bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of tooth function on adjacent alveolar bone and Sharpey's fibers of the rat periodontium
Authors: Short E. , Johnson R. B.
Published: February 2005

There is little information about the effects of short‐term non‐, hypo‐, and hyperfunction of teeth on the (1) mineralization patterns of intrinsic and extrinsic (Sharpey's) fibers and (2) mean number and diameter of Sharpey's fibers of adjacent alveolar bone. The mineral density of intrinsic and Sharpey's fibers and the size and number of Sharpey's fibers could indicate the relative strength of the attachment of a tooth to bone in various functional situations. In the present study, non‐ and hypofunctional situations were created by selective extraction of right molar teeth of the rat; the contralateral teeth were placed in hyperfunction by the surgery. In non‐ and hypofunctionals, intrinsic and Sharpey's fibers of the crestal third of the alveolus were less densely mineralized than in hyperfunctionals or untreated controls. Mean Sharpey's fiber diameters were significantly greater and their mean number/unit area significantly less in non‐ than in hypo‐ or hyperfunctionals or untreated controls (P < 0.001). Mean Sharpey's fiber diameters in hyperfunctionals were significantly less than in untreated controls (P < 0.05). Hypofunction ameliorated the effects of nonfunction on mean diameter and number of Sharpey's fibers, but had little effect on the density of mineralization of either the intrinsic or Sharpey's fibers of the alveolus, suggesting that their mineralization may be controlled by factors other than occlusal forces from the adjacent teeth. Thus changes in the stress/strain environment within the periodontium, coincident to altered occlusal function of the adjacent teeth, rapidly affects the morphology of intrinsic and Sharpey's fibers of alveolar bone and ensures that adequate tooth support is maintained in the new functional situation.
Three‐dimensional computer‐aided analysis of the intraganglionic topography of primary muscle afferent neurons in the rat
Authors: Peyronnard Jean‐Marie , Messier Jean‐Pierre , Dubreuil Martin , Charron Louise , Lebel France
Published: February 2005

A microcomputer system was used to reconstruct, in the L5 dorsal root ganglion (DRG) of the rat, the three‐dimensional arrangement of primary neurons which had been labelled by application of horseradish peroxidase (HRP) and fluoro‐gold (FG) to various muscle nerves of the leg. Analysis of the data and animation of the reconstructed images with commercially available software were instrumental in identifying the preferential intraganglionic locations of the neurons innervating muscles such as the soleus (SOL), the gastrocnemius lateralis (GL), and medialis (GM), or parts of the GM. These locations appeared to be somewhat related to the position of the muscles in the posterior compartment of the leg. Additionally, the study provided quantitative estimates of muscle afferent neuronal populations, allowed a comparison of the labelling performances of HRP and FG, and finally indicated that few DRG neurons project to two different muscles.
Immunocytochemical localization of proteins utilized in the formation of outer dense fibers and fibrous sheath in rat spermatids: An electron microscope study
Authors: Clermont Y. , Oko R. , Hermo L.
Published: February 2005

Affinity purified antibodies prepared against proteins isolated from fibrous sheath (FS) and outer dense fibers (ODF) were utilized in an immunocytochemical study of spermatids at various steps of spermiogenesis. This study, using the immunogold technique, was performed on sections of Epon or Lowicryl embedded tissues examined with the electron microscope. In the case of FS antibodies there was a selective immunoreactivity of the FS itself from step 10 onwards, but no reactivity over the plasma membrane associated FS anlagen. In addition there was a diffuse immunoreaction over the cytoplasmic matrix from step 9 until step 18 of spermiogenesis but no reactivity over the various types of dense bodies (e.g., granulated bodies, reticulated body, etc.) seen in the cytoplasm of these spermatids. In the case of ODF antibodies the ODF were immunolabeled throughout their development from step 11 onward. In addition to a diffuse immunoreactivity of the cytoplasmic matrix of spermatids from step 9 until step 18 of spermiogenesis, there was an immunolabeling of “granulated bodies.” These bodies appeared in relation to ER cisternae during steps 10–14, increased in number and size during steps 15–17 and decreased in number thereafter leaving only a few coarsely granulated bodies in the residual cytoplasm which detached from late step 19 spermatids. No other cytoplasmic structures were labeled with the ODF antibody‐gold complexes. Thus the granulated bodies appeared to serve as a transitory storage site for some proteins destined to form ODF, a major cytoskeletal element of the tail of rat spermatozoa.
Development of the giraffe horn and its blood supply
Authors: Ganey Tim , Ogden John , Olsen John
Published: February 2005

The giraffe horn is an unusual cranial exostosis that lacks clear delineation and categorization as either horn or antler. The distinction between the two is made by contrasting their methods of development and basic composition. This process of development has not been detailed in the giraffe, a factor contributing to the difficulty in distinguishing the classification of these horns. In a chronological series of giraffe horns from prenatal and postnatal animals, we have observed unique morphologies that define their proper location on the skull, the blood supply to them, and the transitions involved in their histological development. While our observations have facilitated the classification of the giraffe horn, our interpretations were not always in accord with previous reports.
Comparison of mesenteric with antimesenteric crypt and villus populations in the mouse jejunal epithelium
Authors: Cheng Hazel , Bjerknes Matthew , Totafurno John
Published: February 2005

Variation in the size and composition of crypts and villi along the length of the intestinal tract is well known. Here we investigate possible variation around the circumference of the intestine. This is a concern because most studies have ignored potential circumferential variation and its implications for experimental design in cell kinetic studies. We compared the crypt and villus populations of the mesenteric half with those of the antimesenteric half of proximal mouse jejunum. The branching crypt index and crypt and villus dimensions were measured. We found no evidence of differences in the branching crypt index, in the mean crypt and villus size, nor in the distribution of crypt and villus sizes between these two populations.
A novel mechanism of capillary growth in the rat pulmonary microcirculation
Authors: Burri Peter H. , Tarek Mojmir R.
Published: February 2005

Postnatally, the rat lung parenchyma undergoes impressive growth. Within four months of birth, lung volume and alveolar and capillary surface areas increase over 20‐fold and capillary volume 35‐fold. Investigation of methacrylate casts of the pulmonary microvasculature revealed that, with age, lung capillaries were not only growing in surface and volume but also increasing their network density. We proposed that the capillary bed grows by formation of slender intravascular tissue pillars and termed this type of growth intussusceptive microvascular growth (Caduff et al., Anat. Rec., 216:154–164, 1986). The aim of this investigation was to detect the presence and to analyze the ultrastructure of slender tissue posts (diameter 1–2.5 μm) extending across the capillary lumina in serial electron microscopic sections of rat lung parenchyma (age 44 days). Computer‐assisted three‐dimensional reconstruction of the capillary lumen confirmed that tissue posts were matching the holes previously observed in casts. Post ultrastructure varied with size from a simple area of interendothelial contact to tissue pillars with a core of interstitial tissue. Based on the changing morphology of the pillars, a hypothesis for their development can be proposed: phase I, creation of a zone of contact between opposite capillary walls (formation of an interendothelial bridge); phase II, reorganization of the intercellular junctions of the endothelium, with central perforation of the capillary layer; phase III, formation of an interstitial post core, with successive invasion by cytoplasmic extensions of myofibro‐blasts, pericytes, and finally interstitial fibers; and phase IV, growth of the slender pillar to a normal full size capillary mesh. These findings support the new concept of intussusceptive growth of the lung capillary system.
Influence of epithelial‐mesenchymal interaction on the viability of facial mesenchyme II: Synthesis of basement‐membrance components during tissue recombination
Authors: Xu Zenglu , Parker Susan B. , Minkoff Robert
Published: February 2005

The presence of basement‐membrane components during tissue separation procedures was determined employing monoclonal antibodies to laminin and type IV collagen. In addition, the reconstitution of basement‐membrane components and the formation of the basement‐membrane were examined is isolated epithelium and mesenchyme and in tissue recombination. Epithelium and mesenchyme of maxillary precesses of chick embryos were seprated by a variety of protocols, including those employed in a prior study (Saber et al: Anat. Rec. 225:56–66, 1989). Results indicated that the protocol previously employed did not remove basement‐membrane components after enzymatic tissue separation. A revised protocol in which the basement‐membrane components (i.e., laminin and type IV collagen) were removed from isolated tissues prior to recombination revealed that a developmetal compartment and a gradient of cell viability, comparable in size and dimensions to that observed in the study of Saber et al. (ibid.) was present in the mesenchyme of recombined explants. Type IV collagen and laminin, therefore, do not appear to be required initially during tissue recombination in order for subsequent growth‐sustaining effects to be expressed. Additional studies revealed, however, that synthesis of basement‐membrane components occurred not only in isolated tissues but was altered markedly by tissue recombination. Culture of isolated tissues demonstrated induction of laminin synthesis in separated epithelium by 24 hours and induction of collagen synthesis in isolated mesenchyme by 24 hours. Recombination of epithelium and mesenchyme, however, resulted in rapid induction of laminin synthesis within 1 hour. Recombination of epithelium and mesenchyme after 24 hours resulted in the presence of laminin not only in epithelium but in mesenchyme as well. Both tissues were required for basement‐membrane formation which appeared to be fully reconstituted by 24 hours in culture. These observations indicate that recombination in culture alters the pattern of synthetic activity of these basement‐membrane components. These can be characterized as “early” (temporal) and “late” (spatial) responses by the recombined tissues.
Expression and ultrastructural immunolocalization of a major 66 kDa phosphoprotein synthesized by chicken osteoblasts during mineralization in vitro
Authors: Gerstenfeld L. C. , Gotoh Y. , McKee M. D. , Nanci A. , Landis W. J. , Glimcher M. J.
Published: February 2005

Embryonic chicken osteoblasts cultured over a 30 day period were used as a model system for studying the expression of bone phosphoproteins during cellular differentiation and the possible role of these proteins in extracellular matrix mineralization. Accumulation of total phosphoprotein in the cultures, as determined by O‐phosphoserine (Ser‐P) and O‐phosphothreonine (Thr‐P) amino acid analysis, revealed a > 10‐fold increase over the 30 day period. Total phosphoprotein synthesis, as assessed by (32P)‐, (3H)‐Ser‐P, and (14C)‐Thr‐P protein labeling, showed the highest levels concurrent with initial mineral deposition within the matrix. The major phosphoprotein present in chicken bones and synthesized by the cultured osteoblasts had a molecular weight of ∼66 kDa. This 66 kDa bone phosphoprotein (66 kDa BPP) was purified to homogeneity and was used for antibody production. Application of this antibody in Western blot analysis revealed that 66 kDa BPP was present only in protein extracts of mineralizing cultured osteoblasts and was absent in cultures of non‐mineralizing chondrocytes, myoblasts, and tendon fibroblasts. The 66 kDa BPP in vitro accumulated continuously in the extracellular matrix in a manner that paralleled both phosphoprotein synthesis and total phospho‐amino acid production. A comparison of the results obtained in vitro to those from developing embryonic tibiae in vivo demonstrated a similar qualitative and temporal expression of phosphoprotein and a continual accumulation of 66 kDa BPP in the matrix with advancing mineralization and developmental age. Ultrastructural immunocytochemistry using the 66 kDa BPP antibody and the protein A–gold technique revealed specific immunolabeling over electron‐dense regions of mineralization in the cultures that appeared identical to the distribution of labeling observed in vivo (McKee et al.: Connect. Tissue Res., 21:21–29, 1989; Anat. Rec. 228:77–92, 1990). These results demonstrate that this major 66 kDa BPP was expressed concurrently with other differentiated osteoblast functions and suggests that it may play a role in the initiation or regulation of mineralization.
Changes in glycoconjugates revealed by lectin staining in the developing airways of Syrian golden hamsters
Authors: Ito Takaaki , Newkirk Carnell , Strum Judy M. , McDowell Elizabeth M.
Published: February 2005

Lectin binding was studied in the developing airways of Syrian golden hamsters on gestational days 11–16 (day 16 is the day of birth). The trachea and lungs were fixed in 4% formaldehyde‐1% glutaraldehyde, 6% mercuric chloride‐1% sodium acetate‐0.1% glutaraldehyde, and 95% ethanol; embedded in paraffin; and stained with eight lectin‐horseradish peroxidase conjugates: Triticum vulgare (WGA), Dolichos biflorus (DBA), Helix pomatia (HPA), Maclura pomifera (MPA), Griffonia simplicifolia I‐B4 (GSA I‐B4), Arachis hypogaea (PNA), Ulex europeus I (UEA I), and Limulus polyphemus (LPA). Each lectin yielded a characteristic staining pattern, which modulated throughout development. In general, changes in staining characteristics of the tracheal epithelium preceded similar changes in the lobar bronchus, bronchiole, and alveolus. In the case of UEA I, MPA, WGA, and HPA, staining increased with time uniformly over the luminal surface of all epithelial cells. However, in the case of PNA, GSA I‐B4, and LPA, after the differentiation of ciliated and secretory cells, the apical surfaces of the ciliated cells stained more intensely than the apical surfaces of the secretory cells. Neuraminidase pretreatment enhanced PNA and GSA I‐B4 staining in both cell types. In the case of PNA, these light microscopic observations were confirmed by ultrastructural study. Unlike the other lectins, the pattern of staining with DBA was unusual. Staining was moderate at first, then decreased (days 13 and 14), then increased at all airway levels. This study shows that different glycoconjugates modulate in airway epithelial cells throughout fetal development.
Estimating anatomical–functional position coordinates in liver tissue
Authors: Barberá‐Guillem E. , Alonso‐Varona A. , Boyano M. D. , Vidal‐Vanaclocha F.
Published: February 2005

Hepatocyte enzyme activity was demonstrated by examining adult C57BL/6 mouse liver cryostat sections under a succinate dehydrogenase (SDH) histochemical reaction, and quantified by microspectrophotometry and microdensitometry. The hepatocyte SDH activity gradient along the path between the portal veins (PV) and efferent terminal hepatic venules (THV) was analyzed by measuring the concentration of the chromophore precipitated in 10 consecutive hepatic parenchymal domains located along imaginary lines drawn across the entire PV‐to‐THV distance. The profiles of intensity or of normalized relative optical density obtained on a high number of lines were correlated with distance values along the PV‐to‐THV pathway, enabling us to establish a general mathematical function relating SDH activity (chromophore concentration) to position values on a scale of 0 to 10 corresponding to the theoretical PV‐to‐THV distance. The equation can be used to interpolate the SDH activity surrounding any intrahepatic object located between the PV and the THV, thus making it possible to calculate the object's anatomical–functional position coordinates in the liver acinus. To demonstrate how this method is used, we have calibrated the intrahepatic position of hemopoietic foci induced in the liver tissue of adult mice treated with phenylhydrazine (PHZ), and show that these foci are located on coordinate 3.31 (maximum range 1.25–4.86) of the sinusoidal domain–that is, on the borderline between Rappaport's acinar zones 1 and 2.
Shaping, invagination, and closure of the chick embryo otic vesicle: Scanning electron microscopic and quantitative study
Authors: Alvarez Ignacio S. , Navascués Julio
Published: February 2005

Scanning electron microscopy, light microscopy, and morphometric analysis were used to study the morphological changes of the otic placode and vesicle before and during invagination and closure processes. Our results reveal that the otic placode undergoes shaping between stages HH9 and HH12; during this period the rostrocaudal axis is shortened, while the lateromedial axis of the placode lengthens. The presence of long cytokinesis bridges during this period suggests that cellular displacements after mitosis may participate in the shaping of the otic placode. The shaping process appears to facilitate the approach of the otic placode to the neural tube. From stage HH12 on, the otic anlage gradually becomes a U‐shaped structure with its medial portion in intimate apposition to the rhombencephalic neural tube. The coincidence in time between the beginning of intimate otic anlage–rhombencephalon contact and active invagination suggests that these two processes are related.

Changes occurring at the edges of the otic vesicle until their disappearance in stage HH17 suggest that, in addition to a process of invagination, the edges of the otic anlage become bent. During closure, cells at the edges of the otic vesicle differ in apical morphology according to their topographical location: The cells between the rostral and lateral edges have elongated apices, in contrast with the polygonal shape of the cell apices in other places of the edges. In the opposite side (between the caudal and medial edges) cell death is observed. Closure of the otic vesicle conceptualized as a zipper‐like model is discussed.

We propose that early development of the otic anlage takes place in four stages: (1) shaping (stages HH9–11); (2) triggering of the invagination (stage HH12); (3) early invagination and lateral bending (stages HH13–15); and (4) late invagination and closure (stages HH16–17).
Atrial‐specific granule number and plasma atrial natriuretic peptide in rats: Effects of beta‐adrenoceptor blockade and sodium intake
Authors: Penner S. Brian , Thliveris James A. , McKenzie John K. , Smyth Donald D.
Published: February 2005

An interrelationship between atrial natriuretic peptide (ANP) and the renin‐angiotensin system has been established. Both of these hormonal systems are modulated by sodium balance. The role of the beta‐adrenoceptor in the regulation of release of ANP is not clear. We therefore undertook a study to examine changes in atrial‐specific granule number and plasma ANP level following beta‐adrenoceptor blockade in rats on low and high sodium intakes. A low‐sodium diet, as compared with a high‐sodium diet, elevated right and left atrial‐specific granule number (right atria 54.6 ± 8.7 vs. 42.3 ± 5.7; left atria 47.7 ± 7.7 vs. 30.6 ± 3.4 granules/unit area) and plasma renin activity (28 ± 3.7 vs. 5.4 ± 0.8 ng Al/ml/hr). Plasma ANP levels were lower in the low‐sodium animals (98 ± 34 vs. 345 ± 38 pg/ml). When treated with the nonspecific beta‐adrenoceptor blocker propranolol, the elevated plasma renin activity and atrial‐specific granule number in rats on a low sodium intake were significantly less. Neither of these parameters changed in rats on a high sodium intake. Conversely, propranolol treatment resulted in lower plasma ANP levels in rats with high sodium intake. The already‐suppressed plasma ANP level in rats on a low‐sodium diet was unaltered with beta‐adrenoceptor blockade. The results suggest that dietary sodium intake is an important determinant of the response of atrial‐specific granule number and plasma ANP levels following beta‐adrenoceptor blockade with propranolol.
Inducible perivascular cells contribute to the neochondrogenesis in grafted perichondrium
Authors: Diaz‐Flores Lucio , Gutierrez Ricardo , Gonzalez Pilar , Varela Hilda
Published: February 2005

Autogeneic perichondrium was implanted above the cremaster muscle of the rat, and the new formation of two types of cartilage (types I and II) was confirmed. Also, granulation tissue was observed before the type II cartilage formation. Under these conditions, the contribution to the neocartilage of graft bed derived cells, mainly of the venule pericytes, was studied. To follow the pericyte lineage, we used a marker—Monastral Blue B—the administration of which was based on the principle of vascular labeling. While the perichondrium was kept free, before its implantation, the preformed (preexisting) venules in the cremaster muscle were exclusively labeled with Monastral Blue B, which was incorporated into the cytoplasm of pericytes and endothelial cells. After perichondrium implantation, the following sequence in tracer distribution was demonstrated. During the earlier stages, labeling was restricted to the pericytes and endothelial cells of venules in the graft bed. Later the tracer was observed in some endothelial cells and pericytes of the growing vessels and in fibroblast‐like cells of the granulation tissue. Finally, some type II neochondrocytes appeared labeled. Tracer was not found in type I neochondrocytes. The presence of label in type II neochondrocytes demonstrates that they arise from progenitor cells present in the graft bed, principally from small venule pericytes. Therefore, the findings in this study provide greater evidence that surrounding soft tissues may increase the process of cartilage regeneration from cells present in the perichondrium by contributing inducible perivascular cells.
The Golgi apparatus of rat pachytene spermatocytes during spermatogenesis
Authors: Suarez‐Quian Carlos A. , An Qu , Jelesoff Nicole , Dym Martin
Published: February 2005

A morphological and immunocytochemical study of the Golgi apparatus in pachytene spermatocytes was performed in an effort to correlate the structure and function of this organelle during meiotic prophase. In stages I‐III of the cycle, the Golgi complex of pachytene spermatocytes is a flattened discoid, 0.5–1 μm in diameter, composed of vesicles interspersed with classically described Golgi cisternae. During subsequent maturation of pachytene spermatocytes (stages IV–XIII), the size of the Golgi complex increases significantly, attaining a size of 2–3 μm. However, unlike pachytene spermatocytes of stages I–III, the majority of the Golgi complex of more mature spermatocytes is characterized by an abundance of distinct stacks of cisternae interspersed with numerous vesicles and tubules. The composition of the Golgi complex was also studied by using two monoclonal antibodies that recognize either the cis or the trans Golgi cisternae, respectively, and employing biotin‐streptavidin‐peroxidase immunocytochemistry in 5 μm frozen sections of testes. Immunodetection of the distinct cisternae revealed that the increase in size of the Golgi complex during maturation of pachytene spermatocytes was due predominantly to an accumulation of trans Golgi; the amount of cis Golgi remained unchanged.

The morphological data presented in this study are consistent with an heightened secretory activity of pachytene spermatocytes during their maturation. In addition, the increase in size of the Golgi apparatus during the extensive prophase of pachytene spermatocytes may suggest that the mechanism employed by germ cells to partition the Golgi complex during the first division of meiosis varies significantly from that of somatic cells undergoing mitosis.
An ultrastructural, morphometric analysis of rabbit fetal lung type II cell differentiation in vivo
Authors: Snyder Jeanne M. , Magliato Susan A.
Published: February 2005

Rabbit lung type II cell differentiation was evaluated by use of ultrastructural, morphometric techniques. Fetal lung epithelial cells decreased in size dramatically from day 19 to day 21 of gestation. Thereafter, the cell and cytoplasmic cross‐sectional area declined gradually until the neonatal time point. The tall columnar cell shape characteristic of fetal lung epithelial cells at early stages of development became cuboidal by day 24 of gestation. The number of mitochondria per μm2 cytoplasmic area in presumptive alveolar epithelial cells and the mitochondrial volume density increased toward the end of gestation. The volume density of glycogen pools within fetal lung epithelial cells reached a plateau on day 21 of gestation and then declined sharply on day 26 of gestation in lamellar body‐containing, type II epithelial cells. Lamellar bodies increased in number and volume density in epithelial cells starting on day 26 of gestation and peaked with respect to these parameters in the neonatal lung tissue. Multivesicular bodies, which are thought to be a precursor to the lamellar body, became more prominent in differentiated type II cells on day 26 of gestation and increased in volume density from day 28 of gestation to the adult time point. The distance between mesenchymal and epithelial cells in fetal lung tissue declined sharply between days 24 and 26 of gestation but remained relatively constant thereafter. Foot processes extending from connective tissue cells contiguous to the epithelium were generally more numerous than those extending from the basal plasma membrane of epithelial cells at every stage of development examined. These data quantitate for the first time key ultrastructural events that occur during the differentiation of fetal lung epithelial cells in vivo.
Initial stages of sperm‐egg fusion in the freshwater teleost, Rhodeus ocellatus ocellatus
Authors: Ohta Tadayuki
Published: February 2005

The morphology of spermatozoa and the initial stages of spermegg fusion at fertilization were investigated ultrastructurally in the rose bitterling, Rhodeus ocellatus ocellatus. Each spermatozoon is composed of a spherical head without an acrosome, two centrioles, a large mitochondrion, and a flagellum. Freeze‐fracture of spermatozoa illustrates that specialized arrays of intramembranous particles (IMPs) are present on the protoplasmic facing (PF) surface of the head plasma membrane at the portion slightly in front of the centrioles. The specialized arrays, whose functions are uncertain, are parallelogram‐like in shape. The distribution of the particles is random and less compact in other areas of the head plasma membrane. The number of particles on the PF surface is larger than that on the extracellular facing (EF) surface. The complementary structures of the specialized arrays are also found on a similar portion of the EF surface. An ultrastructural study clearly shows fusion of gamete plasma membranes at the initial stages of sperm entry into the egg. Membrane fusion is first observed in eggs fixed 10 seconds after insemination in fresh water. The fusion site is the microvillus membrane of a sperm entry site on the egg and the head membrane of the spermatozoon. The plasma membrane fusion of gametes is discussed relative to the distribution of the IMPs and the fusion site.
Organization of the reticular network of rabbit Peyer's patches
Authors: Ohtani Osamu , Kikuta Akio , Ohtsuka Aiji , Murakami Takuro
Published: February 2005

The organization of the network of collagen fibers of rabbit Peyer's patches was examined by scanning electron microscopy (SEM) in alkali‐water macerated tissues. The relationship between this network and the reticular cells within it was further studied by SEM of ultrasonicated tissues. Collagen fibrils (about 60 nm in diameter) formed collagen fibers or sheets. There were sheets of collagen fibrils with numerous pores beneath the patch dome epithelium. Within the patches, collagen fibers repeatedly divided and fused, forming the reticular network. The reticular network within the follicle was looser than within the dome, the corona, or the interfollicular area. The latter three compartments showed similar structures and consisted of numerous intercommunicating small subcompartments. Reticular cells were in contact with groups of free cells lodged in these subcompartments within the reticular network. Reticular cell processes with numerous fenestrations embraced not only collage fibers forming the reticular network, but also sheaths of collagen fibers of blood and lymphatic vessels. Sheaths of collagen fibers of high endothelial venules and lymphatic vessels were also fenestrated, indicating the sites through which lymphocytes and other free cells migrate. These results indicate that the reticular network of Peyer's patches is organized so as to facilitate migration and lodging of free cells and thus facilitate antigen‐to‐cell and cell‐to‐cell interactions during an immune response. The naked areas on the collagen fibers seem to provide a scaffolding for free cells during their migration.
Straining puborectalis reflex: Description and significance of a “new” reflex
Authors: Shafik Ahmed
Published: February 2005

The present communication studies the technique and clinical significance of a new reflex, termed straining puborectalis reflex. Nineteen healthy volunteers with an average age of 38.2 years were studied, including ten males and nine females.

The intravesical pressure, representative of intra‐abdominal pressure, was measured by means of a balloon‐tipped catheter introduced into the urinary bladder and connected to a pressure transducer. The electromyographic (EMG) activity of the puborectalis muscle was recorded using a concentric needle electrode inserted into the muscle. The EMG response of the puborectalis muscle to straining at different pressures was recorded. The response to two types of straining–sudden momentary and slow, sustained–was observed. The procedure was repeated in ten subjects after puborectalis infiltration with xylocaine or saline.

Sudden straining evoked puborectalis contraction, whereas slow, sustained straining did not. Puborectalis contraction increased with the increase in straining intensity. These results were reproducible. The anesthetized puborectalis did not respond to straining, whereas the saline‐infiltrated muscle did. The latency of the reflex was studied.

Besides its role as a voluntary continent sphincter, the puborectalis seems to have a role also in the involuntary continence of the pelvic organs through the straining‐puborectalis reflex. The muscle contracts on sudden straining, sealing the rectal and vesical necks and thereby preventing fecal or urinary leak. However, it is only on sudden straining that the puborectalis contracts. Slow, sustained straining as occurs during defecation and micturition does not evoke the reflex action. The straining puborectalis reflex is informative and may be incorporated as an investigative tool in patients with fecal and urinary control disorders.
Immunocytochemical localization of an oviductal zona pellucida glycoprotein in the oviductal epithelium of the golden hamster
Authors: Abe Hiroyuki , Oikawa Taneaki
Published: February 2005

The immunocytochemical localization of an oviductal glycoprotein associated with ovulated eggs was investigated. Using a monoclonal antibody, we studied three regions of epithelium in the golden hamster oviduct. The monoclonal antibody reacted with the oviductal epithelium throughout the fimbriae and isthmus. Intense binding was observed in the ampulla and isthmus, especially in the caudal isthmus. In addition, reactive materials were present in the ovarian bursal sac and lumen of the ampulla. At the ultrastructural level, the monoclonal antibody reacted specifically with putative secretory granules and Golgi apparatus of nonciliated cells in the oviductal epithelium. Other cellular organelles did not react. Quantitative data indicated that the immunolabelings were intense in the ampullar and isthmic cells but weak in the fimbrial cells. Lipid droplet‐like granules of the fimbriae and lysosome‐like vesicles of the isthmus did not react with the monoclonal antibody. In all cases, ciliated cells did not react with the monoclonal antibody. These results suggest that the glycoprotein is primarily produced and secreted by ampullar and isthmic secretory cells and is then accumulated in the ovarian bursal sac. These findings may provide insight into regional and cellular differences in secretion of the golden hamster oviduct.
Immunocytochemical localization of cathepsin D in rat ventral prostate: Evidence for castration‐induced expression of cathepsin D in basal cells
Authors: Wilson Michael J. , Whitaker John N. , Sinha Akhouri A.
Published: February 2005

Cathepsin D (EC3.4.23.5) is an aspartyl endopeptidase involved in lysosomal proteolysis. Its functional role is uncertain. This study was undertaken to determine the cellular and subcellular distribution of cathepsin D in the normal rat ventral prostate and its possible role in the castration‐induced atrophy of the gland. Cathepsin D was localized immunohistochemically to perinuclear lysosomes in secretory cells, in capillary endothelial cells, and, occasionally, in stromal cells of the untreated animal. Castration resulted in an increased number of cathepsin D‐positive cells in the stroma within 24 hr. By 48 hr after castration autophagolysosomes formed in secretory cells and apoptotic bodies appeared in the epithelium. Although apoptotic bodies generally contained immunoreactive cathepsin D, a subpopulation of larger apoptotic bodies, which commonly rested on the basement membrane and contained multiple inclusions, were more variable in cathepsin D expression. The induction of cathepsin D in dendritic cells basally oriented in the epithelium was noted at 4 days of castration. These cells had a phagocytic phenotype, were distributed periodically along the basement membrane, and were not found in ductal epithelia. Treatment with actinomycin D or hydrocortisone to reduce the rate of regression of the ventral prostate blocked the appearance of these cathepsin D‐positive, basally oriented epithelial cells. Our data indicate that this cathepsin D‐positive, phagocytic cell differentiates from a cell resident in the prostatic epithelium. We suggest that it differentiates from basal cells in the secretory tubuloalveolar portion of the gland and that it is involved in the destruction of regressed secretory cells.
The proximal border of the human respiratory unit, as shown by scanning and transmission electron microscopy and light microscopical cytochemistry
Authors: Have‐Opbroek Ank A. W. Ten , Otto‐Verberne Caroline J. M. , Dubbeldam Jacqueline A. , Dÿkman Joop H.
Published: February 2005

The epithelial cell types present in respiratory (= distal alveolarized) and terminal (= distal nonalveolarized) bronchioles in adult human lung were characterized with scanning and transmission electron microscopy (SEM, TEM) and light microscopic cytochemistry, using specific antibodies against surfactant protein SP‐A and mucins, and Alcian blue/periodic acid‐Schiff (AB/PAS) staining.

In the respiratory bronchiole, two epithelial cell populations share the same basal lamina: one pseudostratified columnar with ciliated, secretory, and basal cells and the other predominantly simple cuboid with some interspersed flat (type I) cells. The columnar secretory cells show the ultrastructure of mucous cells. Light microscopically, they react with mucin antibodies and contain primarily periodatereactive acid mucins. The mucous cells are the distal secretory cells described by Clara (1937). The cuboid cells are identified as type II (precursor) cells based on ultrastructural criteria for embryonic type II cells (Ten Have‐Opbroek et al., 1988a, 1990a), including a cuboid cell shape, a large and roundish nucleus, rough and smooth endoplasmic reticulum (ER), osmiophilic multivesicular bodies, and dense bodies. These dense bodies in turn frequently exhibit—like those in embryonic type II cells—internal vesicles or lamellae, variability in size and shape, a specific relationship to ER and a widespread cytoplasmic distribution. Finally, the cuboid cells show a cytoplasmic staining pattern for SP‐A. The terminal bronchiole is lined by the columnar cell population.

In the respiratory bronchiole, the columnar (bronchial) and cuboid (alveolar) cell populations occupy distinctly different zones (pulmonary artery zone versus remaining wall). The alveolar part of the respiratory bronchiole (called alveolar tubule) defines the proximal border of a true respiratory unit.
Spatial distribution of “Tissue‐Specific” antigens in the developing human heart and skeletal muscle. II. An immunohistochemical analysis of myosin heavy chain isoform expression patterns in the embryonic heart
Authors: Wessels A. , Vermeulen J. L. M. , Virágh S. Z. , Kálmán F. , Lamers W. H. , Moorman A. F. M.
Published: February 2005

The spatial distribution of α‐ and β‐myosin heavy chain isoforms (MHCs) was investigated immunohistochemically in the embryonic human heart between the 4th and the 8th week of development. The development of the overall MHC isoform expression pattern can be outlined as follows: (1) In all stages examined, β‐MHC is the predominant isoform in the ventricles and outflow tract (OFT), while α‐MHC is the main isoform in the atria. In addition, α‐MHC is also expressed in the ventricles at stage 14 and in the OFT from stage 14 to stage 19. This expression pattern is very reminiscent of that found in chicken and rat. (2) In the early embryonic stages the entire atrioventricular canal (AVC) wall expresses α‐MHC whereas only the lower part expresses β‐MHC. The separation of atria and ventricles by the fibrous annulus takes place at the ventricular margin of the AVC wall. Hence, the β‐MHC expressing part of the AVC wall, including the right atrioventricular ring bundle, is eventually incorporated in the atria. (3) In the late embryonic stages (approx. 8 weeks of development) areas of α‐MHC reappear in the ventricular myocardium, in particular in the subendocardial region at the top of the interventricular septum. These coexpressing cells are topographically related to the developing ventricular conduction system. (4) In the sinoatrial junction of all hearts examined α‐ and β‐MHC coexpressing cells are observed. In the older stages these cells are characteristically localized at the periphery of the SA node.
Deep‐etching immunogold replica electron microscopy of cytoskeletal elements in cultured hamster heart cells
Authors: Isobe Yuji , Hou Guan Ren , Lemanski Larry F.
Published: February 2005

A procedure has been developed for the three‐dimensional immunoelectron microscopic localization of cytoskeletal filaments by a deep‐etching replica method in combination with immunogold labeling and/or myosin subfragment 1 (S1) decoration techniques. Neonatal hamster heart cells grown on glass coverslips were extracted with Triton X‐100 or physically permeabilized by breaking open the cell membranes. S1 decoration was performed on some specimens immediately after the permeabilization. After prefixation in formaldehyde, samples were immunostained with poly‐ or monoclonal antibodies to desmin or vimentin, and indirectly tagged with colloidal gold probes by the biotin‐streptavidin method. After postfixation with glutaraldehyde, tannic acid and osmium tetroxide, the cells were freeze‐etched and rotary‐replicated with platinum and carbon in a freeze‐fracture apparatus. Replicas were viewed with a transmission electron microscope using a tilting specimen stage to obtain stereo images. The procedure made it possible to identify the specific filaments within the complex cytoskeletal networks in cultured hamster heart muscle and nonmuscle cells at high resolution and in three dimensions. The method has advantages in its three‐dimensionality and feasibility to evaluate the data by comparing them with those obtained by alternative light microscopic methods. Details of the protocol and a description of the results of using three different antibodies are given.
Cartilaginous bone extremities of growing monotremes appear unique
Authors: Thorp B. H. , Dixon J. M.
Published: February 2005

Cartilage canals are present in the epiphyseal cartilage of most mammals and birds. They are considered necessary for the maintenance of chon‐drocytes and for the formation of epiphyseal ossification centers. The epiphyseal cartilage of marsupials was recently shown not to contain cartilage canals, and placental rats appear not to have cartilage canals, although some confusion exists in the literature. The present study examines the cartilaginous epiphyses and physes from the knee and hip of the rat and the two Australian monotremes (platypus, Ornithorhynchus anatinus and echidna, Tachyglossus aculeatus). In all three species, cartilage canals were absent. Vessels to epiphyseal ossification centers were present, however. In the center of the cartilaginous femoral head of the echidna, but not in the platypus or rat, there was a large cavity, which contained connective tissue and was lined by an endochondrium of chondroproginator cells. These appeared to be contributing to growth of the cartilaginous epiphysis. No similar structure has previously been described in the cartilaginous epiphysis of other species. There was no ligament of the femoral head in the hip joints of the monotremes, and it is suggested the absence of a ligament may be significant in the development of the cavity. It was noted in all specimens that despite being avascular the epiphyseal and physeal cartilage appeared viable and functionally normal. The small size of the cartilaginous epiphyses of the rat may account for their avascularity; but the epiphyses of the monotremes were much larger, especially the echidna, yet still avascular. These features provide strong evidence for fundamental differences between the avascular cartilage of monotremes and the vascular cartilage of most mammals.
Pulmonary development in the fetal lamb: Morphometric study of the alveolar phase
Authors: Docimo Steven G. , Crone Robert K. , Davies Paul , Reid Lynne , Retik Alan B. , Mandell James
Published: February 2005

The alveolar stage of intra‐uterine lung development was analyzed morphometrically in 18 fetal lambs at 112, 124, 142, or 148 (term) days of gestation. The right lungs were fixed at uniform distending pressure and the tissue embedded in Epon for light microscopy. Over the whole period, right lung volume (VL) increased more rapidly than body weight to reach a mean value of 185 cm3 at term. The increase in VL was greatest between 112 and 124 days gestation. Throughout the period of study the distal lung consisted of alveolar‐like air‐spaces lined by walls with a single capillary system. Despite this mature morphology, further differentiation took place as established by two independent measurements. First, interalveolar wall thickness decreased from 4.12 ± .03 μm at 112 days to 2.55 ± .02 μm at term. Secondly, alveolar surface area increased at a greater rate than lung volume (as VL 1.06), suggesting a moderate increase in surface complexity, but not a subdivision of existing air‐spaces. This latter finding was supported by numerical density values which remained fairly constant. We conclude that throughout this period active growth involves the addition of alveolar units of basically similar size. This is a similar process to the one noted previously in postpneumonectomy compensatory growth.
On the question of a subdural space
Authors: Haines D. E.
Published: February 2005

The structure of the meninges, with particular attention to the architecture of the inner portions of the dura mater and the arachnoid mater, has been reviewed in reference to the probable existence of a “subdural” space. The dura is composed of fibroblasts and large amounts of extracellular collagen. The innermost part of the dura is formed by the dural border cell layer. This layer is characterized by flattened cells with sinuous processes, extracellular spaces containing an amorphous material, and the presence of junctions between its cells. The dural border cell layer is continuous with the inner (meningeal) portions of the dura and may be attached to the underlying arachnoid by an occasional cell junction. The arachnoid consists of an outer part, the arachnoid barrier cell layer, and an inner portion, the arachnoid trabeculae which bridge the subarachnoid space. Arachnoid barrier cells are electron‐lucent, closely apposed to each other, and joined by many cell junctions; in this layer there is little extracellular space and essentially no intercellular material. Arachnoid trabecular cells cross the sub‐arachnoid space in a random manner, have extracellular collagen associated with their flattened processes, and form structures of variable shapes and sizes. There is no evidence of an intervening space between the arachnoid barrier cell layer and the dural border cell layer that would correlate with what has been called the subdural space. When a tissue space is created in this general area of the meninges it is the result of tissue damage and represents, in most instances, a cleaving open of the dural border cell layer. In this situation, extracellular spaces in the dural border cell layer are enlarged, cell junctions are separated, and it is probable that cell membranes are damaged. A survey of reports describing the morphology of the inner and outer capsule of so‐called subdural hematomas in humans reveals that dural border cells are found in both parts of the capsule. Also, experimental infusion of blood into this portion of the meninges in animals frequently dissects open the dural border cell layer. These data support the view that what has been called a subdural hematoma is most frequently a lesion found within the layer formed by dural border cells.

It is suggested that the so‐called subdural space is not a “potential” space since the creation of a cleft in this area of the meninges is the result of tissue damage. In this respect it shares no similarities with legitimate potential spaces (i.e., serous cavities) found at other locations in the body. It is concluded that there is no evidence of a subdural space (actual or potential) in the region of the dura‐arachnoid junction and it is suggested that the term spatium subdurale be removed from Nomina Anatomica.
Multiple growth cartilages in the neural arch
Authors: Chandraraj Seba , Briggs Christopher A.
Published: February 2005

The origin of growth cartilages in the neural arch of human fetal vertebrae was investigated in an attempt to resolve the conflicting opinion on ossification in this region. Serial sections of developing vertebrae were examined, and three growth cartilages for each half of the neural arch were found. They have their origin from a single center of ossification. Endochondral bone formation similar to ossification in the diaphysis of a long bone occurs in the neural arch. This information may help in the understanding of how vertebral malformations such as scoliosis and spondylolysis occur during postnatal life.