bluuebunny/crossref_metadata_2025_split huggingface dataset:
Banded spindle‐shaped structures in the notochord of Salmo irideus
Authors: Watanabe K. 
Published: February 2005

AbstractBanded spindle‐shaped structures consisting of packed cylindrical units were observed among the typical collagen fibrils in the notochord sheath or in the intercellular space between notochord cells of Salmo irideus larvae. The banded spindle‐shaped structures showed a regular periodicity ranging from 750–1000 Å and cylindrical structures which appear to be packed in hexagonal arrays so that six cylinders surrounded a central cylinder. Both banded and cylindrical structures appeared to be the same bodies in three dimensions. These banded structures may originate from surrounding collagen fibrils.On the other hand, comb‐shaped structures were found between the elastica externa and the collagen fibrils of the notochord sheath in newly hatched S. irideus larvae and in fry. The width of the structures was about 0.25 Å in the widest part. The banding showed a regular periodicity ranging from 500–600 Å. These structures may play a role in adhesion of the elastica externa to the underlying collagen fibrils of the notochord sheath.
Alterations in the fine structure of cardiac muscle mitochondria induced by hyperthyroidism
Authors: Callas Gerald , Hayes James R. 
Published: February 2005

AbstractChronic hyperthyroidism was induced in radiothyroidectomized adult albino rats by feeding a diet of 0.3–0.4% desiccated thyroid for four to ten weeks. The left ventricle from control and hyperthyroid animals was examined with the electron microscope after perfusion fixation with 3% phosphate buffered glutaraldehyde and postfixation in 1% osmium tetroxide. No differences were discerned in the appearance of the Golgi zone, glycogen, lipid, lysosomes, sarcoplasmic reticulum, or the sarcomere ultrastructure of the ventricle from hyperthyroid animals compared with untreated animals. Changes were noted in the mitochondria. These included marked hypertrophy without increase in numbers and localized areas of vacuolization and disorientation of the cristae. Apparently these changes are reversible since the ventricular mitochondria of previously hyperthyroid animals allowed to return to a euthyroid state were indistinguishable from those seen in the control group.
Ultrastructural differentiation of Leydig cells in the fetal and postnatal hamster testis
Authors: Gondos Bernard , Paup Donald C. , Ross James , Gorski Roger A. 
Published: February 2005

AbstractLeydig cells appear in the hamster testis between 12 and 13 days gestation. The cells are round to oval, with prominent lipid droplets, abundant smooth endoplasmic reticulum, large mitochondria with tubular cristae and well developed Golgi complexes. Cells of this type are found in pairs and groups around interstitial blood vessels during the last three days of gestation and up to the fourth day after birth, when regressive changes begin to appear. During the second postnatal week, most cells in the interstitial regions are undifferentiated, with only a few scattered partially differentiated Leydig cells remaining. The time during which fully differentiated Leydig cells are present encompasses the period of sexual differentiation of the reproductive ducts and the critical period for differentiation of sexual behavior.
Pancreatic islets of the Coturnix quail. A light and electron microscopic study with special reference to the islet organ of the splenic lobe
Authors: Smith Phillip H. 
Published: February 2005

AbstractThe endocrine pancreas of the Coturnix quail consists of two major islet configurations. Islets containing B and D cells are found in all four lobes of the pancreas, but islets consisting of A and D cells occur with regularity only in the third and splenic lobes. Pancreatic islets comprise only a small percentage of the tissue volume in the ventral, dorsal and third lobes. In the splenic lobe, however, one or more A islets surrounded by numerous small B islets may constitute more than 50% of the total cellular mass.Secretory granules of the B cells are aldehyde fuchsin‐positive and show three distinct profiles at the ultrastructural level. The PTAH‐positive A granules are usually round or teardrop shaped and are of uniform electron density. D cells are argyrophilic; their secretory granules are of heterogeneous densities. These cells are located at the peripheries of the B islets, but are freely dispersed in the A islets. At the electron microscopic level, Type IV cells, previously not reported in avian islets, are found mainly in the A islets of this species. This unusual cell type contains granules of differing densities, but, unlike those of the D cell, they are often rod‐shaped and biconcave in profile.Because of the distinct segregation of islet types, and the peculiar arrangement of the D and Type IV cells within the two kinds of islets, it is suggested that the Japanese quail may serve as a model for investigations of avian islet function.
Sequential changes in weight, density, and percentage ash weight of human skeletons from an early fetal period through old age
Authors: Trotter Mildred , Hixon Barbara B. 
Published: February 2005

AbstractThe weight, density and percentage ash weight of the dry, fat‐free osseous human skeleton have been examined from 16 weeks of gestation to 100 years of age. Data were drawn from 426 skeletons of American Whites and Negroes of both sexes.Weight increases exponentially in the fetus and continues to increase to early adulthood, most rapidly in the second decade. A decrease appears about the fourth decade and continues gradually. Estimated loss in skeletal weight throughout the adult period is, on the average, 15.6 gm per year. Proportionate contributions of divisions of the skeleton to its total weight change with age.Densities of bones follow the changing weight pattern. Volume and weight increase concomitantly to adulthood, when weight decreases but not volume.Percentage ash weight increases slightly in the total skeleton and in some bones during the fetal period, with no significant trend thereafter, indicating that change in weight of a dry, fat‐free bone is accompanied by change in ash weight.Race and sex differences are not evident in the fetal skeleton, but become marked by the second decade of life: Negro skeletons exceed White skeletons and male skeletons exceed female skeletons in mean weight and density and, to a lesser degree, in percentage ash weight.
Uptake of exogenous protein by the preimplantation rabbit
Authors: Hastings Richard A. , Enders Allen C. 
Published: February 2005

AbstractA study of the uptake of exogenous proteins, peroxidase, ferritin, and myoglobin by rabbit blastomeres of different developmental stages was undertaken to determine some of the means by which these stages ingest protein. Exposure of embryos in preimplantation stages, ranging from fertilized ovum to late blastocyst, was carried out in vitro with selected in vivo controls. Blastomeres of early cleavage stages up to the morula show little uptake of peroxidase. However, the endocytosis of peroxidase greatly increases with the morula stages and continues at an elevated level through the blastocyst stages. The uptake of the tracer is initially accomplished via micropinocytotic vesicles and tubules and can have several subsequent fates. The tracer can pass into larger vacuoles and be transported into the cavity of the blastocyst, or can pass into multivesicular bodies where it is presumably degraded by the lysosomal system for cellular use. The use of myoglobin at selected blastocyst stages yielded results similar to those obtained with peroxidase. However, the response by the blastomeres to ferritin is different. Endocytosis of ferritin is scant at all preimplantation stages, even though the ferritin has no difficulty reaching the surface of the blastomeres. The experiment with mechanically denuded blastocysts indicated that ferritin did not adsorb to the cell surface.
Breeding activity, preimplantation development, and oviduct histology of the short‐tailed fruit bat, Carollia, in captivity
Authors: De Bonilla Hela , Raseiler John J. 
Published: February 2005

AbstractThe reproductive biology of Carollia was investigated histologically in 113 females sacrificed at timed intervals after mating in a laboratory colony. A high incidence (44%) of non‐pregnant animals could be partially attributed to occasional mating activity at times other than close to ovulation. Breeding success also improved as the males and females were housed together for increasing periods of time. At least 25% of the bats had adrenal cortical‐like tissue in the vicinity of the ovaries.Ovulation of the single ovum usually occurred within 48 hours of the onset of female receptivity to the male. Both ovaries were functional, but there was a tendency towards the alternation of successive ovulations. The blastocyst stage was reached and the zona pellucida was lost in the oviduct between days 10 and 12 post‐coitum. Blastocysts entered the uterus between days 13 and 16. The slow tubal journey of the ovum is presumably related to the occurrence of mensturation close to the time of ovulation and to the fact that most uterine growth is deferred until after ovulation. Additional ovulations and a new conception were observed during the course of several preexisting pregnancies.Differential stimulation of the two oviducts was evident both prior to and after ovulation. The oviductal secretory cells became engorged during the tubal journey of the ovum with a substance that was Alcian blue 8GX‐ and Giemsa (pH 4.5)‐negative. Occasionally this material could be stained by the PAS procedure.
Collagen remodelling by fibroblasts in wound repair. Preliminary observations
Authors: Cate A. R. Ten , Freeman E. 
Published: February 2005

AbstractConnective tissue remodelling has been studied at the fine structural level at the periphery of skin wounds repairing by both first and second intention. The periphery of such wounds was studied as it was predicted that not only would remodelling between old and new connective tissue be taking place, but that the fibroblast would be involved. Excisional and incisional wounds were made in the skin of adult mice and biopsied 14 days later. Our results showed that numerous fibroblasts in the junctional zone between old and new connective tissue exhibited intracellular collagen within vesicles. These findings indicate that the fibroblast is capable of phagocytosing and degrading collagen and has a fundamental role to play in connective tissue remodelling.
Electromyography of pectineus muscle
Authors: Takebe Kyoichi , Vitti Mathias , Basmajian John V. 
Published: February 2005

AbstractUsing bipolar fine‐wire electrodes, we investigated the function of the pectineus muscle. Electromyography revealed that the main function of pectineus muscle is flexion, adduction and medial (not lateral) rotation of the hip joint. These functions suggest that the spasm of this muscle may be important in the cause of deformities in cerebral palsy.
Capacitation of boar spermatozoa: The influence of post‐coital separation of the uterus and fallopian tubes
Authors: Hunter R. H. F. , Hall J. P. 
Published: February 2005

AbstractThe minimum period of uterine exposure required by ejaculated boar spermatozoa as a preliminary to rapid capacitation has been determined after natural or surgical deposition of sperm samples directly into the uterine lumen. Twenty‐four oestrous gilts were mated or inseminated close to the time of ovulation, and 15, 30, 45 or 60 minutes later, the Fallopian tubes were separated from the uterine cornua. The tubes were flushed at pre‐arranged intervals during a second intervention, and the proportion of eggs penetrated and activated examined by phase‐contrast microscopy.On the basis of 166 eggs recovered from eighteen mated gilts, a period of uterine exposure as brief as 30 minutes, when followed by a tubal residence of approximately three hours, permitted 30.3% of the eggs to be activated; this proportion increased to 51.6% and 60.5% if the tubes were isolated 45 or 60 minutes, respectively, after mating (p < 0.001), as did the mean number of spermatozoa associated with the eggs. When the cornua were separated from the tubes 15 minutes after semen deposition into the uterus of six animals, 11.3% of 62 eggs were fertilized during the ensuing three and one half hours, but very few spermatozoa had reached and/or attached to the eggs in this group.It is concluded that a population of boar spermatozoa potentially capable of effecting fertilization may enter the tubes within 15 to 30 minutes of mating near the time of ovulation, and that such vanguard spermatozoa can activate a proportion of the eggs within a further two to three hours. Thus, from a temporal point of view, the major components of the capacitation process in oestrous pigs are inferred to take place in the Fallopian tubes.
Enzymatic liberation of myogenic cells from adult rat muscle
Authors: Bischoff Richard 
Published: February 2005

AbstractFive different proteolytic enzymes, trypsin, pronase, collagenase, papain and ficin, were tested for their ability to liberate mononucleated myogenic cells from adult rat muscle. Fragments of leg and thigh muscle from 350–400 gm rats were incubated with enzyme for one hour and mononucleated cells were separated from the partially digested fragments by centrifugation. Myogenic capacity of the isolated cells was tested in culture using procedures known to support differentiation of embryonic rat muscle. Although all the enzymes released viable cells from the muscle, myogenesis in vitro was obtained only from cells liberated by trypsin or pronase. The other three enzymes released fibroblasts, macrophages and fat cells but no presumptive myoblasts. Light and electron microscopic examination of the digested muscle revealed that the enzymatic release of myogenic cells is dependent upon removal of the basement lamina surrounding the fibers. Trypsin and pronase dissolve the basement lamina, whereas collagenase, papain or ficin do not. These findings demonstrate that a population of myogenic stem cells exists in fully mature, non‐regenerating adult muscle. The frequency of these cells and the conditions required for their release suggest that they are identical with the muscle satellite cells.
The repair of fractured membrane bones in the newly hatched chick
Authors: Hall B. K. , Jacobson H. N. 
Published: February 2005

AbstractRepair of a fractured membrane bone, the quadratojugal (QJ), has been studied in the newly hatched chick. Complete open fractures never united by bony fusion, even in birds maintained for six months post‐fracture. Extraperiosteal connective tissue invaded the fracture gap and formed thick fibrous bundles which stabilised the fracture. Cartilage of two types formed on these bones. One was derived from periosteal cells and the other from osteoblasts or osteocytes. Considerably more cartilage formed in bones partially fractured than in those completely fractured. The “periosteal” cartilage did not form if the periosteum was removed at the time the bone was fractured. This was because, although the fibrous layer of the periosteum regenerated, the cambial layer did not. Metaplastic cartilage did form in the absence of the periosteum.Isolating fractured bones within polyethylene or glass tubes prevented accumulation of a blastema between the bony fragments. Cartilage did not form in side the tubes but did form where the ends of the tubes abutted onto the bones.Large defects in the bones (4 mm gaps, 4 mm of bone in the place of the QJ) healed via fibrous union with minimal osteogenesis and no chondrogenesis.Severing M. depressor mandibulae at the time the bone was fractured inhibited chondrogenesis, favoured osteogenesis and resulted in development of a pseudarthrosis.The potential for differentiation of the cells of the QJ and the role of adjacent tissues as they related to repair of the fracture was discussed, and the ability of cells from membrane bones to become chondrogenic emphasized.
The blood‐brain barrier of the rat choroid plexus
Authors: Davis Donald A. , Milhorat Thomas H. 
Published: February 2005

AbstractFollowing intravenous injection, cytochrome c traverses the capillary endothelium of the rat choroid plexus and permeates the perivascular space and the extracellular space between epithelial cells. The tracer is incorporated into pinocytotic vesicles adjacent to the lateral and basal plasmalemmas. There‐after, cytochrome c is incorporated into multivesicular and dense bodies. Tracerladen vesicles were not found to fuse with the apical plasmalemma and cytochrome c was not discharged into the cerebral ventricles. Acid phosphatase activity of the choroidal epithelium after the administration of cytochrome c was greatly increased and localized in the same intracellular sites shown for cytochrome c. These data suggest that cytochrome c and possibly other proteins that penetrate the choroidal stroma are taken up by the choroidal epithelium and subsequently degraded in lysosomal vesicles. This heterolytic mechanism may be an important means for preventing the entry of certain substances such as proteins into CSF and subsequently into nervous tissue.
The development of proline‐containing extracellular connective tissue fibrils by chick notochordal epithelium in vitro
Authors: Lauscher Cristina K. , Carlson Edward C. 
Published: February 2005

AbstractNotochords were isolated from Hamburger‐Hamilton stages 13–15 chick embryos by trypsinization and microdissection. These were shown by electron microscopy to be completely devoid of extracellular materials or mesenchymal contaminants. Cultivation of notochordal isolates was carried out on a non‐collagenous (Falcon Plastic) substratum for 0 to 48 hours. At 12 hours of in vitro incubation, a discontinuous basal lamina could be demonstrated on the surface of notochordal cells. This was followed by the appearance of microfibrils of various sizes and other components of the extracellular matrix. By 48 hours of in vitro incubation, the same extracellular materials which surround the notochord in vivo (notochord sheath) could be demonstated in vitro.Autoradiographic studies show that tritiated proline is taken up by notochordal cells and secreted to the extracellular space where label is associated with basal lamina, microfibrils and ground substance. When cis‐hydroxyproline, a known collagen‐specific inhibitor is added to the system, tritiated proline label is located primarily intracellularly and fewer areas of active fibrillogenesis are noted. This suggests that ultrastructurally recognizable materials produced by notochordal cells in vitro may be at least partially collagenous. Significantly, these materials are produced in vivo at the same time (following stage 10) that notochordal tissues actively induce somite differentiation and cartilage formation. It seems reasonable that a biochemically or ultrastructurally identifiable component of the extracellular matrix may possibly mediate such induction.
In vitro development of palatal tissues from embryonic mice. I. Differentiation of the secondary palate from 12‐day mouse mebryos
Authors: Tyler Mary S. , Koch William E. 
Published: February 2005

AbstractSingle palatal processes or homotypic paired palatal processes from 12‐day mouse embryos (strain C57B1) were grown in organ culture on Millipore filters. The epithelium along the medial edge of each palatal process became disrupted, and, by 72 hours of culture, paired palatal processes achieved mesenchymal fusion at the site of disruption. The nasal epithelium of paired palatal processes became a recognizable pseudostratified ciliated columnar epithelium by 96 hours of culture, and the oral epithelium became a recognizable stratified squamous epithelium by 120 hours of culture. These events correspond temporally to the differentiation of palatal tissue in vivo. Differentiative changes of single palatal processes followed the same schedule as double processes. Observations also suggest that the epithelium at the tip of the vertically oriented young palatal process corresponds to the medial epithelium of the more advanced horizontal process — these observations have bearing on the mechanism of palatal movement. In addition, the results suggest that a re‐evaluation of the terminology “potential for fusion” is necessary.
Light and electron microscopic study of the effects of ZnSO4 on mouse nasal respiratory epithelium and subsequent responses
Authors: Matulionis Daniel H. 
Published: February 2005

AbstractThe effects of ZnSO4 irrigation on mouse nasal respiratory epithelium (NRE) and subsequent responses of the tissue were studied at the light and electron microscopic levels in two different strains of mice (C57B1/6J and SWR/J).The most marked effect of the ZnSO4 took the form of necrosis and sloughing of surface cells in both strains one‐half day after ZnSO4 irrigation. This treatment caused maximal change in a different cell type in each of the two strains. Ciliated cells were most noticeably affected in the C57B1/6J strain, secretory cells in the SWR/J strain. Subsequent manifestations of recovery differed accordingly in each strain. In the C57B1/6J mice numerous dividing surface cells and large areas of tall nonciliated and ciliating cells were prominent two to five days after treatment. Secretory cells appeared normal but were reduced in numbers during this time, indicating that they were also affected by the treatment. The NRE of this strain was normal by the fourteenth day following treatment. The NRE of SWR/J animals, on the other hand, contained no visibly dividing cells and no large areas of nonciliated cells during the first four days following treatment, although a few ciliating cells were present at this time. The secretory cell population in these animals was normal after five days but individual cells deviated from normalcy by containing numerous dilated cisternae of rough endoplasmic reticulum which persisted in the secretory cells during the remainder of the experiment.
The bony tentorium of the cat: Stereotaxic coordinates
Authors: Lucas E. A. 
Published: February 2005

AbstractThe cat's tentorium cerebelli is an osseous structure which overlies much of the brain stem. None of the current brain atlases list the coordinates of this bony projection. With a stiff wire and a stereotaxic apparatus, the location of its free edge and dorsal surface was mapped in 1.0 mm steps in the skulls of 16 cats. In the midline the dorsal surface meets the calvaria at a point 7 mm posterior and 15 mm superior to the atlas zero (intra‐aural plane + 10 mm horizontal). From this junction it slopes inferiorly and anteriorly between the cerebrum and cerebellum along a 50° slope to terminate along a curved line. In the midline this free edge is located 0.5 mm anterior, and 6.5 mm superior to the atlas zero. It recedes laterally along a curved line to a point 6 mm lateral, 6 mm superior and 3 mm posterior to the atlas zero. The free edge then curves forward and descends to pass through an imaginary line 3 mm anterior and 4.5 mm inferior to the atlas zero. Statistical comparisons between measurements made in male and female cats revealed no significant differences.