP staining of the organelles was less intense in the flattened chondrocytes when compared with those in large mature chondrocytes. The extracellular HID and HID‐TCH‐SP staining were observed in the matrix granules. The diameter of pericellular matrix granules (19 ± 4 nm, mean ± SD; n = 30) was significantly smaller when compared to those in the mature cartilage (P < 0.001). The HID‐TCH‐SP staining was closely associated with collagen fibrils. However, the staining was not seen in collagen fibrils and osmiophilic elastic fibers consisting of elastin and microfibrils. The PA‐TCH‐SP method stained collagen fibrils and microfibrils but did not stain the amorphous elastin. Thus these studies demonstrate that sulfated CC are packaged in chondrocyte secretory granules and are released into the extracellular matrix to form matrix granules, but are not incorporated into collagen fibrils and elastic fibers.
The effect of alloxan, and alloxan‐induced diabetes on the kidney
Authors: Evan Andrew P. , Mong Stephen A. , Connors Bret A. , Aronoff George R. , Luft Friedrich C.
Published: February 2005

Alloxan is known to induce diabetic renal changes as well as causing nephrotoxic alterations. However, no ultrastructural study has been performed to differentiate diabetic verses toxic affects of alloxan to the tubule and/or glomerulus. Therefore the present study used the “protected” kidney model to prevent one kidney from being exposed to the alloxan while allowing the other to receive the drug immediately. In all experimental animals the right renal hilum was gently occluded for 5 minutes and then released. This was performed prior to the injection of alloxan. Subsequently, the left renal hilum was occluded at the time of, and for 5 minutes after, alloxan administration (40 mg/kg i.v.). The experimental rats were divided into three groups: untreated diabetics, diabetics treated with protamine‐zinc‐insulin, and alloxantreated rats that failed to become diabetic. Three groups of controls were included: one group received an equal volume of saline diluent as the experimental rats but no clamping of either renal hilum; another group received the saline and had the left renal hilum occluded for 5 minutes; and a third group had both the right and left renal hila occluded. All animals were followed and sacrificed after 9 weeks. Endogenous creatinine clearance did not change among groups. Alloxan‐treated nondiabetic rats displayed marked interstitial nephritis in unprotected kidneys, while protected kidneys were normal. The diabetic state resulted in mesangial proliferation and focal glomerular basement membrane thickening as well as glomerular capilary endothelial abnormalities and visceral epithelial foot‐process fusion. The endothelial changes consisted of focal areas showing a reduction in the size of endothelial fenestrae. All glomerular changes were ameliorated by insulin treatment. We conclude: (1) alloxan per se is distinctly nephrotoxic; and (2) the glomerular endothelium and epithelium are involved early in the course of experimental diabetes.
Evidence of sequential remodeling in rat trabecular bone: Morphology, dynamic histomorphometry, and changes during skeletal maturation
Authors: Baron Roland , Tross Robert , Vignery Agnes
Published: February 2005

The occurrence of a sequential bone remodeling activity, similar to what is observed in human bone, is demonstrated in rat trabecular bone at the level of the secondary spongiosa. A complete dynamic histomorphometric analysis of the remodeling activity, using undecalcified sections and double fluorescent labels, has consequently been performed in young adults (220 g, 8 weeks old) and in more mature animals (320 g, 12 weeks old). The results showed that, despite a similar trabecular bone volume, younger animals had a five times higher bone formation rate and five times more osteoclasts than more mature animals. The higher bone formation rate was due in part to a threefold higher extent of double‐labeled trabecular bone surface and in part to a 1.5‐fold faster mineralization rate. These results therefore demonstrate a marked slowing down of bone turnover during skeletal maturation in the rat. The values obtained in this study have been compared with measurements made in other parts of the skeleton in the same species (Vignery and Baron 1978, 1980b; Tran Van et al., 1982a) or in humans. This comparison indicated that 12‐week‐old rats had a turnover rate very similar to values observed in iliac crest trabecular bone in adult humans. The rat is therefore a good experimental animal for the study of trabecular bone remodeling but since large variations occur during skeletal maturation, care should be taken in the selection of an age group relevant to the type of questions being asked.
Ultrastructural cytochemistry of proteoglycans associated with calcification of shark cartilage
Authors: Takagi Minoru , Parmley Richard T. , Denys Francis R. , Yagasaki Hiroshi , Toda Yoshihisa
Published: February 2005

Proteoglycans (PGs) as well as sulfated glycosaminoglycans (GAGs) are closely associated with cartilage calcification. An inner zone of endoskeletal tesserae of sharks is composed of a unique calcified hyaline cartilage. Initial calcification can be seen in the cartilage close to the inner zone. We have ultrastructurally examined shark, Triakis scyllia, noncalcifying, calcifying, and calcified cartilage using the tannic acid‐ferric chloride (TA‐Fe), the high iron diamine (HID), and the HID‐thiocarbohydrazide‐silver proteinate (HID‐TCH‐SP) methods for localization of sulfated complex carbohydrates. In noncalcifying cartilage, TA‐Fe and HID strongly stained matrix granules which were round, ovoid, elongated, or irregularly shaped and presumably represented PG monomers. The size and staining intensity of the reactive matrix granules progressively decreased in calcifying cartilage toward the calcification front of the calcified cartilage. Similarly, a progressive decrease in the size of the HID‐TCH‐SP stain deposits in the matrix granules was observed in the calcifying cartilage close to the calcification front and was interpreted as a decrease in length of sulfate containing GAG chains. In the calcified cartilage, the highly calcified areas were often localized in the calcification front and contained few or no small HID‐TCH‐SP stain deposits, whereas the weakly calcified regions contained more stain deposits. These results indicate that partial and complete degradation of sulfated GAGs and/or PGs may be a requisite for calcification of shark cartilage.
Quantitative changes in the morphology of the aging canine prostate
Authors: Zirkin Barry R. , Strandberg John D.
Published: February 2005

Sterological methods at the light and electron microscopic levels were used to examine the morphological changes in the beagle prostate associated with inceasing age and with the occurrence of spontaneous benign hyperplasia. Analyses of semithin sections of tissue embedded in plastic revealed that proliferation of prostatic glandular and stromal components, increase in epithelial cell numbers, and increase in epithelial cell size all contributed to the dramatic increase in prostate weight seen in aging dogs. Analyses at the electron microscopic level revealed that the volume densities of rough endoplasmic reticulum and secretion granules were significantly lower in epithelial cells of the immature prostate than in the prostate of mature dogs (greater than 1.5 years of age). In contrast, no significant difference were seen in the volume densities of rough endoplasmic reticulum, free ribosomes, secretion granules, smooth endoplsmic reticulum, or mitochondria in randomly selected prostatic epithelial cells of dogs 1.5 to 9 years of age, whether or not the prostates were hyperplastic.
Morphological and ultrastructural aspects of the activation of avian medullary bone osteoclasts by parathyroid hormone
Authors: Miller Scott C. , Bowman Beth M. , Myers Ralph L.
Published: February 2005

The activation of physiologically inactive medullary bone osteococlasts by paratathyroid hormone (PTH) was examined using light and electron microscopy and histomorphometric methods. Medullary bone osteoclasts are functionally inactive during the avian egg‐laying cycle when an egg shell is not being calcified in the shell gland. Japanese quail hens were given 0.5 IU/g PTH and the medullary bone osteoclasts were examined up to 90 min later. Administration of PTH results in rapid changes in osteoclast morphology and ultrastructure. Within 10 min ectoplasmic regions containing condensed‐appearing material are evident in areas of the cell adjacent to bone surfaces. In tannic acid‐fixed specimens, these ectoplasmic regions contain bundles of filaments extending perpendicularly from the osteoclast plasma membrane into the cytoplasm. It is in these areas that ruffled border development is initiated. Even at 10 min after PTH administration, mineral crystals are seen between the developing cell surface invaginations and folds. By 15 min after PTH administration, ruffled borders have appeared next to bone surfaces. The rapid development of ruffled borders on medullary bone osteoclasts after PTH is confirmed by electron microscope histormorphometry. By 30 min after PTH administation, ruffled borders are well developed and large endocytic vaculoles are beginning to appear in the osteoclast cytoplasm. Light microscope histomorphometric measurements indicate that osteoclasts are also increasing in size and speeading along bone surfaces with time after PTH administration. This study provides a morphologic and ultrastructural desciption of osteoclast activation by PTH. The results indicate that osteoclasts may effect rapid changes in bone resorption and mineral metabolism due to exogenous PTH in hens.
The anionic barrier system on the mesonephric renal glomerulus of the brown hagfish, Paramyxine atami Dean (cylostomi)
Authors: Tsujii Tadashi , Naito Ichiro , Ukita Satoko , Ono Toshiro , Seno Satimaru
Published: February 2005

The distribution of anionic groups of acid mucopolysaccharides on the surface of glomerular constituents of a brwon hagfish, Paramyxine atami Dean, has been studied morphologically. The ionized anionic groups of acid mucopolysaccharides were labeled on fixed tissues by stainig with cationic cacodylate iron colloid (Fe‐Cac) at pH 4.0. The glomerular permeability to cationic and anionic macromolecules was observed morphologically in the kidney of the animal injected native anionic ferritin (NF) or cationized ferritin (CF) into the dorsal aorta.

Histochemical staining of tissues with Fe‐Cac (pH 4.0) revealed the ionized anionic groups of acid mucopolysaccharides on both luminal and abluminal surfaces of endothelial cells, within the glomerular basement membrane (GBM), and on the visceral epithelial cell surface facing the urinary space. The CF molecules introduced into the dorsal aorta easily passed through the fenestrae of the capillary endothelial cell layer and the thick fibrillar GBM, reaching the urinary space to be adsorbed to the visceral epithelial cell surface or taken up by these visceral epithelial cell. On the other hand, NF hardly passed through the capillary wall. These results show that the nonosmoregulating mesonephric glomerulus of the brown hagfish has a working anionic barrier system. The function of its glomerulus is compared to that of the mammalian metanephric glomerulus.
An immunohistochemical study of nuclear proteins in differentiating epidermal cells
Authors: Fukuyama Kimie , Meceira Juan , Tuffanelli Denny L. , Epstein William L.
Published: February 2005

Both DNA and RNA disappear from the nucleus during differentiation of granular cells into cornified cells but the fate of nuclear proteins remains unknown. We investigated localization of nuclear proteins in rat epidermis by light and electron microscopic immunoperoxidase techniques. As a probe, three sera that reacted, respectively, with the nucleoplasm, nucleolus, and nuclear envelope of basal cells of rat epidermis were used. In granular cells both the antinucleoplasm serum and antinucleolus serum increased intensity of the nuclear staining, but they reacted also with ribosomes, filaments, and periphery of keratohyalin granules in the cytoplasm. The staining appeared diffusely in cornified cells and identification of nuclear components became impossible. In contrast, the antinuclear envelope serum stained only the nuclear outline in granular cells and continued to stain the nuclear contour in cornified cells of the fourth and fifth proximal cell layers. The antigenic components surrounded amorphous but not filamentous materials in cornified cells. These findings suggest that some nuclear proteins become immunologically indistinguishable from cytoplasmic protein. However, the nuclear envelope protien maintains its localization even after nucleic acids are lost and the nuclear space is detectable in cornified cells by use of autoantibody directed to this protein(s).
The effect of age, pairing, copulation, and 2‐Br‐α‐ergocryptine in the male Mongolian gerbil on the prolactin cells in the anterior pituitary identified by immunocytochemical and Herlant's tetrachrome methods
Authors: Ortman Robert , Perez Frank
Published: February 2005

Near‐adjacent, midsagital sections of pituitaries of infantile and adult male Mongolian gerbils in several experimental groups (bachelor, paired, tartaric acid‐injected, postcopulatory gerbil, and postcopulatory animal injected with 2‐bromo‐α‐ergocryptine [CB‐154]), were stained by a modification of Herlant's tetrachrome and by the peroxidase‐labeled antibody method for prolactin. Cell counts of erythrosinophils and cells immunoreactive for prolactin were made. Sequential staining procedures and thin adjacent sections were used to correlate the staining results.

Erythrosinophils were very rare in the infant pituitaries; they increased (P < .01) in numbers in bachelaor pituitaries, remained at the same level (P > .05) in paired animals, increased (P < .01) in the postcopulatory gerbils that were injected with tartaric acid, and increased much less (P < .05) in postcopulatory males that were injected with CB‐154.

Prolactin cells were present in modest numbers in infant pituitaries; they increased (P < .01); in bachelors and reached their highest number in paired animals (P < .001); they remained unchanged (P > .05) in tartaric acid‐injected postcopulatory animals but declined (P < .001) in CB‐154‐injected, postcopulatory animals. The number of prolactin cells was always significantly greater (P < .001) than the number of erythrosinophils.

Correlative studies revealed the erythrosinophils, some of the light blue cells, and some of the chromophobes gave positive immunocytochemical reactions for prolactin.

Apparently, CB‐154 inhibited the erythrosinophils and the immunoreactive prolactin cells in the postcopulatory male gerbil, as indicated by a reduction in the number, size, and staining intensity of the cells.
Lymphocyte proliferation in neonatally thymectomized rats
Authors: Granata Anna Luisa , Vecchi C. , Budassi R. , Corsi A.
Published: February 2005

Autoradiography has been used to evaluate lymphocyte proliferation in the neonatally thymectomized rat in comparison with the normal animal. The data obained show that the proliferative activity of lymphocytes is greatly increased in the thymus‐dependent areas 4–6 weeks after thymectomy, whereas it is normal or slightly increased 3 months laters. It seems plausible to assume that a thymus factor or chalones in situ produced by specific cells normally regulate the proliferation of thymus‐derived cells. The increase of the proliferative activity accounts for the repopulation of the thymus‐dependent areas, which are completely replenished in the older animals. Recirculation of the thymus cells is not confined to the thymus‐dependent areas.
The development of capillaries in the telencephalon of Beagle puppies
Authors: Leuschen M. Patricia , Shuman Robert M. , Nelson Robert M.
Published: February 2005

The microvessels of the telencephalons of Beagle puppies between newborn and 72 hours of age were investigated ultrastructurally at 24‐hour intervals. The morphometry of the microvasculature from the germinal matrix was compared with that of the microvasculature from the borderzone cerebral cortex. The endothelial cell walls of the microvessels from these two sites were similar during the study period, but the lumina of the matrical microvessels were significantly larger than the lumina of the control cortical microvessels. The proportion of matrical microvessels with large lumina undergoes progressive attrition with time. The values (areas) for the lumina of the matrical microvessels, and their distribution, come to resemble those of the cortex. The morphometry of the cortical microvasculature is comparatively static. The data suggest that there is an active modification in the microvasculature of the germinal matrix of the Beagle puppy in the immediate postnatal period.
The effect of beta‐aminoproprionitrile on the periodontal ligament: II. Radioautographic study of collagen secretion from fibroblasts
Authors: Cho Moon‐Il , Garant Philias R.
Published: February 2005

Fibroblasts are distributed evenly throughout the periodontal ligament (PDL) of normal mice. In mice fed beta‐aminoproprionitrile (β‐APN) the fibroblasts undergo aggregation to form palisades of closely juxtaposed cells abutting pools of acellular collagenous matrix. Individual fibroblasts within these aggregates retain their polarized cytoplasmic organization and continue to synthesize and secrete collagen. However, unlike normal PDL fibroblasts, the β‐APN‐treated cells appear immobilized by well‐developed cell‐to‐cell adherens‐type junctions along their lateral surfaces. We studied collagen secretion from β‐APN‐treated fibroblasts by light and electron microscopic radioautography after injection of 3H‐proline. Newly synthesized collagen was secreted from the distal ends of the β‐APN‐aggregated fibroblasts as a distinct band of labeled material, resembling the pattern of matrix deposition seen in osteogenesis and dentinogenesis. The radioactive band of collagenous matrix was displaced further away from the fibroblasts at 2 and 4 days after 3H‐proline injection as more collagen was secreted.

This pattern of radiolabeled collagen secretion confirmed previous observations that PDL fibroblasts are highly polarized and that collagen secretory granules are extruded from the distal or secretory pole of the cell. In normal PDL the even distribution of fibroblasts and the complex interrelationship of their distal cell processes leads to a diffuse pattern of silver grain deposition, masking the oriented flow of new collagen from the distal ends of individual fibroblasts.

Analysis of electron microscopic radioautographs revealed that newly synthesized collagen was packaged and secreted from β‐APN‐treated fibroblasts via the normal cytoplasmic pathways but at a slower rate.
Immunocytochemistry of albumin in hepatocytes after overnight starvation and during a diurnal cycle in young rats
Authors: LeBouton A. V.
Published: February 2005

The indirect immunoperoxidase method was used to identify albumin in hepatocytes of young rats before and after periods of starvation and during a normal diurnal cycle. All liver cells in fed rats contained an abundance of albumin, whereas hepatocytes from overnight fasted animals showed minimal amounts of the protein. Hepatocytes in rats on the diurnal cycle generally contained more albumin during the light phase than in darkness. At the beginning of the dark phase, certain hepatocytes were low in albumin and they were located primarily around portal canals. Halfway through the dark period, these cells had increased in number and were located closer to terminal hepatic venules. Overnight starvation of young rats profoundly lowers hepatocyte albumin and the time of highest liver cell albumin content in the diurnal cycle of fed, young rats is during the first half of the light period.
Immunohistochemical localization of luteinizing hormone‐releasing hormone (LHRH) in the hypothalamus of adult female hamsters treated neonatally with monosodium glutamate or hypertonic saline
Authors: Lamperti Albert A. , Pickard Gary E.
Published: February 2005

The immunohistochemical localization of luteinizing hormone‐releasing hormone (LHRH) was studied in paraffin and vibratome‐sectioned tissue from adult female hamsters that were treated neonatally with monosodium glutamate (MSG) or hypertonic saline. There appeared to be a reduction in LHRH‐positive fibers in the median eminence of animals with an MSG‐induced lesion of the arcuate nucleus in paraffin‐embedded tissue. However, when unembedded tissue was cut on a vibratome, the distribution of LHRH‐positive fibers and perikarya was similar in both groups of animals. Fibers were seen coursing through the periventricular area and lateral hypo‐thalamus to the median eminence. In addition, LHRH‐positive fibers were seen in the organum vasculosum of the lamina terminalis, subfornical organ, septal and preoptic areas, fasciculus retroflexus, habenular complex, and several regions in the basal forebrain. Animals that were pretreated with colchicine had LHRH‐positive perikarya in the medial habenular nucleus, diagonal band of Broca, and the medial olfactory tract.
Embryonic length and cerebral landmarks in staged human embryos
Authors: O'Rahilly Ronan , Müller Fabiola
Published: February 2005

The greatest length (GL) and the crown‐rump (C‐R) length were compared in 43 staged human embryos. It was found that point C, which overlies the middle of the midbrain, was sometimes difficult to locate and that point R is not precise. These disadvantages render the C‐R measurement unsatisfactory. At 4 weeks (stage 13) the GL comes to exceed the C‐R and continues to do so until about 7 weeks (stages 17–19). The maximum difference is approximately 1.5 mm. Thereafter, the two lengths are basically equal and coincide from about stages 18 and 19 onward. In a series of 100 embryos of stages 19–23, female embryos at stages 21 and 22 were found to be shorter (by a mean of 1 mm) than male embryos, but not at stages 19, 20, and 23. The greatest length, which is independent of fixed points, is much simpler to measure than the C‐R length, and it is recommended that it be used instead. It is pointed out that Streeter had already made that substitution. The greatest length has the further advantage of being a practicable measurement from two postovulatory weeks (stage 6) throughout the remainder of the embryonic and also in the fetal period. The lower limbs are excluded from measurement.
Innervation of human bone periosteum by peptidergic nerves
Authors: Grönblad Mats , Liesi Päivi , Korkala Olli , Karaharju Erkki , Polak Julia
Published: February 2005

Nerves exhibiting substance P‐like immunoreactivity were demonstrated in the human periosteum. A network of nerves showing substance P‐like immunoreactivity was seen in the periosteum, while finer strands of immunoreactive nerve fibers were present immediately beneath the surface of the periosteum. Enkephalin‐like immunoreactivity was also studied but could not be demonstrated.

Substance P has previously been suggested to be involved in the mediation of the sensation of pain. The clinically observable marked pain sensitivity of periosteal tissue might be explained by the peptidergic nerves described in this paper.
Development of agranular reticulum in Sertoli cells of the testis of the dogfish Squalus acanthias during spermatogenesis
Authors: Pudney Jeffrey , Callard Gloria V.
Published: February 2005

Biochemical analyses of Squalus testis indicates that key enzymes involved with androgen production increase progressively from immature regions containing spermatogonia to mature regions in the late spermatid stage of maturation (Canick et al., 1983). In an effort to identify cells possessing the cytological characteristics of steroid production and to determine the structural correlates of the observed functional changes, we have carried out an electron microscopic study of Squalus testis. This report demonstrates that Sertoli cells contain a well‐developed agranular reticulum, mitochondria with tubulovesicular cristae, and numerous lipid droplets. Moreover, as germ cells mature, there is an increase in abundance of agranular reticulum in the adjacent Sertoli cells. By the time of spermatid elongation, this has reached dramatic proportions and fills the Sertoli cell as a mass of tubules. These results lead us to conclude that the Sertoli cell is responsible for secretion of the increasing amounts of androgen during the spermatogenetic cycle in Squalus.
Pulmonary type II cell lamellar body ultrastructure preserved by rapid freezing and freeze drying
Authors: McAteer James A. , Terracio Louis
Published: February 2005

Lamellar body ultrastructure was examined in cultured type II alveolar epithelial cells processed by a method of rapid freezing and freeze drying in the absence of both chemical fixation and solvent dehydration. This method of specimen preparation was chosen to optimize the retention of soluble substances within the type II cell. The use of cultured cell aggregates in which type II cells line the free surface facilitated the effectiveness of rapid freezing for the preservation of lamellar body fine structure.

Lamellar bodies preserved by rapid freezing/freeze drying to optimize the in situ retention of intracellular components possess closely adherent concentric membranous lamellae. This supports the contention that the widely appreciated lamellar pattern of the pulmonary lamellar body represents the in vivo molecular organization of intracellular surfactant phospholipids.

Lamellar bodies of frozen/frozen dried type II cells showed none of the often profound lipid extraction artifact produced by conventional processing. Instead they exhibited a substructure with noteworthy characteristics in common with lamellar bodies processed by resin dehydration lipid retention methods (Stratton, 1976). Importantly, the lamellae of frozen/frozen dried lamellar bodies were contiguous, with no interlamellar space, as is commonly observed in solvent‐processed (extracted) specimens. The dimensions of lamellar components in frozen/frozen dried lamellar bodies were, however, different from published values for resin‐dehydrated lipid‐retained specimens. Lamellar width and the widths of component phospholipid head and fatty acid tail regions in frozen/frozen dried lamellar bodies were approximately 35% smaller than values reported for resin‐dehydrated lamellar bodies. This difference was attributed to shrinkage of lamellar components as water was removed from the unfixed tissue during the freeze‐drying process.
Immunoelectron microscopic localization of relaxin in endometrial gland cells of the pregnant guinea pig
Authors: Pardo Rube J. , Larkin Lynn H. , Renegar Randall H.
Published: February 2005

Endometrial gland cells in uteri from late‐pregnant guinea pigs (day 60 to parturition) resembled typical protein‐secreting cells. Extensive rough endoplasmic reticulum and well‐developed Golgi complexes were evident. The most striking features of endometrial gland cells were accumulations of large (≈ 0.5 μm in diameter), dense, membrane‐bounded granules. The granules were located in the supranuclear region of the cell and frequently occurred in close proximity to the plasma membrane adjacent to the lumen of the gland. Thin sections of endometrial gland cells treated with relaxin antiserum and either colloidal gold‐protein A or colloidal gold‐goat antirabbit IgG demonstrated that the granules contained relaxin. These studies provide additional evidence that the uterus of the guinea pig produces relaxin and support the hypothesis that uterin relaxin may play an important role in pregnancy and parturition in the guinea pig.
An electron microscopic study of two types of muscle fibers in the pharyngeal pad of crussian carp, Carassius carassius
Authors: Nakao Taisuke , Ishizawa Akimitsu , Suzuki Satoru , Saito Mitsuo
Published: February 2005

In the pharyngeal pad on the roof of the anterior pharynx of Carassius carassius two types of thin striated muscle fibers (1.5‐10 μm in diameter) were found. No pattern was discerned in the orientation of muscle fibers which form a loose tissue as a whole. One of them (Z fiber) is characterized by position of triads at the level of Z lines, and in the other type (A‐I fiber) they were seen at the junction of the A and I bands.

Three types of intermyofibrous junction are noted between muscle fibers of the same type or between those of different types. The first type possesses ultrastructural features such as a uniform intercellular space about 90 nm which contains the basal lamina, a dense mat of the filamentous material on the sarcoplasmic aspect of the cell membrane, and a connection of myofibrils with the dense layer by thin I band filaments. The second type resembles the previous type but is distinguished from it by the lack of myofibrillar association. The third type is the nexus or gap junction. Intermyofibrous junctions of the second type are most frequently encountered (82%). Those of the first type are less frequently seen (15%), whereas the third type junctions are far less frequently seen (3%).

Nerve endings at the neuromuscular junction of both types of muscle fiber contain numerous small clear vesicles suggesting their cholinergic nature.
Ultrastructural immunocytochemical localization of lysozyme in the mucociliary epithelium of the rabbit endocervix in different hormonal states
Authors: Nicosia Santo V. , Sowinski Janice M. , Chilton Beverly S. , Streibel Ellen J.
Published: February 2005

The distribution of lysozyme in the endocervix of estrous, pseudopregnant, and ovariectomized rabbits was studied using two different immunocytochemical techniques—the unlabeled antibody enzyme method of Sternberger et al. (1970) and the peroxidase‐labeled antibody method of Taylor and Burns (1974). With both procedures, a fine immunostaining precipitate was seen over the entire area of basal mucous granules, while immunodeposits were coarser and mostly located in the outer zone of central and apical granules. A nonspecific staining was noted when tissues were reacted with peroxidase‐antiperoxidase complex alone. This troublesome artifact was abolished by preincubating tissues with human IgA. This step did not affect the specific immunostaining for lysozyme yet nonspecific staining was absent from specificity and method controls carried out for both immunocytochemical procedures. The presence of high levels of lysozyme in the endocervical epithelium of estrous rabbits was also confirmed in enzymatically isolated endocervical epithelia using the lysoplate method of Osserman and Lawlor (1966). Mucous granules and immunostainable intracellular lysozyme were abundant during estrus, decreased during early pseudopregnancy, and were absent after longterm ovariectomy. However, they were restored by the administration of estradiol (5 μ/12 hours/10 days) to ovariectomized animals. These data indicate a common hormonal regulation and secretory mechanism for endocervical mucous glycoproteins and lysozyme.
An ultrastructural morphometric comparison of the peripheral with the hilar air‐blood barrier of dog lung
Authors: Berendsen Peter B. , Ritter Arthur B. , DeFouw David O.
Published: February 2005

Excised and isolated perfused lungs are frequently used as models for studies of fluid flow and membrane transport.

Regional variations of the air and blood vascular compartments of the lung have been recognized to result from gravitational effects. This ultrastructural morphometric study considered the components of the air‐blood barriers of the peripheral and hilar regions of excised dog lungs. The lungs of three mongrel dogs were fixed by endotracheal instillation of glutaraldehyde and immersion in fixative. Stratified random sampling, point counting volumetry, and line intercept counts were used to determine the thicknesses of the air‐blood barrier and the epithelial, interstitial, and endothelial compartments. Point counting volumetry also established the volume density of the alveolar spaces. The morphometric values for structures within the periphery were statistically compared to those within the hilar region by Student's t‐test. Endotracheal and immersion fixation as used in this study, combined with stratified random sampling, equalized regional differences in the alveolar lumen volume and airblood barrier thickness. With these conditions no significant differences in the volume densities of the epithelial and endothelial cells and the interstitium of the air‐blood barrier were identified when those of the hilum were compared to those of the periphery.
Effects of two glycosaminoglycans on seeding of cardiac cushion tissue cells into a collagen‐lattice culture system
Authors: Bernanke David H. , Markwald Roger R.
Published: February 2005

A collagen‐lattice culture model of developing heart valves was utilized to test two glycosaminoglycans, normally found in the cardiac jelly matrix of developing heart valve primordia, for their effects on the capability of mesenchymal derivatives of cardiac cushion endothelial cells to enter the substrate from the surface. Treatment with hyaluronate increased the rate of cell seeding to 2.04 times that of untreated control cultures and 1.82 times that of chondroitin sulfate‐treated cultures. Scanning electron microscopic studies suggested that the increased rate was due to an enhanced disruption of intercellular junctions, influenced by hyaluronate, permitting disengagement of cells from the surface population and migration as mesenchymal cells into the collagen matrix. The results of this study correlate well with the presence of high hyaluronate concentrations in the cardiac jelly matrix beneath the cushion endothelium at periods of active seeding of cushion tissue cells.
Histochemical localization of ouabain‐sensitive, K+‐dependent p‐nitrophenylphosphatase (Na+‐K+‐ATPase) activity in the submandibular gland of the mouse: Effect of androgen, thyroid hormone, or postnatal age
Authors: Sims‐Sampson Graciella , Gresik Edward W. , Barka Tibor
Published: February 2005

Ouabain‐sensitive Na+‐K+‐ATPase activity was localized histochemically in the submandibular gland of the mouse under various conditions using p‐nitrophenylphosphate as substrate at pH 9. In untreated adult males and females, intense staining was seen in the basally striated portions of the epithelial cells lining the excretory and striated ducts. The region of the lateral cell membranes, but not of the apical plasmalemma, also stained. In granular convoluted tubules (GCTs), strong staining was seen only in a narrow band of the basalmost region of the cells; in males this stained region was thinner than in females, and frequently was absent. The baso‐lateral margins of acinar and intercalated duct cells gave a very weak reaction.

In untreated males, or in females that were treated with dihydrotestosterone, overall staining for the enzyme was always less than in untreated females, due to the diminished reactivity of androgen‐stimulated GCT cells and the decreased number of striated ducts. However, in females treated with triiodothyronine, enhanced activity of Na+‐K+‐ATPase was indicated by stronger staining in all cell types, including the hypertrophied GCT cells. Na+‐K+‐ATPase activity was undetected in the submandibular glands at birth, but moderate staining was seen in the larger excretory and striated ducts by 5 days of age. From 10 days of age onward, intense staining was seen in the excretory and striated portions of the ramifying duct system. Developing GCT cells could not be distinguished from their precursor cells in the striated ducts until 25 days of age. These data indicate that the salt‐handling capacity of the submandibular gland of the mouse varies with both endocrine status and age.
Morphology of presumptive slowly adapting receptors in dog trachea
Authors: Krauhs Jane M.
Published: February 2005

The three‐dimensional branching pattern and ultrastructure of afferent myelinated fibers and their terminals located in the trachealis muscle of the dog are described. The afferent endings are believed to be those of the slowly adapting stretch receptors of the trachea. They have structural features typical of mechanoreceptors: distal to the loss of myelin, their shape becomes more irregular and the cytoplasm is filled with mitochondria, glycogen, and osmiophilic bodies. In some places the cell membrane is attached directly to basal lamina without interposition of a Schwann cell. A bundle of unmyelinated fibers accompanies each myelinated fiber and continues for an undetermined distance beyond (luminal to) terminations of the myelinated fiber. The unmyelinated fibers contain many round, clear vesicles and a few dense‐cored vesicles and are also attached directly to basal lamina in places. Three‐dimensional reconstruction of three receptors revealed three quite different branching patterns, but all included apparent rings as part of more or less contorted terminal regions (some neurons apparently having more than one terminal region). No obvious structural basis for the activation of receptors by transverse but not longitudinal stretch was found.
Development of morphologic heterogeneity of hepatocyte mitochondria in the mouse
Authors: Kanamura Shinsuke , Kanai Kazuo , Oka Motoko , Watanabe Jun , Asada‐Kubota Mari
Published: February 2005

The ultrastructure of mitochondria in perioportal and perihepatic hepatocytes from newborn, 5‐, 10‐, and 20‐day‐old, and adult male ddY mice was analyzed by quantitative electron microscopy. In newborn and 5‐ and 10‐day‐old animals, the axial ratio (length per diameter), surface to volume ratio (area of the outer membrane per unit mitochondrial volume), and volume density were not significantly different between periportal and periphepatic cells. In 20‐day‐old and adult animals, the surface to volume ratio was greater in perihepatic cells than periportal cells, and the volume density was greater in periportal cells than perihepatic cells. The axial ratio became greater in perihepatic cells than periportal cells in adult animals. However, there were no differences in the surface density of the outer membrane, and of the inner membrane and cristae between the cells of both zones in all age groups examined. When the data were expressed as volume and area per cell, the patterns of subacinar distribution and age‐related changes differed from the patterns seen in the volume and surface density data mainly in adult animals. This difference was generally caused by the marked increase in hepatocyte volume between 20 days of age and adulthood, especially in perihepatic cells.

The results show that differences between mitochondria in periportal cells and those in perihepatic cells in the shape (the axial and surface to volume ratios), volume density, and area of the outer membrane per cell, evident in adult animals, are not present in newborn animals but arise during postnatal development.
The effects of simulated increases in body weight for 30 and 60 days on bone robusticity of limb bones in rats
Authors: Simon Mark R. , Holmes Kenneth R. , Olsen Aart M.
Published: February 2005

The purpose of this study was to subject groups of weanling male rats each to a specific 10% simulated increase in body weight, ranging from 1.1G–2.0G, using constant centrifugation. (In this paper, “G” is the acceleration due to gravity.) After 30 and 60 days, rats were killed and perfused with 10% buffered neutral formalin (B.N.F.). The humerus, radius, ulna, femur, and tibia were removed, cleared of all soft tissues, weighed, and the total length measured. Bone robusticity was calculated using the ponderal index: bone length/\documentclass{article}\pagestyle{empty}\begin{document}$ \sqrt[3]{{{\rm bone}\,{\rm weight}}} $\end{document}. Tukey's Multiple Range Test was used. The data suggest that the specific limb bone, G, and duration of centrifugation are each factors in the response of limb bones to simulated increases in body weight.
The effects of simulated increases in body weight from birth on bone robusticity of limb bones of rats
Authors: Simon Mark R. , Holmes Kenneth R. , Olsen Aart M.
Published: February 2005

Groups of newborn rats were each subjected to a specific 10% simulated increase in body weight, ranging from 1.1G to 2.0G, to study changes in bone robusticity. (In this paper, “G” is the acceleration due to gravity.) Constant centrifugation was used. At 90 days of age, the rats were killed and the humerus, radius, ulna, femur, and tibia were removed, weighed, and measured. Bone robusticity was calculated using the ponderal index: bone length/\documentclass{article}\pagestyle{empty}\begin{document}$ \sqrt[3]{{{\rm bone}\,{\rm weight}}} $\end{document}. Tukey's Multiple Range Test was used. The data suggest that, for both males and females, bone robusticity is increased with simulated increases in body weight.
Prevention by pinealectomy of short‐photoperiod‐induced ultrastructural changes in the hamster harderian gland
Authors: Diioria Dennis P. , Nadakavukaren Mathew J.
Published: February 2005

Harderian gland ultrastructure was examined at biweeky intervals for 16 weeks after either pinealectomy or sham‐operation of male and female hamsters kept in 1L:23D and 14L:10D photoperiods. Female characteristics such as membrane formations and extensive smooth endoplasmic reticulum appeared in the males kept under short photoperiod conditions. Similarly, male characteristics such as the tubular clusters appeared in the glands of females kept in the short photoperiod. When male and female hamsters were pinealectomized and exposed to the short photoperiod, the glands in each sex retained the characteristics typical of that sex. Atrophy of the testes and uteri was also observed in the sham‐operated hamsters maintained under short photoperiods, but not in the pinealectomized animals. The changes observed in the Harderian glands and reproductive organs of hamsters kept in the short photoperiod were not observed in the hamsters maintained in the long photoperiod. The photoperiod‐induced ultrastructural changes in the hamster Harderian glands are most likely due to changes in hormonal levels brought about by the regression of reproductive organs and can be prevented by pinealectomy.
Effects of progressive hyperglycemia on ovarian structure and function in the spontaneously diabetic Chinese hamster
Authors: Garris David R.
Published: February 2005

The effect of the progressive hyperglycemic condition on ovarian follicular maturation was studied in control, moderate (160–350 mg/d1 blood glucose), and overt (≥ 350 mg/d1 blood glucose), spontaneously diabetic Chinese hamsters. Match‐paired (age, sex, and weight) control and diabetic animals were sacrificed at specific intervals during the development of the diabetic condition; the ovaries were collected and morphometrically analyzed for changes in ovarian follicular growth relative to blood glucose levels. Follicles were classified according to size, number, and condition. The total number of primary (100–200 μm diameter) and secondary (200–350 μm diameter) follicles was reduced in both moderate and overt diabetic females as compared with controls. The percentage of viable (i.e., nonatretic) follicles was greatly reduced in the secondary follicle class of overt diabetic animals as compared with controls. No significant differences were observed in the numbers of viable tertiary (i.e., ≥ 350 μm diameter) follicles in any of the diabetic animals as compared with controls. The percentage of atretic, secondary follicles was greatly increased in the overt diabetic group as compared with controls. These data indicate that the progressive hyperglycemia associated with diabetes in the Chinese hamster induces a severe depression of normal follicular recruitment resulting in an impaired reproductive performance in this species.
Transverse sections of the elbow region in man, made into transparencies and embedded in plastic in a self‐study module
Authors: Lataster L. M. A. , Rensema J. W. , van Mameren H. , Drukker J.
Published: February 2005

This paper describes a valuable tool for medical teaching. It is a detailed description of a method to present transparent sections embedded in plastic, placed in a self‐instruction module by means of a vertical storage system. It includes the use of three‐dimensional graphic reconstructions. Other applications are also indicated.
Mesonephric excretory function related to its influence on differentiation of fetal gonads
Authors: Grinsted Jørgen , Aagesen Lotte
Published: February 2005

The mammalian intermediate fetal kidney, the mesonephros, is known in different species to excrete body waste products during a limited period of fetal life. Recently, the mesonephros and its derivatives have been shown to influence gonadal functions in several ways. Thus, the mesonephric cells are responsible for regulating the onset of meiosis in different mammals by the secretion of two substances, a meiosis‐inducing substance (MIS) and a meiosis‐preventing substance (MPS).

In this paper, the relation between mesonephric kidney function and its influence on the gonads is reviewed through literature studies. It seems that cessation of mesonephric excretion precedes onset of meiosis in the ovary in different species.

It is suggested that the mesonephric renal function interferes with synthesis and/or secretion of MIS or that the excreted products may interfere with the responsiveness to MIS of the germ cells.