bluuebunny/crossref_metadata_2025_split huggingface dataset:
An analytical model for the optimisation of maintenance profitability
Authors: Oke S.A. 
Published: January 2005

PurposeThe paper presents a mathematical model that measures the profitability of the maintenance system based on the traditional accounting definition of profitability. There is currently a dire need for an article presenting a scientific‐based framework for practitioners in maintenance to make optimal instead of sub‐optimal decisions on profitability. Design/methodology/approach – A case study is presented to reflect the actual application of the proposed model. Different situations were considered in modelling to obtain optimal results. Simulation experiments were conducted to demonstrate that maintenance profitability is a reality through the use of differential calculus. Findings – It was observed that the approach presented is a holistic viewpoint of maintenance profitability measurement. Research limitations/implications – An adequate understanding of the maintenance system is needed to properly implement the model. Practical implications – The practical application of the model is that the maintenance system will now be viewed as a value‐adding activity instead of “a necessary evil” or “a bottomless pit for expenses”. Originality/value – This paper fulfils an identified need and offers practical help to managers in taking guided decisions that are optimal.
Secretion of prostatic specific antigen, proliferative activity and androgen response in epithelial–stromal co‐cultures from human prostate carcinoma
Authors: CASTELLÓN ENRIQUE , VENEGAS KARINA , SÁENZ LEONARDO , CONTRERAS HÉCTOR , HUIDOBRO CHRISTIAN 
Published: January 2005

SummaryWe investigate the proliferative activity, prostatic specific antigen (PSA) secretion, morphology and androgen response of human prostate tumour epithelial cells co‐cultured with stromal cells in a bicameral system. Stromal and epithelial cells were isolated from prostate adenocarcinoma by enzyme digestion and cultured in defined media. Immunocytochemistry for prostate carcinoma tumour antigen (PCTA‐1) was performed for culture purity evaluation. Also, the morphology of the epithelial cells in co‐culture was evaluated by electron microscopy. PSA was determined by microparticle enzyme immunoassay (MEIA) automatized protocol and the proliferation was evaluated by a commercial spectrophotometric kit, based on formazan salt formation. Both cell cultures showed more than 90% of purity. The epithelial cell co‐cultures showed marked membrane processes and cell interdigitations. The proliferative activity of the epithelial cells was increased in presence of stromal cells. Also, PSA secretion was significantly increased and maintained for at least 14 days, whereas the androgen response for PSA secretion was evidenced only in co‐culture condition. Primary co‐cultures of epithelial and stromal cells from human prostate carcinoma are able to maintain, for a prolonged time, proliferative and secretory properties as well hormone response, and represent a valuable tool for cellular and molecular studies on prostate cancer.
Comparison of the outcome of intracytoplasmic sperm injection in obstructive and non‐obstructive azoospermia in the first cycle: a report of case series and meta‐analysis
Authors: GHANEM MOHAMED , BAKR NAGWA I. , ELGAYAAR MAHA A. , EL MONGY SHYMAA , FATHY HANAN , IBRAHIM ABDEL‐HAMID A. 
Published: January 2005

SummaryTo investigate the outcome of intracytoplasmic sperm injection with fresh and cryopreserved‐thawed testicular spermatozoa in the first cycle in patients with obstructive azoospermia (OA) and non‐obstructive azoospermia (NOA), a total of 90 cases, 48 OA and 42 NOA were studied. All patients underwent sperm retrieval by testicular sperm extraction (TESE) while their wives received conventional ovarian hyperstimulation. The hormone levels, testicular histology, the rates of sperm retrieval, fertilization, implantation and pregnancy were analysed and evaluated. This study and other four similar studies were subjected to meta‐analysis. Sperm retrieval was successful in 100% OA and 61% NOA. Fresh spermatozoa were used in 87.5% and 92.4% of OA and NOA cases respectively; while cryopreserved‐thawed spermatozoa were used in 12.5% and 7.6% of OA and NOA, respectively. The fertilization, implantation and clinical pregnancy rates were 65.5%, 15% and 25% respectively in OA group, and 54.2%, 5% and 23.1% respectively in NOA group. Sperm status (fresh or thawed), male partner's age, female age and male serum follicle‐stimulating hormone had no significant effect upon fertilization rate, implantation rate, or pregnancy rate per embryo transfer. The results of meta‐analysis indicate that there is no statistically significant difference in clinical pregnancy rates between the two groups. There was a significantly higher fertilization rate among OA patients in all analysed studies (95% CI = 14.29–15.71, d.f. 832, T = 1.96). In conclusion, although the fertilization rate was significantly higher in the OA group in our study and from the given meta‐analysis, there were some differences as regards pregnancy rates. Although the overall effect was more or less similar pregnancy rates in both subtypes of azoospermia, this may not be true if non‐male infertility variables were controlled for in all studies.
Venlafaxine extended release for the treatment of patients with premature ejaculation: a pilot, single‐blind, placebo‐controlled, fixed‐dose crossover study on short‐term administration of an antidepressant drug
Authors: KILIÇ S. , ERGIN H. , BAYDINÇ Y. C. 
Published: January 2005

SummaryIn this study, we aimed at evaluating the efficacy and safety of venlafaxine extended release 75 mg, a serotonin and noradrenaline reuptake inhibitor, in the treatment of patients with premature ejaculation. Thirty‐one patients with intravaginal ejaculation latency of less than 2 min received venlafaxine XR (75 mg/day) or placebo during a 2‐week period for each agent with a washout period of 1 week between agents. Efficacy was assessed for each agent with changes in ejaculation latency measured with a stopwatch and sexual satisfaction scores of patients and partners. Side‐effects, pre‐ and post‐treatment levels of biochemical and spermiogram parameters, follicle‐stimulating hormone (FSH), luteinizing hormone (LH), prolactin and total testosterone were recorded for each agent. Statistical analysis was performed on 21 patients. After 2 weeks of treatment with placebo and venlafaxine, ejaculation latency time was significantly increased from 60.1 ± 39.1 to 126.9 ± 98.3 sec and to 178.1 ± 122.8 sec, respectively (p < 0.0001 for each one). However, the difference between the two agents was insignificant (p = 0.144). Venlafaxine and placebo increased sexual satisfaction scores of both patients and partners similarly, no statistically significant difference was found between them in this respect. The incidence of side‐effects with venlafaxine was indifferent than that of placebo (p > 0.1) except nausea (p = 0.035). Both agents did not change the blood and spermiogram parameters significantly, except FSH increases.Short‐term use of venlafaxine XR 75 mg has only a placebo effect on ejaculation latency and sexual satisfaction scores, therefore, is not appropriate for the patients with premature ejaculation. Further dose‐time studies are required to draw final conclusions on the inefficacy of this drug in premature ejaculation.
Gonadal Steroid Replacement Reverses Gonadectomy‐Induced Changes in the Corticosterone Pulse Profile and Stress‐Induced Hypothalamic‐Pituitary‐Adrenal Axis Activity of Male and Female Rats
Authors: Seale J. V. , Wood S. A. , Atkinson H. C. , Harbuz M. S. , Lightman S. L. 
Published: January 2005

AbstractWe investigated the effects of gonadal hormone replacement on the pulsatile parameters underlying basal circadian corticosterone secretion in castrated male and ovariectomized female rats using an automated sampling system. Blood was collected from freely moving, unanaesthetized rats every 10 min over a 24‐h period and sampling was continued during a noise stress and after lipopolysaccharide (LPS) administration. Castrated male rats had markedly higher corticosterone levels than intact controls. This was reflected by increased number and frequency of pulses in addition to an increase in the pulse height and amplitude under both basal circadian and stress conditions. Hormone replacement with either testosterone or dihydrotestosterone returned these corticosterone levels and circadian profile to those found in intact males, confirming an androgen‐mediated effect. Ovariectomized females had significantly lower basal and stress‐induced corticosterone levels with lower frequency and amplitude of corticosterone pulses than intact females. 17β‐oestradiol replacement returned basal levels, pulsatile measurements and stress‐induced corticosterone levels to those found in intact females. Three hours post‐LPS administration, castrated males demonstrated significantly higher values of parvocellular paraventricular nucleus (PVN) arginine vasopressin and corticotrophin‐releasing factor and anterior pituitary pro‐opiomelanocortin mRNA while ovariectomized females showed significantly lower levels of all three transcripts compared to intact controls. PVN glucocorticoid receptor mRNA levels 3 h post‐LPS administration were significantly decreased in castrated males and significantly increased in ovariectomized female rats. Replacement of gonadal steroids resulted in a return to the levels found in intact controls after LPS. Gonadal steroid replacement is sufficient to reverse changes in the pulsatile characteristics of corticosterone release after gonadectomy. In addition, gonadal steroid replacement reverses stress‐induced alterations in hypothalamic‐pituitary‐adrenal (HPA) activity. These data demonstrate a major contribution of gonadal steroids to the regulation of HPA axis activity and to the pulsatile characteristics of corticosterone release.
Gonadotrophin Inhibitory Hormone Depresses Gonadotrophin α and Follicle‐Stimulating Hormone β Subunit Expression in the Pituitary of the Domestic Chicken
Authors: Ciccone N. A. , Dunn I. C. , Boswell T. , Tsutsui K. , Ubuka T. , Ukena K. , Sharp P. J. 
Published: January 2005

AbstractStudies performed in vitro suggest that a novel 12 amino acid RF amide peptide, isolated from the quail hypothalamus, is a gonadotrophin inhibitory hormone (GnIH). The aim of the present study was to investigate this hypothesis in the domestic chicken. Injections of GnIH into nest‐deprived incubating hens failed to depress the concentration of plasma luteinizing hormone (LH). Addition of GnIH to short‐term (120 min) cultures of diced pituitary glands from adult cockerels depressed follicle‐stimulating hormone (FSH) and LH release and depressed common α and FSHβ gonadotrophin subunit mRNAs, with no effect on LHβ subunit mRNA. Hypothalamic GnIH mRNA was higher in incubating (out‐of‐lay) than in laying hens, but there was no significant difference in the amount of hypothalamic GnIH mRNA in out‐of‐lay and laying broiler breeder hens at the end of a laying year. It is concluded that avian GnIH may play a role in controlling gonadotrophin synthesis and associated constitutive release in the domestic chicken.
Sex Differences in the Distribution and Abundance of Androgen Receptor mRNA‐Containing Cells in the Preoptic Area and Hypothalamus of the Ram and Ewe
Authors: Scott C. J. , Clarke I. J. , Rao A. , Tilbrook A. J. 
Published: January 2005

AbstractRams and ewes show a negative‐feedback response to peripheral treatment with testosterone, with both sexes having a similar degree of suppression in luteinizing hormone (LH) secretion during the breeding season. At least part of the action of testosterone to suppress gonadotropin‐releasing hormone/LH secretion is exerted via interaction with an androgen receptor. The distribution of androgen receptor‐containing cells in the hypothalamus has been described for the ram, but similar studies have not been performed in the ewe. In the present study, we tested the hypothesis that levels of androgen receptor mRNA expression in the preoptic area and hypothalamus would be similar in rams and ewes. Perfusion‐fixed brain tissue was obtained from adult Romney Marsh ewes (luteal phase) and rams during the breeding season (n = 4/sex). Androgen receptor mRNA expression was quantified in hypothalamic sections by in situ hybridization using an 35S‐labelled riboprobe and image analysis. Hybridizing cells were found in the medial preoptic area, bed nucleus of the stria terminalis, anterior hypothalamic area, ventromedial nucleus, arcuate nucleus and premamillary nucleus. The level of androgen receptor mRNA expression was higher in rams than ewes in the rostral preoptic area, caudal preoptic area and rostral portion of the bed nucleus of the stria terminalis, with no sex difference in other regions. The preoptic area and bed nucleus of the stria terminalis are important for reproductive behaviour and the sex differences in androgen receptor mRNA expression at these levels may relate to this. The high level of androgen receptor mRNA expression in the basal hypothalamus, with no sex difference, is consistent with the role of this region in the regulation of gonadotropin secretion.
SPERMIOGENESIS IN THE PULMONATE SNAIL, EUHADRA HICKONIS II. STRUCTURAL CHANGES OF THE NUCLEUS
Authors: TAKAICHI S. 
Published: January 2005

In accordance with the characteristic shape of the nucleus and degree of condensation of the nuclear substance, spermiogenesis in Euhadra hickonis can be roughly divided into four stages. The chromatin in the highly polymorphic nucleus of the first stage, early spermatid, forms relatively thick (ca. 50 nm) fibrils which associate here and there into irregular clumps. In the next stage, the spermatid nucleus becomes conspicuously spherical, its contents appear more finely homogeneous and the irregular clumps of chromatin are few. In the third stage, the nucleus gradually takes on an ellipsoidal shape as the antero‐posterior axis shortens. The anterior part of its envelope becomes structurally modified in preparation for the adherence to it of the developing acrosome, and an implantation fossa forms posteriorly at the center of a second area where the nuclear envelope has been modified. The diameter of the chromatin fibrils again increases and those near the implantation fossa become oriented perpendicular to the nuclear envelope.As the nucleus elongates in the fourth stage, a concentric sheath of microtubules closely surrounds it. These appear to depolymerize as the nuclear elongation proceeds, so that they are no longer present in the head region of the mature spermatozoon. The diameter of the chromatin fibrils increases to about 10 nm and they become oriented parallel to the long axis of the cell. With the decrease in the nuclear volume the fibrils unite laterally to form longitudinal sheets, and these finally merge in the mature spermatozoon into a mass of very dense chromatin without perceptible internal structure.
CYCLIC SURFACE CHANGES IN THE NON‐NUCLEATE EGG FRAGMENT OF XENOPUS LAEVIS
Authors: SAKAI MASAO , KUBOTA HIROSHI Y. 
Published: January 2005

Fertilized uncleaved eggs of Xenopus laevis were divided into nucleate and non‐nucleate egg fragments. Both fragments, together with the whole egg of the same batch, were observed by time‐lapse cinematography.Two kinds of cyclic surface changes, (1) rounding‐up and relaxing movements and (2) surface contraction waves, accompanying each cleavage in the whole eggs and the nucleate fragments, were also observed even in the non‐nucleate fragments although they do not cleave.Cleavage intervals of the whole egg and the nucleate fragment were nearly equal, but the rounding‐up intervals of the non‐nucleate fragment were slightly but definitely longer than the cleavage intervals of the nucleate fragment and the whole egg.
Concanavalin A‐Induced Morphological Changes and Its Binding Sites in Starfish Follicle Cells as Revealed by Electron Microscopy
Authors: KAWAI NORIO , SANO KIYOSHI , NAGAHAMA YOSHITAKA , KANATANI HARUO , HIRANO HIROSHI 
Published: January 2005

Concanavalin A (Con A) stimulates the production in starfish follicle cells of 1‐methyladenine, a hormone which induces oocyte maturation. We have therefore investigated Con A‐induced morphological changes and Con A‐binding sites in the follicle cell using native Con A and horseradish peroxidase‐ or ferritin‐labeled Con A (HRP‐Con A, Fer‐Con A). After isolated follicle cells were incubated with Con A (1 mg/ml), vacuoles, the Golgi complex and multivesicular body‐like organelles (MVBs) became prominent in most of the cells. After follicle cells were prefixed and then incubated with Fer‐Con A for 60 min, tagged ferritin was diffusely and randomly distributed as single or small clustered particles on the cell surface. The incubation of isolated follicle cells with Fer‐Con A for 10 min before fixation resulted in numerous ferritin particles localized along the internalized membrane, and also in vacuoles, MVBs and small lysosome‐like structures. After 60 min incubation with Fer‐Con A, ferritin was further located in large lysosome‐like structures and in vesicles near and in the Golgi area as well as in the organelles described above. HRP‐Con A binding sites were also observed in vacuoles and MVBs of the intact cells.These results suggest that Con A binds at first to the cell surface and causes rapid internalization and that membrane‐bound Con A is easily endocytosed into vacuoles, MVBs and lysosome‐like structures, and is later incorporated in some vesicles in the Golgi area.
Transdifferentiation of Adult Frog Iris in Retina or Lens by Exogeneous Influences
Authors: HOPERSKAYA OLGA A. , ZVIADADZEZ KETEVAN G. 
Published: January 2005

The mechanisms of transdifferentiation of iris epithelial cells of Rana temporaria (Anura) in culture depending on influences from different sources were studied. In terminally differentiated iris cells, the process of transdifferentiation is initiated by dedifferentiation. Melanosomes are shed from iris cells due to cell surface activity. After depigmentation, iris epithelial cells become capable of proliferating and competent to react to the influences of various exogenous factors. Under the influence of retinal factors secreted by lentectomized tadpole eyes, both dorsal and ventral irises are converted to neural retina. Under the influence of factors from eye vesicles, the irises are converted to neural retina as well. Similar results were obtained in transfilter experiments, in which a 3‐day period of transfilter interaction between the irises and eye vesicles ensured depigmentation of the iris followed by transdifferentiation into complete NR with visual receptor. Lentoid formation occurred under the influence of adult frog lens epithelium. Immunofluorescent analysis confirmed the lens nature of the lentoids. In control experiments under the conditions of the tadpole eye orbit, in which programming influences were absent, iris epithelial cells remained unaffected.The problem of true cell‐reprogramming to new differentiation in contrast to expression of inherent properties of the iris epithelial cells is discussed.
Quantitative Analysis of Protein Synthesis Altered by Estrogen in Cultured Xenopus Liver Parenchymal Cell
Authors: KAWAHARA AKIRA , SATO KAZUKI , AMANO MINORU 
Published: January 2005

Using the primary culture system of male Xenopus laevis hepatocytes consisting of more than 95% parenchymal cells, the effect of estradiol‐17 β (10−6M) on protein synthesis was quantitatively analyzed by 3H‐leucine incorporation kinetics and the estimation of specific radioactivity of newly synthesized secretory protein. The cells in a well defined culture revealed high plating efficiency and very low DNA synthetic activity. The cultured cells could synthesize several secretory proteins containing serum albumin. The pattern of secreted proteins in SDS‐polyacrylamide gel electrophoresis (SDS‐PAGE) did not alter with culture time but secretion rate of protein increased for 7 days, starting on the third day following inoculation. Estradiol added to the culture media extensively induced the synthesis of yolk precursor protein vitellogenin which accounted for 40–50% of the overall secretory protein synthesis and 20–30% of the total protein synthesis on day 7 of estradiol treatment. Ultimately, the total protein synthesis and secretory protein synthesis were stimulated 1.2–1.3 fold and 2.0–2.2 fold, respectively, over those of the control cells cultured in the absence of estradiol. These results indicated that the stimulation of protein synthesis was largely due to vitellogenin production. Such an estradiol‐dependent stimulation of protein synthesis was also detected in the low molecular weight protein(s). On the other hand, albumin synthesis was evidently reduced by estradiol. Thus, estradiol had two different effects on protein synthesis.The results obtained in this study will be discussed in relation to the findings o in vivo experiments.
Changes in Activity of Mitochondrial Enzymes during the Development of Xenopus laevis
Authors: NELSON LENNART , LØVTRUP‐REIN HUGUETTE 
Published: January 2005

Changes in activity of mitochondrial enzymes were studied during the embryonic development of Xenopus laevis.The following enzymes were determined: malate dehydrogenase (MDH), isocitrate dehydrogenase (NAD+‐dependent) (IDH), aspartate aminotransferase (GOT), cytochrome oxidase (COX), succinate dehydrogenase (SDH), rotenone‐insensitive NADH cytochrome c reductase (NADH‐red) and monoamine oxidase (MAO). IDH is constant throughout the period studied. COX and SDH, two enzymes of the inner membrane, are constant in pregastrula stages, and subsequently decrease significantly. MDH and NADH‐red are highly active in the pregastrula stages and decline thereafter, while MAO is undetectable during early development and increases significantly only in the larvae. GOT increases during the cleavage stages, being most active in the gastrula stages, and decreases subsequently.The results are discussed in the sense of mitochondrial differentiation during the early development of the amphibian embryo.
Fine Structure and Differentiation of the Acrosome‐Like Structure in the Solitary Ascidians, Pyura haustor aud Styela plicata1
Authors: FUKUMOTO MAKOTO 
Published: January 2005

An acrosome‐like structure has been recognized at the apex of mature spermatozoa of both Pyura haustor and Styela plicata. The acrosome‐like structure of P. haustor is a slightly depressed ellipsoid, approximately 90 nm × 80 nm × 50 nm, in length, width and height, respectively, while that of S. plicata is an antero‐posteriorly elongated, flattened vesicle, approximately 200 nm × 100 nm × 50 nm, in length, width and height, respectively.During spermiogenesis, two vesicles (50–80 nm in diameter) are found in a blister at the apex of early spermatids of both species. These vesicles, presumably derived from the Golgi apparatus, contain moderately electron‐dense material. In late spermatids, these two vesicles appear to fuse to form an acrosome‐like structure.Because of its extremely reduced size and the paucity of its contents, it is unlikely that the acrosome‐like structure of these sperm contain a significant amount of chorion lysin(s). A well developed Golgi apparatus and many Golgi vesicles of various sizes are found in the cytoplasm of spermatids in both P. haustor and S. plicata. It is hypothesized that ascidian spermatozoa contain a poorly developed acrosome, and that the chorion lysin(s) are intercalated into the plasmalemma enclosing the sperm head.