Assessment of DNA Ploidy in the ProMisE molecular subgroups of endometrial cancer.

OBJECTIVE: We sought to determine whether DNA ploidy correlates with the four molecular subgroups of endometrial carcinoma (EC) as determined using ProMisE (Proactive Molecular Risk Classifier for Endometrial Cancer). METHODS: 90 cases of EC previously characterized by clinicopathological parameters, outcomes, and ProMisE molecular subgroup (POLE EDM, MMR-D, p53 wt or p53 abn) were assessed for DNA ploidy using image cytometry. Associations of ploidy with traditional clinicopathological parameters were also tested. RESULTS: Abnormal DNA ploidy status differed amongst the ProMisE groups (p<0.001) and was found in 80.9% (17/21) of p53 abn, 37.0% (10/27) of p53 wt, 28.6% (4/14) of POLE EDM and 14.3% (4/28) of MMR-D. Abnormal DNA content was significantly associated with lower BMI (p=0.034) and grade 3 tumors (p=0.001). In the entire cohort, abnormal DNA content was significantly associated with worse progression free survival (p=0.0094) but not disease specific survival (p=0.249) or overall survival (p=0.187). When examining ploidy within each of the ProMisE groups, abnormal DNA content correlated with worse overall survival (p=0.041) and progression free survival (p=0.011) in the MMR-D group. No statistically significant relationship was seen in the remaining 3 groups. CONCLUSION: Abnormal DNA ploidy status did correlate with the molecular subgroups of EC; abnormal DNA content was seen in the large majority of p53 abn cases. Abnormal ploidy however was also seen in smaller numbers in the p53 wt, POLE EDM and MMR-D groups; therefore abnormal DNA content was not a specific marker for any one molecular group. The addition of ploidy to the ProMisE molecular categories conferred additional prognostic value within the MMR-D group, which merits further study.

The Microbiome: The Trillions of Microorganisms That Maintain Health and Cause Disease in Humans and Companion Animals.

The microbiome is the complex collection of microorganisms, their genes, and their metabolites, colonizing the human and animal mucosal surfaces, digestive tract, and skin. It is now well known that the microbiome interacts with its host, assisting in digestion and detoxification, supporting immunity, protecting against pathogens, and maintaining health. Studies published to date have demonstrated that healthy individuals are often colonized with different microbiomes than those with disease involving various organ systems. This review covers a brief history of the development of the microbiome field, the main objectives of the Human Microbiome Project, and the most common microbiomes inhabiting the human respiratory tract, companion animal digestive tract, and skin in humans and companion animals. The main changes in the microbiomes in patients with pulmonary, gastrointestinal, and cutaneous lesions are described.

Effects of immunization against androstenedione or bone morphogenetic protein 15 (BMP15) on reproductive performance in sheep.

Partial neutralization of bone morphogenetic protein 15 (BMP15) bioactivity by immunization is known to increase ovulation rate in sheep. However, it remains uncertain whether BMP15 vaccination would be a suitable procedure for increasing lambing rate. The aim of this study was to compare the efficacy of a BMP15 vaccination treatment on lamb production to that of commercially-available androstenedione-based vaccines that are used for this purpose. Ewes were immunized for 3 yr against androstenedione, BMP15, or no antigen (control). Vaccination with androstenedione or BMP15 altered (P < 0.05) ovulation rate as well as litter size at midpregnancy, birth, and weaning compared with controls. No differences were detected in the proportions of ewes conceiving in the first cycle or partial failure of multiple ovulations. Both gender and litter size affected birth weight of the lamb (P < 0.05), but no effect of treatment was found. Growth rate was significantly affected (P < 0.05) by gender, birth weight, and the number of lambs raised, but not treatment. In conclusion, immunization against either androstenedione or BMP15 increased ovulation rate. Androstenedione vaccination also increased the number of lambs weaned (P < 0.05). Bone morphogenetic protein 15 vaccination altered the pattern of the number of lambs weaned, but no increase in lamb production was observed as more ewes produced zero or three lambs. Overall, androstenedione or BMP15 vaccination did not significantly affect embryo or fetal survival or lamb performance independently of the effects of these treatments on ovulation rate.

Umbilical cord diameter percentile curves and their correlation to birth weight and placental pathology.

OBJECTIVE: The aims of this study were to develop a nomogram of umbilical cord diameter (UCD) for pathologic examination of the placenta, to identify the umbilical cord components responsible for variations in UCD, and to examine the relationship between UCD and other placental pathologic features and perinatal outcome. STUDY DESIGN: We prospectively collected 497 umbilical cords between 18 and 41 weeks' gestation over a 1-year period. Fresh-tissue UCD were grouped according to gestational age and compared to sonographic and histological measurements. Associations between UCD percentile and placental pathologic findings or obstetrical outcomes were examined. RESULTS: Mean UCD increased with gestational age until a plateau at 1.0 cm in the third trimester, a value that was 0.56 cm less than sonographic measurements prior to delivery and 0.17 cm greater than UCD measured histologically. Umbilical cord components varied with UCD percentile, with umbilical vessel area increased in thick cords (p < 0.001) and Wharton's jelly area reduced in thin cords (p = 0.002). Thin umbilical cords were associated with at least one pathologic histological placental finding (p = 0.02), low placental weight (p < 0.001), single umbilical artery (p = 0.02), marginal cord insertion (p = 0.01), and low infant birth weight (p < 0.001). CONCLUSIONS: This study provides reference curves for post-delivery UCD from 18 to 41 weeks' gestation for use by perinatal pathologists. We show that increased UCD is a function of increased umbilical blood vessel volume and decreased UCD is a function of decreased Wharton's jelly volume. UCD shows a strong association with placental and infant birth weight.

Unfractionated heparin for second trimester placental insufficiency: a pilot randomized trial.

OBJECTIVE: To conduct a pilot randomized controlled trial of unfractionated heparin (UFH) in women considered at high risk of placental insufficiency in the second trimester. METHODS: Women with either false-positive first trimester (pregnancy-associated placental protein-A [PAPP-A] < 0.35 MoM) or second trimester (alpha-fetoprotein [AFP] > 2.0 MoM, inhibin > 3.0 MoM, human chorionic gonadotropin > 4.0 MoM) serum screening tests or medical/obstetric risk factors were screened for placental insufficiency by sonographic evaluation of the placenta and uterine artery Doppler between 18 and 22 weeks. Thrombophilia screen-negative women with two or three abnormal test categories were randomized by 23+6 weeks to self-administration of subcutaneous unfractionated heparin (UFH) 7500 IU twice daily until birth or 34 weeks, or to standard care. Maternal anxiety and other maternal-infant outcomes were determined. RESULTS: Thirty-two out of 41 eligible women consented, with 16 women randomized to UFH and 16 to standard care. There was no statistically significant difference identified between the two treatment groups (standard care vs. UFH) for the following: maternal anxiety score (mean [standard deviation]), 14.2 [± 1.6] vs. 14.0 [± 1.8]; birth weight (median [range]), 1795 [470-3295]g vs. 1860 [730-3050]g; perinatal death, 3 vs. 0; severe preeclampsia, 2 vs. 6; placental weight < 10th percentile, 7 vs. 4; or placental infarction, 4 vs. 3. CONCLUSION: Our study design identified women at high risk of adverse maternal-infant outcomes attributable to placental insufficiency. Women with evidence of placental insufficiency were willing to undergo randomization and self-administration of UFH without increased maternal anxiety.

Pathologic basis of echogenic cystic lesions in the human placenta: role of ultrasound-guided wire localization.

OBJECTIVE: The sonographic appearance of the placenta is normally homogenous throughout the second trimester. A variety of abnormalities in placental texture have been described, some of which may be pathologic and associated with adverse clinical outcomes. We characterized the pathologic basis of one lesion termed echogenic cystic lesions (ECLs) that may be a prognostic marker in intrauterine growth restriction (IUGR). STUDY DESIGN: We retrospectively correlated placental pathology in 50 pregnancies that had a total of 84 ECLs documented by ultrasound prior to delivery. Six additional women with placental ECLs prospectively underwent immediate post-delivery ultrasound-guided wire localization of 9 lesions followed by placental pathology. Obstetric outcome data were recorded. RESULTS: Severe pre-eclampsia (20%) and extreme IUGR (18%) were common outcomes. Of 93 ECLs identified, 46 (49%) gross lesions were found by placental pathology. Inter-villous thrombosis was the most significant lesion found (30/46, 65%) compared to all other lesions (35%; Z-Test, p = 0.007). Ultrasound guidance identified 8/9 (89%) lesions of which 6/8 (67%) were inter-villous thrombosis. Associated lesions (infarction, 36%; advanced villous maturation, 27%) and small placental weight (<10th centile, 38%) were present in 50%, but did not increase the risk of adverse perinatal outcome. CONCLUSIONS: ECLs are most commonly due to inter-villous thrombosis. The adverse clinical outcomes may be mediated by associated lesions not readily detectable by ultrasound. Ultrasound-guided wire localization is a promising research tool for future large-scale cohort studies needed to define the clinical utility of placental ultrasound findings.

Incorporation of femur length leads to underestimation of fetal weight in asymmetric preterm growth restriction.

OBJECTIVE: To review the performance of a variety of biometry formulae for estimated fetal weight (EFW) in the management of severely growth restricted fetuses with abnormal umbilical artery Doppler at a single perinatal institution. METHODS: Forty-three pregnancies were retrospectively reviewed. Inclusion criteria were: chromosomally/ structurally normal fetus; complete ultrasound biometry at < or = 7 days from delivery; EFW < 10(th) centile; absent/reversed end-diastolic flow in the umbilical arteries; and delivery at < 32 + 6 weeks. EFW accuracy and precision were compared among nine formulae utilizing combinations of head circumference (HC), biparietal diameter (BPD), abdominal circumference (AC) and femur length (FL) measurements. RESULTS: Twenty-six (60.5%) fetuses showed asymmetric growth (HC/AC ratio > 95(th) centile). Analysis of the systematic and random errors associated with each formula showed that the birth weight of asymmetrically-grown fetuses was most closely approximated by the Hadlock equation that utilized BPD and AC measurements only. The birth weight of symmetrically-grown fetuses was most closely approximated by EFW derived from Hadlock equations that utilized > or = three biometry measurements, including FL. Incorporation of FL into Hadlock formulae led to significant underestimation of birth weight in the fetuses with asymmetric growth (mean percentage error +/- SD: EFW(FL-AC), -13.3 +/- 9.8%; EFW(BPD-FL-AC), -10.8 +/- 9.8%; EFW(HC-FL-AC), -11.8 +/- 9.3%; EFW(BPD-HC-FL-AC), -11.7 +/- 9.5%; P < 0.001). The same equations were accurate in fetuses with symmetric growth (EFW(FL-AC), 3.1 +/- 10.0%; EFW(BPD-FL-AC), 1.0 +/- 8.9%; EFW(HC-FL-AC), 0.3 +/- 8.7%; EFW(BPD-HC-FL-AC), 0.4 +/- 15.5%). Use of the best performing equation (Hadlock 3), which does not include FL, to estimate weight in asymmetrically-grown fetuses over 28 weeks' gestation, would have reduced the proportion of those with an underestimation of fetal weight of > 100 g from nine (50.0%) to three (16.7%). CONCLUSIONS: Biometry methods that exclude FL should be considered in asymmetric intrauterine growth restriction associated with abnormal umbilical artery Doppler waveforms.

Placental size and the prediction of severe early-onset intrauterine growth restriction in women with low pregnancy-associated plasma protein-A.

OBJECTIVES: Screening studies for trisomy 21 demonstrate that low maternal serum pregnancy-associated plasma protein-A (PAPP-A) at 11-13 weeks' gestation is associated with stillbirth, intrauterine growth restriction (IUGR) and pre-eclampsia in chromosomally normal fetuses. However, the strength of these associations is too weak to justify screening for these placental insufficiency syndromes. Our objective was to evaluate placental size and uterine artery (UtA) Doppler imaging as second-stage screening tests for women with low PAPP-A. METHODS: We prospectively studied 90 normal singleton pregnancies with first-trimester PAPP-A

Glial cell missing-1 transcription factor is required for the differentiation of the human trophoblast.

Mammalian placentation is a highly regulated process and is dependent on the proper development of specific trophoblast cell lineages. The two major types of trophoblast, villous and extravillous, show mitotic arrest during differentiation. In mice, the transcription factor, glial cell missing-1 (Gcm1), blocks mitosis and is required for syncytiotrophoblast formation and morphogenesis of the labyrinth, the murine equivalent of the villous placenta. The human homolog GCM1 has an analogous expression pattern, but its function is presently unknown. We studied GCM1 function in the human-derived BeWo choriocarcinoma cell line and in first trimester human placental villous and extravillous explants. The GCM1 expression was either inhibited by siRNA and antisense oligonucleotides methods or upregulated by forskolin treatment. Inhibition of GCM1 resulted in an increased rate of proliferation, but prevented de novo syncytiotrophoblast formation in syncytially denuded floating villous explants. GCM1 inhibition prevented extravillous differentiation along the invasive pathway in extravillous explants on matrigel. By contrast, forskolin-induced expression of GCM1 reduced the rate of proliferation and increased the rate of syncytialization in the floating villous explant model. Our studies show that GCM1 has a distinct role in the maintenance, development and turnover of the human trophoblast. Alterations in GCM1 expression or regulation may explain several aspects of two divergent severe placental insufficiency syndromes, namely preeclampsia and intrauterine growth restriction, which cause extreme preterm birth.

Early gene expression and morphogenesis of the murine chorioallantoic placenta in vivo and in vitro.

BACKGROUND: In mice the exchange of oxygen and nutrients between mother and fetus occurs in the chorioallantoic placenta where fetal capillaries come in close proximity with maternal blood perfusing trophoblast-lined sinusoids. Despite its critical importance, quantitative in vivo gene expression over the initial stages of chorioallantoic placental development has not been described, nor are there in vitro systems recapitulating the critical syncytiotrophoblast differentiation step in its formation. Here we describe molecular events that occur during the onset of chorioallantoic morphogenesis in mice in vivo, and in placental explant and whole conceptus cultures in vitro. RESULTS: Chorioallantoic morphogenesis began immediately following allantoic fusion with the chorion in vivo, and was associated with significant upregulation of syncytiotrophoblast associated mRNA (Gcm1 and Syncytin A). However mouse placentas with chorioallantoic point attachment cultured with the allantois or as whole conceptuses did not upregulate Gcm1 and/or Syncytin A, suggesting that syncytiotrophoblast differentiation did not occur in vitro. Failure of morphogenesis appeared to be due to failure to sustain in vitro the chorionic trophoblast cells from which the syncytiotrophoblast cells are derived. In vitro culture conditions did support the upregulation of ectoplacental cone marker Tpbpalpha, maintenance of giant cell marker Pl1, and maintenance of Fgfr2 expression; all of which mimicked in vivo events observed over this developmental interval. CONCLUSIONS: We conclude that chorionic trophoblast maintenance and the early events that occur in vivo between chorioallantoic point attachment and primary villous formation are dependent on undefined intrauterine factors that were not present in the in vitro culture system. Nevertheless, in vitro culture conditions were appropriate to reproduce in vivo expression levels of Fgfr2, Pl1, and Tpbpalpha in placental explants.

Screening for placental insufficiency in high-risk pregnancies: is earlier better?

OBJECTIVE: To compare a profile of placental function between the first and second trimesters in pregnancies at high risk of adverse perinatal outcomes attributable to placental insufficiency. STUDY DESIGN: Prospective cohort study in 61 singleton pregnancies. Uterine artery Doppler and placental morphology (shape and texture) were determined at 11-13(+6) weeks and at 18-23(+6) weeks. First trimester (pregnancy-associated placental protein-A [PAPP-A]) and second trimester (total hCG and alpha fetoprotein [AFP]) serum biochemistry were determined. The two screening periods were compared for the prediction of a range of severe adverse perinatal outcomes (intrauterine growth restriction [IUGR], abruption, severe pre-eclampsia/HELLP syndrome, delivery<32 weeks, or stillbirth). RESULTS: Adverse perinatal outcomes occurred in 14 (23%) women; 3 (4.9%) losses<20 weeks, 2 (3.3%) stillbirths>20 weeks, 4 (6.6%) IUGR, 7 (11.5%) severe pre-eclampsia/HELLP syndrome, and 10 (16.4%) deliveries<32 weeks. Abnormal second trimester placental morphology was significantly associated with adverse outcome [+LR: 3.6, 95% CI: 1.3-8.5; -LR: 0.63, 95% CI: 0.36-0.93; p=0.025], as was > or = 1 abnormal second trimester tests [+LR: 5.9, 95% CI: 1.6-24; -LR: 0.68, 95% CI: 0.59-0.89; p=0.005] or > or = 2 abnormal second trimester tests [+LR: 3.6, 95% CI: 1.3-7.7; -LR: 0.58, 95% CI: 0.27-0.94; p=0.035]. No combination of first trimester tests significantly predicted severe adverse perinatal outcomes. A study sample size of 822 women with similar high-risk characteristics would be needed in order to refute the conclusion that present methods of first trimester screening are not inferior to second trimester screening for severe placental insufficiency (p=0.05, power 80%, z-test). CONCLUSIONS: In clinically high-risk pregnancies, prediction of adverse perinatal outcomes using placental function testing is more effective in the second compared with the first trimester.

A study of indoor 220Rn and 222Rn decay product concentrations in the UK.

In order to gain a better understanding of the risk of human exposure to 220Rn indoors, measurements of 220Rn decay products have been performed in a number of houses in England. The study focused mainly on areas where above-average indoor 220Rn concentrations were to be expected because of geological or other factors. Thoron (220Rn) in room air comes mainly from the building materials, with an additional contribution from soil gas; therefore, 220Rn concentrations were examined in relation to building materials as well as location. Measurements were carried out in 23 houses. The mean equilibrium equivalent 220Rn (EET) concentration found was 0.39 Bq m-3 and the mean equilibrium equivalent 222Rn (EER) concentration was 17.8 Bq m-3. The 220Rn concentration values and EET/EER ratios found in this investigation correspond well with other published results. Values imply that the 220Rn concentrations in English dwellings are a far less important problem than 222Rn concentrations.

Enhancement of orimulsion biodegradation through the addition of natural marine carbon substrates.

Orimulsion is a bitumen-based heavy fuel that is a less expensive alternative to traditional fuel oils. However, because its density is intermediate between that of freshwater and seawater, in the event of a spill, the fuel could strand in the sediments. Previous work indicated that only 0.6-2.7% of the bitumen would degrade in long incubations of marine sediments. We added various natural carbon substrates to stimulate the degradation of bitumen by native populations of benthic bacteria. The concentration and carbon isotopic signature of the respired carbon dioxide was measured to partition the substrates that supported bacterial respiration. We found that the addition of seagrass and pinfish stimulated the degradation of bitumen by as much as 2-9-fold relative to incubations without these substrates. Biodegradation of bitumen may be enhanced by the addition of natural marine carbon substrates and may be a useful approach for bioremediation. Preadaptation of the bacteria to bitumen did not significantly enhance their ability to degrade it.

Method for enumeration of 5-cyano-2,3-ditoyl tetrazolium chloride (CTC)-active cells and cell-specific CTC activity of benthic bacteria in riverine, estuarine and coastal sediments.

Bacteria are the most abundant and active organisms in marine sediments and are critical for nutrient cycling and as a food source to many benthic and pelagic organisms. Bacteria are found both as free-living cells and as particle-associated cells, which can make investigations of these communities difficult. We found that common procedures for extracting bacteria from sediments leave the bacteria clay particle-associated and the clay particles clump, which reduce the reproducibility of direct counts. We optimized a sonication/surfactant method that produces a homogeneous suspension of bacterial cells against a uniform background of clay particles, which results in reproducible samples for epifluorescence microscopy. We developed a method to estimate CTC-positive cells and cell-specific CTC content in intact cores of surficial sediment communities from riverine, estuarine and coastal sites. Benthic bacterial abundances averaged 4.9x10(8) cells/g dry wt sediments in Apalachicola River, Florida sediments, 4.9-13.8x10(9) cells/g dry wt sediments in a variety of Apalachicola Bay sediments and 3.6x10(8) cells/g dry weight in shallow, anoxic Gulf of Mexico sediments. Percent CTC-positive cells ranged from low values of 9-10% CTC-positive cells in Apalachicola River and Apalachicola Bay sediments to high values of 25% CTC-positive cells in anoxic Gulf of Mexico sediments. After correction for abiotic CTC reduction and chlorophyll interference, estimates of cell-specific CTC reduction ranged from 0.15 to 0.55 fmol CTC(red)/active cell in the Apalachicola Bay sediments to 1.6 to 3.8 fmol CTC(red)/active cell in anoxic Gulf of Mexico sediments.

Community violence exposure and children's social adjustment in the school peer group: the mediating roles of emotion regulation and social cognition.

This study reports a cross-sectional investigation of the relation between community violence exposure and peer group social maladjustment in 285 inner-city children in Grades 4-6 (mean age = 10.3 years). Children completed an inventory assessing exposure to community violence through witnessing and through direct victimization. A peer nomination inventory was then administered to assess social adjustment with peers (aggression, peer rejection, and bullying by peers). In addition, social-cognitive biases and emotion regulation capacities were examined as potential mediators. Analyses indicated that violent victimization was associated with negative social outcomes through the mediation of emotion dysregulation. Witnessed violence was linked only to aggressive behavior. Social information processing, rather than emotion dysregulation, appeared to mediate this association. These results demonstrate that violence exposure is linked to multiple levels of behavioral and social maladjustment and suggest that there are distinct patterns of risk associated with different forms of exposure.

Results of serial vestibular testing in unilateral Ménière's disease.

OBJECTIVE: To determine the prevalence and character of vestibular abnormalities and the changes in vestibular function that occur in unilateral Ménière's disease. STUDY DESIGN: Retrospective case review. SETTING: Ambulatory patients at a tertiary care facility. PATIENTS: Entry criteria included a diagnosis of unilateral Ménière's disease and test results from at least two vestibular test sessions at the Johns Hopkins Otologic Vestibular Laboratory. One hundred twenty-two cases were evaluated. MAIN OUTCOME MEASURES: Electronystagmographic evaluation, including caloric testing; audiometric tests; and medical records. RESULTS: Caloric weakness was demonstrated in 58% of patients on the involved side and in 19% on the normal side. Complete paralysis was found in 7%. Directional preponderance was seen in 33% of patients and completely normal scores in 27%. During the course of the disease, responses become weaker in 26% of patients and stronger in 11%. Of 39 patients tested more than twice, 26% showed both increases and decreases in caloric responses. After an acute attack, only one of eight patients showed a depressed response on the diseased side, and three showed an increased response. Spontaneous nystagmus, seen within 24 hours of an attack in 54 cases, was directed away from the diseased ear in only about one half of the cases. Benign paroxysmal positional vertigo was found in 44% of these patients. CONCLUSIONS: Possible pathophysiologic explanations for the various test results in Ménière's disease are discussed. Interpretation of caloric test results should take into account the absolute value of the slow phase eye speed scores, in addition to the right-left difference score. Also, established standards for the normal range of fluctuation in both absolute and comparative scores should be used when more than one test session has been undertaken.

Anaerobic respiratory growth of Vibrio harveyi, Vibrio fischeri and Photobacterium leiognathi with trimethylamine N-oxide, nitrate and fumarate: ecological implications.

Two symbiotic species, Photobacterium leiognathi and Vibrio fischeri, and one non-symbiotic species, Vibrio harveyi, of the Vibrionaceae were tested for their ability to grow by anaerobic respiration on various electron acceptors, including trimethylamine N-oxide (TMAO) and dimethylsulphoxide (DMSO), compounds common in the marine environment. Each species was able to grow anaerobically with TMAO, nitrate or fumarate, but not with DMSO, as an electron acceptor. Cell growth under microaerophilic growth conditions resulted in elevated levels of TMAO reductase, nitrate reductase and fumarate reductase activity in each strain, whereas growth in the presence of the respective substrate for each enzyme further elevated enzyme activity. TMAO reductase specific activity was the highest of all the reductases. Interestingly, the bacteria-colonized light organs from the two squids, Euprymna scolopes and Euprymna morsei, and the light organ of the ponyfish, Leiognathus equus, also had high levels of TMAO reductase enzyme activity, in contrast to non-symbiotic tissues. The ability of these bacterial symbionts to support cell growth by respiration with TMAO may conceivably eliminate the competition for oxygen needed for both bioluminescence and metabolism.

A novel alpha 2-adrenoceptor antagonist attenuates the early, but preserves the late cardiovascular effects of intravenous dexmedetomidine in conscious dogs.

OBJECTIVES: To test the hypothesis that L-659,066, a peripherally acting alpha 2-adrenoceptor agonist, will abolish the early pressor response but preserve the late depressor action of intravenous dexmedetomidine in conscious, unsedated dogs. DESIGN: A prospective investigation. SETTING: A laboratory research. PARTICIPANTS: Nine chronically instrumented dogs. INTERVENTIONS: Dogs received dexmedetomidine, 5 micrograms/kg intravenously, in the presence or absence of L-659,066, 0.1, 0.2, or 0.4 mg/kg intravenously, pretreatment in a random fashion determined with a Latin square design on different experimental days. MEASUREMENTS AND MAIN RESULTS: Systemic and coronary hemodynamics were assessed under control conditions, 30 minutes after administration of L-659,066 and 5 and 60 minutes after intravenous administration of dexmedetomidine. Dexmedetomidine alone acutely increased mean arterial pressure (106 +/- 3 to 175 +/- 4 mmHg; p < 0.05), left ventricular (LV) systolic and end-diastolic pressures, systemic vascular resistance (3,400 +/- 350 to 13,360 +/- 2,290 dyne.s.cm-5; p < 0.05), and coronary vascular resistance (2.69 +/- 0.19 to 4.18 +/- 0.43 mmHg.Hz-1.10(-2); p < 0.05) and decreased LV +dP/dtmax and cardiac output (2.6 +/- 0.3 to 1.3 +/- 0.2 L/min; p < 0.05). Dexmedetomidine alone decreased heart rate, mean arterial pressure, and LV systolic pressure and caused sustained reductions in +dP/dtmax and cardiac output up to 60 minutes after administration. L-659,066 alone increased heart rate, +dP/dtmax, cardiac output, and coronary blood flow velocity and decreased systemic vascular resistance. Mean arterial and LV pressures and coronary vascular resistance were unchanged. Pretreatment with L-659,066 abolished the acute dexmedetomidine-induced increases in mean arterial pressure, LV pressures, systemic and coronary vascular resistance and decreases in +dP/dtmax and cardiac output. In contrast, reductions in mean arterial pressure and LV systolic pressure observed 60 minutes after administration of dexmedetomidine were preserved in dogs receiving L-659,066. Cardiac performance, systemic vascular resistance, and coronary hemodynamics were also maintained to a greater degree 60 minutes after dexmedetomidine administration in the presence of L-659,066. CONCLUSION: L-659,066 prevents the immediate pressor effects of 5 micrograms/kg of intravenous dexmedetomidine but preserves the majority of the late beneficial cardiovascular effects of this selective alpha 2-adrenoceptor agonist in conscious dogs.

Representation of sound localization cues in the auditory thalamus of the barn owl.

Barn owls can localize a sound source using either the map of auditory space contained in the optic tectum or the auditory forebrain. The auditory thalamus, nucleus ovoidalis (N.Ov), is situated between these two auditory areas, and its inactivation precludes the use of the auditory forebrain for sound localization. We examined the sources of inputs to the N.Ov as well as their patterns of termination within the nucleus. We also examined the response of single neurons within the N.Ov to tonal stimuli and sound localization cues. Afferents to the N.Ov originated with a diffuse population of neurons located bilaterally within the lateral shell, core, and medial shell subdivisions of the central nucleus of the inferior colliculus. Additional afferent input originated from the ipsilateral ventral nucleus of the lateral lemniscus. No afferent input was provided to the N.Ov from the external nucleus of the inferior colliculus or the optic tectum. The N.Ov was tonotopically organized with high frequencies represented dorsally and low frequencies ventrally. Although neurons in the N.Ov responded to localization cues, there was no apparent topographic mapping of these cues within the nucleus, in contrast to the tectal pathway. However, nearly all possible types of binaural response to sound localization cues were represented. These findings suggest that in the thalamo-telencephalic auditory pathway, sound localization is subserved by a nontopographic representation of auditory space.

The methanogenic archaeon Methanosarcina thermophila TM-1 possesses a high-affinity glycine betaine transporter involved in osmotic adaptation.

Methanogenic Archaea are found in a wide range of environments and use several strategies to adjust to changes in extracellular solute concentrations. One methanogenic archaeon, Methanosarcina thermophila TM-1, can adapt to various osmotic conditions by synthesis of alpha-glutamate and a newly discovered compatible solute, Ne-acetyl-beta-lysine, or by accumulation of glycine betaine (betaine) and potassium ions from the environment. Since betaine transport has not been characterized for any of the methanogenic Archaea, we examined the uptake of this solute by M. thermophila TM-1. When cells were grown in mineral salts media containing from 0.1 to 0.8 M NaC1, M. thermophila accumulated betaine in concentrations up to 140 times those of a concentration gradient within 10 min of exposure to the solute. The betaine uptake system consisted of a single, high-affinity transporter with an apparent K3 of 10 microM and an apparent maximum transport velocity of 1.15 nmol/min/mg of protein. The transporter appeared to be specific for betaine, since potential substrates, including glycine, sarcosine, dimethyl glycine, choline, and proline, did not significantly inhibit betaine uptake. M. thermophila TM-1 cells can also regulate the capacity for betaine accumulation, since the rate of betaine transport was reduced in cells pregrown in a high-osmolarity medium when 500 microM betaine was present. Betaine transport appears to be H+ and/or Na+ driven, since betaine transport was inhibited by several types of protonophores and sodium ionophores.