bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modification of the Nucleolar Structure of the Rat Oocyte Observed Just before Maturation
Authors: MERVEILLE C. , BAECKELAND E. , RENARD A. M. 
Published: December 2006

During the last several years, the study of the nucleolus and, more specifically, its structure has been the object of much research.1 The observation of the state of the nucleolus, its composition, and its spatial organization allows us to appreciate the synthesis and metabolism of ribonucleic acids (rRNA).Vacuoles have been observed in the nucleolus in some cells, such as those of cotton fibers2 the embryonic root cells of Zea Mays,3 tobacco cells,4 and so on. This is also the case in oocytes, for instance, in Xenopus5 and in the teleost fish, Xiphophorus helleri.6 The rat oocytes from antral follicle often have germinal vesicles possessing spherical inclusions. With mature rats, Tsafiri and Kraicer7 have noticed these formations in 91% of the nucleoli. We have also found them in nearly all oocytes from adult rats, but not in those from prepubertal untreated rats.8 Bomsel‐Helmreich et al.9 have published illustrations showing that these cavities can be clearly distinguished at the interior of very large nucleoli belonging to human oocytes in mature ovarian follicles.To our knowledge, the origin, development and significance of these nucleolar vesicles have not yet been established with certainty.
Chromosomal Preparations from Human Oocytes
Authors: WRAMSBY H. , FREDGA K. , LIEDHOLM P. 
Published: December 2006

It appears that the chance of an in vitro fertilization (IVF) embryo to produce a pregnancy carried to term is about 10%.1 Consequently, one of the most important factors in increasing the pregnancy rate after in vitro fertilization and embryo transfer is replacement of multiple embryos.2 When we consider that the estimated human fecundity rate is about 25%,3 it seems likely that the quality of the embryo is one determining factor for a successful pregnancy rate. Different types of defects of gametes and embryos might contribute to the explanation of why the vast majority of IVF embryos do not give rise to any sign of pregnancy after replacement.It is well documented that chromosomal abnormalities among first trimester spontaneous abortions occur at a rate of about 60%, indicating that chromosomal abnormalities might be common in human gametes and early development stages.4 Abnormal karyotypes found were aneuploidy (i.e., complements with one extra or one missing chromosome) and polyploidy.Recently, a new technique allowing direct analysis of the chromosomal constitution of human spermatozoa has been reported.5 This technique utilizes the ability of capacitated human spermatozoa to penetrate zona‐free hamster oocytes. Five to 10% of penetrating human spermatozoa have shown chromosomal abnormalities. Various degrees of hyperploidy and hypoploidy ranging from three extra to three missing chromosomes were found in a series of 1000 human spermatozoal chromosome constitutions.6 It is interesting to note that among spontaneous first trimester abortions such serious numerical abnormalities have not been found.4
The Selection of Couples for in Vitro Fertilization and Embryo Replacement
Authors: STEPTOE PATRICK 
Published: December 2006

Some of the obvious factors that affect the success rates, in terms of living children, of in vitro fertilization (IVF) are the ages of the patients, the quality of ovulation and spermatogenesis, and the general and gynecologic health of the female partner in terms of the safe initiation and maintenance of a pregnancy to full term.Discussion of the selection of patients must take into account the indications for IVF and embryo replacement (ER). The clinical applications at present are infertility due to: (1) problems of ovum pickup and transport associated with pelvic pathology or absence of the oviducts; (2) oligospermia; (3) prolonged unexplained infertility; and (4) combined male and female factors.
Psychosocial Testing and Pretreatment of Women for in Vitro Fertilization
Authors: KEMETER PETER , EDER ANSELM , SPRINGER‐KREMSER MARIANNE 
Published: December 2006

Thanks to extensive media coverage, both the public, in general, and infertile patients desiring children, in particular, have been alerted to the fascinating prospects of in vitro fertilization (IVF) and embryo transfer (ET). Many infertile couples would do anything to have a child of their own. As a consequence, they have come to attach high hopes to this new method, just as they were hopeful of other methods in the past.The patients’attitudes have thus remained the same. Therefore, we ourselves should continue to bring to bear the whole body of knowledge on the pathogenesis of sterility and infertility as well as their psychosocial background when counseling patients on any new treatment modality. For this reason it would seem appropriate to review some of the results accumulated in an ongoing study of sterility and infertility which is being carried out by the Institute of Reproductive Endocrinology and in Vitro Fertilization in cooperation with several departments of the University of Vienna since 1978.1–5
Secretory Vesicle Cytochrome b561: A Transmembrane Electron Transportera
Authors: FLEMING PATRICK J. , KENT UTE M. 
Published: December 2006

SUMMARYThe major function of cytochrome b561 is now clear. This transmembrane protein transports electrons across a secretory vesicle bilayer to supply electrons to monooxygenases inside the secretory vesicle.Cytochrome b561 has been localized not only to adrenergic secretory vesicles, where it supplies electrons to dopamine β‐hydroxylase, but also to peptidergic secretory vesicles that contain peptidyl α‐amidating monooxygenase.15,21 Thus, one would expect to 6nd cytochrome b561 in the membranes of all neuroendocrine cells that contain amidated peptide secretory products. In addition, its wide Occurrence as an integral membrane protein of secretory vesicles may make it useful for investigation of vesicle biogenesis and turnover.One of the most important potential roles of cytochrome b561 is that it can be used as a model protein to investigate long‐range biological electron transport. This cytochrome is a single polypeptide, which can be purified easily and reconstituted into a functional assembly. It also catalyzes an experimentally unambiguous transmembrane transport of electrons. A full molecular characterization of the structure and function of this cytochrome may provide insights into biological electron transfer which would otherwise be difficult or impossible to obtain.
Adsorption Kinetics of Protein Mixtures A Tentative Explanation of the Vroman Effect
Authors: CUYPERS PETER A. , WILLEMS GEORGE M. , HEMKER H. COENRAAD , HERMENS WIM TH. 
Published: December 2006

SUMMARYA model for protein adsorption kinetics has been presented. This model includes diffusion‐limited adsorption, adsorption and desorption rate constants kon and koff, which are dependent on the surface concentration, and an interaction term for the mutual influence of the adsorbed protein molecules. It has been shown that, in first approximation, values of kon and & Koff are exponential functions of the surface concentration. Assuming an adequate interaction term, it is possible to show with this model for a mixture of proteins that the ratio of the absorbed proteins is strongly dependent on the overall surface concentration even if the ratio of the bulk concentrations of these proteins is kept constant. Differences in interaction terms for the different proteins offer a possible explanation for the peculiar behavior of plasma protein adsorption on a surface at different dilutions of the plasma, the so‐called Vroman effect.
Efficacy of Recombinant Human Granulocyte‐macrophage Colony‐stimulating Factor in Rhesus Monkeys
Authors: MAYER P. , LAM C. , OBENAUS H. , LIEHL E. , BESEMER J. 
Published: December 2006

SUMMARYThe glycosylated and the non‐glycosylated recombinant human granulocyte‐macrophage colony‐stimulating factor (rh GM‐CSF) expressed in Chinese hamster ovary cells and E. coli, respectively, were administered in rhesus monkeys either by the subcutaneous (three times daily) or intravenous route (6‐hr infusions) for seven consecutive days. Within 24 hr peripheral white blood cells (WBC) increased 2‐3‐fold over normal values. Thereafter, the WBC increased steadily in a dose‐dependent manner to reach maximum levels on the last day of or one day after the treatment period. The differential counts showed that neutrophils contributed to 50‐80%, eosinophils to 10‐20%, monocytes to 2‐7%, and lymphocytes to 15–30% of the WBC rise. No effect was found on platelets and erythrocytes. After termination of treatment, WBC counts returned to normal levels within one week. Subcutaneously administered CSF was more effective in inducing leukocytosis than that injected intravenously. In addition to the rise in WBC, the administered rh GM‐CSF also enhanced the oxidative metabolism and bactericidal activity of the circulating mature granulocytes isolated from the blood of monkeys treated with rh GM‐CSF. These results show that glycosylated or non‐glycosylated rh GM‐CSF is both an effective stimulator of leukocytosis and a potent activator of the functional activity of mature granulocytes in vivo.
Health Research in Africa: Priorities, Promise, and Performance
Authors: LUCAS ADETOKUNBO O. 
Published: December 2006

I am delighted to participate at this conference because it gives me the opportunity of acknowledging the contributions of individuals, institutions and agencies who have dedicated their skills and resources to the fight against death, disease, and disability in developing countries. I am particularly pleased to join in congratulating Dr. Ken Warren, not only for his direct contributions as a research scientist on tropical diseases, but more importantly for his inspiration and support, which has encouraged and enabled many others to work on these problems.I have been asked specifically to provide an African perspective and I would like to examine the subject of health research in Africa by reviewing the subject in three historical periods: (a) the colonial era, (b) the post‐independence period, and (c) the future.
Free Radicals in the Genesis of Alzheimer's Diseasea
Authors: RICHARDSON J. STEVEN 
Published: December 2006

As part of an ongoing investigation of the role of oxygen free radicals in Alzheimer's disease (AD), the formation of peroxidation products, the activities of free radical defense enzymes, and the level of total iron were determined in autopsy brain tissue from donors with AD and from age‐matched non‐demented donors. Calcium uptake was also investigated in mitochondria harvested from fibroblasts grown in tissue culture from skin samples taken from brain donors.Compared to controls, homogenates of AD frontal cortex produced elevated levels of peroxidation products and this difference was amplified in a dose‐dependent manner by iron (1 to 200 μM). Peroxidation produced by 200 μM iron was reduced dose dependently by the lazaroid U‐74500A. The IC50 was 10 μM in AD cortex and 2.5 μM in controls.Superoxide dismutase (SOD), one of the free radical defensive enzymes, was reduced by 25 to 35% in AD frontal cortex, hippocampus and cerebellum. In other brain areas, SOD did not differ between AD and control. The activities of catalase and glutathione peroxidase were the same in AD and control samples. Endogenous iron levels were higher in AD frontal cortex (2.5 nmol/mg protein) than in controls (1.5 nmol/mg protein).Calcium uptake by AD fibroblast mitochondria is 50% lower than in controls under basal conditions. Following exposure to 200 μM iron, mitochondrial calcium uptake is increased by 58% in AD and by 38% in controls. Pretreatment with 200 μM U‐74500A or 1 mM deferoxamine, prior to exposure to 200 μM iron, gave complete protection to control mitochondria but gave only partial protection to AD mitochondria.These studies indicate that in AD, both CNS and peripheral cells show increased sensitivity to oxygen free radicals. The source of this increased sensitivity has not yet been identified but could reflect either reduced free radical defenses or increased free radical formation or both. Work is underway using electron paramagnetic resonance spectrometry to determine in vivo, premortem free radical activity in AD patients.
Comparative Effects of Aging Process on Phosphatidylcholine Biosynthesis Pathway: A Key Role for CTP‐Phosphocholine Cytidylyltransferase?
Authors: LEPAGNOL J. M. , HEIDET V. 
Published: December 2006

The effects of aging on phosphatidylcholine (PtdCho) biosynthesis were investigated in liver and brain subcellular fractions of the rat, by studying the activity and regulation of CTP phosphocholine cytidylyltransferase (CT), the rate limiting enzyme in PtdCho biosyntheses. With both tissues, CT activity was present in cytosolic and microsomal fractions, but in brain, CT activity seemed to escape to an inhibiting feed back mechanism. In brain, CT activity was greater in the microsomal fraction, whilst in liver, a higher CT activity was seen in the cytosolic fraction.In liver fractions of aged animals, there was no significant change in CT activity or its sensitivity to negative feedback regulation, as compared to young animals. In contrast, a progressive age related decline in CT activity was observed in the brain microsomal fraction. Furthermore, the incorporation of newly formed CDPCho into PtdCho was also reduced in aged animals, and paralleled the decreased incorporation of choline in PtdCho. The age‐related decrease in CT activity cannot be explained by product feed back inhibition or decreased diacylglycerol levels.Since PtdCho is a major membrane lipid, the reduction in CT activity may lead to a decreased membrane integrity and fluidity during the aging process, and these effects may be greater in neuronal cells.
Protein Phosphorylation Regulates Relative Utilization of Processing Pathways for Alzheimer β/A4 Amyloid Precursor Proteina
Authors: GANDY SAMUEL E. , CAPORASO GREGG L. , BUXBAUM JOSEPH D. , SILVA ODETE DA CRUZ E , IVERFELDT KERSTIN , NORDSTEDT CHRISTER , SUZUKI TOSHI , CZERNIK ANDREW J. , NAIRN ANGUS C. , GREENGARD PAUL 
Published: December 2006

The Alzheimer amyloid precursor protein (APP) is a phosphoprotein, and the phosphorylation state of APP at Ser655 can be regulated by protein kinase C, calcium/calmodulin‐dependent protein kinase II, and okadaic acid‐sensitive protein phosphatases. Other enzymes may also play a role at Ser655 of APP and, perhaps, at other residues.Signal transduction via protein phosphorylation regulates APP metabolism. In particular, APP processing via the nonamyloidogenic secretory cleavage pathway is increased following the activation of protein kinase C or the inactivation of okadaic acid‐sensitive protein phosphatases.The mechanism(s) by which protein phosphorylation regulates APP secretory cleavage include (among others): substrate activation, substrate redistribution, protease activation and/or protease redistribution. Current experimental evidence will be discussed, addressing the relative importance of each of these possibilities and the implications for these events in the modulation of β/A4‐amyloidogenesis.
Decreased Density of Forebrain Cholinergic Neurons and Disintegration of the Spatial Organization of Behavior in Experimental Autoimmune Dementia (EAD)a
Authors: MICHAELSON DANIEL M. , DUBOVIK VLADIMIR , FAIGON MARIA , EILAM DAVID , FELDON JORAM 
Published: December 2006

Experimental autoimmune dementia (EAD) is a rat model designed to examine the potential role of anti‐cholinergic neurons antibodies (Abs) in the neuropathology of Alzheimer's disease (AD) and dementia. We have previously shown that sera of AD and Down's syndrome patients contain Abs which bind specifically to the high molecular weight neurofilament protein (NF‐H) of the purely cholinergic electromotor neurons of Torpedo. Production of such Abs in EAD rats by prolonged immunization with Torpedo cholinergic NF‐H results in the accumulation of IgG in the septum and hippocampus of the immunized rats and in memory deficits.In the present study, we examined immunohistochemically whether the anti‐cholinergic NF‐H immune response of the FAD rats affects their brain cholinergic neurons. In addition, since dementia is associated with severe deterioration in the spatio‐temporal organization of behavior, we examined whether EAD rats also mimic this important feature of dementia. The results obtained show that production in EAD rats of anti‐cholinergic NF‐H Abs similar to those found in AD patients results in a marked decrease in the density of forebrain cholinergic neurons and in derangements in the spatio‐temporal organization of their behavior. These findings may replicate pathogenic processes in AD and support a role for anti‐cholinergic NF‐H Abs in the degeneration of cholinergic neurons in the disease.
Neural Transplantation for Neurodegenerative Diseases: Past, Present, and Futurea
Authors: REDMOND D. EUGENE , ROTH ROBERT H. , SPENCER DENNIS D. , NAFTOLIN FREDERICK , LERANTH CSABA , ROBBINS RICHARD J. , MAREK KENNETH L. , ELSWORTH JOHN D. , SASS KIMBERLEE J. , TAYLOR JANE R. , SLADEK JOHN R. 
Published: December 2006

After almost 100 years of sporadic, and marginally successful, studies of neural transplantation in animals, we are now on the threshold of a clinical treatment of the damaged brain. The initial studies of neural transplantation have focused on Parkinson's disease, primarily as a model for a more general strategy of “repair by cellular replacement.” Parkinson's is known to result from the loss of a small population of cells that produce the essential neuromodulator, dopamine, for much of the brain. Further, the disease is improved significantly, during the early part of its course, by chemical augmentation of dopamine activity through drug therapies, such as l‐dopa. Finally, the disease is often fatal in spite of the best medical treatments, therefore justifying more radical therapeutic experiments. If transplantation of brain cells can be accomplished successfully in humans, as it has been in animals, then replacement of a small population of dopamine‐producing cells in Parkinson's disease should have important functional effects and possibly reverse the course and symptoms of the disease. Other useful applications will surely follow for conditions affecting millions of people for whom medicine now has only palliative and ineffective treatments.Just as Parkinson's disease is a model clinical condition for testing cellular replacements, fetal neural tissue transplants are also a first step for a broader strategy of molecular and cellular therapies. Fetal cells are, in many respects, the best replacements one could imagine, since precursor cells have the capacity to develop into every cell found in the adult. So, the best replacement for a dopamine neuron would likely be a precursor dopamine neuron or “neuroblast.” Animal research through 1985 had demonstrated the unique properties of such fetal cells, but survivability after transplantation had not been attained with primate or human neural tissue. Our programs developed techniques to transplant monkey fetal neural tissue, to cryopreserve it, and to reverse functional effects of the neurotoxin, MPTP, in monkeys. This technique was applied to the collection and preservation of human tissue, and preliminary successful results have been obtained in patients with idiopathic Parkinson's disease. Others have reported success with different techniques in two MPTP‐Parkinsonian patients and a small number of patients with idiopathic disease. If the most dramatic improvements can be replicated consistently and the benefits last for a reasonable period without complications, a clinical treatment might develop using “random‐source” fetal cadaver cells.
Topological Partition Relations of the Form ω*→(Y)12a
Authors: COMFORT W. W. , KATO AKIO , SHELAH SAHARON 
Published: December 2006

ABSTRACT. THEOREM. The topological partition relation ω*→ (Y)12(a) Fails for every space Y with |Y| |Mg 2c;(b) Holds for Y discrete if and only if |Y| |Ml c;(c) Holds for certain nondiscrete P‐spaces Y;(d) Fails for Y=ω Imu {p} with p∉ω*;(e) Fails for Y infinite and countably compact.
Metabotropic Glutamate Receptors Regulate APP Processing in Hippocampal Neurons and Cortical Astrocytes Derived from Fetal Ratsa
Authors: LEE R. K. K. , JIMENEZ J. , COX A. J. , WURTMAN R. J. 
Published: December 2006

It has previously been shown that stimulation of muscarinic m1 or m3 receptors can, by generating diacylglycerol (DAG) and activating protein kinase C (PKC), accelerate the breakdown of the amyloid precursor protein (APP) to form soluble, non‐amyloidogenic peptides (APPs). This relationship has been demonstrated in human glioma and neuroblastoma cells as well as in transfected human embryonic kidney (HEK) cells and PC12 cells.1,2We now provide evidence that stimulation of metabotropic glutamate receptors (mGluRs), which also are coupled to DAG and PKC, similarly accelerates processing of APP into non‐amyloidogenic APPs in hippocampal neurons and cortical astrocytes derived from normal fetal rats. The mGluR antagonist, L(+)‐2‐amino‐3‐phosphonopropionic acid (L‐AP3), and GF 109203X, an inhibitor of PKC, both blocked the release of APPs from hippocampal neurons and astrocytes evoked by glutamate receptor stimulation. Inasmuch as glutamatergic neurons in cortex and hippocampus are known to be damaged in Alzheimer's disease, our findings suggest that amyloid formation may be enhanced by the resulting glutamate deficiency and that selective mGluR agonists may be useful in facilitating synaptic efficacy and treating the disease.
The Jordan Curve‐type Theorems for the Funnel in 2‐dimensional Semiflows
Authors: CIESIELSKI KRZYSZTOF 
Published: December 2006

ABSTRACTWe investigate “the past” of a nonstationary point x in a semiflow π: ℝ+ x M→M on a 2‐manifold M. In a natural way there are defined two boundary trajectories Ta and Tb; by the funnel we mean F(x) ={y:π(t, y) =x for some t} and we put D(x) ≈F(x)\(Ta∪Tb). We show that if x is not a point of negative unicity, then D(x) is homeomorphic to ℝ2. Also, if T is a nonboundary trajectory through x, then D(x)\T has two components for a regular point x and D(x)\T has two or three components for a periodic point x.
Iwasawa‐type Decomposition in Compact Groups
Authors: ITZKOWITZ GERALD , WU TA SUN 
Published: December 2006

ABSTRACTIwasawa in his famous paper “On some types of topological groups,” proved a number of decomposition theorems for compact groups. Among them is the theorem stating that a compact connected group G can be written as G=Z(G) · [G, G], where Z(G) is the center of G and [G, G] is the commutator subgroup of G. Later authors have refined this result to the statement that G=Z(G)o· [G, G], where Z(G)o is the component of the identity of Z(G). In the present paper we show that these theorems may be further strenghthened to the following statement: Let G be a compact group and let N be a compact normal subgroup of G. If either G=A·N, where A is a compact connected Abelian group, or if G/N is connected, then G=ZG(N)o·N, where ZG(N)o is the component of the identity of the centralizer in G of N. The proof of this result has a number of interesting corollaries.
Intersection Properties of Open Sets. IIe
Authors: JUHÁSZ I. , NAGY ZS , SOUKUP L. , SZENTMIKLÓSSY Z. 
Published: December 2006

ABSTRACTA topological space is called P2 (P3, P<ω) if and only if it does not contain two (three, finitely many) uncountable open sets with empty intersection. We show that (i) there are 0‐dimensional P<ω spaces of size 2ω, (ii) there are compact P<ω spaces of size ω1, (iii) the existence of a Ψ‐like examples for (ii) is independent of ZFC, (iv) it is consistent that 2ω is as large as you wish but every first countable (and so every compact) P2 space has cardinality ≤ω1.