bluuebunny/crossref_metadata_2025_split huggingface dataset:
Scanning microscopy of collagen in the basement lamella of normal and regenerating frog tadpoles
Authors: Overton Jane 
Published: February 2005

AbstractThe arrangement of collagen fibers over the body surface in the basement lamella of Pseudaeris and Xenopus tadpoles is described. It can be viewed by scanning microscopy after removal of epidermis and basal lamina by trypsin treatment of alcohol fixed tissue. The orthogonal array is modified in regions where fiber direction changes extensively such as the base of the ventral fin or the posterior part of the head. In these regions “exceptional points” in the orthogonal pattern occur, as described by Rosin (1946). The pattern is bilaterally symmetrical. In the region of the nasal opening the orthogonal pattern is replaced by a mat of randomly oriented fibers. In tail regeneration the wound area is marked by aberrant disposition of collagen anteriorly then a mat of randomly disposed fibers followed posteriorly with a sharp transition to the orthogonal pattern of the regenerate. No fiber terminations could be seen in normal or regenerating regions of the lamella.
Semicircular canal radii of curvature (R) in cat, guinea pig and man
Authors: Curthoys I. S. , Blanks R. H. I. , Markham C. H. 
Published: February 2005

AbstractThe radii of curvature (R) of the horizontal (Rh), anterior (Ra) and posterior (Rp) semicircular canals were measured by a new technique (called ROTA) for cat, guinea pig and man. For each canal, data points from the ossecus canal were rotated and plotted by computer such that the plane of the sheet of computer plot corresponded to the plane best fitting that canal. The radius of each osseous canal was determined and where necessary, the radius of the are of data points was corrected for thickness of the absent tissue. For cat, guinea pig and man there are differences in R between canals within a labyrinth suggesting that if other things are equal there could be differences in the average mechanical sensitivity of the canals, which is consistent with physiological recordings from primary vestibular neurons in the cat, The Rs determined by ROTA are compared with Rs determined by conventional histological means.
Anatomy and histology of the alimentary tract of the desert millipede Orthoporus ornatus (Girard) (Diplopoda: Spirostreptidae)
Authors: Nunez F. S. , Crawford C. S. 
Published: February 2005

AbstractThe alimentary tract of the desert millipede Orthoporus ornatus is essentially a straight tube consisting of a histologically distinct foregut, midgut, pylorus, hindgut, and rectum. Common to each region, but often different in regional appearance, are an outer sheath layer, longitudinal and circular muscle layers, a basement membrane, and an inner epithelial layer. Foregut and midgut lumina are lined by a cuticular intima, while a peritrophic membrane occurs in the midgut lumen.Gut structure is considered in the context of the known feeding habits and digestive efficiency of this long‐lived, seasonally restricted detritivore.
Ca+2‐accumulating components in developing skeletal muscle
Authors: Smalls Charley M. , Goode Dennis 
Published: February 2005

AbstractThis ultrastructural study on the localization of Ca+2 in developing skeletal muscle indicates that the formation of calcium‐accumulating components begins during embryonic development. Both oxalate and pyroantimonate techniques are used to localize Ca+2 in distinct cellular components of chick pectoral and sartorius muscles. Two major sites for Ca+2 accumulation are present in ultrathin sections of embryonic and post‐embryonic muscles: the terminal cisternae of the sarcoplasmic reticulum and specific lines in the I‐bands. Calcium oxalate‐accumulating vesicles are present in the smallest recognizable myotubes at the twelfth day of incubation, but calcium‐accumulating components are not seen at myofibrillar I‐band sites until the fourteenth to seventeenth days of incubation. The fact that myofibrils first form and later in development accumulate a Ca+2‐binding component suggests that this Ca+2‐binding component is not necessary for the formation of myofibrils, but is added to myofibrils before hatching to serve a probable regulatory role in contraction.
Sense organs on the antennal flagellum of psocids (Insecta, Psocoptera)
Authors: Slifer Eleanor H. , Sekhon Sant S. 
Published: February 2005

AbstractThe sense organs on the antennal flagella of five species of winged psocids belonging to two families of Psocoptera, Psocidae and Leptopsocidae, have been examined. All agree in possessing tactile hairs, thick‐walled chemoreceptors and long, porous chemoreceptors. Thin‐walled chemoreceptors were identified in all species except Metylophorous novaescotiae. Coeloconic chemoreceptors were present in all species except Echmepteryx hageni. Campaniform sense organs were found only in Metylophorus novaescotiae and Psocus leidyi.
Mechanics of the syrinx in Gallus gallus. II. Electromyographic studies of Ad Libitum vocalizations
Authors: Gaunt Abbot S. , Gaunt Sandra L. L. 
Published: February 2005

AbstractRecords of electrical activity in the tracheal muscles of domestic chickens were obtained for a variety of ad libitum vocalizations. Primary attention was given to an analysis of events during the most complex call, crowing.Three pairs of muscles, Mm. tracheohyoideus, tracheolateralis, and sternotrachealis, can affect the configuration of a chicken's syrinx. The firing patterns of the three muscle pairs are related to their different abilities to affect the tension of the syringeal membranes. The influence of M. tracheohyoideus is most indirect and imprecise, and its role the least clearly defined. It appears to adjust the position of the trachea so that the syrinx is isolated from unpredictable and/or undesirable consequences of nuchal position and tracheal elasticity, and also helps draw the glottis caudad, thereby deepening the pharyngeal chamber. The other two muscles interact to control the tension of the vocal membranes. M. sternotrachealis relaxes the membranes by drawing the drum of the trachea caudad, or, via the syringeal ligament, by rotating the pessulus cranioventrad, or both. M. tracheolateralis tenses the membranes and/or prevents caudal movement of the origin of M. sternotrachealis, a necessity if the syringeal ligament is to rotate the pessulus.Vocalization depends on both syringeal configuration and appropriate air flow. Hence, tracheal muscles, syrinx, air sacs, and ventilatory muscles cooperate to form a vocal system. Cooperation elicits a surprising degree of redundancy. At least one call, a high pitched wail, may be produced by two very different techniques.
Chromatin diminution in early embryogenesis of Ascaris lumbricoides L. var. suum
Authors: Goldstein Paul 
Published: February 2005

AbstractThe occurrence of chromatin diminution in early Ascaris lumbricoides L. embryos has been studied in detail, and it is shown that it is possible to preselect three characteristic types of mitoses: pre‐diminution, diminution, and post‐diminution mitosis. The first three embryonic mitotic divisions are of the pre‐diminution type. Chromatin diminution occurs after the third mitosis, but there is a variation from embryo to embryo as to whether or not chromosomal diminution occurs during the fourth, fifth, and six divisions. However, the seventh embryonic division, which gives rise to an eight‐cell embryo, always exhibits chromatin diminution. Subsequent mitoses of somatic cells already in the diminished state are of the post‐diminution type of mitosis.
A new ganglion in male Moniliformis moniliformis (Acanthocephala)
Authors: Dunagan T. T. , Miller Donald M. 
Published: February 2005

AbstractA new ganglion identified as the bursal ganglion is described from male Moniliformis moniliformis. This ganglion is located adjacent to the pseudocoel and longitudinal muscle fibers and medial to the dorsal lacunar canal about 1 mm from the posterior end of males with non‐everted bursa The ganglion consists of four large club‐shaped cells with single nuclei and bipolar neurons.The ganglion cells are paired with one neuron from each cell innervating the opposite side of the worm.
Efferent connections of the striatum in Tupinambis nigropunctatus
Authors: Hoogland P. V. 
Published: February 2005

AbstractThe striatum of the lizard Tupinambis nigropunctatus lies in the lateral wall of the telencephalon and consists of two major subdivisions: the dorsal striatum and the ventral striatum.Electrolytic lesions were placed in all parts of the striatal complex and in adjacent areas and the subsequent anterograde degeneration was studied using the Nauta‐Gygax and Fink‐Heimer techniques. Lesions in the dorsal striatum cause terminal degeneration in the ventral striatum both ipsi‐ and contralaterally. In addition, projections have been found to the lateral amygdaloid nucleus and to parts of the dorsal striatum not affected by the lesion. Following lesions in the ventral striatum fiber degeneration could always be observed in the ventral peduncle of the lateral forebrain bundle.Corresponding terminal degeneration was found in the anterior and posterior entopeduncular nuclei, the tegmentum mesencephali, the substantia nigra, the prerubral area, the mesencephalic central grey and the lateral cerebellar nucleus. When the large celled part of the ventral striatum was involved in the lesion additional degeneration could be traced to the nucleus rotundus via the dorsal peduncle of the lateral forebrain bundle.
The functional morphology and possible taxonomic significance of the parapodia of the maldanid polychaetes Clymenella torquata and Euclymene oerstedi
Authors: Pilgrim Muriel 
Published: February 2005

AbstractThe morphology of the chaetae of the maldanid polychaetes Clymenella torquata (Leidy) and Euclymene oerstedi (Claparède) (= Caesicirrus neglectus Arwidsson, '11) are described and related to movements observed in the laboratory. Graphs are constructed of the number and length of the neuropodial chaetae of each chaetiger throughout the body of Clymenella and of species of the genera Euclymene, Macroclymene and Axiothella, and show a characteristic and relatively constant pattern for each species. This work suggests that in making taxonomic decisions, more attention should be paid to the overall pattern of the neuropodial chaetae and less to the confusing distinction between aciculae and rostral uncini.
The actions of three hamstring muscles of the cat: A mechanical analysis
Authors: Peters Susan E. , Rick Christine 
Published: February 2005

AbstractAn analysis of mechanical and architectural aspects of three hamstring muscles in the cat, semitendinosus (ST), semimembranosus anterior (SMa), and semimembranosus posterior (SMp), is presented based on whole muscle tetanic tension profiles. Length‐active tension curves for each muscle were obtained by electrical stimulation of the whole muscle with a train of stimuli at 100 pulses per second (pps) for 600 milliseconds.Information from motion picture analysis (Goslow et al., '73) and electromyographic (EMG) activity (Engberg and Lundberg, '69) as seen during the step cycle is combined with analysis of joint torques to present a picture of the differential functions of the three muscles. The length‐active tension characteristics of ST and SMa are such that they develop high amounts of tension throughout their physiological excursions. Maximal tension is produced over a much more limited range by SMp. A division of labor for the three muscles is proposed: the one‐joint SMa is shown to be a primary hip extensor whose action facilitates smooth oscillation of the leg. Torque and electrical activity during the step cycle indicate the two‐joint ST is a primary knee flexor. The more limited range of maximum torque and variable EMG pattern of the other two‐joint muscle, SMp, relate to the fact that it has primary activity during high speed gaits when it may act to initiate spine flexion and assist in hip extension.Excursion and activity data have led to the conclusion that biarticular muscles (ST and SMp) may benefit from the combined action of two joints to maintain near maximal tension and torque during active phases of the step cycle. Thus, biarticular muscles may have evolved as much for the mechanical and physiological benefits they derive as for two‐joint action itself.
Ankle flexor muscles in the cat: Length‐active tension and muscle unit properties as related to locomotion
Authors: Goslow G. E. , Cameron W. E. , Stuart D. G. 
Published: February 2005

AbstractThe mechanical properties of the whole muscle and fast‐twitch muscle units of the cat hindlimb pretibial flexors have been explored and related to normal locomotion. Tibialis anterior (TA) is parallel‐fibered and functionally crosses a single joint, the ankle, whereas extensor digitorum longus (EDL) is pinnate and spans the ankle, knee, metatarsophalangeal and interphalangeal joints. The active tetanic tension of TA remains near its peak value over a range of muscle lengths associated with normal ankle movement. In contrast, the length‐tension curve of EDL is sharply peaked. However, normal corollary action of the knee, ankle and metatarsophalangeal joints during stepping minimizes EDL's excursion and maintains it at or near a length optimal for peak tension development. EDL is capable of producing synchronous but sterotyped digit and ankle movements while TA provides for independent ankle flexion at all relevant joint angles.The mechanical properties of 84 TA and 98 EDL fast‐twitch muscle units were studied by measuring twitch contraction time (≤45 msec), peak tetanic tension, response to repetitive stimulation, and contractile fatigue resistance during electrical stimulation of single alpha axons, functionally isolated from ventral root filaments. These mechanical properties were essentially similar for both muscles with the exception of mean peak tetanic tension which was 30% lower for TA units (14 gm‐wt) than for EDL units (20 gm‐wt). A high proportion of units in both muscles demonstrated fatigue resistance which is reflective of the repetitive, phasic demand upon these muscles during locomotion.
Tongue evolution in the lungless salamanders, family plethodontidae. II. Function and evolutionary diversity
Authors: Eric Lombard R. , Wake David B. 
Published: February 2005

AbstractA recently presented model of tongue projection dynamics is used to generate a series of predictions concerning morphologies to be expected under selection for increased distance of projection, increased speed of projection, and increased directional versatility. A general understanding of biomechanical events and the model are used as points of departure for making specific predictions concerning details of structure in skeletal, muscular and connective tissue components of the tongue and associated structures. Comparative methods are used to examine these predictions in the genera of plethodontid salamanders. These salamanders are known to project their tongues to different degrees, and this knowledge is used to test the hypotheses concerning morphological specialization. Three distinct groups of plethodontid salamanders have evolved specializations for long distance projection, and these genera differ from one another in important ways in respect to specific character complexes. For example, the tropical genera and Hydromantes use CBII as the major force transmission element in the skeleton, while Eurycea and its allies use CBI in this role. Hydromantes differs from both in having a uniquely proportioned and structured hyobranchial skeleton and associated musculature. Less extreme specializations for tongue projection are found in different combinations in three other groups. Finally, two distinct groups of generalized species having only limited tongue projection capabilities are recognized, each having a unique complex of inter‐related features. Each of these eight groups is recognized and characterized as a functional mode, and hypotheses concerning the biomechanical meaning of the character complexes of each are formulated.
The craniocaudal extent of the glycogen body in the domestic chicken
Authors: Sansone Frances M. 
Published: February 2005

AbstractAll birds have a glial enclosed, glycogen‐containing structure in the lumbosacral region of their spinal cords. Recently, a dorsal, central, glycogen‐rich area surrounding the central canal in the brachial spinal cord was described in domestic chickens. In order to topographically delineate and histochemically describe this structure, fresh, frozen serial sections of chicken brains and spinal cords were processed for glycogen content, phosphorylase, succinic dehydrogenase and cholinesterase activities. The glycogen‐rich area surrounding the central canal in the lumbosacral region is found at all levels of the spinal cord and lower medulla. In the upper medulla, it is located in the midline floor immediately ventral to the ependyma. It persists in this position until the level of the oculomotor complex where it ends. Phosphorylase positive regions closely parallel the glycogen distribution. No succinic dehydrogenase or cholinesterase activities are found in these areas.
The structure of the salivary glands of the human soft palate
Authors: Black Jerry B. 
Published: February 2005

AbstractThe glandular layer constitutes the greatest bulk of the human soft palate and is composed of individual compound tubulo‐acinar salivary glands. Connective tissue partitions of the submucosa divide the glandular layer into lobules of irregular shapes and sizes. The glands are interwoven and bound firmly together by a connective tissue stroma rich in elastic fibers. The secretory units consist of elongated, branched, and sometimes convoluted tubules lined by a single layer of pyramidal mucous cells.Mucous secretion by acini is supplemented to some degree by mucous acinar cells, which were found as epithelial components of all ducts except the main excretory ducts, suggesting a diffuse distribution of progenitor cells. Some mucous acini communicate with highly convoluted intercalated ducts which occupy partially isolated positions within inter‐ and intralobular connective tissue septa. These ducts follow the connective tissue septa and eventually join the main duct system. The significance of this system of intercalated ducts is not known. A supplemental functional role is hypothesized.
On the neurosecretory system of Dendrobaena atheca Cernosvitov
Authors: Baid I. C. , Gorgees Najem S. 
Published: February 2005

AbstractFour kinds of neurosecretory cells A, B, U and C are distinguished in the central nervous system of Dendrobaena atheca Cernosvitov. A cells, which show different morphological characteristics under different physiological states and during their cyclic changes, are the most active neurosecretory cells. They form the outer layer of the cortical cell zone in the cerebral ganglion. B cells are large and medium sized and are distributed in all parts of the central nervous system. U cells are found only in the sub‐pharyngeal ganglion while C cells are distributed in the sub‐pharyngeal as well as in the ventral nerve cord ganglion. The number and secretory activity of C cells decrease in caudal direction. Further, Gomori‐positive cells are also observed in the ganglia of the vegetative nervous system.A rudimentary neurohaemal organ, the storage zone, has been observed in the cerebral ganglion and there appears to be another neurohaemal area in the ventral nerve cord ganglion. The storage zone is formed by the terminal ends of the axons of A cells. The chrome alum haematoxylin phloxin (CHP) and aldehyde fuchsin (AF) positive substances in the form of granules are found in this area. The cerebral ganglion is richly supplied by blood capillaries. The distal end of the axons of B cells are swollen like a bulb while in some cases the axons are united to form an axonal tract. Extra‐cellular material is abundant in different parts of the nervous system. In all cell types, the perinuclear zone is the first to show activity in the secretory cycle. It appears that the nucleus may be involved in the elaboration of the neurosecretory material in the cells.
Fine structure of the tracheoles of the lantern of a photurid firefly
Authors: Ghiradella H. 
Published: February 2005

AbstractThe lantern tracheoles of the firefly, Photuris, are unusual in that their walls are reinforced by cuticular bars. The tracheoles are stiff and resist collapse under conditions which flatten more typical tracheoles. This reinforcement and the structural resemblance of the tracheal end cell to cells considered to be active in moving ions and fluid is taken as evidence suggesting that the flash may be turned on and off by control of the oxygen supply and that said control may involve some sort of osmotic mechanism.
Observations on the morphology of the developing primate cornea: Epithelium, its innervation and anterior stroma
Authors: Ozanics V. , Rayborn M. , Sagun D. 
Published: February 2005

AbstractA survey is made of some ultrastructural features of the developing cornea of Macaca mulatta. The observations are confined to the anterior central area, starting with the lens vesicle stage and progressing through midgestation, when the morphologic characteristics of the cornea are fully established. Subepithelial filaments and some partially aggregated collagen fibrils are present in the earliest embryo and are of a size and appearance similar to those in the future vitreous cavity. Epithelial secretory activity points to, but does not prove direct contribution to the deposition of the acellular matrix components beneath it. No trace of a structured, orthogonal collagenous stroma can be visualized. The primitive endothelium forms prior to the fibroblast invasion of the distended filamentous matrix. Bowman's layer has undoubted epithelial contributions. Its aggregated collagen fibrils have approximately the same diameter as those of the anterior stroma. Intraepithelial appearance of single nerve fibers and fascicles takes place during the first trimester of gestation, as soon as the two continuous epithelial layers are formed. Terminal areas approach closely to the basal cell's nucleus, without touching it. The plasmalemma of the invaginating nerve fiber is surrounded by that of the epithelial cell in a mesaxon‐like manner, with occasional gap junctions uniting adjoining neural and epithelial cell membranes. The fetal neurites contain microtubules, some clear vesicles and dense vacuoles resembling those of mature monamine and non‐monamine neurons. Mitochondria are small and compact, their presence indicating a high rate of metabolic activity in the immature terminal area.
A histochemical study of the muscles of Drosophila melanogaster
Authors: Deak I. I. 
Published: February 2005

AbstractThe thoracic muscles of Drosophila melanogaster can be classified into two classes, the fibrillar and the tubular muscles, on morphological grounds. Histochemical techniques were used to characterize these two classes of muscle according to their content of various enzymes (α‐glycerophosphate, NAD‐dependent isocitrate, malate and succinate dehydrogenases, fumarase, acid phosphatase, adenosine triphosphatase and acetylcholinesterase) and of glycogen. These investigations showed that the two muscles types are histochemically very different and, further, that the morphologically similar tubular muscles are heterogeneous with respect to their enzyme content. In particular, the tergal depressor of the trochanter of the second leg, the largest of the tubular muscles, has considerably less of all the enzymes studied, with the exception of acetylcholinesterase, than all the other tubular muscles examined. The histochemical techniques were also used to follow the changes in enzyme levels that occur during development of the indirect flight muscle fibres. All the enzymes that are present in adult flight muscles showed an increase in staining intensity throughout muscle development. Some minor differences were observed in the time of appearance and rate of increase of intensity of the different enzymes.