bluuebunny/crossref_metadata_2025 huggingface dataset:
Circulation of cerebrospinal fluid in the bullfrog, Rana catesbiana
Authors: Tornheim Patricia A. , Foltz Floyd M.
Published: February 2005

In order to demonstrate features of the cerebrospinal fluid (CSF) path in the amphibian, 2‐6 m̈l of either Evans Blue‐albumin (EBA) or ferrocyanide were injected into the ventricular system of anesthetized bullfrogs. The animals were sacrificed 1 to 135 minutes after injection by either quick freezing (EBA injections) or fixative perfusion (ferrocyanide injections). The contents of the cranial and vertebral cavities were then examined grossly and histologically for distribution of the tracers. In all animals, the tracers were seen throughout the ventricular cavity and in the subarachnoid space surrounding the caudal hindbrain. The site of communication between these two fluid spaces was the posterior tela of the hindbrain. Within this tela, “pores” were found between groups of pavement‐like ependymal cells. In many animals, tracer was also observed in the vertebral subarachnoid and epidural spaces, adjacent to spinal nerve roots. In three EBA‐injected animals, this tracer was also seen in the subcardinal lymph spaces. These findings suggest that the subarachnoid space in the bullfrog communicates functionally with the ventricular system by way of specialized “pores” in the posterior tela of the hind‐brain. There is also indication of movement of fluid within the subarachnoid space which is predominately caudal in direction, with a primary absorptive path for CSF that consists of a perineural route to the lymphatic system.
Effect of thyroparathyroidectomy (TPX) on the zona reticularis: A quantitative ultrastructural study
Authors: Conran Richard M. , Nickerson Peter A.
Published: February 2005

Atrophy of zona reticularis cells was observed two weeks after surgical thyroparathyroidectomy (TPX). Quantitative morphological techniques for electron microscopy showed significant decreases in the volume of cytoplasm, nucleus, mitochondria, smooth endoplasmic reticulum and lipid droplets in the zona reticularis of TPX rats. In addition, many mitochondria contained lipid droplets, some of which occupied virtually the entire matrix of mitochondria. The volume per cell of mitochondria with these inclusions increased significantly after TPX. The lipid droplets may well arise from cytoplasmic droplets by increased transport or reduced metabolism of cholesterol, or by direct incorporation of droplets into the mitochondrial matrix. The serum corticosterone level of TPX rats sacrificed under quiescent conditions did not differ significantly from that of controls. Hypothyroidism induced a significant increase in the volume of peroxisomes per cell in TPX animals which may be related to changes in lipid metabolism or transport.
Role of the left interventricular sulcus in formation of the interventricular septum and crista supraventricularis in normal human cardiogenesis
Authors: Meredith M. Alexander , Hutchins Grover M. , Moore G. William
Published: February 2005

Serial sections of normal human embryos were studied and three‐dimensional images reconstructed to determine the early development of the interventricular septum. The position of the interventricular septum is determined in stage 9 of normal development by the formation of the left interventricular sulcus. As a result of unknown properties of the cells of the myocardial layer, the left interventricular sulcus persists while the right disappears, producing the initial lateral asymmetry of the primary heart tube. By stage 14, the left interventricular sulcus forms a spiral which is continuous with the developing interventricular septum. The dorsal limb of the spiral passes to the right between the atrioventricular canal and the origin of the outflow tract, and is lost in the wall of the trabeculated right ventricle. It appears that this dorsal limb of the spiral is the precursor of part of the cirsta supraventricularis. The midportion of the sulcus, the bulboventricular groove, becomes the socalled fibrous continuity between the aortic and mitral valves. The ventral limb of the spiral passes caudally in the anterior interventricular groove and then dorsally and cranially toward the dorsal cushion of the atrioventricular canal. The ventral limb of the spiral is continuous with the crest of the muscular interventricular septum, which develops by apposition of tissue from the expanding right and left ventricles. From stage 14 to stage 19, the muscular interventricular septum, the atrioventricular endocardial cushions, and the ventricular end of the spiral ridges of the outflow tract appose and fuse. Subsequent formation of the membranous interventricular septum completes the physical separation of the right and left ventricles.
Morphological study of the desert heteromyid kidney with emphasis on the genus perognathus
Authors: Altschuler Eric M. , Nagle Ray B. , Braun Eldon J. , Lindstedt Stan L. , Krutzsch Philip H.
Published: February 2005

The renal morphology of three species of desert dwelling Perognathus rodents were compared to Dipodomys and two species of sympatric cricetid rodents. Perognathus has a highly adapted unipolar kidney capable of urine concentration up to 7,500 mOsm/KgH2O. Two major modifications were observed in these kidneys. (1) There is elongation of both the inner and outer medulla. When the thickness of the regions in P. penicillatus are factored by kidney weight it is found that the outer medulla is 3.8 and the inner medulla is 2.2 times greater in length than the extensively studied Dipodomys merriami. (2) There is great variance in glomerular size with approximately 20% of the glomeruli being very large and located in the juxta medullary region. These glomeruli are 1.5‐1.6 times greater in diameter than the more numerous superficial glomeruli. These structural modifications are quantitated and the functional implications are discussed particularly in relation to urine concentrating ability in these desert inhabitants.
Ability of neural crest cells from the embryonic chick to differentiate into cartilage before their migration away from the neural tube
Authors: Hall Brian K. , Tremaine Robert
Published: February 2005

Whether neural crest cells from the avian embryo are determined for chondrogenesis before they begin their migration away from the neural tube (i.e., before H. H. stages 8.5‐9) was investigated by establishing neural folds from embryos of H. H. stages 5‐11 either in organ culture, or as grafts to the chorioallantoic membranes of host embryos. Cartilage differentiated from neural folds taken from embryos of H. H. stages 5‐7 but not from those taken from older embryos. This stage specific pattern was reversed when the tissue adjacent to the neural tube was grafted to the chorioallantoic membrane. Cartilage only formed from tissues isolated later than H. H. stage 8; i.e., when these adjacent tissues contain neural crest cells. We concluded that neural crest cells are determined for chondrogenesis while still in the neural tube and before their migration to the face and head. This is in contrast to the situation in the only other group which has been examined, the urodele amphibians.
Phenytoin (dilantin)‐induced cleft lip and palate in a/j mice: A scanning and transmission electron microscopic study
Authors: Sulik K. K. , Johnston M. C. , Ambrose L. J. H. , Dorgan D.
Published: February 2005

High incidences of cleft lip and palate (CLP) Produced by maternal intraperitoneal administration of 75 mg/kg pehnytoin on gestational day 10 to A/J mice are associated with asevere size reduction in the lateral nasal process. Scanning and transmission EM analyses of this region demonstrate a marked change in the morphology of the mesenchymal cells underlying the surface epithelium in treated versus control day 11 (7‐tail somite) embryos: long, branching cellular processes, which form a dense meshwork that appears to interact with the epithelial basement lamina in control embryos are undeveloped or absent in phenytoin‐treated embryos. The ultrastructural morphology of these cell processes is described and their possible importance in normal development is discussed. Scanning EM observations of incomplete clefts of the lip which frequently result from phenytoin treatment indicate that Simonart's bands form from fusionof the lateral and medial nasal processes in association with a lack of fusion of the maxillary process with the medial nasal process.
Surface area ratios II. A stereological method for estimating changes in average cell volume and frequency
Authors: Bolender Robert P.
Published: February 2005

The study describes a stereological method for detecting relative changes in cells‐with respect to their average volumes and to their frequencies within one cm3 of exocrine cells. The method is based on surface area ratios (Bolender, '1979) and can detect changes comparable to those obtained with the numerical density approaches (Loud, '68; Weibel et al., '69; Bolender, '74; Williams, '77). The new method requires only intersection counts‐ the same ones that are used for surface density estimates‐ and, as a result, avoids the difficult and often problematic procedures of the numerical densities. In analyzing the cellular changes in vitro, the choice of either a zero or timed control was found to exert a major influence on the results. Timed controls were required to “isolate” the experimentally induced changes from those Produced by the incubation medium.
The course, relations and distribution of the inferior alveolar nerve and its branches in the cat
Authors: Robinson P. P.
Published: February 2005

The course, relations and distribution of the inferior alveolar nerve and its branches in the cat are described. The nerves have been studied by dissection, histologically and by using electrophysiological techniques. Dissection revealed a basic pattern on which some individual variation was Superimposed. The inferior alveolar nerve has three branches Supplying thealveolar process (alveolar branches), one branch SUPPLying the canine and incisor region (caninelincisor branch) and four mental branches (posterior, mainand 2 anterior). Fibres Supplying the teeth were found in all except the mental branches. pulpal, periodontal and buccal gingival margin fibres from an individual tooth generally travelled together, but often in more than one branch. Branched axons Supplying both tooth pulp and an area of mental skin were found. The axons branched a t the point of separation of the appropriate mental nerve from the main trunk. A cutaneous midline overlap of 1–2 mm was found, but there was no transmedian innervation of tooth pulps.
Maturation of the proximal tubule in the puppy kidney:A comparison to the adult
Authors: Hay Don A. , Evan Andrew P.
Published: February 2005

Two‐ to four‐ day‐ old beagle puppy kidneys were prepared fortransmission and scanning electron microscopy and compared to similarly prepared adult tissues. proximal tubules of puppy kidneys which contained nephrons in various stages of differentiation were examined andmaturational changes were described. Lateral surface contours of proximal tubular cells were initially smooth and relatively unfolded, but progressively acquired complex processes that may be recognized as lateral ridges and lateral‐basal processes. Basal projections began as short, stubby processes and gradually took on either a narrow, plate‐like or finger‐like appearance. Mitochondria, lysosomes and apical vacuoles increased in number as the tubules matured. Mitochondria lacked orientation in outer cortical tubules, but exhibited some vertical arrangement within basal processes in inner cortical tubules. Despite features indicating advanced maturation of tubules in the inner cortex, puppy kidneys lacked the lipid droplets characteristic of the adult. Thus, differentiation of this portion of the developing nephron into S, S2 and S, segments was notpossible at day 4.Morphometric analyses of the lateral and basal membrane surface concentrationof proximal convoluted tubules from the puppy revealed all cells to have significantly smaller membrane area than that of the adult. However, the inner cortical cells of the puppy had a greater surface concentration than those of the outer cortex. The reduced transport capacity of the puppy proximal tubule may be related to the lack of segmentation and/or reduced lateral‐basal surface area.
Cytological events associated with in vitro aged and fertilized rabbit eggs
Authors: Meyer Norman L. , Longo Frank J.
Published: February 2005

The morphogenetic events associated with rabbit eggs aged in vitro for 12 to 50 hours prior to mixing with sperm have been examined by light and electron microscopy. After 12 hours in culture, morphological alterations of the meiotic spindle and the cortex of unfertilized eggs were evident. By 24 to 50 hours in culture, unfertilized eggs contained subnuclei, structures which formed when individual and/or groups of meiotic chromosomes dispersed and became invested by a double‐laminated structure reminiscent of a nuclear envelope.

Although most eggs obtained 11.5 to 12 hours after induced ovulation and in vitro fertilized displayed morphogenetic patterns similar to those described for in vivo fertilized ova, some (10%) contained three pronuclei. Many eggs obtained 13 to 15 hours after induced ovulation and subsequently mixed with sperm in vitro appeared to undergo processes of fertilization typical of in vivo fertilized eggs, however, approximately 30% contained subnuclei in association with the male pronucleus. Few eggs (15%) aged 12 hours prior to in vitro fertilization displayed patterns of pronuclear development and association typical of fertilized unaged ova. Subnuclei developed in many of the fertilized ova. Supernumerary sperm nuclei, which did not develop into male pronuclei, were observed in some zygotes. Cleavage of eggs aged 12 hours prior to fertilization was abnormal or retarded. After 24 hours in culture approximately 16% of the eggs fertilized. Seventy percent of the fertilized eggs failed to Support the development of a male or female pronucleus.
Effect of uncouplers of oxidative phosphorylation on microtubule location and surface structure in murine mast cells
Authors: Bergstrom‐Porter Beverly , Shelton Emma
Published: February 2005

“Uncouplers” of oxidative phosphorylation (sodium azide, DNP, and oligomycin) alter the location of microtubules within murine mast cells. Both cytoplasmic microtubuless, perpendicular to the plasma membrane within cell surface folds, and intranuclear microtubules wereobserved. In addition, one or more dense plaque‐like structures adjacent the plasma membrane in mast cells appeared following incubation in the antimetabolities. Intranuclear microtubules and cytoplasmic microtubules within the cell surface ridges disappeared in azide‐treated mast cells that were reincubated or “recovered” in PBS. However, both these structures remained in oligomycin‐ and DNP‐treated murine mast cells following reincubation.
Induction of exocytosis from glomus cells by incubation of the carotid body of the rat with calcium and ionophore A23187
Authors: GröUnblad Mats , EräUnköU Olavi , Erikärkerman Karl
Published: February 2005

Carotid bodies from adult rats were electron microscopically studied after incubation in glucose‐containing salt solutions containing calcium and/or ionophore A23187 or neither. In the absence of the ionophore, adding or omitting calcium had no effect on the fine structure of theglomus cells. Incubation in the medium containing both 1 mM calcium and the ionophore caused the appearance of exocytotic membrane profiles in several glomus cells. Exocytosis was not seen when only A23187 and endogenous calcium was present. For exocytosis to occur, calcium appeared to be essential and the event seemed to be due to a rise in the intracellular calcium concentration caused by the ionophore.
Milk lipid absorption and chylomicron production in the suckling rat
Authors: Berendsen Peter B. , Blanchette‐Mackie E. Joan
Published: February 2005

Structural correlates of milk lipid absorption and chylomicron production were studied in 10‐day‐old suckled rats. The gastric and duodenal contents and duodenal mucosae were examined with the light and electron microscopes. In the gastric lumen the milk lipid globule cores were smooth, circular and uniformly electron opaque. Many membranes and lamellar structures with a trilaminar and multilamellar appearance were adherent to the peripheries of the cores. In the central duodenal lumen the milk lipid globule cores were also smooth, circular and uniformly electron opaque. Very few milk lipid globules in the duodenal lumen showed adherent membranes or lamellae. Membrane fragments and lamellae were present in the lumen separate from the milk lipid globules. In the duodenal lumen between villi the milk lipid globules had multiple electron lucent indentations of the core. It is believed that the irregular peripheries of the milk lipid globule cores are the result of lipolysis within the duodenal lumen acting at the milk lipid globule surface. This lipolysis of triacylglycerol would produce amphiphilic lipids which may result in the electron lucent spaces at the milk lipid globule periphery. The absorptive epithelial cells along the length of the duodenal villus varied in structure relative to their position at the tip, middle, or base of the villus. Typical mid‐villus epithelial cells contained lipid droplets averaging 0.3‐μm diameter in the smooth and rough endoplasmic reticulum and in Golgi complexes in the apical cytoplasm. Villus tip and villus base cells contained large lipid droplets between 7–16 μm. Only a few 0.3‐μm lipid droplets were present within these cells. These large lipid droplets appeared to be accumulations of triacylglycerol present in the apical cytoplasm associated with lamellar and membranous structures. Numerous chylomicrons were present between epithelial cells located in the middle region of the villus while significantly fewer chylomicrons were seen between epithelial cells at the tip and base of the villus. These observations suggest that the cells at the middle of the duodenal villus of suckling rats were more efficient in the production of chylomicron triacylglycerol derived from incoming milk triacylglycerol than cells at the tip and base of the villus.
Ultrastructural changes in Leydig cells of streptozotocininduced diabetic rats
Authors: Orth Joanne M. , Murray Frederick T. , Bardin C. Wayne
Published: February 2005

Hyperglycemia (experimental diabetes) was induced in adult male rats by destruction of the pancreatic beta cells with a single intravenous injection of streptozotocin (STZ). Testes from diabetic, from insulin‐treated diabetic, and from sham‐injected normal rats were fixed by vascular perfusion. The fine structure of Leydig cells was examined at two, three, and four weeks after the STZ injection in the untreated diabetic animals, and at four weeks in the controls and insulin‐treated diabetic rats. A number of morphological changes was observed in Leydig cells of untreated diabetic animals. Most obvious of these was an accumulation of lipid droplets, not normally present in Leydig cells in adults of this species. Smooth endoplasmic reticulum (SER) was markedly reduced in Leydig cells of the hyperglycemic rats. Several types of intracellular bodies were seen exclusively in Leydig cells of the untreated diabetic animals. Many resembled secondary lysosomes or dense bodies, while others appeared to be autophagic vacuoles. In addition, a small, granule‐containing lamellar structure was seen either within a typical dense body or free in the cytoplasm. Myelin‐like structures were commonly observed within the cytoplasm of the Leydig cell or within mitochondria. The appearance of the mitochondria in diabetic rats was otherwise normal. The extracellular spaces surrounding Leydig cells from untreated hyperglycemic rats also contained large accumulations of myelin‐like material. These structural changes appear to be direct consequences of the diabetic state of the animals, since the ultrastructure of insulin‐treated diabetic rats did not differ from that of the controls. These findings may reflect an alteration or breakdown of Leydig cell components normally involved in the synthesis of androgen, and correlate with previous reports of lowered circulating levels of testosterone in diabetic rats.
Regeneration of acini in submandibular gland autografts
Authors: Sharawy Mohamed , O'Dell Norris L.
Published: February 2005

Regeneration of submandibular gland (SMG) secretory parenchyma is remarkably impaired in salivary gland diseases and under experimental conditions such as in tissue culture and after isografting. In our study acinar regeneration was found to depend on the site where the SMG tissue was implanted. Implantation of several 2–3 mm3 fragments of SMG subcutaneously in the back of the same donor adult male rat resulted in initial necrosis and mononuclear cell infiltration of the autograft. Then there was epithelial proliferation with the appearance within 28 days of lobules which contained numerous duct‐like structures and only a few or no acini. In contrast, implanting SMG fragments in the anatomical bed of the donor gland resulted in the appearance of a more differentiated autograft. Although the initial tissue changes were similar to those seen in the autografts in the subcutaneous tissues of the back, the SMG autograft in the neck also contained numerous acini by 42 and 56 days after implantation. These data support the view that the implantation site influences the course of cytodifferentiation in SMG autografts.
Distribution of taste buds on fungiform and circumvallate papillae of bovine tongue
Authors: Davies Richard O. , Kare Morley R. , Cagan Robert H.
Published: February 2005

The distribution of taste buds on the fungiform and circumvallate papillae of the cow tongue has been determined. The two tongues studied were from Holstein‐Friesian cows four to six years of age; they contained 14,765 and 21,691 taste buds, respectively. The tip of the tongue is well supplied with fungiform papillae, and the posterior portion contains the circumval‐late papillae. The midportion of the tongue contains relatively few taste papillae.

The fungiform papillae contained 1,580 and 1,838 taste buds on the two tongues, respectively, and the circumvallate papillae were estimated to contain 13,185 and 19,853 taste buds. The highest concentration of taste buds therefore occurs in the circumvallate papillae; these relatively few papillae contain approximately 90% of the taste buds. On a circumvallate papilla, taste buds are found only on the papillary sidewall, with none either on the apical surface of the papilla or on the outer wall of the moat.
Fiber size distribution in the flexor carpi radialis muscle of the cat
Authors: Gonyea William J.
Published: February 2005

The pennate flexor carpi radialis muscle of the cat has been shown to have a compartmentalized distribution of muscle fiber types. The possibility exists that the oxidative regions of the FCR are primarily concerned with fine movements including postural adjustments, while fast‐twitch glycolytic region is used more for phasic movements. Muscle fiber diameters were measured for all three fiber types to determine if there was a compartmentalization of fiber size that might reflect differences in motor performance between the different regions of the same muscle. This study has demonstrated that the oxidative fiber types are significantly larger in the oxidative compartment when compared with the same fiber types in the glycolytic compartment and that the cross‐sectional area of the oxidative region is dominated by oxidative fibers. The glycolytic fibers are significantly larger in the glycolytic compartment when compared to those in the oxidative region of the muscle and they constitute the major fiber type in this region.
A study of the effect of pregnancy on muscle fibers of the rectus abdominis muscle of the rat
Authors: Martin William D.
Published: February 2005

Samples of the rectus abdominis muscle were taken from Sprague‐Dawley rats at 0, 3, 6, 9, 12, 15, 18, and 21 days of pregnancy, and at 1, 3, 6, 9, 12, and 15 days of postpartum. Sections were incubated for actomyosin adenosine triphosphatase activity following preincubation at a basic pH. Muscle fibers within a unit area of each sample were identified as to fiber type according to their enzyme activity, and the population of each type counted. The proportion of each fiber type was calculated and the diameter of 24 fibers of each type measured. No changes were noted in the muscle fiber proportions through the course of the experiment. Differential changes in muscle fiber diameters were noted in each of the three muscle fiber types. Slow oxidative fibers underwent an increase in diameter through the last half of pregnancy. The diameter was further increased as stretch of the muscle was released after birth, and did not decrease in the postpartum period. Fast glycolytic fibers decreased in diameter during the last half of pregnancy, but returned to the prepregnancy diameter in the first postpartum day. The diameter of the fast oxidative glycolytic fibers remained unchanged through the course of pregnancy and in the postpartum period.
Anatomic Models of the tracheobronchial and pulmonary regions of the rat
Authors: Yeh H. C. , Schum G. M. , Duggan M. T.
Published: February 2005

Models of the lung airways of a rat were developed from complete measurements of the tracheobronchial airways. A silicone rubber cast of the tracheobronchial airways of a rat lung was prepared and all individual airway segments down to and including the terminal bronchioles were measured to obtain the segment diameters, lengths, branching angles and angles of inclination to gravity. Models of the rat tracheobronchial airways were constructed based on the original measurements and the subsequent analysis. Some mathematical assumptions about acinar anatomy distal to terminal bronchioles were made to extend the models to include pulmonary regions. Emphasis was placed on the “Typical Path Lung Model” which used one typical pathway to represent either a whole lung or a lobe of the lung. The models are simple and can be applied in calculation of physiologic variables or particle deposition during inhalation in various lobes of the lung.
Electron microscopic observations on the yolk sac of the Indian fruit bat, Rousettus leschenaulti (Desmarest) (Pteropidae)
Authors: Karim K. B. , Wimsatt W. A. , Enders A. C. , Gopalakrishna A.
Published: February 2005

The yolk sac of the Indian fruit bat Rousettus leschenaulti is unique since during the course of development it become converted into a solid, richly vascular endocrine gland‐like structure with both the endodermal and mesothelial cells undergoing substantial hypertrophy. The yolk sac is progressively drawn from the abembryonic (antimesometrial side) to the embryonic pole (mesometrial side) of the chorionic sac where in late stages it comes to rest against the placental disc. The endodermal cells become grouped into clusters of acinus‐like structures surrounded by the columnar mesothelial cells; the yolk‐sac lumen is in most instances obliterated. Individual endodermal cells are large in comparison to mesothelial cells. The endodermal cell population varies between cells with abundant agranular ER and areas devoid of organelles to others with dense cytoplasm containing stacks of granular ER. All endodermal cells have numerous mitochondria and a few lipid droplets.

The mesothelial cells are columnar with either dome‐shaped, pointed or flattened apices bearing numerous elongate microvilli; within these are parallel‐arranged microfilaments. While the apical cytoplasm shows the presence of absorptive tubules. coated vesicles and caveolae, the basal cytoplasm contains a few small mitochondria. Some mesothelial cells contain lipid droplets in their basal cytoplasm. On structural bases it is postulated that the mesothelial cells are absorptive in function while the endodermal cells are synthetic and secretory.
A Morphometric analysis of the glomerular capillary wall of a new strain of genetically hypertensive mice
Authors: Rosenberg Warren , Schlager Gunther , Gennaro Joseph F.
Published: February 2005

An investigation was performed on a new strain of genetically hypertensive mice to study those aspects of the renal glomerulus which have in the past been implicated in the etiology of renal parenchymal hypertension. Morphometric analyses were carried out utilizing a computerized graphic data analysing system on information obtained through transmission electron microscopy. Chronically hypertensive animals exhibited thinner basement membranes with numerous sub‐epithelial focal thickenings, which were largely absent from the normotensive controls. No difference was noted in the width of the epithelial slit pores (interpedicelar spaces). The glomerular capillary loops of the hypertensive animals appeared otherwise unremarkable, as did the urinary space and parietal epithelium of Bowman's capsule. No evidence of renal parenchymal pathologies implicated in the etiology of systemic hypertension was observed, therefore, these animals would seem to be suitable models for human essential hypertension.
Variations in the aortic origin of intercostal arteries in man
Authors: Khan Sabiha , Haust M. Daria
Published: February 2005

The variation in the origin of the (posterior) intercostal arteries was examined in 79 aortae of children who ranged in age from 1 day to 15 years and died of various causes. The distribution, size and number of the origins of the (usually present: 9) pairs of these arteries varied widely. The most commonly observed patterns were as follows: variation in distance between arteries of a given pair; variation in spacing between adjacent pairs; presence of a supernumerary single artery or of a pair; absence of one or both arteries of a given pair; unequal size of the orifices of a pair; complete division of a single artery into two branches beyond its origin; and an incomplete division of a single artery by a partial septum.

Of interest appears to be the absence of one (in 59 instances) or both (in 17 instances) arteries of the same pair; the tenth intercostals were most commonly so affected. It would require a prospectively designed study to ascertain whether the absence of any of the intercostal arteries may have a clinical effect in man. Since these arteries supply directly or indirectly not only the intercostal and pectoral muscles, serratus anterior and the muscles of the back, but also the spinal cord, and in addition, provide cutaneous and a few mammary branches, functional correlations in the absence of given arteries may prove to havepractical implications.
Morphologic features of the caudal neurosecretory system in the blueback herring, Pomolobus aestivalis
Authors: Kriebel Richard M. , Burke Jack D. , Meetz Gerald D.
Published: February 2005

The caudal neurosecretory system of the blueback herring, Pomolobus aestivalis, captured in freshwater, was examined. Neurosecretory cells were identified readily in terminal spinal cord segments. The axonal processes of these neurosecretory cells formed a discrete, ventrally placed bundle which terminated in a conspicuous ventral enlargement from the filum terminale. This enlargement comprises the neurohaemal contact zone or urophysis. The neurosecretory terminals were engorged with secretory granules in these fishes from a freshwater environment.

The non‐neuronal component of the urophysis also was examined in this study. These glial cells were dispersed throughout the urophysis. Most often they were found ensheathing the terminal neurosecretory processes. These cells showed a resemblance to neurohypophysial pituicytes. Although mentioned in the literature, these glial cells have not been examined with the electron microscope. The ultrastructural features of the glial cells and their relation to the neurosecretory constituents are described in this report.
Genesis, ultrastructure and cytochemical study of the cat eosinophil
Authors: Presentey B. , Jerushalmy Z. , Ben‐Bassat M. , Perk K.
Published: February 2005

Eosinophils from cat bone marrow and peripheral blood were studied by electron microscopy and cytochemical procedures. The maturation of eosinophils and formation of typical granules were described. Contrary to the accepted opinion that the core of animal's eosinophilic specific granules have a crystal‐like structure, our observations revealed that the core has a myelin‐like cylindrical appearance, whose layered formation proceeds from the inside outwards.

Electron microscopic observations revealed that localization of reaction product to potassium pyroantimonate and phosphotungstic acid and to acid phosphatase activity was similar to that of eosinophils of man and other animals. Antimonate deposits and acid phosphatase activity were detected between the layers of the myelin‐like structure of the core. Eosinophil granules failed to yield a positive reaction for peroxidase activity. The secretory activity of the eosinophil is discussed.
A freeze‐fracture study of intercellular junctions between various kinds of epithelial cells surrounding common endolymphatic space in the hearing organ of the chick
Authors: Hirokawa Nobutaka
Published: February 2005

Intercellular junctions between various epithelial cells in the hearing organ (basilar papilla) of the chick were studied with the freeze‐fracture technique. The effects of hypertonic solutions on the intercellular junctions were also examined.

The basilar papilla of the chick is primarily composed of hair cells and supporting cells in the neuroepithelium, specialized columnar cells (TMC) which attach to the tectorial membrane, and light cells (LC) and dark cells (DC) in the tegmentum vasculosum. All of these epithelial cells surround a common endolymphatic space. The tight junctions between hair and supporting cells, and those between adjacent supporting cells in the neuroepithelium are 0.1–0.3 μm in depth and display the usual network of branching and anastomosing strands of shared intramembrane proteins. The tight junctions in the tegmentum vasculosum have the same structure as in the neuroepithelium. In contrast, the tight junctions between the TMCs are extremely well developed: They are 1–2 μm in depth. In freeze‐fracture replicas, they appear as a fingerprint pattern of unbranched parallel particulate strands, running both parallel and perpendicular to the cell surface. After exposure to hypertonic solutions, all the epithelial cells are shrunken and intercellular spaces are expanded; all tight junctions, however, are intact.

Thus, tight junctions in the basilar papillae are resistant to dissociation by hypertonic solutions. The usual zonulae occuludentes in the neuropithelium and tegmentum vasculosum are thought to prevent diffusion of endolymph through the intercellular spaces of epithelial cells. However, the tight junctions on the TMCs may function not only as a diffusion barrier, but also provide structural support to the cells anchoring the tectorial membrane which receives mechanical forces induced by the vibration of the basilar membrane.

Extensive gap junctions are found between all the supporting cells (supporting cells in the neuroepithelium, TMCs, and LCs in the tegmentum vasculosum) surrounding the endolymphatic space.
Effects of age and dietary restriction on the kidney glomeruli of mice: Observations by scanning electron microscopy
Authors: Johnson J. E. , Barrows C. H.
Published: February 2005

A study was undertaken to examine, by scanning electron microscopy (SEM), the kidney glomeruli of control mice 1 mo, 10 mo, and 24 mo of age, as well as dietarily restricted mice 10 mo and 24 mo of age. One month old female C57BL/6J mice were offered one of the following: (1) a control diet containing 24% protein fed ad lib; (2) the control diet fed on alternate days (intermittently fed); or (3) a diet containing 4% protein fed ad lib. Animals were sacrificed, by aldehyde perfusion at 1 mo, 10 mo, and 24 mo of age. The kidneys were sliced and prepared for SEM.

There was a significant age‐related increase in glomerular diameter and amount of microvilli on the podocyte surface (microvillus index). Although the diameters of the podocytes increased approximately 20% with age, these differences were not statistically significant. Feeding a 4% protein diet resulted in smaller diameters of glomeruli and podocytes as well as smaller microvilli indices as compared to those of control animals. Although similar differences were observed in the kidneys of intermittently fed animals, only the microvillus index was statistically significant. Therefore, dietary manipulations, which have been shown to increase life span, result in marked morphological differences when compared to control animals.
Modification of mitochondria‐rich cells in different ionic conditions: Changes in cell morphology and cell number in the skin of xenopus laevis
Authors: Ilic Vesna , Brown Dennis
Published: February 2005

Xenopus laevis were kept in salt water (1.25% NaCl), distilled water, or tapwater for a month. Compared to the animals kept in tap water, the number of mitochondria‐rich (MR) cells in the NaCl‐adapted animals was significantly reduced, while it was increased in those maintained in distilled water. In addition, the MR‐cells of NaCl‐adapted animals lost their slender flask shape and developed large deposits of glycogen. The alteration of this cell type in conditions of high or low salinity may reflect a role of MR‐cells in adaptation to different ionic environments.
Distribution and morphometric quantitation of pancreatic endocrine cell types in the frog, rana pipiens
Authors: Kaung Hue‐Lee Cheng , Elde Robert P.
Published: February 2005

Cells reactive to anti‐anglerfish insulin, anti‐porcine glucagon, anti‐synthetic somatostatin, and anti‐bovine pancreatic polypeptide were identified in adult Rana pipiens male pancreases using peroxidase anti‐peroxidase immunohistochemistry. Insulin positive cells are columnar shaped and arranged in cords. Glucagon positive and somatostatin positive cells are located around the core of insulin positive cells. Isolated cells and clusters of cells of only one cell type are also found. Adjacent sections stained with anti‐glucagon and anti‐bovine pancreatic polypeptide showed that glucagon positivity and pancreatic polypeptide positivity are found in the same cells. Comparison of double stained adjacent sections confirmed the presence of these two antigens in the same cells, and further showed the occasional presence of cells which are positive to only glucagon or pancreatic polypeptide. Staining of rat pancreas with these two antisera showed that glucagon and pancreatic polypeptide are present in two distinct cell populations.

Morphometric quantitation of immunohistochemically stained sections of Rana pipiens pancreases showed that about 2% of the pancreas is endocrine tissue. Of this, 43% is compared of insulin positive cells, and 43% is occupied by glucagon‐pancreatic polypeptide positive cells. Somatostatin positive cells occupy about 14% of the total islet volume.

The presence of glucagon and pancreatic polypeptide in the same cell population in the frog, but in different cell populations in mammals, may reflect special functional adaptation in this species, or a close relation of these two hormones and their cells of production during evolution.
Ultrastructural effects of riboflavin deficiency on rat hepatic mitochondria
Authors: Tandler Bernard , Hoppel Charles L.
Published: February 2005

The hepatic mitochondria of rats fed a riboflavin‐deficient diet were examined by electron microscopy. Discoidal mitochondria with elongated cristae increased in frequency from day 4 to day 12 of the test diet. At day 22, sheaves of closely packed cristae were present in many otherwise typical mitochondria. At day 53, numerous cupshaped mitochondria appeared; these often nested one inside the other. From this day onward, the mitochondria showed a tendency towards increasing size. By day 82, some had a diameter greater than 8 μm. These and other, smaller mitochondria often contained extremely prominent matrix granules. The production by riboflavin‐deficiency of giant mitochondria in the rat liver appears to be unrelated to their capacity to carry out oxidative metabolism.
Dynamic histomorphometry of alveolar bone remodeling in the adult rat
Authors: Vignery Agnes , Baron Roland
Published: February 2005

Alveolar bone normally undergoes remodeling on one side of the socket and modeling on the opposite side as the tooth migrates at a rate of 6.7 μm per day. Periodontal ligament width, however, remains constant. Because of this very high turnover rate, this bone is a good model to study bone modeling and remodeling activities. This study was undertaken in order to measure the different cellular events occurring during tooth migration along the alveolar bone of the rat. The histomorphometric measurements performed on this model permitted us to calculate the duration of each phase of the remodeling cycle, i.e., resorption lasts about 1.5 days and reversal about 3.5 days. Since the duration of the forming phase is about 1 day (Guyomard and Baron, ′74), the total duration of each remodeling cycle is about 6 days. This time is very short compared to 60–120 days in adult human trabecular bone. Additionally, in this model each osteoclast resorbs 2–4 times its own volume of bone per day. Based on this knowledge, it will be possible to measure accurately the effects of experimental conditions on bone cells and bone remodeling in this rat alveolar bone model.
Deformities in the head region of late spermatids of hypophysectomized‐hormone‐treated rats
Authors: Russell Lonnie D.
Published: February 2005

Testosterone capsules implanted in hypophysectomized rats prevented tubulobulbar complexes from forming in many late spermatids. These spermatids also displayed an accumulation of cytoplasm (swelling) in the perinuclear region of the head. Other spermatids with normal or near‐normal numbers of tubulobulbar complexes showed a typical perinuclear space. The results indicate, but do not prove, that development of tubulobulbar complexes (and their subsequent phagocytosis) is essential for the normal elimination of cytoplasm that takes place prior to sperm release.
Three‐dimensional electron microscopy of mitochondria and endoplasmic reticulum in the red muscle fiber of the rat diaphragm
Authors: Rambourg A. , Segretain D.
Published: February 2005

The three‐dimensional arrangement of mitochondria and endoplasmic reticulum in the red muscle fiber was studied both in thick sections of the rat diaphragm fixed in glutaraldehyde and impregnated with uranyl acetate followed by lead and copper citrate, and in thin sections of glutaraldehyde fixed tissue treated with ferrocyanide‐reduced osmium. The mitochondria were located either at the periphery of the fiber, where they were spherical, or between the myofibrils, where they formed longitudinal columns of rectangular, slightly flattened elements. From both types of mitochondria, thin, elongated branches arose at right angles that formed transversely oriented mitochondrial pairs at the I band level. At the periphery of the fiber, the endoplasmic reticulum took the appearance of a subsarcolemmal network of tubular cisternae oriented parallel to the cell surface. In the juxtanuclear region, it was made up of spherical masses composed of tightly knitted tubules that were interconnected by more loosely anastomosed tubules. In between the myofibrils, it was composed of longitudinally oriented repetitive units whose structure varied according to their position in front of the A or I bands of the myofibrils. In front of the A band, the endoplasmic reticulum appeared as a single sheet of anastomotic tubules compressed between the adjacent myofibrils, whereas at the I band level, its tubular elements passed in front and behind the transverse expansions of the mitochondria to form an intricate multilayered network in front of the Z line.
The stereoscanning electron microscopy and ultrastructural histochemistry of the avian and reptilian surfactant systems: Indian dove, desert spiny and taiwan golden skink lizards
Authors: Wetzstein H. Y. , Stratton C. J. , Olson N.
Published: February 2005

Lung tissues from the Indian dove, Scardafella inca, desert spiny lizard, Sceloporus magister, and the Taiwan golden skink lizard, Mabuya aurates, were studied by transmission electron microscopy utilizing ruthenium red as a carbohydrate stain and with the so‐called lipid‐carbohydrate retention procedures to elucidate the morphology of the surfactant systems. Stereoscopic scanning electron microscopic procedures were utilized for a comparative anatomical study of these three species, and the results were compared with the rat and frog in the companion article. The avian lung tissues demonstrated several peculiarities. The ciliated epithelial cells of the bronchus had cytoplasmic ciliated projections between the boundaries of mucus secreting cells. The discrete morphology of the main bronchus, secondary bronchi, parabronchi, and the air capillaries, and their three‐dimensional morphologic perspective were elucidated. The skink illustrated an arrangement of primary, secondary, and tertiary septa, with elaborate tertiary septal pits, similar to the amphibian. All septa contained a solid connective tissue core. The desert lizard was similar to the skink except the tertiary septal pits were rudimentary. All three species had a modified great alveolar pneumocyte and a laminated surfactant which included a carbohydrate matrix material between layered phospholipid‐based membranes. The ruthenium red additionally stained the homogeneous surface‐lining material. A comparative analysis of the surfactant systems of these three species with each other, and with the rodent and amphibian in the companion article, were discussed in terms of phylogenetic origin.
Intraepithelial asymmetric‐unit‐membrane plaques in mammalian urinary bladder
Authors: Alroy Joseph , Weinstein Ronald S.
Published: February 2005

Asymmetric‐unit‐membrane (AUM) plaques are major components of the luminal surface of superficial cells in mammalian urinary bladder. We have now demonstrated ultrastructurally identical AUM plaques in intraepithelial locations, at the lateral and basal surfaces of superficial cells and at the apical surfaces of intermediate epithelial cells in the urinary bladder. Typically, luminal apposing AUM plaques are present in clusters. Similar plaque clusters are present on apposing surfaces of cell pairs within the epithelium. These intraepithelial plaque clusters are in register, although often separated by a wide interspace. In areas where they come into closer apposition, they form membrane complexes resembling but distinctly different from certain types of cell‐to‐cell junctions. Both luminal and intraepithelial AUM plaques serve as membrane attachment sites for cytoplasmic microfilaments. Their intraepithelial location and association with microfilaments support the hypothesis that AUM plaques serve a mechanical function and modulate cell surface area during the urinary bladder distention‐contraction cycle.