bluuebunny/crossref_metadata_2025 huggingface dataset:
Juvenile diet restriction and the aging and reproduction of adult Drosophila melanogaster
Authors: Tu Meng‐Ping , Tatar Marc
Published: November 2003

Mutations of the insulin signal pathway in Drosophila melanogaster produce long‐lived adults with many correlated phenotypes. Homozygotes of insulin‐like receptor (InR) and insulin‐like receptor substrate (chico) delay time to eclosion, reduce body size, decrease reproduction and increase life span. Because these mutations are expressed through all life stages it is unclear when insulin signals must be reduced to increase life span. As a first analysis of this problem in D. melanogaster we have manipulated the larval diet to determine if changes in metabolic regulation at this stage are sufficient to slow aging. We controlled the dietary yeast fed to third instar larvae and studied the size, mortality, fecundity and hormones of the resulting adults, which were fed a normal, yeast‐replete diet. Adults from yeast‐deprived larvae phenocopied many traits of InR and chico mutants: small body size, delayed eclosion, reduced ovariole number and reduced age‐specific fecundity. But unlike constitutive mutants of the insulin/IGF system, adults from yeast‐deprived larvae had normal patterns of demographic senescence, and this was accompanied by normal insulin‐like peptide and juvenile hormone syntheses. Surprisingly, the normal aging in these adults was also associated with greatly reduced fecundity. Although nutritional conditions of the larvae can affect the subsequent body size and fecundity of adults, these are not sufficient to slow aging.
Real‐time imaging of transcriptional activation in live cells reveals rapid up‐regulation of the cyclin‐dependent kinase inhibitor gene CDKN1A in replicative cellular senescence
Authors: Herbig Utz , Wei Wenyi , Dutriaux Annie , Jobling Wendy A. , Sedivy John M.
Published: November 2003

Cellular replicative senescence is a permanent growth arrest state that can be triggered by telomere shortening. The cyclin‐dependent kinase (Cdk) inhibitor p21CIP1/WAF1 (p21), encoded by the CDKN1A gene, is a critical cell cycle regulator whose expression increases as cells approach senescence. Although the pathways responsible for its up‐regulation are not well understood, compelling evidence indicates that the upstream triggering event is telomere dysfunction. Studies of replicative senescence have been complicated by the asynchrony of its onset, which is caused by the continuous and stochastic variability in individual cell lifespans. In fact, the actual entry into senescence has never been observed in a single unperturbed cell. We report here a new in vitro human model system that allows entry into senescence to be monitored in real‐time in individual viable cells. We used homologous recombination to generate non‐immortalized fibroblast cells with the enhanced yellow fluorescence protein (EYFP) gene knocked into one CDKN1A gene copy, allowing promoter activity to be visualized as fluorescence intensity. Gamma irradiation, DNA‐damaging drugs, expression of p14ARF or oncogenic Ras, and replicative exhaustion all resulted in elevated EYFP expression, demonstrating its proper control by physiological signalling circuits. Analysis by time‐lapse microscopy of cultures approaching replicative senescence revealed that p21 levels rise abruptly in individual aging cells and remain elevated for extended periods of time.
Fast anterograde transport of Herpes Simplex Virus: Role for the amyloid precursor protein of Alzheimer's disease
Authors: Satpute‐Krishnan Prasanna , DeGiorgis Joseph A. , Bearer Elaine L.
Published: November 2003

Anterograde transport of herpes simplex virus (HSV) from its site of synthesis in the neuronal cell body out the neuronal process to the mucosal membrane is crucial for transmission of the virus from one person to another, yet the molecular mechanism is not known. By injecting GFP‐labeled HSV into the giant axon of the squid, we reconstitute fast anterograde transport of human HSV and use this as an assay to uncover the underlying molecular mechanism. HSV travels by fast axonal transport at velocities four‐fold faster (0.9 µm/sec average, 1.2 µm/sec maximal) than that of mitochondria moving in the same axon (0.2 µm/sec) and ten‐fold faster than negatively charged beads (0.08 µm/sec). Transport of HSV utilizes cellular transport mechanisms because it appears to be driven from inside cellular membranes as revealed by negative stain electron microscopy and by the association of TGN46, a component of the cellular secretory pathway, with GFP‐labeled viral particles. Finally, we show that amyloid precursor protein (APP), a putative receptor for the microtubule motor, kinesin, is a major component of viral particles, at least as abundant as any viral encoded protein, while another putative motor receptor, JIP 1/2, is not detected. Conventional kinesin is also associated with viral particles. This work links fast anterograde transport of the common pathogen, HSV, with the neurodegenerative Alzheimer"s disease. This novel connection should prompt new ideas for treatment and prevention strategies.
RENAL RESEARCH INSTITUTE SYMPOSIUM: Disablement and Rehabilitation in End‐Stage Renal Disease
Authors: Tawney Katherine W. , Tawney Paul J. W. , Kovach Jim
Published: November 2003

Patients with end‐stage renal disease (ESRD) are encumbered by disabilities in spite of advances in medical treatments. Research shows that exercise training is one way to improve physical work capacity and reduce functional limitations that impede role behaviors, such as shopping, personal care, homemaking, and yard maintenance. However, exercise training does not ameliorate some of the psychosocial and environmental factors that exacerbate disabilities for patients with ESRD. A disability process model described in this review illustrates that disability prevention may be more effective if exercise rehabilitation is integrated with self‐management education. Research is needed to delineate which disabilities in patients with ESRD are a product of psychosocial factors and physical environments. Once identified, those disability risk factors that are amenable to change can guide the development of tailored rehabilitation interventions.
RENAL RESEARCH INSTITUTE SYMPOSIUM: The Practical Problem of Improving Quality in Multicenter Dialysis Facilities
Authors: Balter Paul
Published: November 2003

Multifacility dialysis groups are frequently interested in improving overall quality and find that there are major differences between individual units. Upper management must consider what strategy is needed for the whole company and what strategy must be formulated by individual facilities. To make substantive changes, management must decide to adopt a new culture of true teamwork, drive out fear, and emphasize leadership and education both at the management level and in the individual unit. Both at the corporate and unit levels, leaders must be chosen who are able to recognize people who have the ability, the educational background, the enthusiasm, and the time to direct change. Empowering the individual units and individual employees to make changes and be enthusiastic about improvement is the key to success.
RENAL RESEARCH INSTITUTE SYMPOSIUM: Cellular Mechanisms of Bone Resorption Induced by Metabolic Acidosis
Authors: Krieger Nancy S. , Bushinsky David A. , Frick Kevin K.
Published: November 2003

Metabolic acidosis increases urine calcium excretion without an increase in intestinal calcium absorption, resulting in a net loss of bone mineral. In vitro metabolic acidosis induces bone calcium efflux initially by physicochemical dissolution and subsequently by cell‐mediated mechanisms involving inhibition of osteoblasts and stimulation of osteoclasts. In bone, prostaglandins (PGs) are important mediators of bone resorption and we have recently determined that acid‐induced bone resorption is mediated by PGs. Utilizing neonatal mouse calvariae in culture, we found that decreasing pH by a reduction in bicarbonate concentration, a model of metabolic acidosis, induced an increase in net calcium efflux and in medium prostaglandin E2 (PGE2) levels, both of which were inhibited in the presence of indomethacin. There was a direct correlation between calcium flux and medium PGE2. If pH is lowered to a comparable degree by an increase in pCO2 to model respiratory acidosis, there was no significant stimulation of net calcium efflux from the calvariae and no stimulation of PGE2 production. We have also shown that metabolic acidosis alters osteoblastic expression of a specific osteoclastogenic factor, RANKL, and this response is also PG dependent. Incubation of calvariae in acid medium stimulated expression of RANKL RNA in parallel with the increased calcium flux. Both responses were inhibited in the presence of indomethacin. Thus metabolic, but not respiratory, acidosis induces production of bone PGE2, which mediates acid‐induced bone resorption.
RENAL RESEARCH INSTITUTE SYMPOSIUM: Longitudinal Study of Apoptosis in Chronic Uremic Patients
Authors: D'Intini Vincenzo , Bordoni Valeria , Fortunato Antonio , Galloni Elisabetta , Carta Mariarita , Galli Francesco , Bolgan Irene , Inguaggiato Paola , Poulin Sonya , Bonello Monica , Tetta Ciro , Levin Nathan , Ronco Claudio
Published: November 2003

Uremia is associated with a state of immune dysfunction, increasing infection and malignancy rates. Dysregulation of homeostasis may be directly related to abnormal apoptosis regulation, a process which is crucial for the maintenance of the biologic system. Abnormal apoptosis rates (ARs) have been reported in the literature. We performed a longitudinal study over a 10‐week period in three groups of uremic subjects—hemodialysis (HD), peritoneal dialysis (PD), and predialysis chronic renal failure (CRF). Our results showed that ARs were consistent over the observed period. Monocytes extracted from HD and CRF subjects had higher ARs compared to PD and controls (HD: 26.06 ± 8.82; CRF: 26.96 ± 12.81; PD: 14.77 ± 5.87; C: 11.42 ± 4.60) when placed in culture medium. The plasma of HD and CRF subjects when incubated with U937 cells had a stronger apoptogenic potential compared with PD and controls (HD: 26.08 ± 11.39; CRF: 24.87 ± 9.07; PD: 12.13 ± 4.51; C: 11.69 ± 4.02). Inflammatory markers (C‐reactive protein [CRP], procalcitonin) and cytokines (interleukin [IL]‐1β, IL‐2, IL‐10) had a generally poor correlation except for tumor necrosis factor (TNF)‐α (p < 0.001). The phagocytic ability of U937 cells when incubated with the various plasma demonstrated impaired response in the HD and CRF subjects (HD: 27.56 ± 6.67; CRF: 30.24 ± 9.08; PD: 36.55 ± 9.80; C: 40.04 ± 6.98). These results suggest continuous renal purification, such as in continuous ambulatory peritoneal dialysis (CAPD), may have advantages over intermittent therapies in regulating apoptosis and maintaining biologic function and homeostasis.
RENAL RESEARCH INSTITUTE SYMPOSIUM: Surveillance of Access Function by the Blood Temperature Monitor
Authors: Schneditz Daniel , Kaufman Allen M. , Levin Nathan
Published: November 2003

Low access blood flow is considered the most important cause of peripheral vascular access thrombosis, particularly with grafts. The measurement of access flow is time consuming, operator dependent, and may affect the efficiency of dialysis so that it cannot be done with every treatment. The measurement of recirculation, however, is possible with every treatment and can be done automatically when using the thermodilution offered by the blood temperature monitor (BTM). Since BTM recirculation always includes a component related to cardiopulmonary recirculation, the threshold to detect access recirculation in peripheral arteriovenous grafts and native fistulas must be shifted from zero recirculation applicable for bolus techniques to 15% for the slow thermodilution technique. In one study, recirculation in native arteriovenous fistulas was measured with every treatment in 80 patients over a period of 6 months. Nine of 11 interventions performed during the entire observation period were triggered by a BTM recirculation above the threshold. Two fistulas thrombosed in spite of a BTM recirculation below the threshold. BTM recirculation to detect fistulas for revision is sensitive (81.8%) and specific (98.6%) in the presence of cardiopulmonary recirculation and can be done with minimum intervention and without loss of efficient treatment time.
RENAL RESEARCH INSTITUTE SYMPOSIUM: Effect of Time on Sensitivity and Specificity of Access Flow in Predicting Thrombosis
Authors: Weitzel William F. , Segal Jonathan H. , Leavey Sean F. , Saran Rajiv , Swartz Richard D. , Messana Joseph M.
Published: November 2003

Dialysis access monitoring may help decrease thrombosis‐related morbidity. We investigated the effect of time elapsed since an access flow measurement on test accuracy of a novel flow monitoring method called variable flow (VF) Doppler. A retrospective review was conducted in 36 patients with prosthetic grafts for vascular access using access thrombosis as the clinical endpoint. Receiver operator characteristic (ROC) curves and test sensitivity and specificity were determined for various follow‐up time intervals. ROC analysis showed increasing test discrimination for shorter time intervals. Sensitivity and specificity for a commonly used surveillance threshold (600 ml/min) showed specificity that was little changed (88–93%) from follow‐up time intervals of 15 days to 6 months. However, sensitivity was low (21%) at 6 months, increased to 50% at 2 months, 67% at 1 month, and 100% at 15 days (a single event). Low access blood flow using VF Doppler predicts near‐term thrombosis. These data further imply that the discriminative value of access flow monitoring appears to be highly dependent on time from the flow measurement, improving with shorter time intervals from the measurement.
Sampling Techniques Influence Understory Plant Trajectories After Restoration: An Example from Ponderosa Pine Restoration
Authors: Korb Julie E. , Covington W. W. , Fulé Peter Z.
Published: November 2003

Abstract Although there is no one correct technique for sampling vegetation, the sampling design chosen may greatly influence the conclusions researchers can draw from restoration treatments. Considerations when designing vegetation sampling protocol include determining what sampling attributes to measure, the size and shape of the sampling plot, the number of replicates and their location within the study area, and the frequency of sampling. We installed 20 point‐intercept transects (50‐m long), 8 belt transects (10 × 50 m), 10 adapted Daubenmire transects (four 0.5 × 2‐m plots), and 4 modified‐Whittaker plots (20 × 50 m with smaller nested plots) in treatment and control units to measure understory herbaceous response in a forest restoration experiment that tested different treatments. Point‐intercept transects on average recorded at least twice as much plant cover as did adapted Daubenmire transects and modified‐Whittaker plots taken at the same location for all control and treatment units. Point‐intercept transects and adapted Daubenmire plots on average captured fewer rare and exotic species in the control and treatment units in comparison with the belt transects and modified‐Whittaker plots. Modified‐Whittaker plots captured the highest species richness in all units. Early successional understory response to restoration treatments was likely masked by the response of the herbaceous community to yearly climatic variation (dry vs. wet years). Species richness and abundance were higher in wet years than dry years for all control and treatment units. Our results illustrate that sampling techniques can greatly influence perceptions of understory plant trajectories and therefore the interpretation of whether restoration goals have been achieved. In addition, our results suggest that restoration monitoring needs to be conducted for a sufficient length of time so that restoration treatment responses can be detected.
Extirpation or Coexistence? Management of a Persistent Introduced Grass in a Prairie Restoration
Authors: Wilson Scott D. , Pärtel Meelis
Published: November 2003

Abstract Introduced perennial grasses are one of the greatest constraints to prairie restoration. Herbicides suppress but do not eliminate introduced grasses, so we explored the interaction of herbicide with two additional controls: heavy clipping (to simulate grazing) and competition from native species. A 50‐year‐old stand of the introduced perennial grass Agropyron cristatum (crested wheatgrass) in the northern Great Plains was seeded with native grasses and treated with herbicide annually for 7 years in a factorial experiment. Clipping was applied as a subplot treatment in the final 3 years. Both herbicide and clipping significantly reduced the cover of A. cristatum, but clipping produced an immediate and consistent decrease, whereas herbicide control varied among years. The cover of A. cristatum decreased significantly with increasing cover of a seeded native grass, Bouteloua gracilis (blue grama), suggesting that both top‐down (i.e., grazing) and bottom‐up (i.e., resource competition) strategies can contribute to A. cristatum control. No treatment had any effect on the seed bank of A. cristatum. Even in the most effective control treatments, A. cristatum persisted at low amounts (approximately 5% cover) throughout the experiment. The cover of B. gracilis increased significantly with seed addition and herbicide, and, after 7 years, was similar to that in undisturbed prairie. The total cover of native species increased significantly with clipping and herbicide, and species richness was significantly higher in plots receiving herbicide. Clipping season had no effect on any variable. In summary, no method extirpated A. cristatum, but clipping reduced its cover by 90% and doubled the cover of native species. Extirpation might not be a realistic goal, but relatively simple management allowed coexistence of native species.
Planted Riparian Buffer Zones in New Zealand: Do They Live Up to Expectations?
Authors: Parkyn Stephanie M. , Davies‐Colley Rob J. , Halliday N. Jane , Costley Kerry J. , Croker Glenys F.
Published: November 2003

Abstract River and stream rehabilitation projects are increasing in number, but the success or failure of these projects has rarely been evaluated, and the extent to which buffers can restore riparian and stream function and species composition is not well understood. In New Zealand the widespread conversion of forest to agricultural land has caused degradation of streams and riparian ecosystems. We assessed nine riparian buffer zone schemes in North Island, New Zealand that had been fenced and planted (age range from 2 to 24 years) and compared them with unbuffered control reaches upstream or nearby. Macroinvertebrate community composition was our prime indicator of water and habitat quality and ecological functioning, but we also assessed a range of physical and water quality variables within the stream and in the riparian zone. Generally, streams within buffer zones showed rapid improvements in visual water clarity and channel stability, but nutrient and fecal contamination responses were variable. Significant changes in macroinvertebrate communities toward “clean water” or native forest communities did not occur at most of the study sites. Improvement in invertebrate communities appeared to be most strongly linked to decreases in water temperature, suggesting that restoration of in‐stream communities would only be achieved after canopy closure, with long buffer lengths, and protection of headwater tributaries. Expectations of riparian restoration efforts should be tempered by (1) time scales and (2) spatial arrangement of planted reaches, either within a catchment or with consideration of their proximity to source areas of recolonists.
Compromise of Clathrin Function and Membrane Association by Clathrin Light Chain Deletion
Authors: Wang Jingshan , Virta Valerie C. , Riddelle‐Spencer Kathryn , O'Halloran Theresa J.
Published: November 2003

While clathrin heavy chains from different species are highly conserved in amino acid sequence, clathrin light chains are much more divergent. Thus clathrin light chain may have different functions in different organisms. To investigate clathrin light chain function, we cloned the clathrin light chain, clcA, from Dictyostelium and examined clathrin function in clcA–mutants. Phenotypic deficiencies in development, cytokinesis, and osmoregulation showed that light chain was critical for clathrin function in Dictyostelium. In contrast with budding yeast, we found the light chain did not influence steady‐state levels of clathrin, triskelion formation, or contribute to clathrin over‐assembly on intracellular membranes. Imaging GFP‐CHC in clcA– mutants showed that the heavy chain formed dynamic punctate structures that were remarkably similar to those found in wild‐type cells. However, clathrin light chain knockouts showed a decreased association of clathrin with intracellular membranes. Unlike wild‐type cells, half of the clathrin in clcA– mutants was cytosolic, suggesting that the absence of light chain compromised the assembly of triskelions onto intracellular membranes. Taken together, these results suggest a role for the Dictyostelium clathrin light chain in regulating the self‐assembly of triskelions onto intracellular membranes, and demonstrate a crucial contribution of the light chain to clathrin function in vivo.
Effect of enucleation on protein synthesis during maturation of bovine oocytes in vitro
Authors: Bell J. C. , Smith L. C. , Rumpf R. , Goff A. K.
Published: November 2003

The role of the nucleus in protein synthesis reprogramming during oocyte
maturation was examined in immature or mature bovine oocytes, enucleated at
the germinal vesicle (GV) stage or the metaphase II (MII) stage. Cumulusoocyte
complexes (COCs) were denuded before or after
maturationin vitro. Denuded oocytes were
(i) enucleated at the GV or MII stage (after DNA
staining and ultraviolet (UV) exposure), (ii) stained
and exposed to UV but not enucleated, or (iii) used as
controls. After treatment, oocytes were labelled for 4 h
with35S-methionine or were matured for 24 h before
labelling. GV- or MII- karyoplasts and small portions of cytoplasm
(cytoplasts), removed during enucleation, were also labelled. Labelled
oocytes, karyoplasts or cytoplasts were prepared for one-dimensional
polyacrylamide gel electrophoresis. Incorporation of labelled methionine into
oocyte protein was measured. Enucleation did not affect protein synthesis
reprogramming, but incorporation of 35S-methionine in
immature UV-stained oocytes was high-possibly due to nuclear repair
mechanisms. Protein proles of GV- and MII- karyoplasts differed from those of
immature and mature oocytes. In conclusion, normal protein synthesis
reprogramming in the cytoplasm can occur in the absence of the nucleus, and
specic proteins are synthesized in the nuclear region.
Plant-derived immunocontraceptive vaccines
Authors: Smith G. , Walmsley A. , Polkinghorne I.
Published: November 2003

The use of transgenic or virus-infected plants to produce vitally needed
vaccines for developing nations has been made possible by rapid advances in
plant molecular biology and biotechnology during the last decade. Plant-based
vaccines would be a welcome development for many impoverished countries that
lack the capital-intensive infrastructure required to produce much-needed
vaccines. The approach would also be ideally suited to the delivery of oral
immunocontraceptive vaccines to a wide range of herbivore species. This review
looks at the progress made to date in the use of plants for vaccine
production, how this technology may be used in the future to deliver
immunocontraceptive vaccines to free-ranging wildlife species, and the many
problems that will have to be overcome if this promising approach is to ever
‘bear fruit’.
Case studies in wildlife immunocontraception: wild and feral equids and white-tailed deer
Authors: Kirkpatrick J. F. , Jr J. W. Turner , Liu I. K. M. , Fayrer-Hosken R. , Rutberg A. T.
Published: November 2003

Non-lethal management methods are required for wild equids that are protected
by law and for deer inhabiting areas where lethal controls are not legal or
safe. Single or multiple inoculations of porcine zona pellucida (PZP) vaccine
have been delivered to wild horses and deer by means of darts. Contraceptive
efficacy in horses after two inoculations ranged from 90% to
100%, and after a single inoculation ranged from 19% to
28%. Mares given a controlled-release form of the vaccine had foaling
rates ranging from 7% to 20%. No detectable changes in social
organization or behaviours among treated horses occurred. Contraceptive
effects were reversible after 4 consecutive years of treatment but 5–7
years of treatment resulted in ovulation failure and decreased urinary
oestrogen concentrations. Among deer, two inoculations were
70–100% effective in preventing fawns, but one inoculation
yielded a contraceptive efficacy of ≤20%, with pregnancies occurring
late in the breeding season; a single annual booster inoculation reduced
fertility to 20% in the second year. Energy costs of extended breeding
seasons were less than those resulting from pregnancy. After two years of
treatment, ovaries appeared normal. These studies suggest that PZP
immunocontraception can be successfully applied to certain free-roaming
populations of wild horses and deer.
Immunocontraception in rodents: a review of the development of a sperm-based immunocontraceptive vaccine for the grey squirrel (Sciurus carolinensis)
Authors: Moore H. D. M. , Jenkins N. M. , Wong C.
Published: November 2003

The strategy for developing contraceptive vaccines for wild rodents will
depend on the species. In rats and mice, high all-year birth rates, high
levels of dispersal and promiscous mating systems suggest that, if
immunocontraception was used alone, >90% of the population would
have to sterilized to achieve the desired control. In Britain, the grey
squirrel (Sciurus carolinensis) may be a better
candidate to investigate the feasibility of a contraceptive vaccine in
rodents. This introduced species is a seasonal breeder with a much lower
population turnover than rats or mice. As well as causing damage to woodland,
it has ousted the native red squirrel (S. valgaris) from
most of the UK. A humane and selective method for the control of grey
squirrels is therefore highly desirable
Numerous sperm-specific antigens have been identified on rodent spermatozoa.
Monoclonal antibodies to particular components block sperm–egg
interactions in laboratory animals and cross-react with grey squirrel
spermatozoa. In vitro fertilization assays indicate that
squirrel sperm–egg binding may be inhibited also. Currently, a cDNA
library obtained from grey squirrel testis is being screened to identify genes
encoding specific sperm antigens involved in fertilization. Methods of
enhancing immunogenicity after oral immunization using microparticle carriers
and immune-stimulating complexes are currently under investigation.
Australian and New Zealand mammal species considered to be pests or problems
Authors: Cowan P. E. , Tyndale-Biscoe C. H.
Published: November 2003

In New Zealand and Australia, 25 and 16 introduced mammals are viewed as
pests, respectively, as well as a further 17 native mammals in Australia. Most
introductions were deliberate and the deleterious effects became apparent
later. These pests affect primary production, act as a sylvatic reservoir of
disease, cause degradation of natural ecosystems, or threaten rare or
endangered native animals and plants. Many species have multiple impacts. In
Australia, some native mammals, particularly kangaroos and wallabies, are also
controlled because of their adverse impacts on primary production.
In both countries, current control depends largely on the use of poisons,
shooting, the spread of disease (in the case of rabbits), trapping, habitat
alteration, and commercial or recreational hunting. Methods of control by
interfering with fertility (immunocontraception) are currently being
investigated for rabbits, house mice, foxes, and kangaroos in Australia, and
for the brushtail possum in New Zealand. If these methods prove effective,
they may be applied to other mammal pests, but the need to tailor the
particular approach to the ecology and behaviour of the species means that
there will be a necessarily long lead time
Ethical aspects and dilemmas of fertility control of unwanted wildlife: an animal welfarist’s perspective
Authors: Oogjes Glenys
Published: November 2003

Proposals to manipulate the fertility of wild, free-living animals extend the
domination humans already exercise over domesticated animals. Current lethal
methods for population control include poisoning, trapping, hunting, dogging,
shooting, explosives, fumigants, and deliberately introduced disease. Animal
welfare interests are based on individual animal suffering, but those
interests are often overshadowed by labelling of groups of animals as pests,
resource species, national emblem or endangered species. Public concern for
animal welfare and acceptance of new population control methods will be
influenced by such labels.
The animal welfare implications of new population control technology must be
balanced against the existing inhumane lethal methods used. It will be
difficult to resolve the dilemma of a mechanism for disseminating a fertility
control agent that will cause some animal suffering (e.g. a
genetically-manipulated myxoma virus for European rabbits), yet may reduce
future rabbit populations and therefore the number suffering from lethal
methods. An Animal Impact Statement is proposed as a tool to assist debate
during development of fertility control methods and for decision making prior
to their use. A comprehensive and objective Animal Impact Statement may
introduce an ethic that moves the pendulum from attitudes that allow sentient
animals to be destroyed by any and all available means, towards a more
objective selection of the most effective and humane methods.
Hormonal and non-hormonal agents at implantation as targets for contraception
Authors: Nie Gui-Ying , Butt Anna R. , Salamonsen Lois A. , Findlay Jock K.
Published: November 2003

The processes leading to implantation and the establishment of pregnancy
involve hormonal and non-hormonal agents that offer opportunities as targets
for contraception. Hormonal agents include progesterone, luteolytic factors
(prostaglandin F2α ) and embryonic signals
(chorionic gonadotrophin, oestradiol-17β, interferon-τ ) responsible
for maintaining the corpus luteum. Non-hormonal agents include surface
antigens (attachment and adhesion molecules), vasoactive agents,
tissue-remodelling enzymes (matrix metalloproteinases) and inhibitors (TIMPs),
growth factors (epidermal growth factor and insulin-like growth factor
families) and cytokines (such as leukaemia inhibitory factor,
colony-stimulating factor-1, interleukin-1 (IL-1) and IL-6) associated with
the pre-attachment period and the apposition, adhesion and invasion of the
blastocyst. This review describes some of the hormonal and non-hormonal agents
present at the time of implantation that may be exploited as targets for
contraception in feral species. Particular attention is paid to the mouse as
an experimental model and potential target species. The considerable species
differences which exist in the modes of implantation and placentation and the
way in which the female ‘recognizes’ the presence of a viable
conceptus offer a means of conferring species specificity on potential
contraceptive targets for feral species.
Modelling immunocontraception in disseminating systems
Authors: Barlow N. D.
Published: November 2003

Vectored immunocontraception is a novel technology and simple models are
described to help predict whether, and how, it might work. That is, given that
an effective immunocontraceptive agent can be produced, and given that it can
be inserted into a microparasitic or macroparasitic infective vector, would
the vector persist and reach a high prevalence in the host and, if so, would
it sterilize a sufficient proportion of the host breeding population to
significantly reduce its density? Both conditions are necessary for success.
The first question is an epidemiological one, relating solely to disseminating
systems and differing according to whether the vector itself is newly
introduced or pre-existing. If it is newly introduced, the assumption is that
it is present in some other geographical areas occupied by the same target
species, or is found in closely-related species. If the vector already exists
in the population, the issue is one of competition between the engineered and
wild-type vectors.
The second question is an ecological one, common to both non-disseminating and
disseminating systems. Whatever level of sterilization the immunocontraception
provides must translate into a significant reduction in population density,
having regard to the nature and extent of compensatory, density-dependence
mechanisms in the population.
These two questions, together with other more minor issues, are addressed in
turn with particular reference to models for immunocontraception of brushtail
possums (Trichosurus vulpecula)in New Zealand.
Effects of pivalic acid and sodium pivalate on L-carnitine concentrations in the cauda epididymidis and on male fertility in the hamster
Authors: Lewin L. M. , Fournier-Delpech S. , Weissenberg R. , Golan R. , Cooper T. , Pholpramool C. , Shochat L.
Published: November 2003

In this study, administration of pivalic acid or its sodium salt was found to
decrease the L-carnitine concentration in the epididymal lumen of the hamster;
it also tested whether this decrease affected sperm cell motility, chromatin
structure, or fertilizing capacity. Provision of pivalic acid or its sodium
salt (20 mM or 40 mM) in the drinking water of mature male golden hamsters for
30 days reduced (by 72%, 75%, and 83% in three
experiments) the L-carnitine concentration of the cauda epididymidis but did
not inhibit sperm chromatin condensation, as assessed by flow cytometry. The
treatments did not alter the location of motile sperm in the epididymidis nor
did they appreciably affect the motility of sperm obtained from the distal
cauda epididymidis. The numbers and percentage of ova that reached the 2-cell
stage 36–40 h after uterine insemination with spermatozoa from control
and treated hamsters served as a measure of sperm fertility. Treatment with
pivalic acid or sodium pivalate did not render male hamsters infertile
although it appeared to reduce the fertilizing ability of their spermatozoa.
These results suggest that the high concentration of L-carnitine present in
the lumen of the cauda epididymidis is not required for maturation of sperm
chromatin or development of sperm motility.
Regulation of bovine cervical secretion of prostaglandins and synthesis of cyclooxygenase by oxytocin
Authors: Shemesh Mordechai , Dombrovski Ludmila , Gurevich Michael , Shore Laurence S. , Fuchs Anna-Rita , Fields Michael J.
Published: November 2003

Prostaglandin E2 (PGE2) can cause
softening of the bovine cervix at oestrus when receptors for oxytocin (OT) are
maximally present, indicating a relationship between OT and
PGE2 production. It was therefore determined whether OT
can stimulate prostaglandin synthesis or induce cyclooxygenase expression in
cervical external os segments obtained from pre-oestrous–oestrous cows.
Tissues were minced and incubated (50–100 mg mL-1
6 h-1) in the presence of OT (10 ng
mL-1), progesterone (P4)(5 ng
mL-1) and/or indomethacin (5 µg
mL-1). It was found that OT stimulated basal
PGE2 (7·79 ± 1·22 ng 100
mg-1 , mean±s.e.m.; n
= 6) in external os segments from pre-oestrous–oestrous cows
(P < 0·03), whereas P4
and indomethacin inhibited basal and OT-stimulated PGE2 production
(P < 0·05). Basal prostaglandin
F2α (PGF2α )
production was minimal (<1 ng 100 mg-1 ) and OT had
no effect on its production.
Expression of cyclooxygenase was measured by Western blot analysis following
incubation of the tissue (100 mg 1·5 mL-1 3
h-1 ) in the presence of OT (10 ng
mL-1 ) and in the presence of P4
(5 ng mL-1 ). It was found that OT stimulated the
induction of cyclooxygenase II (79±10%; n
= 7, P < 0· 05). In contrast,
P4 inhibited the basal expression of this enzyme
(-40±5%, n = 7,
P < 0· 05) in the presence or absence of OT.
It is concluded that, in vitro, OT stimulates
PGE2 synthesis by the bovine cervix at oestrus and that
this effect is mediated by cyclooxygenase.
Role of epidermal growth factor and insulin-like growth factor-I on porcine oocyte maturation and embryonic development in vitro
Authors: Grupen Christopher G. , Nagashima Hiroshi , Nottle Mark B.
Published: November 2003

The effects of epidermal growth factor (EGF) and insulin-like growth factor-I
(IGF-I) on the in vitro maturation of porcine oocytes
were examined. Oocytes obtained from the ovaries of slaughtered prepubertal
gilts were matured in modified Medium 199 supplemented with 25% porcine
follicular ßuid and gonadotropins, and fertilized
in vitro. Oocytes were either xed 16 h later to assess
fertilization or cultured for 7 days to assess embryonic development. In
Experiment 1, the addition of EGF to maturation medium increased the
percentage of meiotically mature oocytes (88% v.
70%; P < 0· 001) but did not affect the
proportion of fertilized or cleaved oocytes. Blastocysts derived from oocytes
matured in medium supplemented with 10 ng mL-1 EGF had a
greater number of cells compared with those of control blastocysts
(51·1 ± 5· 1 v. 36·0
± 3·1; P < 0· 02). In Experiment
2, the addition of IGF-I to maturation medium had no effect on meiotic
maturation, fertilization or embryonic development. Our ndings demonstrate
that EGF plays an important role in both the meiotic and cytoplasmic
maturation of porcine oocytes in vitro.
Effect of culture, incubation and acrosome reaction of fresh and frozen-thawed ram spermatozoa for in vitro fertilization and intracytoplasmic sperm injection
Authors: Gómez M. C. , Catt J. W. , Gillan L. , Evans G. , Maxwell W. M. C.
Published: November 2003

This study evaluated different sperm treatments for fertilization of sheep
oocytes by intracytoplasmic sperm injection (ICSI) and
in vitrofertilization (IVF). In Experiment 1, fresh and
frozen semen was separated by Percoll centrifugation and incubated at 30°C
or 39°C in HSOF or BSOF medium for 1 h before use for IVF or ICSI. For
IVF, oocytes were inseminated and incubated with sperm for 30 min, 4 h and 19
h. Sperm were assessed for acrosome integrity after Percoll centrifugation and
1 h incubation, and those used for IVF were assessed after each period of
exposure to the oocytes. Fertilization rates after ICSI were higher for fresh
than for frozen-thawed sperm and were highest 19 h after IVF with fresh or
frozen-thawed sperm in the presence of HSOF at 30°C. In Experiment 2,
fresh semen was separated by Percoll centrifugation and incubated for 5 h in
HSOF, and the acrosome reaction was induced with lysophosphatidylcholine.
Acrosome integrity was then assessed. Fertilization rates after ICSI were
similar for acrosome-reacted and control spermatozoa. These results suggest
that induction of the acrosome reaction in spermatozoa before ICSI is
unnecessary, whereas a capacitating treatment of spermatozoa is required
before IVF.
Sexual maturation and fertility of male and female mice exposed prenatally and postnatally to trivalent and hexavalent chromium compounds
Authors: Al-Hamood M. H. , Elbetieha A. , Bataineh H.
Published: November 2003

The reproductive toxicity of trivalent and hexavalent chromium compounds was
investigated in male and female mice exposed to 1000 ppm chromium chloride and
potassium dichromate via their mother during gestational and lactational
periods.
Fertility was reduced in male offspring exposed to either trivalent or
hexavalent chromium compounds. Body weights and weights of testes, seminal
vesicles and preputial glands were reduced in trivalent-exposed male
offspring.
The exposure of female mice offspring to trivalent and hexavalent chromium
compounds delayed sexual maturation. Fertility was reduced in female offspring
exposed to either trivalent or hexavalent chromium compounds. The exposure of
female mice to hexavalent chromium compound reduced the number of
implantations and viable fetuses respectively. Body weight and weights of
ovaries and uteri were reduced in trivalent-exposed female offspring.
The results indicate that under our experimental conditions, the exposure of
male and female mice offspring to either trivalent or hexavalent chromium
compounds during gestational and lactational periods impair reproductive
functions and fertility in adulthood.
Physiological limits to further improvement in the efficiency of oestrous synchronization in goats
Authors: Freitas V. J. F. , Freitas G. Baril , Martin G. B. , Saumande J.
Published: November 2003

The variability between animals in the timing of oestrus after administration
of a synchronization treatment seems to explain the low rate of fertility in
goats inseminated at a predetermined time after progesterone withdrawal. Two
experiments were performed during the breeding season to test whether the
variation was due to the exogenous hormone regime or to the endogenous
physiology of the animals. Twenty-one goats were given a synchronization
treatment consisting of a vaginal sponge impregnated with 45 mg of
fluorogestone acetate (FGA) for 11 days associated with intramuscular
injection of 400 I.U. of equine chorionic gonadotrophin (eCG) and 50 µg
of cloprostenol 48 h before sponge removal. Progesterone concentrations were
measured during the subsequent cycle and the patterns were modelled to allow
precise determination of the onset of luteolysis. Oestrus and the luteinizing
hormone (LH) surge began 33·0 ± 6·8 h and 76·0
± 33·0 h after sponge withdrawal, v.
43·4 ±5·7 h and 90·0 ± 36·0 h after
natural luteolysis. For both observations, the between-goat variability was
larger during the natural than during the synchronized oestrus
(P < 0·05). The duration of the oestrous cycle
was independent of the number of corpora lutea (CL), whereas the duration of
luteal phase was shorter in goats with 2–3 CL (16·4 ±
0·9 day than in those with 1 CL: 17·7 ± 1·3 day;
P < 0·05).
In the second experiment, 20 goats were ovariectomized and given a vaginal
sponge as described above. Sixteen h after sponge removal, they were injected
with 50 µg of oestradiol benzoate (ODB). This treatment was repeated
with the second sponge being inserted 1–2 days after observation of
oestrus. Oestrus and LH surge were observed: 32·8 ± 6·8 h
v.27·8 ± 7·8 h after the first ODB
injection, and 36·6 ± 7·3 h v.
34·3 ± 4·8 h after the second ODB injection. No
relationship was observed between data of the two experiments. In both cases,
the variability in the occurrence of oestrus and LH surge was of the same
order as observed in the first experiment. This study shows that the timing of
oestrus and LH surge is less variable after progestagen treatment than during
a natural oestrous cycle. Moreover, a significant proportion of variability is
inherent in the delays following the oestradiol peak, suggesting that further
improvement in the synchronizing capacity of treatment based on progestagen
administration is unlikely. Extra keyword: progestagens.
Influence of maternal bodyweight on size, conformation and survival of newborn lambs
Authors: Clarke Lynne , Yakubu David Pam , Symonds Michael E.
Published: November 2003

Although body condition score was not significantly different between light
(<55 kg, n = 6) and heavy (≥60 kg,
n = 70 ewes at mating, it declined between Day 30
and Day 90 of gestation in light but not heavy ewes, and remained lower up to
term. All ewes bore twins, delivered near term (Days 144–146) by
Caesarean section. One lamb was immediately placed into a warm (30°C; WD)
and its twin into a cool (15°C; CD) ambient temperature, and tissues were
sampled at 0·5 h or 6 h. All CD lambs born to light ewes exhibited
hypothermia and/or respiratory failure and did not survive longer than 30
min; these symptoms were not observed in their WD twins or any lamb born to
heavy ewes. Total lamb birth weight, placental weight and fetal cotyledonary
weight were lower with light than with heavy ewes. Lambs born to light ewes
had less perirenal adipose tissue and smaller liver, heart, kidneys, brain,
adrenals and thyroid, although their heart, brain and pancreas represented a
larger proportion of total bodyweight; pancreas weight was similar to that in
lambs born to heavy ewes. Hence, maternal bodyweight critically influences
placental weight and lamb size and survival after birth.
Is the acrosome reaction a prerequisite for sperm incorporation after intra-cytoplasmic sperm injection (ICSI)?
Authors: Sathananthan A. H. , Szell A. , Ng S. C. , Kausche A. , Lacham-Kaplan O. , Trounson A.
Published: November 2003

There is debate as to whether the acrosome reaction is necessary for sperm
incorporation after intra-cytoplasmic sperm injection (ICSI). Ultrastructural
evidence is presented to show that the acrosome reaction could occur in the
ooplasm before sperm incorporation in mature human oocytes or the acrosome
could be discarded intact before sperm incorporation in immature oocytes,
matured in vitro. Both germinal vesicle and growing
follicular oocytes showed sperm chromatin decondensation, with discarded
acrosomes close to the sites of incorporation, and were able to form male
pronuclei. This is probably the first report of microfertilization of a
growing oocyte with a reticulate nucleolus by ICSI. The acrosome reaction,
when it occurs, is preceded by acrosome swelling and is followed by
vesiculation of surface membranes exposing the inner acrosome membrane, as
observed on the surface of the zona during IVF or in the perivitelline space
after subzonal sperm injection. These sperm were probably capacitated at the
time of ICSI. There was subtle evidence of leaching of the acrosomal matrix
from intact discarded acrosomes and from partially depleted acrosomes attached
to decondensing spermheads. These sperm were probably not fully capacitated at
the time of ICSI. It is concluded that both the acrosome reaction and acrosome
deletion are possible prerequisites to sperm incorporation after ICSI.
Micromolar concentration of pentoxifylline improves development in vitro of hamster 8-cell embryos: conrmation of biological viability by embryo transfer
Authors: Ain Rupasri , Seshagiri P. B.
Published: November 2003

The inßuence of the sperm motility stimulant pentoxifylline (PF) on
preimplantation embryo development in hamsters was evaluated. Eight-cell
embryos were cultured in hamster embryo culture medium (HECM)-2, with or
without PF (0· 0233·6 mM). There was 90%, 37% and
29% inhibition of blastocyst development by 3·6 (used for human
sperm), 0·9 and 0 ·45 mM PF, respectively. However, 23 µM
PF (exposed to hamster oocytes during IVF) signicantly
(P < 0·05) improved blastocyst development
(63· 6% v. 51· 8%); morulae
development was, however, not curtailed by 0·45 mM or 0·9 mM PF
(51·8%±6·0 or
50·5%±11·3, respectively). Post-implantation
viability of PF-treated embryos was assessed by embryo transfer; 43% of
80 PF-treated embryos implanted compared with 40% of 79 control
embryos. Of the 9 recipients, 6 females delivered pups (19, i.e. 16% of
transferred embryos or 53% of implanted embryos). These data show that
in hamsters, continuous presence of PF at 0·45-3·6 mM is
detrimental to 8-cell embryo development whereas 23 µM PF improves the
development of embryos to viable blastocysts which produce live offspring.