bluuebunny/crossref_metadata_2025 huggingface dataset:
Differential connexin distribution accommodates cardiac function in different species
Authors: van Kempen Marjan J. A. , Velde Ingrid Ten , Wessels Andy , Oosthoek Petra W. , Gros Daniel , Jongsma Habo J. , Moorman Antoon F. M. , Lamers Wouter H.
Published: February 2005

Using immunohistochemical staining, the distribution of connexin40 (Cx40) and connexin43 (Cx43) was studied in rat, guinea pig, porcine, bovine and human hearts. These species display differences in the degree of morphological differentiation of the conduction system. This study was performed in the anticipation that comparison of the distributions of Cx40 and Cx43 in young and adult specimens may provide clues as to the physiological role of connexins in the heart. To a large extent, the distribution patterns of Cx40 and Cx43 are comparable between species. In neonates and adults, Cx43 was immunolocalized throughout the working myocardium, but in the conduction system Cx43 was detected only after birth. Cx40 was found to appear slightly earlier in development than Cx43 and to disappear when levels of Cx43 became more abundant. This time course was seen in working myocardium and in the ventricular conduction system. Together these data suggest that expression of Cx40 induces or facilitates expression of Cx43, while abundant expression of Cx43 in turn leads to suppression of Cx40 expression. The exceptions to this may represent blocks in this potential regulatory sequence. A second conclusion is that Cx40 and Cx43 containing gap junctions appear in the ventricular conduction system from distal to proximal and only after birth. This indicates that terminal differentiation of the conduction system occurs unexpectedly late in development. © 1995 Wiley‐Liss, Inc.
Elaboration of an oviductin by the oviductal epithelium in relation to embryo development as visualized by immunocytochemistry
Authors: Kan Frederick W. K. , Roux Emmanuelle
Published: February 2005

The hamster oviduct secretes a high molecular weight antigen that belongs to the family of glycoproteins known as oviductins. In the present study, using immuno‐electron microscopy, we examined the location of this hamster oviductin‐1 (Hm Ov‐1) in hamster oviductal oocytes and early embryos up to the blastocyst stage. The immunoreactive pattern of Hm Ov‐1 changes markedly during the embryo development. In oviductal oocytes prior to fertilization, Hm Ov‐1 was associated exclusively with the zona pellucida. Following fertilization, immunolabeling was detected in the perivitelline space and over the plasma membrane of 2‐cell, 4‐cell, and 8‐cell embryos as well as young blastocysts. The change of the immunoreactive pattern was accompanied by the formation of an abundant number of coated pits, endocytic vesicles, multivesicular bodies, and lysosomal‐like structures which were strongly labeled by gold particles. These immunogold‐labeled cytoplasmic organelles characteristic of the endosomal‐lysosomal apparatus were particularly evident in 2‐cell, 4‐cell, and 8‐cell embryos and showed a decrease in number in the blastocysts. The close resemblence between the labeled flocculent material detected in the perivitelline space and that found in the zona matrix of early embryos and blastocysts suggested that the Hm Ov‐1‐associated electron‐dense, flocculent material in the perivitelline space originated from the zona pellucida and was later endocytosed by the blastomeres through coated pits and endocytic vesicles. The detection of Hm Ov‐1 in numerous multivesicular bodies and lysosomal structures indicated that the oviductin is eventually degraded. Although the exact functional role of Hm Ov‐1 is not known, the presence of a copious amount of Hm Ov‐1 in early hamster embryos may be ascribed to a special relationship between this particular oviductin and embryo development. © 1995 Wiley‐Liss, Inc.
Bovine oviductal epithelial cells (boec) and oviducts: I. For embryo culture. Ii. Using sem for studying interactions with spermatozoa
Authors: Suzuki Hiroyuki , Foote Robert H.
Published: February 2005

The oviduct (uterine tube) plays a major role in reproduction. It is a dynamic organ which selectively permits a few sperm to undergo capacitation and reach the oocyte which has continued to undergo maturation following ovulation. Then following fertilization the embryo undergoes cleavage before arriving in the uterus. Extensive information has become available from in vitro studies on oocytes as well as spermatozoal interactions with oviductal cells. Bovine oviduct epithelial cell (BOEC) monolayers with simple media provide an environment in which zygotes can be cultured to blastocysts in 6 days with cell numbers essentially equivalent to blastocysts grown totally in the donor animal. These yield normal pregnancy rates upon transfer. The simple protein‐free media currently under test hold promise for elucidating specific requirements of the preimplantation embryo and these defined conditions facilitate many related studies on in vitro fertilization and genetic engineering of embryos.

The second part of this paper is an extensive study on the interaction of fresh and frozen‐thawed bull spermatozoa with BOEC and segments of intact oviducts as viewed by SEM. Both types of oviductal cells were incubated at 39°C for 0, 3, 6, and 9 hours, using material obtained from periovulatory cows. Sperm attached immediately to both types of epithelium and reached a peak at 3 hours. They were found primarily in the furrows of the intact oviducts. Secretory droplets appeared rapidly on the anterior portion of the sperm head and acrosomal changes were evident in 3 hours, similar to those reported in vivo. Changes were more rapid with frozen‐thawed sperm. © 1995 Wiley‐Liss, Inc.
Functions of proteins secreted by oviduct epithelial cells
Authors: Gandolfi Fulvio
Published: February 2005

Studies on embryonic development in vitro as well as observations in vivo, suggested that two aspects of oviduct physiology are important for early development. On one side has to be considered the oviduct “environment”: temperature, pH, osmotic pressure, nutrients, oxygen tension, free radical scavengers, etc. On the other, the oviduct “active components”: stimulatory and/or regulatory molecules, supposed to finely regulate the fertilisation process and the first differentiative steps.

While the physical environment of the oviduct has been under investigation for some decades, studies on oviduct‐specific molecules and their functions have only been developed much more recently. The amount of information on this topic, however, has rapidly reached the size that demands a summary.

In this review the descriptive literature on oviduct specific proteins will be examined as a basis for illustrating the possible functions of these molecules. In particular their role in fertilisation and early embryonic cleavages will be analysed in some details. Finally a section is devoted to the presence and physiological significance of growth factors in oviduct fluid. © 1995 Wiley‐Liss, Inc.
Quantitative and three‐dimensional aspects of the rat parathyroid gland in normo‐, hypo‐, and hypercalcemia
Authors: Wernerson Annika , Svensson Olle , Reinholt Finn P.
Published: February 2005

The ultrastructure of the rat parathyroid has been under study for more than 35 years, but controversies still exist, especially regarding structure‐function relationships. The present review focuses on recent morphological parathyroid research on rats under normal conditions and in various states of disturbed calcium metabolism. To facilitate discussions on functional aspects, current biochemical data, particularly those dealing with the regulation of parathyroid hormone synthesis and release, are also considered. Our results from quantitative studies and from investigations employing serial sectioning form the basis for the discussions. A central issue is whether the parathyroid secretory cells undergo secretory cycles. Prompted by results obtained from improved fixation procedures and serial sectioning, we question the basis for the theory of secretory cycles. Since the rat parathyroid secretory cell is polar, a single section is not an appropriate sample for estimating functional activity and for comparing the structure and distribution of intracellular components of adjacent cells. The heterogeneity in ultrastructural appearance of intracellular vesicles calls for the use of specific markers in relating the structure of the vesicular compartment to intracellular processing of hormone. The importance of unbiased quantitative techniques is illustrated in discussions on cell number and size for estimating the response of the parathyroid gland to different functional states or disorders demanding changes in secretion of parathyroid hormone, e.g., hyper‐ and hypocalcemia. © 1995 Wiley‐Liss, Inc.
Human lung volume, alveolar surface area, and capillary length
Authors: Wiebe Britt Marie , Laursen Henning
Published: February 2005

We compare the effectiveness of morphometric methods for extimating lung parameters. Various stereological methods are applied on human lungs and described in detail. The lung volume was estimated by Cavalieri's principle and by fluid displacement. But methods are reliable, but Cavalieri's principle is superior when systematic sections are needed or when volumes of parts of the lung are wanted. Point counting demonstrated that 87.5% of the lung is parenchyma, 5.4% is vessel volume, and 7.1% is bronchia volume. Alveolar surface was estimated on vertical and isotropic uniform random tissue (IUR) sections. The capillary length and length density was estimated on projected images of vertical slices (Gokhale method) and on IUR sections. Only minute differences were found whether IUR sections or vertical sections were used. Of the total variation, approximately 2% was due to the stereological variation and approximately 98% was due to the biological variation on IUR sections and vertical sections. Estimates for volumes, surfaces, and lengths coming from model‐based and design‐based methods gave similar results for human lungs. In our hands, the design‐based methods were easier to use and required less time. However, only the design‐based methods offer the guarantee of an unbiased estimate. © 1995 Wiley‐Liss, Inc.
Dysmyelination in class I MHC transgenic mice
Authors: Turnley Ann M. , Morahan Grant.
Published: February 2005

Why is it that oligodendrocytes do not normally express major histocompatibility complex (MHC) molecules? To examine the effect of aberrant MHC expression in oligodendrocytes, transgenic mice have been produced which expressed the class I MHC gene, H‐2Kb, under direction of the MBP promoter [Turnley et al. (1991b) Nature, 353:566‐569; Yoshioka et al. (1991) Mol. Cell. Biol., 11:5479‐5486]. A proportion of these mice exhibited a shivering phenotype, with tonic seizures and early death. Oligodendrocyte function and viability was shown to be affected, resulting in severe dysmyelination of the CNS. Is this phenomenon of cell damage due to aberrant expression of MHC molecules restricted to oligodendrocytes, and could other, non‐MHC molecules, when aberrantly expressed, result in similar cell damage? This paper discusses these questions and examines possible mechanisms for the oligodendrocyte damage and hypomyelination observed in these transgenic mice. Finally, the implications of aberrant MHC expression in oligodendrocytes for demyelinating diseases such as multiple sclerosis are discussed. © 1995 Wiley‐Liss, Inc.
Reconstruction of the glia limitans by sub‐arachnoid transplantation of astrocyte‐enriched cultures
Authors: Franklin R. J. M. , Blakemore W. F.
Published: February 2005

Lesions in CNS white matter involving loss of glial cells with concurrent destruction of the glia limitans lead to widespread remyelination of CNS axons by Schwann cells. Previous studies have demonstrated that this situation can be changed by transplanting cultured CNS glial cells into lesions early on in the repair process. In this study we have transplanted cultured astrocytes into the sub‐arachnoid space above such a lesion in order to (1) influence the normal repair process by transplant‐assisted reconstruction of the glia limitans, and (2) explore the potential of a minimally invasive route for introducing cells to white matter lesions. In some cases, it proved possible to influence normal repair by transplanting cells via the sub‐arachnoid route, although the results were inconsistent. However, the experiment permitted observations to be made on the migration of transplanted astrocytes across the surface of and within the spinal cord. © 1995 Wiley‐Liss, Inc.
Theory and practice of stereological techniques applied to the estimation of cell number and nuclear volume in the testis
Authors: Wreford Nigel G.
Published: February 2005

The historical background to contemporary approaches to the estimation of cell/ nuclear number and volume in the testes is reviewed. The limitations of older geometric model‐based approaches to the estimation of cell/nuclear number are discussed, and the need for absolute estimates of cell number rather than ratio estimates is examined. The physical and optical disector approaches to the direct estimation of numerical density and, hence, absolute cell number are presented together with data illustrating their operational efficiency in the testis. New approaches to the direct estimation of nuclear/cell volume, using the point‐sampled intercept family of methods, are presented and illustrated, using the example of the Sertoli cell nucleus. The use of both classical transverse and the newer vertical section approaches is explored. Estimation of Sertoli cell/nuclear volume in the volume (point‐sampled intercept procedure) and number (nucleator and rotator methods) distributions on both conventional transverse and vertical sections is discussed. The use of transverse sections of the testis is shown to produce a consistent bias in the estimation of Sertoli cell nuclear volume in 120‐day‐old animals, with all the estimators. Comparison of the Sertoli cell nuclear volume (measured on vertical sections) in the volume and number‐weighted distribution suggests a coefficient of variation of volume in the number distribution of 0.4–0.5, suggesting either a random or stage‐dependent variation in Sertoli cell nuclear size which requires further exploration. © 1995 Wiley‐Liss, Inc.
Integumentary changes during moulting of arthropods with special reference to the subcuticle and ecdysial membrane
Authors: Taylor Ronald L. , Glenn Richards A.
Published: February 2005

At or shortly prior to the separation of the cuticle and the epidermis a cuticular layer appears to be added to the inner surface of the old cuticle. The term interzone cuticle is applied to this layer. The interzone cuticle appears to give rise to the ecdysial membrane.

Ecdysial membranes are characterized by the fact that they (1) vary in position with respect to the moulting fluid and old cuticle, (2) are generally quite thin, transparent, delicate membranes, (3) contain chitin, (4) vary in their resistance to the action of the moulting fluid, and (5) generally have the same stainng properties as the subcuticle, due primarily to the presence of a mucous material present in the subcuticle which becomes attached to the inner surface of the ecdysial membrane and which is believed to function as a lubricant at ecdysis.

The ecdysial membrane and subcuticle are structurally quite different when examined under the electron microscope.

No particular evolutionary significance can be ascribed to the existence of an ecdysial membrane — such membranes being found all the way from the primitive Collembola to the advanced Hymenoptera. Any possible function(s) of the ecdysial membrane has yet to be discovered. Various functions are suggested for the subcuticle, all of which are consistent with its reactions to various histochemical reagents.

Additional observations were made and discussed concerning (1) the reactions of various portions of the cuticle at various stages to the PAS test, (2) the staining reactions of cuticle undergoing enzymatic degradation by the moulting fluid, and (3) the distinct staining reactions of the intersegmental membranes and basement membranes.
Innervation of the hand muscles of Didelphis marsupialis virginiana, Kerr
Authors: Brandell Bruce R.
Published: February 2005

An investigation of the innervation of the hand muscles of the opossum, Didelphis marsupialis virginiana, Kerr, was made to determine the pattern of hand muscle innervation in a relatively primitive quadruped mammal. Four pairs of preserved opossum hands were dissected, and the innervation of their muscles studied with a stereobinocular microscope. The distributions of the median and ulnar nerves to the hand muscles are outlined, and the details of distribution are illustrated by means of seven diagrams.

Peculiar anastomoses were consistently found between the superficial interdigital rami of the median nerve and branches of the deep volar ramus of the ulnar nerve, and the short deep flexors of digit II consistently received all, or a part, of their innervation from superficial interdigital rami of the median nerve. Five features of these unusual nerve connections and distributions are summarized and discussed.
A histochemical study of follicular atresia in the snake ovary
Authors: Guraya Sardul S.
Published: February 2005

By employing histochemical techniques, the follicular atresia and problems of interstitial cells have been worked out in the ovaries of two species of snakes (Naja tripudians and Bungarus coeruleus). Large follicles with a polymorphic granulosa show more atresia from September to November. Details of morphological and histochemical changes in the yolk nucleus substance, mitochondria and lipid bodies of oocyte and granulosa have been described. During atresia the theca interna is greatly hypertrophied and is loaded with lipids consisting of first phospholipids, then phospholipids and triglycetides and finally triglycerides, cholesterol and its ester and little phospholipids. Finally the oocyte, zona pellucida, granulosa cells and most of the cells of theca interna regress and disappear, leaving behind some residual cells of theca interna. The histochemistry of normal and atretic follicle of snakes and lizards has also been compared and contrasted with that in mammals. The “interstitial cells” of snake ovary have been discussed in the light of recent researches carried out on similar cells in the mammalian ovary.
Some observations on the anterior pituitary of the domestic fowl with the aid of the electron microscope
Authors: Payne Fernandus
Published: February 2005

Lipid accumulations in the gonadotrophs of the pituitaries of aging and castrate fowl have been demonstrated. Secretory granules and mitochondria play no part in their formation. Some lipids, perhaps all, occupy the cavities of the ER. The ER is a highly variable organelle, appearing as spherical or irregularly shaped vesicles in gonadotrophs or as lamellae in acidophiles. The Golgi complex is typical of pituitary cells in general. There are no bodies in the enlarged cavities of the complex and convincing evidence for the origin of all secretory granules within the small vesicles of the complex is lacking. Many secretory granules appear to be without membranes and to lie free in the cytoplasmic matrix. Observations on the pituitaries of broody hens confirm earlier conclusions that the broody cells appear during the incubation period and that they are small cells with large nuclei and reduced cytoplasm. The study also confirms the accumulation of secretory granules in laying hens at one side of certain cells which are interpreted to be either LH or FSH producing basophiles. Thiouracil feeding brings about some unexpected granular accumulations in the ER vesicles of thyrotrophs of the fowl pituitary. The granules may fuse to form larger structures with concentric rings. Whether the effect is direct or indirect through the thyroid is uncertain, but thiouracil feeding and thyroidectomy produce similar effects upon the pituitary. The interpretation of these changes remains to be determined.
Implant‐induced accessory limbs in urodeles: Fresh, frozen, and boiled tissues
Authors: Stevens J. , Ruben L. N. , Lockwood D. , Rose H.
Published: February 2005

Implants were made into forelimbs of Triturus viridescens using fresh, frozen and boiled kidney and liver of T. viridescens and R. pipiens. Limbs were recovered at intervals up to 70 days post‐implantation.

Kidney implants from Wisconsin R. pipiens gave twice as many extensive accessory structures as did Vermont frog kidney. Total induction percentages, however, were similar.

Quantitative and qualitative parameters for implant‐induction of accessory structures were investigated. The decrease in antigenicity and increased rate of cytolysis of frozen implants resulted in increased similarity between frog and newt kidney in rate and pattern of breakdown and in rates of induction. Modification of rate and duration of the release of the stimulating factor from the implant did not result in induction by liver implants.

No evidence was found for any increase in innervation prior to or coincident with blastema formation. Implantation and implant cytolysis may cause hypersensitivity of limb tissues to the normal innervation pattern or trophic stimuli from the implant may act with those from the injured limb tissues to produce growth.

The general pattern of host reaction to the implanted material was studied and described.
The structure of the digital setae of lizards
Authors: Ruibal Rodolfo , Ernst Valerie
Published: February 2005

Light and electron microscope studies of the digital lamellar setae of geckos and anoline lizards demonstrate that the free ends of the setae consist of flattened spatulas of less than 1 μ in width. The anoline setae are simple structures usually less than 30 μ in length and with a single terminal spatula to each seta. In contrast the setae of geckos are complex structures of about 100 μ in length, with numerous branchings, and having many spatulas per seta. The spatulas of Gekko and Aristelliger were smaller (0.2‐0.4 μ in width) than the spatulas of Anolis (0.8 μ in width). The electron microscope studies indicate that the scales of lizards appear to be covered with small epidermal spines (1.5 μ long). The setae of anoles and geckos are considered to have evolved independently from these more primitive epidermal spines. It is further suggested that the mechanism that allows the lamellae to adhere to the substratum is a surface phenomenon. The spatulas provide a large surface that is in contact with the substratum and thus produces a large total frictional force. The α layer of the lizard stratum corneum can be readily identified in the lamellae. However, the structure of the β layer is not easily interpreted and there is evidence of a fibrous layer between the Oberhautchen and the α layer in the skin of the outer lamellar surface.
The rat submaxillary salivary gland. A correlative study by light and electron microscopy
Authors: Tamarin Arnold , Sreebny Leo M.
Published: February 2005

The rat submaxillary salivary gland has five distinct parenchymal zones.

Acini consist of secretory and myoepithelial cells. An extensive network of canaliculi connect the many cells within an acinus to the main lumen. The fine structure of acinar secretory cells suggests that they are capable of great synthetic capacity; each cell having a large amount of ergastoplasm, many Golgi zones, and a great amount of secretory material. It is proposed that these cells are of the continually secreting type.

Intercalated ducts consist of cuboidal cells and myoepithelium. This segment connects the acini to the main conduit system of the gland. The fine structure of the cuboidal cells indicates that they are essentially nonsecretory.

The granular duct consists of three types of columnar cells; (a) dark narrow cells which contain many free ribosomes but no ergastoplasm or granules, (b) light granular cells which have varying amounts of ergastoplasm and granules, (c) dark granular cells which are full of granules while the other cell constituents including the nucleus, occupy a basal position. It is proposed that these three cells represent different secretory stages of the same cell type. This supports the interpretation that secretion in these cells is not continuous, but cyclic in nature.

The striated duct forms a small portion of the total gland parenchyma and consists of tall columnar cells with extensive infolding of the basal plasma membrane, relatively little ergastoplasm and very few granules. It seems likely that ion and water metabolism is a specialized function of this segment.

The excretory duct consists of three cell types: (a) tall columnar light cells, (b) dark columnar vesiculated cells and (c) small basal cells. The basal infoldings of these cells and the arrangement of many capillaries around these ducts suggests that this segment is primarily concerned with water transport.
The ultrastructure of the germinal epithelium of the mouse ovary
Authors: Wischnitzer Saul
Published: February 2005

It was demonstrated that the germinal (surface) epithelium around the mouse ovary consists of simple squamous, cuboidal and columnar arrangements of cells. With the electron microscope it was shown that these cells have the usual cytoplasmic constituents such as the Golgi complex, mitochondria, ergastoplasm, and free ribosomes. Their nuclei are surrounded by a bilamellar envelope with coarse granular masses of nuclear material being distributed along its inner surface. From the surface of these cells extend numerous microprojections which usually are irregular in squamous cells, but are villus‐like on the cuboidal and columnar forms. These microvilli appear to be simply extensions of the cell surface and apparently reflect the capacity of mesothelium for such specialization at its free surface. The intercellular boundaries are seen to consist of wavy, downward extensions of the plasma membrane or a complex irregular interdigitation of coarse lateral processes. The latter form is especially prominent between squamous cells. A membrane is present at the basal cell surface. The observations concerning the presence of microprojections and the nature of the intercellular boundaries were discussed in the light of the controversies on these subjects which appear in the early literature. The possible permeability of the germinal epithelium and its functional significance during maturation of the ovary were also discussed.
An analytical study of coitus in Aedes aegypti (Linnaeus)
Authors: Jones Jack Colvard , Wheeler Ronald E.
Published: February 2005

Pre‐copulatory behavior of male Aedes involves pursuit, tarsal contact, ventral orientation, and terminalial contact. Copulation itself involves seizure of the female's cerci by the male's claspers, extension of the male's paraprocts, erection of the aedeagus, and ejaculation. The male's ability to copulate is prevented by damaging or removing his seventh abdominal segment. If this segment is left intact, his freshly removed abdomen can copulate with a freshly isolated female's abdomen when their terminalia are rubbed together appropriately. The male's genital apparatus accurately “recognizes” the terminalium of an inseminated female, and forced‐copulation cannot be induced. The claws at the ends of the male's claspers are inserted into the bases of the female's cerci. The thumbs of the apical paraprocts of the male fit into a temporary coital cavity within the upper vagina. The hooks of the male's apical paraprocts are inserted into the female's cloacal hollow. The teeth on the distal end of the aedeagus ratchet into the teeth on the dorsal vaginal valve and evert the upper vagina. The posterior ends of the seminal vesicles and accessory glands open and contractions of these organs release seminal material only into the bursa of the female.
The structure of bone marrow. Functional interrelationships of vascular and hematopoietic compartments in experimental hemolytic anemia: An electron microscopic study
Authors: Weiss Leon
Published: February 2005

In hematopoietic marrow, sinuses form a system of vessels running radially from the periphery toward the central longitudinal vein. Hematopoietic tissue, having the form of cords, lies between the sinuses.

The wall of the vascular sinus of the marrow, in fullest development, is trilaminar. It consists of a lining cell, basement membrane and adventitial cell. It may, however, consist of lining cell alone. Occasionally, the wall is bilaminar, made up of lining cell and basement membrane, or lining cell and adventitial cell. The adventitial cell and lining cell are reticular cells and may exactly resemble one another. But often the adventitial cell, and occasionally, the lining cell of a sinus may be very voluminous and rarefied, extending among the hematopoietic cells. The mural reticular cells, particularly the adventitial cells, may be phagocytic. The adventitial cells, moreover, contain fat droplets, and may accumulate the unilocular fat deposit characteristic of a fatty marrow.

Megakaryocytes lie outside the sinus discharging platelets through mural apertures. In places, fairly large segments of sinus wall may become attenuated, pierced by apertures and, perhaps, drop out, with the result that the sinus is enlarged. Normo‐blasts, reticulocytes and myelocvtes enter the circulation by passing into a sinus. Three mechanisms are present: (1) They may pass through existing apertures or (2) create an aperture by pressing into a sinus wall. (3) A segment of wall may drop out setting heretofore extravascular cells into the circulation.

Adventitial spurs or processes extend from the sinus into the perisinus tissue. These spurs are of the same structure as the sinus wall. The perisinus tissue, present as cords between sinuses, is typically filled with hematopoietic and other free cells. The adventitial processes, together with the reverse surface of the sinus walls, incompletely bound the intersinus hematopoietic cords. The intersinus space may thereby have the same contour as sinuses. They differ from sinuses in containing many hematopoietic cells and in being less completely bounded by wall.

It is postulated that the sinuses and intersinal cords form a reciprocating system wherein portions may become vascular (sinal) or extravascular (cordal) depending upon the requirements for hematopoiesis, blood flow, blood storage and delivery of cells to the blood. The reciprocation is effected by the ready capacity of sinal walls and adventitial spurs to take form, change disposition and break down.
Femoral glands of the lizard, Crotaphytus collaris
Authors: Cole Charles J.
Published: February 2005

The anatomy of the femoral glands in an iguanid lizard, Crotaphytus collaris collaris (Say), is described. The 48 lizards (including three embryos) from which glands were examined were obtained throughout their season of activity at one locality in Kansas.

In animals of both sexes the glands lie in a linear series on the ventral aspect of each thigh. They are composed of branching tubes and tubules of epidermal and dermal origin. The row of femoral pores is the only external manifestation of the glands.

Post hatching, the glands of males increase in size and complexity; little onto‐genetic change occurs in the glands of females.

The relative length of the glands appears to vary seasonally in adult males suggesting variation in their activity. The greatest relative sizes occur in the breeding season.

At times a stratum corneum, continuous with the stratum corneum of the skin, occurs in the duct of the gland internal to part of the secretion plug. Formation of the stratum corneum seems to be initiated in the autumn prior to hibernation, and the stratum corneum removes the outer part of the secretion plug in the next ecdysis; meanwhile, production of a new secretion plug is initiated.

The anatomy of the femoral glands in Crotaphytus is similar to that of the described glands of other species of lizards.
The structure and formation of the cuticulin layer in the epicuticle of an insect, Calpodes ethlius (Lepidoptera, Hesperiidae)
Authors: Locke Michael
Published: February 2005

The cuticulin layer is defined as the dense lamina (120–175 Å thick in Calpodes larvae, depending upon the stage) forming the outer part of the epicuticle in insects. It completely invests an insect except for the gut and the openings of some sense organs. It is the first layer to be secreted during the formation of new cuticle. The formation of the cuticulin membrane may be a useful model for studying the origin of membranes in general. It arises as a triple layer de novo and is not a modified plasma membrane. Growth is by accretion at the edges of patches of cuticulin which increase in area until they cover the new surface. The triple layer (i.e. three dense laminae) may develop striations about 30 Å apart transverse to the membrane, which perhaps form a sieve allowing small molecules to pass while protecting the cell from enzymes in the molting fluid. A similar porous structure persists in the tracheoles. After the resorption of molting fluid the triple layered structure again becomes obvious and the outermost layer separates from the other two to become what may be the surface lipid monolayer. The surface patterns in cuticle of various sorts probably arise by buckling of the cuticulin layer as it increases in surface area.
Response of hair types in mice to higher doses of x‐rays
Authors: Galbraith Donald B.
Published: February 2005

Doses of x‐rays exceeding 1,000 r delivered to resting hair follicles of mice cause a variable greying response ranging from 60 to 100%. The purpose of this study was to study this phenomenon with specific reference to the response of zigzags and overhairs to irradiation. Accordingly, mice were exposed to 1,200 r and 1,300 r of x‐rays and the response of hairs from a known area was compared with that of unirradiated controls and mice given 600 r, 800 r and 1,000 r, of radiation. It was found that at the higher doses, variations in total greying response were paralleled by variations in the response of both zigzags and overhairs, that there is relatively greater epilation of overhairs, and that zigzags contribute most heavily to both the white and the totally pigmented fractions. The results of this study therefore do not support the previous suggestion that the variable greying response is a function of a relative increase of pigmented overhairs in conjunction with selective damage of zigzags.
The megachiroptera and vespertilionoidea of the microchiroptera
Authors: Pye Ade
Published: February 2005

The structure of the external ears and the ultrasonic cries produced by one member of the single family of Megachiroptera and six representatives of the Vespertilionoidea of the Microchiroptera have been described. All the specimens were intra‐vitally fixed and the preparations have been examined, photographed and measured. Brief notes are given on the middle ear and the following measurements have been made on the cochlea: the general size of the cochlea in various dimensions, the width and thickness of the basilar membrane, the size of the spiral ligament and the height of the cells of Claudius. In conclusion it can be said that there are marked differences in the structure of the cochleae of the two suborders, as well as within the superfamily Vespertilionoidea.
Some observations on spermatogenesis in Gelastocoris oculatus (hemiptera) with the aid of the electron microscope
Authors: Payne Fernandus
Published: February 2005

The nuclear cap in the spermatogonial and early spermatocyte cells of Gelastocoris is an aggregate of closely packed mitochondria with their long axes perpendicular to the nuclear membrane. Eventually in the early growth period, the mitochondria move from the cap and appear to become more or less equally distributed in the cytoplasm where they remain until their fusion in the spermatid to form the nebenkern. The Golgi complex consists of clusters of lamellae and vesicles, the Golgi bodies. Granules form within the vesicles, increase in size, move from their place of origin and become distributed at random in the cytoplasm. They are the pro‐acrosomal granules and at the end of the growth period fuse to form the proacrosome, about which Golgi bodies collect. The Golgi bodies, however, never fuse into an acroblast. At one end of the oval‐shaped pro‐acrosome is a small dark body and a less dense vesicle the future of which is uncertain. The dark body eventually occupies a position at the tip of the acrosome. The pro‐acrosome, after moving to the side of the nucleus opposite the nebenkern, differentiates into the acrosome which elongates into a tail‐like structure. The nuclear membrane of some spermatocytes may appear wave‐like in cross section, with the crest and trough different in appearance. Near the membrane and in the troughs of the waves large clusters of granules are frequently present. Similar clusters may be found elsewhere in the cytoplasm. Presumably they had their origin near the membrane but this is not conclusive. Bodies of indeterminate origin and structure may be present in the cytoplasm. They could be lysosomes but evidence is lacking. In late spermatocytes and in spermatids, a group of ten or twelve granules is present. They are smaller than the pro‐acrosomal granules, are always closely associated and pass as a group into the tail. Their significance is unknown. The endoplasmic reticulum is typical of cells in general. There are no granule accumulations within the vesicles as in some secretory cells. Vesicles of various shapes and sizes are present within the centrosphere of the first meiotic division. While their location is similar to that of the centriole, the identity of the vesicles is uncertain.
Fine structural organization of the rectum in the blowfly, Calliphora erythrocephala (Meig.) with special reference to connective tissue, tracheae and neurosecretory innervation in the rectal papillae
Authors: Gupta Brij L. , Berridge Michael J.
Published: February 2005

The rectal epithelium of Calliphora is made up of three quite distinct cell types: rectal, cortical and junctional cells.

The thin wall of the rectal pouch is made up of rectal cells which are relatively simple and unspecialized; their general structure does not suggest any direct participation in ion transport.

A function of ion and water transport can probably be ascribed to the cortical cells, which are arranged in the form of four cones which project into the rectal lumen. The cavity of each cone is filled up with tracheae, nerve and neurosecretory terminals, and connective tissue to form medulla. The medulla and cortex are separated from each other by deeply staining bridges or trabeculae to form an infundibular space. The most conspicuous feature of the cortex is the presence of an extensive intercellular sinus formed by complex infoldings of the lateral plasma‐membranes. It is postulated that fluid, which is absorbed from the rectal lumen, is transported into the intercellular sinus and finally reaches the haemolymph via the infundibular space. The actual site of ion transport is probably the stacks of lateral plasma‐membrane which are closely associated with mitochondria.

The junctional cells, which are packed with microtubules, form a collar around the base of the papillae at the point of their insertion into the rectal wall.

It is suggested that the neurosecretory terminals present in the medulla might release a hormone which controls rate of ion and water reabsorption by the papillae cells.
Sense organs on the antennal flagellum of a walkingstick Carausius morosus Brünner (Phasmida)
Authors: Slifer Eleanor H.
Published: February 2005

The long, filamentous antennal flagellum of Carausius morosus has on it three types of sense organs (1) tactile hairs, (2) thick‐walled chemoreceptors and (3) thin‐walled chemoreceptors. Tactile hairs and thick‐walled chemoreceptors are present on all of the 40 or more flagellar subsegments while thin‐walled chemoreceptors are limited to about one‐third of them. Thin‐walled chemoreceptors are present on subsegments nine and ten, one of the subsegments between 15 and 20 and from approximately the thirtieth subsegment to the distal end of the antenna. A description of each of these sense organs is given. No coeloconic or campaniform sense organs were found.
Early ossification in the skeleton of the sucker (Catostomus macrocheilus) and the guppy (Poecilia reticulata)
Authors: Weisel George F.
Published: February 2005

Catostomus macrocheilus, a sucker, and Poecilia reticulata, a live‐bearer, are subjected to dissimilar mechanical stresses while most of their bony structures are forming. Osteogenesis occurs in the sucker when it is a free‐living larva, whereas in the livebearer it occurs intrafollicularly. The first‐formed bones ofboth species are those that meet functional demands and are subjected to the greatest stresses. These are the movable bones associated with the acts of respiration and feeding, and some of the axial bones. The cranial roof is the last to calcify. The primary differences in osteogenesis of the two species, such as in the vertebral column and caudal fin, can be correlated with differences in stress. Surface forces on calcifiable tissue perhapsassist in the deposition of calcium salts.
Intramitochondrial transformations during oocyte maturation in the mouse
Authors: Wischnitzer Saul
Published: February 2005

An electron microscope study of oocyte maturation in the mouse revealed that some mitochondria undergo gradual transformation in their ultrastructural appearance. In very young oocytes these mitochondria were already found to contain vacuoles, one in each such organelle. In somewhat older oocytes more mitochondria displayed vacuoles which generally appeared to be getting larger. These intramitochondrial vacuoles were found to be essentially optically empty structures surrounded by a single membrane. In favorable sections someof the developing vacuoles had a bottle‐shaped appearance, the constricted end of which was attached to the inner limiting membrane of the mitochondrion. With further maturation of the oocytes vacuoles having a pear‐shaped appearance became evident. An hypothesis was presented outlining the mode of formation of these vacuoles by expansion of the individual cristae. Intramitochondrial transformations occuring during both oogenesis and spermatogenesis in mammals were reviewed.
Fine structure of nerve cells in a planarian
Authors: Lentz Thomas L.
Published: February 2005

The fine structure of the nerve cell types in the white planarian Procotyla fluviatilis were described. Ganglion cells comprise the major portion of the brain. These cells are irregular in shape with several cytoplasmic processes and contain ribosomes, a sparse endoplasmic reticulum, microtubules, lysosomes, and a Golgi apparatus with numerous small vesicles. Granule‐containing cells are situated in the peripheral regions of the brain and along the nerve cords. These cells contain ribosomes, rough‐surfaced endoplasmic reticulum and a Golgi apparatus with associated dense granules. The granules occupy most of the cytoplasm and are ∼ 750A in diameter with moderately dense contents, ∼ 750A with opaque contents, and ∼ 1000A with contents of medium density. These granules are similar to those in the nervous systems of higher animals that contain epinephrine, norepinephrine, and neurosecretory substance, respectively. Each cell contains predominantly one type of granule although there is some intermixing of granules and intermediate types between the three most abundant granules. Small clear vesicles, resembling cholinergic synaptic vesicles, and all types of dense granules occur in the neuropil and within nerve endings.
Morphological and histochemical studies on oogenesis in Callosobruchus analis Fabr. (Bruchidae‐Coleoptera)
Authors: Aggarwal Surinder K.
Published: February 2005

The ovary in Callosobruchus analis consists of telotrophic ovarioles with the so called nurse cells confined to one chamber at the anterior end of the ovariole. There are three types of lipids in the ovary: (1) L1 bodies that are present in the early oocytes, in the posterior prefollicular tissue and in the follicular epithelium and contain unsaturated phospholipids; (2) L2 bodies that have a complete or incomplete sheath of phospholipids and a triglyceride core; (3) L3 bodies that are formed of highly saturated triglycerides. Lipids are absent from the trophic tissue. In a mature oocyte the L1 and L2 bodies are cortical in distribution while the L3 bodies are centrally located.

The mitochondria contain lipoproteins with RNA. The yolk spheres are acid mucopolysaccharides and protein in nature. The precursors of the yolk spheres appear first in the cortical coplasm and are absent from the follicular epithelium or the trophic tissue. The nucleolus of the oocyte shows evidence of extrusions that are believed to pass into the ooplasm.

There are no nutritive cords connecting the trophic tissue to the oocytes; nor is there any evidence of any histochemically demonstrable nutritive material being contributed to the oocyte by the trophic tissue. The circumstantial evidence points towards a contribution of the raw materials to the oocyte by the haemolymph either through or in between the follicular epithelium in some soluble form or as submicroscopic particles.
The distribution and neuroanatomy of the labellar sense organs of the blowfly Phormia regina Meigen
Authors: Wilczek Maria
Published: February 2005

The labellar hairs of the blowfly Phormia regina Meigen are arranged in a definite pattern. Topographically they can be divided into the following groups: prickles, bristles, intermediate hairs, large hairs, largest hairs, marginal hairs. On the basis of dimensions they fall into four groups. The total number of hairs is somewhat variable. The mean for males is 122.65 hairs on one lobe; for females, 128.82 hairs. The interpseudotracheal papillae vary both in position and number. The mean for males is 65.9 papillae; for females, 67.65. The labial nerve divides, in the labellum, into four principal branches which consist of proximal processes of the sense cells of all hairs and interpseudotracheal papillae. Preparations stained by methylene blue revealed numerous multipolar cells. It was impossible to decide with certainty whether they are nerve cells, perilemma cells, or tracheal cells. They did not stain with silver. Numerous free endings revealed in preparations by use of Kenyon's method appeared to be the finest tracheoles seen on preparations stained by the method of Romanes.
The recognition, distribution and ultrastructure of hydrozoan nerve elements
Authors: Jha Raj K. , Mackie G. O.
Published: February 2005

Silver stained Cordylophora were examined by light and electron microscopy, which provided a general picture of nerve cell forms and distribution for comparison with electron micrographs of osmium‐fixed tissues from the same hydroid. Muscle, nerve and neurosensory components were studied in the nectophore of Nanomia (O. Siphonophora) and in the hydromedusae Sarsia and Euphysa by means of vital staining and optical and electron microscopy of epon sections; particular attention was given to relationships and interconnections between the cellular elements of the two marginal nerve rings. Mitochondrial size, numbers and types of vesicles and the occurrence of neurotubules and of parts of sensory cilia may provide useful ultrastructural clues for recognizing nerve elements, but serial sections are often needed to make identification conclusive.

In Cordylophora and Nanomia, some neurites contain massed A vesicles (membrane‐bounded dense granules) suggestive of neurosecretion (cf. reports on Hydra). However, a small type of A vesicle also occurs at synapses in Sarsia, indicating a probable role here in junctional transmission. Vesicles occur on both sides of some synapses (as previously reported for Cyanea) but on one side only in others, these being the first examples of polarized junctional ultrastructure in coelenterates.