Articular degeneration after subchondral cementation for giant cell tumors at the knee.

PURPOSE: To quantify joint degeneration and the clinical outcome after curettage and cementation in subchondral giant cell tumors of the bone (GCTB) at the knee. METHODS: We conducted a retrospective analysis of 14 consecutive patients (seven female, seven male) with a mean age of 34 years (range 19-51) who underwent curettage and subchondral cementation for a biopsy-confirmed GCTB at the distal femur or the proximal tibia between August 2001 and August 2017, with a mean follow-up period of 54.6 months (range 16.1-156 months). The Whole-Organ Magnetic Resonance Imaging Score (WORMS), Kellgren-Lawrence (KL) classification, and Musculo-Skeletal Tumor Society (MSTS) score were assessed. RESULTS: Radiological degeneration progressed from preoperative to the latest follow-up, with a median WORMS from 2.0 to 4.0 (p = 0.006); meanwhile, the median KL score remained at 0 (p = 0.102). Progressive degeneration (WORMS) tended to be associated with the proximity of the tumor to the articular cartilage (mean 1.57 mm; range 0-12 mm) (p = 0.085). The most common degenerative findings were cartilage lesions (n = 11), synovitis (n = 5), and osteophytes (n = 4). Mean MSTS score increased from 23.1 (preoperatively) to 28.3 at the latest follow-up (p < 0.01). Seven patients (50%) were treated for a local recurrence, with six revision surgeries performed. Removal of the cement spacer and filling of the cavity with a cancellous autograft was performed in seven patients. Conversion to a total knee arthroplasty was performed in one patient for local tumor control. CONCLUSIONS: Cementation following the curettage of GCTB around the knee is associated with slight degeneration at medium-term follow-up and leads to a significant reduction in pain. Removal of the cement and reconstruction with an autograft may be beneficial in the long term.

Installing oncofertility programs for breast cancer in limited versus optimum resource settings: Empirical data from 39 surveyed centers in Repro-Can-OPEN Study Part I & II.

PURPOSE: As a further step to elucidate the actual diverse spectrum of oncofertility practices for breast cancer around the globe, we present and discuss the comparisons of oncofertility practices for breast cancer in limited versus optimum resource settings based on data collected in the Repro-Can-OPEN Study Part I & II. METHODS: We surveyed 39 oncofertility centers including 14 in limited resource settings from Africa, Asia & Latin America (Repro-Can-OPEN Study Part I), and 25 in optimum resource settings from the United States, Europe, Australia and Japan (Repro-Can-OPEN Study Part II). Survey questions covered the availability of fertility preservation and restoration options offered to young female patients with breast cancer as well as the degree of utilization. RESULTS: In the Repro-Can-OPEN Study Part I & II, responses for breast cancer and calculated oncofertility scores showed the following characteristics: (1) higher oncofertility scores in optimum resource settings than in limited resource settings especially for established options, (2) frequent utilization of egg freezing, embryo freezing, ovarian tissue freezing, GnRH analogs, and fractionation of chemo- and radiotherapy, (3) promising utilization of oocyte in vitro maturation (IVM), (4) rare utilization of neoadjuvant cytoprotective pharmacotherapy, artificial ovary, and stem cells reproductive technology as they are still in preclinical or early clinical research settings, (5) recognition that technical and ethical concerns should be considered when offering advanced and innovative oncofertility options. CONCLUSIONS: We presented a plausible oncofertility best practice model to guide oncofertility teams in optimizing care for breast cancer patients in various resource settings.

Low Dose Aspirin in high-risk pregnancies: The volatile effect of acetylsalicylic acid on the inhibition of platelets uncovered by G. Born's light transmission aggregometry.

Preeclampsia still represents a life-threatening pregnancy complication, associated with severe maternal and neonatal morbidity and mortality. Low-dose Aspirin is advised to avoid preeclampsia in high-risk pregnancies worldwide. As Aspirin does not cover all women at risk, the prescription raises questions concerning optimal target population, dosage, and onset of therapy. The aim of this study was to test platelet responsiveness on Aspirin by optical aggegrometry, to gain robust biochemically assessment data of Aspirin in an obstetric cohort. 248 women at high risk for development of preeclampsia were included in the study. Aspirin-prophylaxis was administered either in 100 mg (n = 229) or 150 mg (n = 90) daily. Dosing of 100 mg Aspirin was maintained if testing revealed a sufficient platelet inhibition. If platelet inhibition was insufficient, dosage was increased to 150 mg Aspirin and re-testing was advised. 91 patients (91/229 = 39.7%) presented a sufficient inhibitory Aspirin effect at a dosage of 100 mg, but in 138 patients LTA showed an inadequate Aspirin response (138/229 = 60.3%). In 19 women 150 mg Aspirin was administered as starting dose due to new recommendations. Of all women at 150 mg Aspirin 64 did not properly respond (35.4%). The overall rate of sufficient responding women regardless the Aspirin dose was 64.6%. This study demonstrates still an insufficient inhibition of platelet aggregation in about 1/3 of women even with a dosage of 150 mg Aspirin daily, who might potentially benefit from further increase. These data show, that there is a need for further research to allow a personalized approach for individualized Aspirin therapy, maximizing the preventive benefit for mother and child.

Eye changes in space : New insights into clinical aspects, pathogenesis, and prevention.

BACKGROUND: More than ever research into changes in the eye caused by long-term space flight is becoming the focus of the international and national space agencies National Aeronautics and Space Administration (NASA), European Space Agency (ESA) and German Aerospace Center (DLR). In addition to space radiation-induced cataract formation considerable eye changes, summarized under space flight-associated neuro-ocular syndrome (SANS), can occur. OBJECTIVE: This article gives an overview of the current state of research and future directions in the field of research concerned with ocular alterations in SANS and presents the relevance for terrestrial ophthalmological research. MATERIAL AND METHODS: An analysis of existing publications on SANS in PubMed and reports on the risk of SANS published by the NASA of the USA was carried out. RESULTS: The reasons for the development of the eye changes in space have not been clarified. Factors such as the increase in intracranial pressure, fluid shifts, hypercapnia and genetic factors are the subject of intensive research efforts. A terrestrial model for the induction of papilledema could be established (bed rest studies with -6° head-down tilt as a space analogue). Countermeasures for the development of eye changes, such as intermittent artificial gravity, are the subject of current research studies. CONCLUSION: Research into SANS as part of bed rest studies will provide further important insights in the future for space research and also for terrestrial research. Clinical research projects can be derived from space research.

[From human terrestrial models to new preventive measures for ocular changes in astronauts : Results of the German Aerospace Center studies]. / Von humanen terrestrischen Modellen zu neuen Präventionsansätzen für Augenveränderungen bei Astronauten : Ergebnisse der Studien des Deutschen Zentrums für Luft- und Raumfahrt.

BACKGROUND: Ocular changes in astronauts, particularly the spaceflight associated neuro-ocular syndrome (SANS), pose a medical challenge for which no suitable preventive measures exist. During long-duration spaceflight missions, e.g. to the Moon and Mars, SANS and radiation-induced cataract could affect the health and performance of crews and jeopardize the success of missions. Mechanistic studies and development of preventive measures require suitable terrestrial models. OBJECTIVE: Overview on the most recent research and future plans in space medicine. MATERIAL AND METHODS: Search for relevant publications using PubMed. RESULTS: Bed rest studies at the German Aerospace Center (DLR) demonstrated that strict bed rest in a -6° head down tilt position reproduces changes just like SANS on Earth. This model including creation of optic disc edema is applied in human studies testing influences of artificial gravity through short arm centrifugation as a preventive method. The unique research facility :envihab provides the opportunity to also simulate the ambient conditions of the International Space Station during bed rest studies. CONCLUSION: Future head down tilt bed rest studies will serve to systematically test preventive measures for SANS. Similar investigations would be difficult to realize under real space conditions. Through close collaboration between space medicine and terrestrial ophthalmology, this research can benefit patients on Earth.

[Dependency of intraocular pressure on body posture in glaucoma patients : New approaches to pathogenesis and treatment]. / Lageabhängigkeit des Augeninnendruckes bei Glaukompatienten : Neue Ansätze zur Pathogenese und Therapie.

BACKROUND: Human intraocular pressure (IOP) depends on the position of the head in relation to the body in space. Physiologically, the IOP increases in a lying position compared to an upright posture. Microgravity in space also appears to cause an increase in intraocular pressure, accompanied by other ophthalmological changes, which are summarized under the term spaceflight associated neuro-ocular syndrome (SANS). Bed rest studies are being carried out to investigate the effects of weightlessness on the human body. So here there is an intersection between research into SANS and glaucoma. Increased intraocular pressure remains the most important risk factor for glaucoma development and progression that can be influenced by treatment. The influence of position-dependent IOP fluctuations on glaucoma is still not sufficiently understood. MATERIALS AND METHODS: A literature search was carried in PubMed on the subject of IOP fluctuations related to posture. Analysis and evaluation of the published study results and a summary of available clinical data. RESULTS: The increase in IOP when changing from a seated to a lying body position is greater in glaucoma patients with an increase of up to 8.6 mm Hg compared to healthy subjects with an increase up to 5 mm Hg. In small pilot studies the increase in lying IOP in some glaucoma patients and healthy volunteers could be attenuated by elevation of the head by 30%. A lower compartmental pressure in the subarachnoid space has been associated with glaucoma and may represent a risk factor for glaucoma development. Not only the level of IOP but also IOP fluctuations were associated with an increased risk of disease progression. CONCLUSION: The clinical significance of IOP peaks during sleep on glaucoma is still not sufficiently understood. New methods for continuous IOP measurement offer promising opportunities for further research into the importance of IOP fluctuations related to changes of body and head posture.

[Eye changes in space : New insights into clinical aspects, pathogenesis and prevention]. / Augenveränderungen im All : Aktuelles zu Klinik, Pathogenese und Prävention.

BACKGROUND: More than ever research into changes in the eye caused by long-term space flight is becoming the focus of the international and national space agencies National Aeronautics and Space Administration (NASA), European Space Agency (ESA) and German Aerospace Center (DLR). In addition to space radiation-induced cataract formation considerable eye changes, summarized under space flight-associated neuro-ocular syndrome (SANS), can occur. OBJECTIVE: This article gives an overview of the current state of research and future directions in the field of research concerned with ocular alterations in SANS and presents the relevance for terrestrial ophthalmological research. MATERIAL AND METHODS: An analysis of existing publications on SANS in PubMed and reports on the risk of SANS published by the NASA of the USA was carried out. RESULTS: The reasons for the development of the eye changes in space have not been clarified. Factors such as the increase in intracranial pressure, fluid shifts, hypercapnia and genetic factors are the subject of intensive research efforts. A terrestrial model for the induction of papilledema could be established (bed rest studies with -6° head-down tilt as a space analogue). Countermeasures for the development of eye changes, such as intermittent artificial gravity, are the subject of current research studies. CONCLUSION: Research into SANS as part of bed rest studies will provide further important insights in the future for space research and also for terrestrial research. Clinical research projects can be derived from space research.

Endometrial uNK cell counts do not predict successful implantation in an IVF population.

STUDY QUESTION: Are uterine natural killer (uNK) cell numbers and their distribution relative to endometrial arterioles altered in women with recurrent implantation failure (RIF) compared to women with embryo implantation success (IS)? SUMMARY ANSWER: uNK cell numbers and their distribution relative to endometrial arterioles are not significantly different in women with RIF compared to women in whom embryo implantation occurs successfully following IVF. WHAT IS ALREADY KNOWN: uNK cells are regulators of decidual angiogenesis and spiral arteriole remodelling during early pregnancy. Although some studies have shown that uNK cell numbers may be altered in women with RIF, the methods used to measure uNK cell numbers have proven inconsistent, making reproduction of these results difficult. It is unclear, therefore, whether the results reported so far are reproducible. Moreover, it is not known how uNK cell numbers may impact IVF outcomes. Despite the lack of conclusive evidence, uNK cell numbers are often evaluated as a prognostic criterion in women undergoing assisted reproductive procedures. STUDY DESIGN, SIZE, DURATION: Endometrial pipelle biopsies were collected 6-8 days post-LH surge in natural cycles from women with RIF (n = 14), women with IS (n = 11) and women with potential RIF at the time of the study (PRIF; n = 9) from 2013 to 2015. PARTICIPANTS/MATERIALS, SETTING, METHODS: uNK cells (i.e. CD56+ and/or CD16+ phenotypes) and their distribution relative to endometrial arterioles were investigated by standard immunohistochemistry protocols and quantified using Aperio ScanScopeXT images digitized by ImageJ and deconvoluted into binary images for single cell quantification using a Gaussian Blur and Yen algorithm. MAIN RESULTS AND THE ROLE OF CHANCE: There was no significant difference in the cell density of CD56+ or CD16+ uNK cells in women with RIF compared to women with IS or PRIF. There was a higher proportion of uNK cells in the distal regions compared to the regions closest to the arterioles in all patient groups. Further, we identified a significant reduction in uNK cell density in women who had a previous pregnancy compared to those who had not, regardless of their current implantation status. LARGE SCALE DATA: Not applicable. LIMITATIONS, REASONS FOR CAUTION: Spiral arterioles could not always be accurately identified by digital image analysis; therefore, all endometrial arterioles were selected and analysed. Patient numbers for the study were low. However, as the clinical phenotypes of each patient were well defined, and endometrial dating was accurately determined by three independent pathologists, differences between patient groups with respect to the uNK numbers and distribution should have been measurable if uNK cell counts were to be useful as a prognostic marker of RIF. WIDER IMPLICATIONS OF THE FINDINGS: Our findings demonstrate that CD56+ and CD16+ uNK cell numbers are not significantly different in women with RIF in a typical cohort of women undergoing IVF. Further, prior pregnancy was associated with a significantly reduced number of uNK cells in both the RIF and IS patient groups, suggestive of a long-term pregnancy induced suppression of uNK cells. Combined, these findings do not support the clinical value of using uNK cell numbers as a prognostic indicator of implantation success with IVF treatment. STUDY FUNDING/COMPETING INTEREST(S): Funding for this work was provided by Royal Women's Hospital Foundation. P.P. was supported by an NHMRC Early Career Fellowship [TF 11/14] and W.T.T. was supported by an NHMRC Postgraduate Scholarship [1055814]. The authors do not have any competing interests with this study.

Tempering aversive/traumatic memories with cannabinoids: a review of evidence from animal and human studies.

RATIONALE: Aversive learning and memory are essential to cope with dangerous and stressful stimuli present in an ever-changing environment. When this process is dysfunctional, however, it is associated with posttraumatic stress disorder (PTSD). The endocannabinoid (eCB) system has been implicated in synaptic plasticity associated with physiological and pathological aversive learning and memory. OBJECTIVE AND METHODS: The objective of this study was to review and discuss evidence on how and where in the brain genetic or pharmacological interventions targeting the eCB system would attenuate aversive/traumatic memories through extinction facilitation in laboratory animals and humans. The effect size of the experimental intervention under investigation was also calculated. RESULTS: Currently available data indicate that direct or indirect activation of cannabinoid type-1 (CB1) receptor facilitates the extinction of aversive/traumatic memories. Activating CB1 receptors around the formation of aversive/traumatic memories or their reminders can potentiate their subsequent extinction. In most cases, the effect size has been large (Cohen's d ≥ 1.0). The brain areas responsible for the abovementioned effects include the medial prefrontal cortex, amygdala, and/or hippocampus. The potential role of cannabinoid type-2 (CB2) receptors in extinction learning is now under investigation. CONCLUSION: Drugs augmenting the brain eCB activity can temper the impact of aversive/traumatic experiences by diverse mechanisms depending on the moment of their administration. Considering the pivotal role the extinction process plays in PTSD, the therapeutic potential of these drugs is evident. The sparse number of clinical trials testing these compounds in stress-related disorders is a gap in the literature that needs to be addressed.

Survey of Reproductive Experiences and Outcomes of Cancer Survivors Who Stored Reproductive Material Before Treatment.

STUDY QUESTION: What are the reproductive experiences and outcomes of people who store reproductive material before cancer treatment? SUMMARY ANSWER: Of respondents who had tried to achieve pregnancy since completing cancer treatment almost all had succeeded, in most cases through natural conception. WHAT IS KNOWN ALREADY: People of reproductive age who are diagnosed with cancer can cryopreserve reproductive material to guard against the adverse effects on fertility of gonadotoxic treatment. Little is known about the reproductive outcomes of people who undergo fertility preservation before cancer treatment. STUDY DESIGN, SIZE, DURATION: Cross-sectional survey. PARTICIPANTS/MATERIALS, SETTING, METHODS: Women and men who had stored reproductive material before cancer treatment at two private and one public fertility clinics up to June 2014 and were at least 18 years old at the time were identified from medical records and invited to complete an anonymous questionnaire about their reproductive experiences. MAIN RESULTS AND THE ROLE OF CHANCE: Of the 870 potential respondents 302 (171 female and 131 male) returned completed questionnaires yielding a response rate of 34.5% (39.5% and 29.7% for female and male respondents, respectively). Current age was similar for women and men (37.2 years) but men had been diagnosed with cancer significantly earlier in life than women (28.2 versus 30.3 years, P = 0.03). Almost two-thirds of respondents wished to have a child or another child in the future, some of whom knew that they were unable to. One in ten respondents was a parent before the cancer diagnosis and around one-third had had a child since diagnosis or was pregnant (or a partner in pregnancy) at the time of the survey. Of those who had tried to conceive since completing cancer treatment (N = 119) 84% (79% of women and 90% of men) had had a child or were pregnant (or a partner in pregnancy). Most of the pregnancies since the diagnosis of cancer occurred after natural conception (58/100, 58%). Of the 22 women (13% of all women) and 35 men (27% of all men) who had used their stored reproductive material four women (18%) and 28 men (80%) had had a child or were pregnant or a partner in pregnancy at the time of completing the survey. The most commonly stated reason for not using the stored material was not being ready to try for a baby. LIMITATIONS, REASON FOR CAUTION: The relatively low response rate, particularly among men, means that participation bias may have influenced the findings. As type of cancer was self-reported and we did not ask questions about respondents' cancer treatments, it is not possible to link reproductive outcomes to type of cancer or cancer treatment. Also, there is no way of comparing the sample with the populations they were drawn from as data on reproductive outcomes of people who store reproductive material before cancer treatment are not collected routinely. This might have led to over- or underestimates of the reproductive experiences and outcomes reported in this paper. WIDER IMPLICATIONS OF THE FINDINGS: The findings add to the limited evidence about the reproductive outcomes of this growing group of people and can be used to inform the advice given to those contemplating fertility preservation in the context of cancer. STUDY FUNDING/COMPETING INTERESTS: The study was funded by the National Health and Medical Research Council (APP1042347). The authors have no conflicts of interest to declare. TRIAL REGISTRATION NUMBER: Not applicable.

Evidence of estrogenic endocrine disruption in smallmouth and largemouth bass inhabiting Northeast U.S. national wildlife refuge waters: A reconnaissance study.

Intersex as the manifestation of testicular oocytes (TO) in male gonochoristic fishes has been used as an indicator of estrogenic exposure. Here we evaluated largemouth bass (Micropterus salmoides) or smallmouth bass (Micropterus dolomieu) form 19 National Wildlife Refuges (NWRs) in the Northeast U.S. inhabiting waters on or near NWR lands for evidence of estrogenic endocrine disruption. Waterbodies sampled included rivers, lakes, impoundments, ponds, and reservoirs. Here we focus on evidence of endocrine disruption in male bass evidenced by gonad histopathology including intersex or abnormal plasma vitellogenin (Vtg) concentrations. During the fall seasons of 2008-2010, we collected male smallmouth bass (n=118) from 12 sites and largemouth bass (n=173) from 27 sites. Intersex in male smallmouth bass was observed at all sites and ranged from 60% to 100%; in male largemouth bass the range was 0-100%. Estrogenicity, as measured using a bioluminescent yeast reporter, was detected above the probable no effects concentration (0.73ng/L) in ambient water samples from 79% of the NWR sites. Additionally, the presence of androgen receptor and glucocorticoid receptor ligands were noted as measured via novel nuclear receptor translocation assays. Mean plasma Vtg was elevated (>0.2mg/ml) in male smallmouth bass at four sites and in male largemouth bass at one site. This is the first reconnaissance survey of this scope conducted on US National Wildlife Refuges. The baseline data collected here provide a necessary benchmark for future monitoring and justify more comprehensive NWR-specific studies.

Cancer therapeutic potential of combinatorial immuno- and vasomodulatory interventions.

Currently, most of the basic mechanisms governing tumour-immune system interactions, in combination with modulations of tumour-associated vasculature, are far from being completely understood. Here, we propose a mathematical model of vascularized tumour growth, where the main novelty is the modelling of the interplay between functional tumour vasculature and effector cell recruitment dynamics. Parameters are calibrated on the basis of different in vivo immunocompromised Rag1(-/-) and wild-type (WT) BALB/c murine tumour growth experiments. The model analysis supports that tumour vasculature normalization can be a plausible and effective strategy to treat cancer when combined with appropriate immunostimulations. We find that improved levels of functional tumour vasculature, potentially mediated by normalization or stress alleviation strategies, can provide beneficial outcomes in terms of tumour burden reduction and growth control. Normalization of tumour blood vessels opens a therapeutic window of opportunity to augment the antitumour immune responses, as well as to reduce intratumoral immunosuppression and induced hypoxia due to vascular abnormalities. The potential success of normalizing tumour-associated vasculature closely depends on the effector cell recruitment dynamics and tumour sizes. Furthermore, an arbitrary increase in the initial effector cell concentration does not necessarily imply better tumour control. We evidence the existence of an optimal concentration range of effector cells for tumour shrinkage. Based on these findings, we suggest a theory-driven therapeutic proposal that optimally combines immuno- and vasomodulatory interventions.

Efficacy and security of ivermectin given orally to rats naturally infected with Syphacia spp., Giardia spp. and Hymenolepis nana.

The results of this study show that the oral administration of ivermectin (48 mg/L) repeatedly for 72 h used in accordance with the present protocol is a safe and highly effective treatment for Giardia spp. and Hymenolepis nana in laboratory rat colonies. The drug can be easily and safely administered using drinking water. This simple regimen should control pinworm infection (Syphacia muris), a problem that can be endemic in laboratory colonies. Experiments using healthy animals are likely to generate more consistent results, thereby requiring a reduced number of animals per group.

Women's reflections on fertility and motherhood after breast cancer and its treatment.

Breast cancer and its treatment have complex ramifications for women of reproductive age, including reduced fertility. With the aim of increasing understanding of what it means to women to manage fertility and motherhood in the years after a diagnosis of breast cancer, in-depth qualitative interviews were conducted with 10 women aged 26-45 years, living in Victoria, Australia, who had been diagnosed with breast cancer aged 25-41. Transcripts were analysed thematically and interpreted within narrative theory. Six themes linking breast cancer to fertility and motherhood were identified: diagnosis as a pivotal life event, robbed of time and choice, significance of fertility, being a mother, narrative justification, and life after breast cancer treatment. Women without children described a preoccupying sorrow about lost fertility. Women's accounts yielded evidence of narrative meaning-making, including justifying their decisions and actions in relation to survival, treatment and fertility, and coping with adversity by developing consoling plots. Breast cancer, fertility and reproductive health are inter-linked in diverse ways which have immediate and long-term consequences. Even if women are receiving optimum fertility management, it is evident that some women of reproductive age will need continuing post-cancer care to manage and ameliorate ramifications of diminished or lost fertility.

First reported clinical pregnancy following heterotopic grafting of cryopreserved ovarian tissue in a woman after a bilateral oophorectomy.

Ovarian tissue cryopreservation and transplantation is a form of fertility preservation offered to young women at high risk of losing ovarian function after cancer treatment. While there have been successful births resulting from orthotopic site grafts, we report the first case of an ongoing pregnancy from a heterotopic graft in a patient who had previously undergone bilateral oopherectomy for a granulosa cell tumour. Frozen-thawed ovarian tissue was transplanted to the anterior abdominal wall. Subsequent ovarian stimulation and transabdominal ultrasound-guided oocyte retrieval from the grafts resulted in two oocytes. These were fertilized with ICSI and two embryos were transferred. Serial ultrasounds have confirmed an ongoing 26-week intrauterine twin pregnancy. Thus, this first demonstration of a pregnancy from a heterotopic graft site provides unequivocal evidence that cryopreservation preserves complete follicle development and that normal ovarian function can occur at a non-ovarian site. This provides optimism for further efforts to assist women who have had oophorectomy and pelvic surgery or radiotherapy, without an appropriate orthotopic site for grafting.

Event-related potential markers of brain changes in preclinical familial Alzheimer disease.

OBJECTIVES: Event-related potentials (ERPs) can reflect differences in brain electrophysiology underlying cognitive functions in brain disorders such as dementia and mild cognitive impairment. To identify individuals at risk for Alzheimer disease (AD) we used high-density ERPs to examine brain physiology in young presymptomatic individuals (average age 34.2 years) who carry the E280A mutation in the presenilin-1 (PSEN1) gene and will go on to develop AD around the age of 45. METHODS: Twenty-one subjects from a Colombian population with familial AD participated: 10 presymptomatic subjects positive for the PSEN1 mutation (carriers) and 11 siblings without the mutation (controls). Subjects performed a visual recognition memory test while 128-channel ERPs were recorded. RESULTS: Despite identical behavioral performance, PSEN1 mutation carriers showed less positivity in frontal regions and more positivity in occipital regions, compared to controls. These differences were more pronounced during the 200-300 msec period. Discriminant analysis at this time interval showed promising sensitivity (72.7%) and specificity (81.8%) of the ERP measures to predict the presence of AD pathology. CONCLUSIONS: Presymptomatic PSEN1 mutation carriers show changes in brain physiology that can be detected by high-density ERPs. The relative differences observed showing greater frontal positivity in controls and greater occipital positivity in carriers indicates that control subjects may use frontally mediated processes to distinguish between studied and unstudied visual items, whereas carriers appear to rely more upon perceptual details of the items to distinguish between them. These findings also demonstrate the potential usefulness of ERP brain correlates as preclinical markers of AD.

Protein synthesis in dorsal hippocampus supports the drug tolerance induced by prior elevated plus-maze experience.

Tolerance to the anxiolytic-like effect of drugs may develop because of a memory derived from prior experience in certain apparatuses such as the elevated plus-maze (EPM). Activity in basolateral amygdala was shown to be required for consolidating this knowledge. The dorsal hippocampus (DH) is also implicated in long-term memory consolidation, a process relying on new protein synthesis. It is unknown, however, whether the DH protein synthesis disruption would prevent the phenomenon rendering animals unresponsive to benzodiazepines in the EPM retest. To address this, we bilaterally infused the protein synthesis inhibitor anisomycin (ANI) into the rat DH 0, 3 or 6 h after, or 15 min before, the EPM test. DH infusion of ANI (80 µg) around the time of EPM testing preserved the anxiolysis of the midazolam (MDZ; 0.5 mg/kg, i.p.) in rats retested in the EPM 24 h later, suggesting that information consolidated by DH protein synthesis impacts on the subsequent animal's responsiveness to this drug. To examine whether impaired memory acquisition could also contribute to the prevention of MDZ tolerance seen in EPM-experienced animals infused with ANI before testing, the EPM retest was performed 3 h after testing to coincide with the temporal window in which short-term memory remains, for the reason that this process does not require protein synthesis for its formation. The pretest DH anisomycin infusion's ability to prevent the MDZ tolerance on retesting was now missing. This result confirms a specific action of the ANI on memory consolidation. We also found that rats express further avoidance to open-arms in the EPM retest. However, neither pretest nor posttest DH ANI infusion interfered with this pattern of results exhibited by EPM-experienced rats.

Activity in prelimbic cortex is required for adjusting the anxiety response level during the elevated plus-maze retest.

The prelimbic (PL) subregion of medial prefrontal cortex has been implicated in anxiety regulation. It is unknown, however, whether PL cortex also serves to fine-tuning the level of anxiety-related behavior exhibited on the next exposure to the same potentially threatening situation. To address this, we infused cobalt (1.0 mM) to temporarily inactivate the PL cortex during testing, post-testing or retesting in the elevated plus-maze (EPM). This protocol was chosen because it allowed us to concurrently investigate anxiety and the process of aversive learning and memory. PL cortex inactivation during the EPM testing increased the exploration of open-arms, substantiating its role in anxiety. PL cortex inactivation during the EPM retesting counteracted the further avoidance to open-arms exhibited by rats. Interestingly, as evidenced by min-by-min analysis, the cobalt-treated group behaved on EPM retesting as did the vehicle-treated group on EPM testing. This result may imply that activity in PL cortex is necessary for retrieving previously learned information that adjusts the anxiety response level on EPM retesting. Alternatively, a simple reduction in anxiety could explain the cobalt-induced increase in retest open-arms exploration. Neither test nor post-test PL cortex inactivation affected the further avoidance to open-arms observed on EPM retesting. To extend the investigation of PL cortex role in the regulation of open-arms avoidance, we infused other drugs prior to testing or retesting in the EPM. Antagonism of PL cortex adrenergic beta-1 receptors with atenolol (10 nmol), cholinergic muscarinic receptors with scopolamine (20 nmol) or glutamatergic N-methyl-d-aspartic acid (NMDA) receptors with AP5 (6.0 nmol) interfered with the level of open-arms exploration on testing, but not on retesting.