bluuebunny/crossref_metadata_2025_split huggingface dataset:
5‐Hydroxytryptamine causes contraction of smooth muscle cells in preovulatory hamster follicles
Authors: Talbot Prudence , Schroeder Paul C. 
Published: June 2005

AbstractWe have examined the effect of 5‐hydroxytryptamine (5‐HT) on ovaries removed from hamsters and placed in culture 12 or 13 hours after hCG injection. The four responses to 5‐HT which were studied include: (1) contraction of follicular smooth muscle cells (SMC), (2) formation of a V‐shaped constriction in the base of follicles, (3) changes in the profile of follicles, and (4) changes in intrafollicular pressure. Our results show that 10−3 M 5‐HT alters the ultrastructure of follicular SMC to that characteristic of a contracted state. The contraction of these SMCs produces in turn: (1) a V‐shaped constriction in the base of the follicle similar to that observed in unstimulated 13 hour ovaries undergoing in vitro ovulation (Martin and Talbot, '81a), and (2) a change in the profile of the follicle which becomes taller and more spherical, but not identical to the “true” tall follicle seen during normal in vitro ovulation. The fact that 5‐HT does not change the follicle to a “true” tall profile and does not induce immediate ovulation in most cases (even though SMC are contracted) suggests to us that the apices of these follicles were not sufficiently weakened by enzymes to permit immediate rupture when SMC contracted. The response of SMC to 5‐HT was immediate, rapid, sustained at least 10 minutes, and could be inhibited by methysergide. The latter observation suggests that 5‐HT interacts with “D” receptors of SMC and not “M” receptors of nervous tissue. The degree of contraction elicited by 5‐HT varied from one follicle to another; many SMC did not appear maximally contracted by morphological criteria. Intrafollicular pressure increased in most follicles treated with 5‐HT; pressure returned to initial levels relatively quickly, presumably because fluid was able to seep through developing ruptures in the apex. Intrafollicular pressure does not increase during unstimulated in vitro ovulation (Schroeder and Talbot '82). We interpret the intrafollicular pressure data of this study to mean that 5‐HT elicits a much more rapid contraction of SMC than would ordinarily occur in vitro. Thus, SMC contraction in follicles not stimulated by 5‐HT would be a slow, gradual, process allowing constant or decreasing levels of pressure to be maintained. Our observations are important in directly showing that: (1) 5‐HT stimulates contraction of SMCs in hamster follicles, and (2) this contraction produces a V‐shaped constriction in the base of the follicle and a change in the profile of the follicle, and (3) that intrafollicular pressure will increase abruptly upon strong, simultaneous contraction of follicular SMC. These observations provide further support for our earlier statement that SMC function in hamster ovulation (Martin and Talbot,'81a).
Remarkable blood catecholamine levels in forced dived ducks
Authors: Hudson Dennis M. , Jones David R. 
Published: June 2005

AbstractLevels of circulating epinephrine (E) and nor‐epinephhrine (NE) were measured in duck blood before, during, and after forced dives which were extended close to the limit of underwater endurance. Both E and NE increased by, on occasion, three orders of magnitude. After surfacing, plasma catecholamine levels fell rapidly. The reason for this enormous amine release in forced dived ducks remains a matter of speculation.
Cellular localization of estradiol in the Harderian gland of the female armadillo
Authors: Weaker Frank J. , Villareal Cynthia , Sheridan Peter J. 
Published: June 2005

AbstractAdult female armadillos were injected with tritiated estradiol. The Harderian gland was removed and processed for autoradiography. Nuclear uptake and retention of the steroid were observed in the duct of the gland, the periductal mucous cells of the mucus‐secreting lobules, and the fibroblasts in the interstitial connective tissue.
β‐Alanine oxidation in the liver of the little skate, Raja erinacea
Authors: Leech Anthony R. , Goldstein Leon 
Published: June 2005

AbstractThe pathway of β‐alanine (BALA) oxidation was examined in the liver of the little skate, Raja erinacea. BALA oxidation in liver slices was reduced by inhibitors of transamination and mitochondrial electron transport. Experiments with liver homogenates indicated that BALA was oxidized by a two step process: (1) transamination of BALA to malonate semialdehyde (MSA) and (2) conversion of MSA to CO2 and acetate. Increases in BALA oxidation during osmotic stress are probably mediated by changes in substrate concentration rather than alterations in enzyme levels.
Penetration of zona‐free hamster eggs by boar sperm treated with the ionophore A23187 and inhibition of penetration by antiplasma membrane antibodies
Authors: Smith Michael , Peterson R. N. , Russell Lonnie D. 
Published: June 2005

AbstractUncapacitated boar sperm treated with the divalent cation ionophore A23187 in the presence of calcium bind to and penetrate zone‐free hamster eggs. Penetration by ionophore‐treated sperm is, however, blocked when sperm are pretreated with antisperm plasma membrane Fab. The antibody apparently interferes with the interaction of sperm surface antigens with the egg plasma membrane since the antibodies have no significant effect on the motility of sperm nor on the induction of the acrosome reaction by the ionophore. The assay described herein is useful for studying the role of sperm surface antigens in the penetration and fertilization of eggs.
Levels of cyclic GMP and cyclic AMP in regenerating forelimbs of adult newts following denervation
Authors: McLaughlin Hooley M. G. , Rathbone Michel P. , Liversage Richard A. , McLaughlin Danielle S. 
Published: June 2005

AbstractThe effect of short‐term denervation (0, 12, 24, and 72 hours) on the levels of cyclic 3′5′‐guanosine monophosphate (cGMP) and cyclic 3′5′‐adenosine monophosphate (cAMP) in adult newt (Notophthalmus viridescens) fore limbs at 15, 22, and 35 days of regeneration was investigated. Regenerate blastema and stump cyclic nucleotide levels were compared with those of the contralateral intact forelimb and hindlimb, with levels in the normally regenerating blastema, and with levels measured in the forelimbs of intact, nonoperated animals. Variations in cyclic nucleotide levels occurred according to regeneration stage and tissue type. Changes in level were noted immediately upon denervation and subsequently at other sample times in all regenerate and control series. Parallel fluctuations occurred in regenerate stump and contralateral intact forelimbs. Our results from nonamputated denervated and sham‐denervated animals indicate that short term, denervation‐associated cyclic nu eotide fluctuations cannot be attributed solely to the loss of innervation.
Incorporation of [14C]glucose into the tunic of the ascidian, Ciona intestinalis (linnaeus)
Authors: Robinson William E. , Kustin Kenneth , McLeod Guy C. 
Published: June 2005

AbstractThe tunic of Ciona intestinalis contains tunicin fibers, blood cells, and a mucopolysaccharide ground substance. [14C]Glucose is rapidly taken up by the epidermal cells of the body wall underlying the tunic. Radioactivity is incorporated into the tunic, eventually becoming uniformly distributed throughout this structure during the 21‐day postlabeling period. This labeled material is easily removed by mild acid hydrolysis, a procedure that separates the ground substance and most protein from the tunic. We conclude that the majority of the [14C] glucose is utilized by the epidermal cells in the production of the mucopolysaccharide of the ground substance. Some label remains associated with the tunic residue even after extensive acid hydrolysis, however, indicating that only a small amount of the labeled glucose may be incorporated into the tunicin fibers themselves.
Nocturnal rhabdom cycling and retinal hemocyte functions in crayfish (Procambarus) compound eyes. II. Transmission electron microscopy and acid phosphatase localization
Authors: Waterman Talbot H. , Piekos W. Barry 
Published: June 2005

AbstractCytoplasmic synthetic organelles (Golgi complexes, polysomes, and rough and smooth endoplasmic reticulum) are present in most photoreceptor cells of the crayfish retina in winter throughout the late‐night 24:00 to 06:00 h period. These same retinular cells contain few or no lysosome‐like bodies. There is no evidence for autophagic receptor membrane breakdown even during the degradative phase (24:00 to 02:00 h) of the late‐night quadrant.The fine structure of rhabdom microvillus bases and their continuity with retinular cell somata and endoplasmic reticulum differ characteristically in each of the three successive turnover phases between 24:00 and 06:00 h. Typical stalked attachment of microvillus clusters to retinular cell bodies is resumed by 06:00 h.A minority of retinulas are severely abnormal. Their rhabdoms are shorter and closer to the basement membrane while their receptor cell nuclei have descended proximally. During the degradative phase, the retinular somata may lack synthetic organelles altogether while their rhabdoms are disorganized, detached from their parent cytoplasm, and occasionally invaded by hemocytes. In contrast, synthetic organelles are numerous in the cytoplasm during the late synthetic phase (03:00 to 04:00 h) when photoreceptor membranes are less disrupted and cytoplasmic bridges between rhabdoms and cell bodies are intact.Both moderate late‐night degradation of the rhabdom and the less frequent catastrophic breakdown seem to be mediated by extracellular lysozymes provided in part by retinal hemocytes. Acid phosphatase localization at the beginning of the degradative phase (24:00 to 00:30 h) demonstrates that invasive granulocytes are a primary source of this enzyme. Another hemocyte function previously hypothesized is proven here by finding phagocytized fragments of rhabdom and other retinal elements in most of the retinal macrophages during late‐night synthetic and resting phases.
Effects of microphthalmic white (Miwh) on the number and function of cutaneous melanocytes
Authors: Pratt Bruce M. 
Published: June 2005

AbstractMicrophthalmic white (Miwh), when heterozygous, causes dilution of black fur to a uniform gray color. Miwh/+ also reduces the coloration of ear and tail skin. The present study, a quantitative assessment of the effects of Miwh/+ on cutaneous melanocytes, demonstrates that the primary effect of Miwh/+ on cutaneous pigmentation is to reduce the number of epidermal melanocytes. There is also indirect evidence that Miwh/+ reduces the rate of melanosome production within follicular melanocytes. These actions of Miwh/+ cause both lightened coloration of ear and tail skin and the deposition of fewer numbers of smaller melanosomes within the hair.
Distribution of photoreceptors inducing ciliary reversal and swimming acceleration in Blepharisma japonicum
Authors: Matsuoka Tatsuomi 
Published: June 2005

AbstractThe distribution of photoreceptors was examined with respect to those initiating ciliary reversal and those inducing acceleration of swimming. Ciliary reversal was caused when a light stimulus was applied to the anterior end of the animal; the response did not occur when the light was applied to a region within the posterior three‐fifths of the animal. On the other hand, acceleration of swimming was induced by light application to both anterior and posterior fragments. These differences in response suggest that the photoreceptors initiating ciliary reversal are different from those inducing acceleration of swimming.
Morphological and physiological identification of motor neurons innervating flight musculature in the cockroach,Periplaneta americana
Authors: Ritzmann Roy E. , Fourtner C. R. , Pollack Alan J. 
Published: June 2005

AbstractMorphological and physiological data were used to establish which motor neurons innervate known wing elevator and depressor muscles. Nerves to identified muscles were backfilled to establish the neuropilar morphology of neurons innervating each muscle. Individual motor neurons were recorded intra‐cellularly during flight sequences and then filled. The intracellularly identified cell was then matched with backfilled cells that had similar ganglionic morphology, exited the same nerve root, and had the same function during the flight cycle. In this way the target muscle of five elevator and five depressor motor neurons was established.
Catalytic properties of the sperm‐specific lactate dehydrogenase (LDH X or C4) from different species
Authors: Coronel Carlos E. , Burgos Carlos , Gerez De Burgos Nelia M. , Rovai Leonor E. , Blanco Antonio 
Published: June 2005

AbstractA comparative study of catalytic properties of the sperm‐specific lactate dehydrogenase (EC 1.1.1.27) isozyme X or C4 from a variety of animals (boar, bull, goat, Guinea pig, man, mouse, pigeon, rabbit, and rat) is presented. Optimum concentration and Km values for pyruvate, inhibition by substrate, and activity against analog substrates (α‐ketoacids with linear and branched chains from 4 to 6 carbon atoms) for isozyme X of different species showed significant differences. The observed properties are correlated with available evidence on the metabolic role of the enzyme.
Thiosemicarbazide‐induced osteolathyrism in metamorphosing Xenopus laevis
Authors: Newman Samuel M. , Dumont James N. 
Published: June 2005

AbstractExposure of Xenopus laevis tadpoles to thiosemicarbazide (TSC), at concentrations from 10 to 75 mg/liter, causes an inhibition of metamorphosis and produces the classic manifestations of the experimental disease, osteolathyrism. Concentration‐dependent effects of TSC exposure are observed in growth rate and in the severity of the osteolathyrogenic effect. Concentrations allowing the most rapid growth produce the more extreme osteolathyrogenic defects. Osteolathyrism in these animals is identical in characteristics to the condition described in a wide variety of vertebrate species.In Xenopus, osteolathyrism is expressed morphologically as anomalies in bone development, skeletal conformation, and abnormal connective tissue organization in the aorta wall. The underlying defect responsible for these observations is apparently a perturbation of collagen fiber formation and maturation, as evidenced ultrastructurally by aberrant distribution and packing of collagen fibers. It is suspected that TSC produces this effect by altering the availability of copper ion, a cofactor to lysyl oxidase, an essential enzyme for intermolecular cross‐linking of procollagen. This step in collagen metabolism has been consistently implicated as the site of action of several osteolathyrogenic agents.Xenopus tadpoles present a classic response to this known osteolathyrogen and demonstrate a high degree of uniformity of response within the experimental groups. In view of the developmentally significant events accessible with this system and inherent logistic and economical advantages, the metamorphosing tadpole of Xenopus holds considerable potential for the experimental analysis of teratogenic agents and events.
Immunofluorescent localization of a seminal vesicle proteinase inhibitor in the female reproductive tract of naturally inseminated mice
Authors: Nicholson Nanette , Irwin Michael , Poirier Gary R. 
Published: June 2005

AbstractThe indirect immunofluorescent technique was used to localize a low molecular weight, acid‐stable proteinase inhibitor of seminal vesicle origin in the female reproductive tract of mice. In recently inseminated animals (0, 2, and 4 hr postcoitus) the inhibitor was localized in the copulatory plug, on the epithelia of the vaginal fornix and cervix, in the uterine lumen, and on the apical surface of the uterine epithelium. Ten hours postcoitus the inhibitor was found in localized areas on the uterine epithelium, in a sperm‐leucocyte mass in the uterine lumen, and in the copulatory plug. The inhibitor was not found in females 24 hr postcoitus. The inhibitor could not be localized in the oviducts of any of the animals tested. The data are interpreted to mean that the inhibitor, transported to the female at ejaculation, coats the surface of the female reproductive tract protecting it from acrosomal enzymes or from invasion by spermatozoa or pathogens.
Effects of protease inhibitors on early events in the conjugation of Paramecium caudatum
Authors: Kitamura Akio 
Published: June 2005

AbstractThe effects of 11 different protease inhibitors on mating reactivity and pair formation in the conjugation process of the ciliated protozoan Paramecium caudatum were investigated. Of the 11 inhibitors tested, six microbial and three synthetic inhibitors showed no effect on either pair formation or mating reactivity even at their highest concentrations. Soybean trypsin inhibitor and ovomucoid also showed no effect on pair formation even though they temporarily repressed mating reactivity. These results indicate that the process of pair formation during the conjugation process does not involve an extracellular proteolytic reaction.
Reassortment of cells according to position in mouse morulae
Authors: Surani M. Azim H. , Handyside Alan H. 
Published: June 2005

AbstractSixteen‐cell mouse morulae were disaggregated and blastomeres originally occupying outer or inner positions were separated. Outer, inner, or unsorted populations of blastomeres were labeled with either trinitrobenzene sulphonic acid (TNP) or fluorescein isothiocyanate (FITC) and individual blastomeres aggregated to unlabelled partially decompact eight‐ to ten‐cell morulae. After up to 6 h in culture, the positions of the labelled blastomeres within the aggregates were examined. The combined results demonstrated that between 86 and 92% of outer cells remained on the surface of the aggregate and flattened into extensive polygonal shapes, whereas 76–77% of the inner cells had become engulfed by the host morula cells and retained their initial spherical shape. Using unsorted cells, 33–37% were internalised, which is compatible with the most recent estimates of the presence of six to eight inner cells at the 16‐cell stage. The possibility that differential adhesiveness of the outer and inner cells is involved in the allocation of cells to the trophectoderm and inner cell mass of the blastocyst is discussed.
Intrafollicular pressure promotes partial evacuation of the antrum during hamster ovulation in vitro
Authors: Talbot Prudence 
Published: June 2005

AbstractThe role of intrafollicular pressure in evacuation of the hamster cumulus from the follicle at ovulation was investigated experimentally in vitro. Previous work has shown that the cumulus is generally evacuated in two stages (Talbot, '82). Phase 1 occurs immediately at rupture and is characterized by rapid (<60 seconds) extrusion of about 20% of the cumulus and usually the oocyte. Phase 2 includes the gradual (2–10 minutes) removal of the remainder of the cumulus and collapse of the follicle wall. Fresh or aged follicles (approximate intrafollicular pressures = 2.1 or 0.0 mmHg, respectively) were poked with “0” gauge insect pins to produce a rupture site in their apices. Of 69 fresh follicles tested, 68 responded with phase 1 extrusion; 57 of the 68 evacuated the oocyte in addition to a significant portion of the cumulus. In contrast, only seven out of 80 aged follicles showed phase 1 extrusion, and only three out of these seven extruded the oocyte. To verify that phase 1 extrusion in fresh follicles was due to intrafollicular pressure and not smooth muscle cell (SMC) contraction, some fresh poked follicles were fixed for microscopy. Twelve of 14 follicles had flat bases or small V‐shaped constriction in their bases, indicating SMC contraction had not occurred. This was further substantiated by examining several follicles with transmission electron microscopy; SMC in the theca externa were relaxed by morphological criteria. To determine if phase 2 extrusion occurred in poked follicles, fresh follicles were poked, cultured in vitro for 3 hours, and examined microscopically. Phase 1 occurred in all follicles after poking. The remainder of the cumulus was eventually evacuated from the antrum, although much more slowly than during normal in vitro ovulation. The follicle wall did not collapse in these trials. We conclude that intrafollicular pressure is responsible for phase 1 extrusion, i.e., rapid passage of part of the cumulus and oocyte through the rupture site, and that intrafollicular pressure will promote phase 1 extrusion in the absence of SMC contraction. The remainder of the cumulus can be evacuated in the absence of IFP and collapse of the follicle wall; perhaps this occurs by hydration of that portion of the cumulus evacuated during phase 1. Hydration would tend to expand the cumulus and pull the remaining cumulus from the antrum. These results establish a role for intrafollicular pressure in hamster ovulation.
Fertilization and cleavage of bovine follicular oocytes in rabbit reproductive tracts after maturation in vitro
Authors: Fukui Yutaka , Fukushima Moriyuki , Ono Hitoshi 
Published: June 2005

AbstractBovine follicular oocytes cultured in vitro in Ham's F‐12 based medium for 27 hours were transferred to the oviducts of rabbits pretreated with 75 IU hCG 24 hours previously. Frozen‐thawed bull spermatozoa were inseminated into the uterus of rabbits 0, 2, 4, 6, 9, and 12 hours before oocyte transfer. Fertilization and cleavage were examined in the oocytes recovered from the oviduct and uterus 24 and 48 hours later. The criteria of fertilization were the presence of an enlarged sperm head, sperm tail, and pronuclei in the vitellus. Bull spermatozoa inseminated 4 hours before oocyte transfer showed the highest rates of fertilization at both 24 and 48 hours (35% and 38%) compared to the other preincubation times. The numbers of cleaved oocytes were also greater at these times. The results indicate that the capacitation time of cryopreserved bull spermatozoa in the rabbit reproductive tract is the same as in the bovine tract—i.e., 4–6 hours.
Photoperiodic control of reproduction in a female migratory bunting (Emberiza bruniceps)
Authors: Tewary P. D. , Tripathi B. K. 
Published: June 2005

AbstractTwo series of experiments were performed with photosensitive female redheaded buntings. In the first series, birds were exposed to various cycles (8L/16D, 12L/12D, 13L/11D, 15L/9D, and 20L/4D) for 35 days. In the second, birds were maintained for a period of 120 days under long day lengths (15L/9D), short day lengths (8L/16D), and normal day lengths (NDL). Periodic laparotomies of birds under these schedules indicated that long days induced ovarian growth followed by regression and refractoriness, short days were ineffective, and that the birds in NDL showed ovarian growth during periods in the summer of increasing day lengths, followed by spontaneous regression. Groups of photorefractory birds in long days were transferred to short days (8L/16D) for different periods in order to terminate the refractoriness before returning them to 15L:9D for another 20 days. The results from both series of experiments suggest that the female redheaded bunting uses photoperiods as a primary environmental source of information in regulating its reproductive responses. The threshold for its gonadal activities is a photoperiod of 12–13 h daily. A period of insensitivity (photorefractoriness) develops in buntings that are photostimulated, requiring about 8 weeks of short days for its termination.