bluuebunny/crossref_metadata_2025 huggingface dataset:
Terminal Nerve Complex
Authors: Demski L.S.
Published: July 2008

Cranial nerve 0 or the terminal nerve (nervus terminahs: TN) refers to a nerve or in some cases possibly a complex of nerves that most likely derive from the olfactory placodes and relate the most anterior forebrain derivatives to nasal and olfactory structures. Such a nerve(s) has been observed in at least some stages of development in all major groups of vertebrates save myxinoids or haghsh. The phylogenetic variation of TN components is presented in some detail. The functions of TN components are not yet well identified, but some indications are that it is sensory but not chemosensory, controls blood vessels and glands in the nose and has peptide-containing fibers that may control reproductive development and behavior as well as other neural functions. This paper has three parts: (1) a historical review, which provides a conceptual framework necessary for understanding current problems in the anatomy and physiology of the TN; (2) a section on recent studies in areas selected for their potential impact on understanding the TN, and (3) a brief summary, which provides some tentative answers to the questions ‘what is the TN and what does it do?’ and suggests directions for continued research on the TN.
What’s so Special about Special Visceral?
Authors: Finger T.E.
Published: July 2008

The brainstem is classically divided into functional columns including special and general subdivisions for somatic and visceral components. The term ‘special visceral motor’ is applied to branchiomotor nuclei, while ‘special visceral sensory’ refers to nuclei devoted to incoming gustatory and olfactory senses. The use of the term ‘special visceral motor’ is questioned in that the branchiomotor neurons function more like general somatic than general visceral motoneurons. The designation of taste and smell as ‘special visceral sensory’ systems seems inconsistent on several bases. First, taste and smell are not homologous systems: (1) the receptors are grossly dissimilar in morphology and relationship to other elements of the nervous system; (2) the two systems mediate very different behaviors and respond to different types of chemical stimuli, and (3) chemosensory systems are not ‘special’ (i.e. limited to cranial nerves) in that solitary chemoreceptor cells, which are distributed across the body surface, can be innervated by spinal or cranial nerves. Finally, taste is considered ‘special’ because it involves specialized chemosensory end organs; the visceral nerves also provide innervation to other specialized chemoreceptors (e.g. carotid body) which are considered part of the general visceral sensory system. Thus the term ‘special visceral sensory’ appears without solid foundation when applied to gustatory systems in contradistinction to nongustatory branchial and thoracic interoceptive systems. A reformulation of the functional columns of the brainstem is suggested in which six columns can be identified: (1) somatic motor; (2) branchial motor; (3) visceral motor; (4) visceral sensory; (5) somatic sensory, and (6) hair cell (dorsolateral placode) sensory.
Organization of the Vagus in Elasmobranchs: Its Bearing on a Primitive Gnathostome Condition
Authors: Sperry D.G. , Boord R.L.
Published: July 2008

The vagus nerve of the clearnose skate, Raja eglanteria, on the basis of its central and peripheral patterns and in light of the embryonic origin of its innervation fields, is viewed as a collector of separate elements. The peripheral elements include a series of branchial nerves to a segmented pharynx, an intestinal nerve to an unsegmented gut, a nerve or nerves to the heart, and an accessory nerve to a cucullaris muscle. The central elements include a sensory column, a dorsal motor column, and a ventral motor column. The dorsal motor column and sensory column are segmented in register with the branchial and intestinal nerves. Motoneurons that supply the branchial muscles of somitic origin are only located in the rostral segmented portion of the dorsal motor column. Preganglionic parasympathetics to the enteric plexus, presumably derived from circumpharyngeal crest, form the caudal portion of the dorsal motor column and are probably also present in the rostral segmented portion. Cardiac preganglionic parasympathetics to a visceral field of cardiac crest origin occur in the rostral portion of the ventral motor column as well as in the dorsal motor column. Accessory motoneurons that supply the cucullaris, likely a part of the general body musculature, are unrelated to other vagal motoneurons and form a separate nucleus (caudal ventral motor nucleus) located at spinal levels. The central and peripheral vagal nerve patterns of elasmobranchs suggest a highly conserved, ancestral gnathostome condition.
Evolutionary Diversification of Cranial and Spinal Nerves and Their Targets in the Gymnophione Amphibians
Authors: Wake M.H.
Published: July 2008

The ancestral gymnophione (caecilian) became elongate and limbless early in its history. Further structural reduction, including loss of components, followed by redirection and occasionally cooption of remaining structures, particularly muscles and nerves, has evolved. Function may remain that of the ancestral condition, or may change dramatically. Examples include the evolution of the tentacle, the jaw-closing apparatus, and the hypobranchial musculature, including their innervation. ‘Regressive’ evolution has provided opportunity for new structural-functional relationships and for increased variation.
Morphometric Study of Ovarian Follicular Growth during the Estrous Cycle of the Laboratory-Maintained Indian Desert Gerbil, Meriones hurrianae (Jerdon)
Authors: Saidapur S.K. , Kamath S.R.
Published: July 2008

The pattern of changes in the population of healthy and regressing follicles in relation to the estrous cycle, was studied in the recently domesticated desert gerbil, Meriones hurrianae, which exhibits a longer cycle (proestrus: 1.5 days; estrus: 1 day; metestrus: 1.5 days; diestrus: 3 days). As the granulosa cell layers were not distinct, the follicles were classified on the basis of their morphology and size (group I: small preantral follicles; group II: large preantral follicles; group III: small antral follicles; group IV: medium-sized antral follicles; group V: large-sized follicles; group VI: Graafian follicles). Regressing follicles were classified likewise. Five animals were used for each stage of the cycle. One ovary from each gerbil was serially cut and stained with hematoxylin-eosin. Healthy and regressing follicles were found throughout the cycle. The follicular development occurred typically in a biphasic manner. In phase A, in which follicles reach the antral stage, the growth of oocytes and follicles is linearly correlated, whereas, in phase B, oocyte size remains stationary while follicle size increases due to accumulation of antral fluid. However, oocyte growth and nucleus growth are positively and linearly correlated (r = 0.74). The healthy follicles under 260 μm (groups I, II) do not fluctuate in the ovary of cyclic gerbils, whereas follicles in group III (261–350 μm) increase significantly (p < 0.05) at estrus and those of group IV in diestrus. Further, healthy group III follicles are reduced in diestrus while regressing follicles in group III increase. These findings thus suggest that the antral follicles are rescued from atresia at estrus. Further selection of follicles for growth and ovulation, or their exit through atresia occurs in diestrus. The gerbil produces 3 ova per ovary during each cycle, and the growth of selected follicles is completed in two cycles (14–15 days). Atresia in preantral follicles is characterized by the degeneration of oocytes followed by the granulosa cells, whereas initiation of atresia among antral follicles is due to pyknosis of the granulosa followed by the degeneration of oocytes. Occasionally, pseudomaturation divisions occur in regressing follicles prior to oocyte fragmentation. In addition to the commonly occurring types of atresia in the gerbil, occasionally intraovarian release of oocytes from the regressing follicles is encountered.
Spacing of Central-Peripheral Transitional Nodes of Rat Motoneurones
Authors: Bristol D.C. , Cremin P.M. , Fraher J.P.
Published: July 2008

Node of Ranvier distribution is examined in the two basic types of CNS-PNS transitional zone (TZ) related to rat spinal nerves. Type 1 TZ is short and lies at the cord surface. Type 2 is long and lies in the proximal part of the rootlet. Nearest neighbour distance measures the length between adjacent node centres and is a better estimate of node spacing than simple density measurements. Many nearest neighbour distances measure less than 10 µm. The nearest neighbour distance means (ca. 13.5 µm) and distributions are similar in both TZ types, suggesting that developmental influences on node separation are also similar in both locations. Fibres traversing the TZ are separated by large amounts of astrocytic tissue. This may prevent functional interaction between their closely packed nodes.
Intracellular Gonadotropin-Releasing Hormone Immunoreactivity in Gonadotrophs of Intact or Castrated Male Rats: Semiquantitative Estimation of Testosterone and GnRH Antagonist Treatment
Authors: Morel G. , Aubert M.L. , Dubois P.M.
Published: July 2008

Changes in intracellular gonadotropin-releasing hormone (GnRH) immunoreactivity (GnRH-IR) in pituitary gonadotrophs were assessed by the use of a semi-quantitative immunocytochemical method in male rats undergoing various manipulations known to greatly modify gonadotropin secretion. In basal conditions, immunoreactive GnRH was localized in the cytoplasmic matrix, the secretory granules and the nucleus of these cells. Following intravenous stimulation with GnRH (100 ng i.v.), the GnRH-IR increased rapidly in all these three sub-cellular compartments, peaking at 15 min. In untreated, long-term castrated rats, GnRH-IR increased both in the basal state and after administration of GnRH. Injection of the castrated rats with testosterone propionate reduced the observed GnRH-IR to the level observed in intact rats. Acute or chronic treatment of castrated rats with a potent GnRH antagonist rendered GnRH-IR completely undetectable in all the three previously positive subcellular compartments of gonadotrophs, and GnRH-IR did not reappear after stimulation with GnRH. In sum, the fact that modifications of GnRH immunoreactivity are observed in rat gonadotrophs: (1) confirms the GnRH internalization process; (2) suggests different sites of action for GnRH within the cell, and (3) demonstrates rapid clearance of intracellular GnRH after stimulation.
Length and Caudal Level of Termination of the Spinal Cord in Thai Adults
Authors: Boonpirak N. , Apinhasmit W.
Published: July 2008

An analysis of the lengths of spinal cords was conducted using data from 129 adult Thais, 73 males and 56 females, who ranged in age from 20 to 95 years with an average age of 66.6 ± 16.6 years. The lengths of spinal cords ranged from 30 to 49 cm with a mean of 40.8 ± 3.2 cm. The average cord length in males (42.3 ± 2.5 cm) was significantly greater than that in females (38.9 ± 3.1 cm; p < 0.05). The site of caudal termination of the spinal cord varied from the middle third of the twelfth thoracic vertebra to the upper third of the third lumbar vertebra. The mean level of cord termination was located opposite the intervertebral disc between the first and the second lumbar vertebrae, and there was no significant difference between the sexes (p > 0.05). The length of the vertebral column was also measured in 16 cases. It ranged from 64.5 to 70.5 cm with an average of 68.4+3.5 cm. There was a significant correlation between the length of the spinal cord and the length of the vertebral column (p < 0.01).
Immunohistochemical Study of the Distributions of the Peptide- and Catecholamine-Containing Nerves in the Omasum of the Sheep
Authors: Yamamoto Y. , Kitamura N. , Yamada J. , Yamashita T.
Published: July 2008

The distribution in the sheep omasum of peptide- and catecholamine-containing neurons was investigated by an immunohistochemical technique using antibodies against six neuropeptides and two catecholamine-synthesizing enzymes. In the myenteric plexus, both nerve cell bodies and nerve fibers were positively immunostained for substance P (SP), methionine enkephalin (ENK), vasoactive intestinal polypeptide (VIP), neuropeptide Y (NPY) and galanin (GAL). In contrast, immunoreactivity specific for calcitonin gene-related peptide (CGRP), tyrosine hydroxylase (TH) and dopamine-β-hydroxylase (DBH) was detected only in nerve fibers. In the omasal wall, nerve fibers with SP- and ENK-like immunoreactivity were prominent in the outer muscle layer, while numerous nerve fibers with VIP-, NPY- and GAL-like immunoreactivity were observed in the inner muscle layer. In the lamina propria mucosae, and in particular in the omasal papillae, a dense network of peptide-containing nerves was found. The distribution of nerves with CGRP-like immunoreactivity was different from that of other immunoreactive nerves. The networks of nerves with TH-, DBH- and NPY-like immunoreactivity were concentrated around the vascular components. The results of this study indicate the complexity of the enteric nervous system in the sheep omasum, reflecting the multiple functions of the nerves in the regulation of motility and/or absorption and secretion.
A Comparison of Rat Extensor digitorum longus and Gastrocnemius medialis Muscle Architecture and Length-Force Characteristics
Authors: Huijing P.A. , Nieberg S.M. , v.d. Veen E.A. , Ettema G.J.C.
Published: July 2008

During isometric contractions, muscle length, fibre and aponeurosis length and angles, and force exerted were quantified in order to assess factors contributing to length range of active force exertion. Comparisons of rat gastrocnemius medialis (GM) and extensor digitorum longus (EDL) muscles are of interest as fibre and aponeurosis length as determined at muscle optimum length are similar but fibre and aponeurosis angle are considerably smaller for EDL than for GM. On the basis of this, a wider length range between muscle optimum and active slack length was predicted initially for GM because of the expected higher angular contribution to accumulated length change. However, measurements of length-force characteristics revealed similar values for this length range. Therefore, quantification of length changes of fibre and aponeurosis as well of angular contributions to this length range was performed. Compared to their value at muscle optimum length, changes of fibre length were very similar for the two muscles. Fibre length changes normalized for muscle length changes ranged from approximately 90% near optimum length to approximately 65% near active slack length. Aponeurosis length changes normalized for muscle length changes were similar near optimum length for both muscles (approximately 5%) but deviated substantially near muscle active slack length (approximately 20% for GM and 35% for EDL). Cumulative angular contributions to muscular length changes were maximally 6% for EDL and 14% for GM. The reason for the relatively large length change of EDL aponeurosis could not be explained by different material properties but is likely to be related to yet an additional factor contributing to length range of active force generation: the distribution of mean sarcomere length of fibres with respect to muscle length. A piece of evidence for possible differences in such a distribution between GM and EDL is the difference of muscle length (approximately 1 and 2 mm over muscle optimum length respectively) at which optimum sarcomere length was found for distal fibres of the muscles.
Patterns of Capillaries in Developing Cerebral and Cerebellar Cortices of Rats
Authors: Yu B.P. , Yu C.C. , Robertson R.T.
Published: July 2008

Patterns of capillaries in cerebral and cerebellar cortices were studied in developing rats. In cerebral cortex, the ventricular zone is well vascularized throughout the developmental period. The cell dense cortical plate is poorly vascularized, with capillary branches appearing in individual layers as they emerge from the cortical plate. In cerebellar cortex, the external granular layer appears devoid of capillary branches. Capillary branching appears first in the Purkinje and granule cell layers and later in the molecular layer. These results indicate: (1) an inside-out pattern of development of capillaries in both cortices, and (2) marked differences in vascularization of the proliferative zones for cerebral and cerebellar cortical neurons.
Musculotopic Organization of Muscle Afferents in the External Cuneate Nucleus of the Gerbil as Revealed by Transganglionic Transport of Horseradish Peroxidase
Authors: Lan C.T. , Wen C.Y. , Shieh J.Y.
Published: July 2008

The projections of muscle afferents from six regions (hand, forearm, arm, thorax, shoulder and neck) to the external cuneate nucleus (ECN) of gerbils were investigated using transganglionic transport of horseradish peroxidase (HRP). These were chiefly ipsilateral projections which terminated in six discrete longitudinal columns in the ECN. A medial cell column confined to the caudal ECN received projections from the hand muscles, while the ventromedial and ventro-lateral cell columns in the posterior half of the ECN received projections from the forearm and arm muscles respectively. In the caudal ECN, the thoracic and shoulder muscles were represented by the dorsomedial and dorsolateral cell columns respectively. The last mentioned two columns extended anteriorly into the rostral ECN occupying a dorsal and intermediate portion leaving the ventral portion which represented the neck muscles. The latter also extended posteriorly into the middle 1/3 of ECN occupying a lateral portion. Serial sections and reconstruction studies showed that the ECN was located in the dorsal region of the upper medulla, approximately 0.3–1.8 mm rostral to the obex. The rostro-caudal extent of the six cell columns from hand proximally to neck were measured to be 0.5–0.8, 0.3–1.1, 0.3–1.3, 0.4–1.8, 0.4–1.8 and 0.8–1.8 mm rostral to the obex.
Cadherins as Determinants of Tissue Morphology and Suppressors of Invasion
Authors: Behrens J.
Published: July 2008

During the past years cell-cell adhesion molecules of the cadherin family have been recognized as major regulators of such diverse processes as normal morphogenesis and tumor metastasis. Since the list of new cadherin family members is constantly growing, the functional spectrum of these proteins is likely to broaden. This review will describe our current knowledge on cadherins and point out new aspects of cadherin function and regulation.
Two Distinct Types of Reticular Cells in the Pig Sheathed Artery
Authors: Miyata H. , Abe M. , Takehana K. , Yamaguchi M. , Masty J. , Iwasa K. , Hiraga T.
Published: July 2008

The morphology of reticular cells of the sheathed arteries, in the red pulp of pig spleen, was studied by using transmission electron microscopy; and their histochemical reactivity with periodic acid-thiocarbohydrazide-silver proteinate (PA-TCH-SP). The phagocytic ability was evaluated by injecting colloidal carbon into the splenic artery. Reticular cells of the sheathed arteries were classified as type I and type II cells. Type I cells have a nucleus with scanty chromatin, and the cytoplasm reacts positively to PA-TCH-SP. The PA-TCH-SP-positive granules are considered to be subunits of β-glycogen particles based on their morphological features. Type II cells have a nucleus with abundant chromatin and are not stained by PA-TCH-SP. Both types of reticular cells are connected with reticular fibers. Results of the colloidal carbon injection showed that type I reticular cells did not ingest carbon particles during the time frame of the experiment, whereas type II reticular cells are phagocytic and ingested carbon.
Secretory Disorders in Pituitary Thyrotropes of Streptozocin-Diabetic Male Rats
Authors: Bestetti G.E. , Brändli E. , Rossi G.L.
Published: July 2008

Pituitary cells transport secretory products from deep cytoplasmic portions towards the subplasmalemmal region (SPL) by two mechanisms: (a) the regulated, secretagogue-dependent and (b) the secretagogue-independent constitutive pathway. Since thyrotropin (TSH) secretion is impaired in diabetes, we studied both pathways in the thyrotropes of control and streptozocin (STZ)-treated male rats. By electron microscopy, we measured the nucleus and cytoplasm area and counted the secretory granules. In 4 selected SPL (500 nm deep) areas per cell we also counted the marginated secretory granules and measured their area. Moreover, after TSH indirect immunogold labelling we counted immunogold particles on (a) the secretory granules of the SPL and (b) the intergranular SPL cytoplasm. To check the background staining we also counted immunogold particles on nonthyrotropic cells. In diabetic compared with control thyrotropes we found: (a) cytoplasmic atrophy and increased number of secretory granules per cytoplasm unit area, (b) reduced number of secretory granules in the SPL (blunted regulated secretion), (c) larger secretory granules in the SPL (abnormal secretory granule maturation), (d) decreased immunogold labelling of secretory granules in the SPL (reduced TSH transported by each secretory granule towards the cell membrane) and (e) decreased immunogold labelling of the intergranular SPL cytoplasm (blunted constitutive secretion). Our data suggest reduced regulated and constitutive TSH secretion and may thus contribute to a better understanding of the hypothyroidism in STZ-diabetic rats.
Anatomic Variations of the Deep Palmar Arteries in Man
Authors: Mezzogiorno A. , Passiatore C. , Mezzogiorno V.
Published: July 2008

The deep palmar circulation is constituted by the deep palmar arch. In most cases this is a complete arch formed by the radial artery and its continuation to a deep branch of the ulnar artery. In a few cases, the deep palmar circulation is formed only by the radial or the ulnar artery. Only rarely is there a complete absence of the deep palmar arch. A series of 60 vascular casts was examined in order to identify the primary variants of the deep palmar arterial supply. Four anatomic patterns were identified: (1) radioulnar (66.67%); (2) radial-anastomotic (21.67%); (3) radial (8.33%), and (4) ulnar (3.33%). Two distinct types of the radioulnar variant were observed, a proximal and a distal one, named according to the origin of the deep palmar branch.
Early Morphological Changes in Crohn’s Disease
Authors: Schattenfroh S. , Bartels M. , Nagel E.
Published: July 2008

Recent ultrastructural investigations revealed early epithelial lesions in Crohn’s disease, while a specific morphological pattern was not identifiable. An increase in plasma cells, lymphocytes, macrophages, mast cells, eosinophilic and neutrophilic granulocytes, as well as focal edema and inflammation of tissue structures was seen in the lamina propria, submucosa and deeper layers. The results are consistent with the frequent discussion about a pathogenetically significant defect of the mucosal ‘barrier function’, which consists of mechanical, cellular, humoral, immunological and nonimmunological mechanisms, including different histotopographically defined lines of defense of the epithelium and lamina propria. An intact epithelial layer plays an important role as the first line of defense. It is evident that components of the epithelial barrier (absorptive cells, goblet cells, Paneth cells, M cells) show ultrastructural signs of alteration or injury, while the primary agent or event remains unknown. Another pathomechanism would be a preexisting defect in intestinal ‘barrier function’. Such a defect would result in an increased uptake of, or an inadequate immune reaction to, ubiquitously occurring antigens/agents (with genetic predisposition). However, no primary defect of epithelial or inflammatory cells has been definitely identified so far. Direct toxic damage of tissue secondarily introducing the inflammatory changes is also possible. Although the morphological alterations in Crohn’s disease are not yet clearly understood and exactly interpreted, transmission electron microscopy has been helpful in defining early lesions and has led to further knowledge about the pathogenesis of this disease.
Cartilage in the Aortic Valve and Its Relationship with the Aortic Valve Morphology in Syrian Hamsters
Authors: Sans-Coma V. , Franco D. , Durán A.C. , Arqué J.M. , Cardo M. , Fernández B.
Published: July 2008

We conducted a light-microscopic histologic study of the aortic valves of 224 Syrian hamsters aged between 1 and 771 days. Most of the hamsters examined belonged to a single laboratory-inbred family with a high incidence of bicuspid aortic valves (BAVs). In 146 specimens the aortic valve was tricuspid, and in 107 of them the ventral commissure was more or less fused. The remaining 78 specimens showed a BAV with the aortic sinuses oriented ventrodorsally. In 33 BAVs a raphe was located in the ventral aortic sinus. Cartilaginous foci were present in the aortic valves of 86 specimens, 40-771 days old. The foci were located at two different sites, namely in the ventral wall of the valve and/or in the dorsal aortic sinus. Statistical analyses substantiate that (1) chondrogenesis begins earlier in BAVs, and especially in those having a raphe, than in tricuspid aortic valves and (2) the location of the cartilaginous foci is significantly associated with the morphology of the aortic valve. The present findings support the hypothesis that, in the Syrian hamster, cartilage forms in the aortic valve as a response to locally intense mechanical stimulation.
Ontogeny of Arginine Vasopressin -Immunoreactive Neurons in the Hypothalamus of Fetal and Newborn Sheep
Authors: Faucher D.J , Evans P.J. , Khurana R. , Miller M.M.
Published: July 2008

Arginine vasopressin (AVP) is a peptide hormone which is found in neurons within the paraventricular (PVN) and the supraoptic (SON) nuclei of the hypothalamus. In fetal sheep, this neuropeptide is involved in maturational processes and adaptive responses to ‘stress’. This study examined the effect of age on the total number and distribution of AVP-containing neurons in the PVN and SON of fetal sheep and newborn lambs by quantitative light-microscopic immunocytochemistry. Serial coronal sections of hypothalami from three groups of animals were studied: fetuses at 104–109 days of gestation (n = 6) comprising the early group, fetuses at 130–139 days of gestation (n = 5) comprising the late group and newborn lambs at 12–20 postnatal days (n = 5) comprising the neonatal group. This period of development was chosen since adaptive mechanisms to stress are operative at or near the time of birth. Hypothalamic dimensions were measured to determine if maturation had an effect on the size of the AVP-containing subregions of the hypothalamus during this period of development. Dimensions included: ventricle height, optic chiasm width, distances from the dorsal margin of the ventricle to the lateral and medial margins of the optic tract, and distance between the medial margins of the optic tracts. As expected, with increase in maturational age, overall dimensions of the AVP-containing subregions increased significantly (p < 0.05). When early- and late-gestation fetuses were compared to newborn lambs, there was a significant increase in the total number of immunoreactive neurons in both the PVN (p < 0.01, Anova) and SON (p < 0.001, Anova) with age. With advancing age, we also observed an increase in the density of AVP neurons in the middle subregion of the PVN and in the midrostral subregion of the SON. These data suggest that, during the late gestational and early postnatal period, de novo synthesis of AVP genes occurs in these hypothalamic nuclei. This study provides a baseline for further investigation to study the effects of stress on these neurons in the developing ovine fetus and newborn lamb.
Ultrastructural Changes in the Hypothalamic Paraventricular Nucleus of the Streptozotocin-Induced Diabetic Rat
Authors: Dheen S.T. , Tay S.S.W. , Wong W.C.
Published: July 2008

This study describes the ultrastructural and morphometric changes in the hypothalamic paraventricular nucleus (PVN) of the streptozotocin-induced diabetic rat. During the acute phase (3 days after induction of diabetes), dendrites were swollen and appeared to have a watery cytoplasm. The affected dendrites were postsynaptic to seemingly normal axon terminals. During the intermediate phase (1-9 months after induction of diabetes), the neuronal somata contained numerous vacuoles of various sizes which were probably formed from dilated rough endoplasmic reticulum. Several unidentifiable vacuolated profiles were also seen in the neuropil. During the late phase (12 months after induction of diabetes) electron-dense dendrites and axon terminals were readily encountered in the neuropil. Most of the electron-dense dendrites were postsynaptic to normal as well as electron-dense axon terminals. Some of the electron-dense axon terminals formed axosomatic synapses with seemingly normal somata. Perivascular glial cells in the neuropil were in the process of phagocytosis. At 1-12 months of diabetes, the sizes of the somata and nuclei of PVN neurons were significantly increased in comparison with age-matched control rats.
Nitric Oxide – A Novel Autonomic Neurotransmitter
Authors: Grozdanovic Z. , Brüning G. , Baumgarten H.G.
Published: July 2008

Considerable evidence suggests that nitric oxide (NO) acts as a nonadrenergic noncholinergic (NANC) transmitter at autonomic neuroeffector junctions. NO is generated enzymatically from L-arginine by a constitutive, cytosolic, Ca2+/calmodulin-activated NO synthase (NOS): NADPH- and tetrahydrobiopterin-dependent cytochrome P-450-type hemoprotein. Electrophysiological and pharmacological data indicate that NO fulfils most of the criteria for a neurotransmitter. It is released from axon terminals when invaded by action potentials and mimics the effect of nerve stimulation. The changes in the mechanical and/or electrical activity of smooth muscle preparations in response to transmural stimulation of NANC nerves are antagonized by inhibitors of NO synthesis or oxyhemoglobin, an NO scavenger. NO acts principally by stimulating soluble guanylate cyclase. Studies on the histochemical localization of NOS point to the involvement of the neural L-arginine-NO pathway in the regulation of vascular tone and of several aspects of respiratory, gastrointestinal, and genitourinary tract functions.
Pattern of Iron Storage in the Rat Heart Following Iron Overloading with Trimethylhexanoyl-Ferrocene
Authors: Braumann A. , Wulfhekel U. , Nielsen P. , Balkenhol B. , Düllmann J.
Published: July 2008

Female Wistar rats with slight iron deficiency anemia were kept on a diet containing 0.5% trimethylhexanoyl (TMH)-ferrocene for up to 79 weeks. In the state of iron deficiency, the heart was free of light-microscopically detectable iron. After 7 weeks of the TMH-ferrocene diet, the first iron-positive granules appeared in perivascular macrophages. Further oral administration caused a progression of iron deposition in these cells, visible in the form of a granular staining but also as a diffuse iron staining of the cytoplasm. Accordingly, at the electron-microscopical level, the iron was stored partly as free ferritin molecules in the cytosol, and partly in lysosomes in the form of ferritin and/or hemosiderin. After 11 weeks, further iron-positive cells with relatively small dark-blue granules were found in the vicinity of capillaries, which could be identified as fibrocytes by means of electron microscopy. In addition, slight iron deposition occurred in the endothelial cells of the cardiac capillaries, likewise mainly in the form of small, uniform siderosomes. The myocytes showed no product of Perls’ Prussian blue reaction during the whole period of investigation. From the 11th week onwards, discrete ferritin molecules were detected electron microscopically within lysosomes of these cells. Their amount increased slowly with progression of the TMH-ferrocene feeding period. Free ferritin molecules could be observed in the cytosol of fibrocytes, endothelial cells and myocytes in only very slight concentrations, whilst they were more plentiful in macrophages. In hereditary hemochromatosis and posttransfusional siderosis, the iron is found predominantly in myocytes and appears to cause cell damage, whilst this is not the case in experimental iron overload in rats.
A New Method for Practicing Exploration, Dissection, and Simulation with a Complete Computerized Three-Dimensional Model of the Brain and Skull
Authors: Schubert R. , Höhne K.H. , Pommert A. , Riemer M. , Schiemann T. , Tiede U. , Lierse W.
Published: July 2008

In current practice, anatomical atlases are based on a collection of planar images presented in a book or, recently, stored on digital media. We present a new kind of interactive true three-dimensional (3D) anatomical atlases based on a volume model derived from MRI and CT. The model has a two-layer structure. The lower level is a volume model with a set of semantic attributes connected to each voxel. The semantic attributes are assigned by an anatomist using a volume editor. The upper level represents a set of relations between these attributes. Interactive visualization tools such as multiple surface display, preparation of transparent material and cutting are provided. It is shown that the combination of this model with advanced tools for volume visualization provides the ‘look and feel’ of real dissection. The system therefore represents a bridge between real dissection of a cadaver and textbooks and classical atlases of anatomy. First tests have shown that the atlas system may be used successfully for teaching anatomy, but also as a reference for radiologists or surgeons. The powerful underlying data structure potentially includes all classical visual teaching aids. As a replacement of classical atlases, however, spatial resolution has still to be improved.
Ultrastructural Studies on Tumor Capillaries of a Rat Rhabdomyosarcoma during Fractionated Radiotherapy
Authors: Zywietz F. , Hahn L.S. , Lierse W.
Published: July 2008

Sequential morphological changes in tumor capillaries of isotransplanted R1H rat rhabdomyosarcoma were observed weekly by transmission electron microscopy during fractionated radiotherapy (75 Gy/25 fractions/5 weeks). During the first 2 weeks of irradiation (up to 30 Gy), edema of the tumor capillary wall was induced. Swollen endothelial cells bulged into the vascular lumen and were surrounded by a widened subendothelial space with increased amounts of collagen fibrils (subendothelial edema). The endothelial lining was preserved up to the 3rd week of irradiation (45 Gy). Prolonged irradiation was associated with progressive destruction of the vascular wall including shrinkage, gradual loss of cell contacts, disappearance of the normal chromatin pattern, and increase of cytoplasmic vacuoles in endothelial cells as well as disruption of basal laminae. One week after the end of radiotherapy (75 Gy), the tumor capillaries showed complete necrosis. Progressive damage to tumor capillaries in the course of fractionated radiotherapy might have adverse effects on blood supply and thus on tumor oxygenation.
Ultrastructure of Epithelial Cells of the Chick Embryo Thymus
Authors: Chan A.S.
Published: July 2008

The ultrastructure of the stromal cells of the thymuses of chick embryos from the 13th to 19th day of incubation was investigated. At the 13th day, the non-lymphoid elements consist mainly of undifferentiated and epithelial cells. The dominant cystic cells are organized to form intra- and intercellular cysts and cleft-like spaces. By the 15th day, cysts are more conspicuous, and the cystic cells are marked by an increase in cytoplasmic organelle content. Isolated foci of cystic cells with no apparent connections to cysts are also observed. Myoid cells, characterized by the presence of myofibrils, are identifiable at this stage. Endocrine-like cells show synthetic and secretory activities and are distributed in cystic epithelium or among other cell types. Dendritic cells and macrophages are also observed among the other cells. Between the 15th and 19th day, there is a further increase in size and frequency of the cysts. Myoid and endocrine-like cells are also more prevalent.
Postnatal Development of the Vaginal Epithelium in the Mongolian Gerbil (Meriones unguiculatus)
Authors: Kress A.
Published: July 2008

This study examines the normal postnatal (p.n.) development of the Mongolian gerbil’s vagina from birth to the age when consistent cyclic changes of the estrus occur. At birth, the Müllerian vagina has a lumen and is lined by a pseudostratified or 2- to 3-layered epithelium. The cells contain large amounts of glycogen. The sinus vagina forms a solid plate and contains hardly any glycogen. During the first few p.n. days the cell layers separate, and the newly formed lumen becomes continuous with the Müllerian vagina. Only a vaginal closure membrane persists. Between p.n. days 10 and 15 the epithelium increases in height reaching 2–5 cell layers. The amount of glycogen diminishes, but in the luminal cells the first mucous granules develop. Leukocyte diapedesis starts, and immature Langerhans cells become discernible. Between p.n. days 18 and 30 the apical cells become mucified, and some shedding of these cells begins. Between p.n. days 36 and 45 bundles of keratin filaments appear in many of the luminal mucous cells intermingled with the mucous granules. In the middle layers keratin filaments, keratohyalin granules and membrane-coating granules indicate the beginning of the keratinization process. Diapedesis of leukocytes may lead to cell aggregations below top layers. By day 50 the shedding of the mucous cell layers reveals the underlying keratinized cell layers which then become exfoliated. The first steps of the estrous cycle show a heterogeneous pattern. At about p.n. day 60 the cycle becomes established.
Histochemical Demonstration of Phospholipid Containing Choline in the Cytoplasm of Murine Decidual Cells
Authors: Alberto-Rincon do Carmo , de Paiva Sade , Abrahamsohn P.A. , Zorn T.M.T.
Published: July 2008

The localization of lipids in the endometrium of virgin and 6- to 9-day-pregnant mice was detected by histochemical methods. Total lipids (as shown by staining with Sudan black) and phospholipids containing choline (PCC) were detected. Sections subjected to reactions that have been proposed for the demonstration of vitamins E and D and cholesterol gave negative results. In the virgin animals, lipids were found in epithelial cells but not in the endometrial stroma. On the other hand in the pregnant animals, the endometrial stroma contained both Sudan-black-stained lipids and PCC. Maximal staining was reached on day 8 of pregnancy. The staining was more conspicuous in the more differentiated decidual cells adjacent to the embryos than in the less differentiated predecidual cells. The nondecidualized stroma, situated peripherally near the myometrium did not stain for lipids. In the cytoplasm of decidual cells the reaction for PCC was observed in the form of granules, which were often arranged in groups surrounding the nuclei. We suggest that decidual cells store PCC to be mobilized as a precursor for mediators of decidualization, such as prostaglandins, that would act as paracrine inducers of the decidual reaction.
Effects of Androgen Deprivation in the Goat Epididymis
Authors: Goyal H.O. , Hutto V. , Maloney M.A.
Published: July 2008

With the deprivation of both circulating androgen (CA) and luminal androgen (LA; orchiectomized goats), the epithelial height (EH) in regions I–IV of the epididymis was reduced to 28, 67, 58 and 56% of that of controls, respectively, but it was increased to 109% of that of controls in region V. Similarly, the volume density of epithelium (VDE) in regions I–V was reduced to 33, 49, 45, 41 and 70% of that of controls, respectively. Conversely, in the absence of LA only (extratesticular-rete-ligated goats), while both EH and VDE were reduced to almost 50% of those of controls in region I, they remained similar to those of controls in other regions. The morphological changes in the epithelium such as cytoplasmic regression, loss of stereocilia and disorderly arrangement of epithelial cells were maximal in region I, moderate in regions II–IV and minimal in region V. Testosterone treatment appreciably reduced the degenerative changes caused by orchiectomy in all regions except region I where the restorations were marginal at best. Hence, the results suggest a differential epididymal response to androgen deprivation. Whereas the LA and/or other rete fluid components seem essential for maintaining the epithelial structure of region I, the CA alone can maintain, at least partially, the epithelial structure of regions II–IV and almost completely that of region V.
Nodule Formation and Calcification of Mandibular Condylar Cartilage Cell Cultures Mimic in vivo Ultrastructure
Authors: Engel F.E. , Swain L.D. , Dean D.D. , Boyan B.D.
Published: July 2008

Mandibular condylar cartilage (MCC) of growing mammals contains four layers of cells which display a series of increasingly differentiated phentoypes and which culminate in a terminally differentiated cell that produces a calcified matrix. In this study, MCC cells were placed into culture in Dulbecco’s modified Eagle’s medium containing 10% fetal bovine serum and 50 µg/ml ascorbic acid. After 12 h in culture, transmission electron microscopy revealed the presence of multiple cell types that underwent differentiation with additional time in culture. By 7 days, fusiform-shaped cells were seen that contained numerous actin-like cytofilaments and micropinocytotic vesicles characteristic of myofibroblasts. Chondroblast-like cells were also observed. By 10 days, without addition of β-glycerophosphate or dexamethasone, these cellular events culminated in the formation of mineralized nodules containing matrix vesicles. The nodular surface at day 13 consisted of two or more layers of myofibroblast-like cells, while the deeper zones of the nodule contained cells displaying a morphology typical of calcified hypertrophic chondroblasts. These ultrastructural observations are consistent with the hypothesis that cells from the MCC are capable of recapitulating in culture the maturational events seen in vivo. This cell culture model may be useful for investigating cell-mediated cartilage calcification without the addition of exogenous phosphate or other regulatory factors.
Side Branches of the Pulmonary Artery in the Hilar Region
Authors: Takahashi M. , Murata K. , Mishina A. , Mori M. , Shimoyama K. , Morita R.
Published: July 2008

The pulmonary air space between the large bronchi at the hilum is supplied by small daughter bronchi that stem from axial main branches. In this study, we evaluated the morphological appearance of the pulmonary artery which corresponds to the daughter bronchus using an inflated-fixed lung specimen. In contrast to the relationship in the subpleural area, the pulmonary artery did not follow the corresponding airway in the area supplied by the daughter bronchus. Only at the tip of the terminal bronchiole was a close association found. Each terminal bronchiole showed a tendency to receive its blood supply from the nearest parent branch of the pulmonary artery.
Differential Lectin Binding to the Fibrinoid of Human Full-Term Placenta: Correlation with a Fibrin Antibody and the PAF-Halmi Method
Authors: Lang I. , Hartmann M. , Blaschitz A. , Dohr G. , Kaufmann P. , Frank H.-G. , Hahn T. , Skofitsch G. , Desoye G.
Published: July 2008

Placental fibrinoid is thought to contain various glycoproteins originating from cell secretion and tissue degeneration, occasionally merged with fibrin. Information on the characteristics and derivation of the various fibrinoid components, however, is still fragmentary. Therefore, the present histochemical study on acetone-fixed placental tissue sections compared the staining pattern of FITC-con-jugated lectins from Ulex europaeus (UEA-I), Bandeiraea simplicifolia (BS-I) and Lycopersicon esculentum (LEA) with the reactivity of a fibrin antibody and a modified paraldehyde-fuchsin stain. Using different color reactions, the latter histological method identified two types of fibrinoid, which correlated well with fibrin-type and matrix-type fibrinoid. Immunohistochemically, fibrin was detected at the intervillous border of the basal plate, in some inner parts and in perivillous fibrinoid. UEA-I bound to endothelial cells and partially to fibrin-type fibrinoid of villi and the basal plate, thus indicating a reaction with immured and disintegrated remnants of endothelial and blood cells. LEA stained fibrin-negative (i.e. matrix-type) fibrinoid homogeneously within the basal plate; the small reactive areas within the perivillous fibrinoid may belong to degenerating trophoblastic residues, because in villi LEA specifically reacted with the syncytiotrophoblast. BS-I heterogeneously labeled matrix-type fibrinoid deposits in the basal plate which surrounded decidual cells and subpopulations of extravillous trophoblast. In cell islands, BS-I also stained fibrinoid surrounding trophoblast cells heterogeneously. The data (1) confirm the existence of two types of placental fibrinoid, fibrin-type and matrix-type fibrinoid, (2) suggest that both types of fibrinoid contain different glycoconjugates, and (3) demonstrate the practical usefulness of the modified paraldehyde-fuchsin method for the identification of the two types of fibrinoid.
Changes Associated with the Basal Lamina during Metamorphosis of Xenopus laevis
Authors: Murata E. , Akita M. , Kaneko K. , Merker H.-J.
Published: July 2008

We examined the changes in the morphology of the basal lamina of the colon, abdominal wall and tail muscles of tadpoles during metamorphosis and compared our results to those previously obtained for the small intestine. At the early stage of metamophic climax (stages 60–62), we observed a curving of the basal lamina along the processes of the epithelial cells. At a later stage of metamophic climax (stages 63–66), more extensive curving and folding of the basal lamina were observed. The basal lamina of the mesothelial cells in the abdominal wall did not change extensively as compared to the colon. Folded basal lamina was observed among degenerated muscle cells. Our results suggest that the folding of the basal lamina depends on the degree of deformation of the particular organ, which occurs mainly by physical factors such as the shortening or shrinking of the organ due to cellular degeneration. Cells that are newly differentiated produce an additional basal lamina, which results in transient doubling or layering. The combination of physical factors and cell differentiation results in a basal lamina that is more complex and contains folds and layers.
Synaptic Relations of GABAergic Neurons in the Area Postrema
Authors: Guana J.-L. , Wang Q.-P. , Ochiai H. , Nakai Y.
Published: July 2008

γ-Aminobutyric acid (GABA)-like immunoreactive neuronal profiles and their synaptic relations in the area postrema of the rat were studied by ultrastructural immunocytochemistry using an antibody directed against GABA. GABA-like immunoreactive (GABA-LI) perikarya and dendrites usually received synaptic inputs from nonimmunoreactive axon terminals. These synaptic contact zones were mostly asymmetrical. Conversely, GABA-LI axon terminals were found to make synapses with nonimmunoreactive perikarya and dendrites, usually of the symmetrical type. Furthermore, GABA-LI axon terminals in synaptic contact with GABA-LI perikarya and dendrites were sometimes found. Although some GABA-LI axon terminals were in close vicinity of other nonimmunoreactive axon terminals, no clear synaptic contacts could be found. On the other hand, GABA-LI profiles could be found close to the capillaries, although they were always separated by a thin layer of glial processes. The above results suggest that the GABAergic neuron receives information from both the circulating blood and other neurons and then performs its depressor function through other neurons.