Monitoring Compound-Related Effects on Coagulability in Rats and Cynomolgus and Rhesus Monkeys by Thrombin Generation Kinetic Measurement.

Thrombin generation assay (TGA) is a sensitive method for the assessment of the global clotting potential of plasma. This kinetic assay can detect both hypocoagulable and hypercoagulable conditions: delayed or reduced thrombin generation leading to a prolonged clotting time, or induced thrombin activity, shifting the coagulation cascade toward thrombosis. The purpose of this study is to qualify the TGA in nonhuman primates (NHP) and rats for its use during nonclinical in vivo and in vitro studies. Blood was drawn from nonanesthetized animals, and platelet-poor plasma was obtained after double centrifugation; coefficients of variation were <10% for all derived parameters of thrombin generation assessed with 5 pM of tissue factor. Thrombin generation was evaluated in vitro in rat and NHP plasmas with ascending doses of unfractionated heparin (UFH), recombinant tissue factor, and anticoagulant compounds. Thrombin generation was decreased with UFH and anticoagulant compounds, but was increased in the presence of tissue factor, in a dose-dependent manner. In a rat model of inflammation, animals were administered a low dose of lipopolysaccharides. Thrombin generation measurements were decreased 3 hours post-LPS administration with a nadir at 24 hours, while thrombin-antithrombin complexes reached a peak at 8 hours, supporting an earlier production of thrombin. In conclusion, these data demonstrated that TGA can be performed in vitro for screening of compounds expected to have effects on coagulation cascade, and thrombin generation can be measured at interim time points during nonclinical in vivo studies in rats and NHP.

Short, natural, and extended photoperiod response in BC2F4 lines of bread wheat with different photoperiod-1 (Ppd-1) alleles.

Flowering is a critical period in the life cycle of flowering plant species, resulting in an irreversible commitment of significant resources. Wheat is photoperiod sensitive, flowering only when daylength surpasses a critical length; however, photoperiod insensitivity (PI) has been selected by plant breeders for >40 years to enhance yield in certain environments. Control of flowering time has been greatly facilitated by the development of molecular markers for the Photoperiod-1 (Ppd-1) homeoloci, on the group 2 chromosomes. In the current study, an allelic series of BC2F4 lines in the winter wheat cultivars 'Robigus' and 'Alchemy' was developed to elucidate the influence on flowering of eight gene variants from the B- and D-genomes of bread wheat and the A-genome of durum wheat. Allele effects were tested in short, natural, and extended photoperiods in the field and controlled environments. Across genetic background and treatment, the D-genome PI allele, Ppd-D1a, had a more potent effect on reducing flowering time than Ppd-B1a. However, there was significant donor allele effect for both Ppd-D1a and Ppd-B1a, suggesting the presence of linked modifier genes and/or additional sources of latent sensitivity. Development of Ppd-A1a BC2F4 lines derived from synthetic hexaploid wheat provided an opportunity to compare directly the flowering time effect of the A-genome allele from durum with the B- and D-genome variants from bread wheat for the first time. Analyses indicated that the reducing effect of Ppd-A1a is comparable with that of Ppd-D1a, confirming it as a useful alternative source of PI.

Effects of feeding a high omega-3 fatty acids diet in dogs with naturally occurring osteoarthritis.

The aim of this randomized, placebo-controlled and double-blinded trial was to compare the effect of a veterinary therapeutic diet (VTD) rich in omega-3 fatty acids (omega-3) from fish origin to a regular diet used as control (CTR) over a period of 13 weeks in dogs afflicted by naturally occurring osteoarthritis (OA). Thirty privately owned dogs were selected. Dogs had lameness confirmed by an orthopaedic examination, had stifle/hip OA and had locomotor disability based on the peak of the vertically oriented ground reaction force (PVF) measured using a force platform. At Baseline, all owners were asked to determine 2-5 activities of daily living that were the most impaired. Activities were scores (0-4) in accordance with severity using case-specific outcome measures (CSOM). The PVF was also measured. Dogs (15/group) were then randomly assigned to receive either the CTR or the VTD. The CSOM was completed twice weekly. The recording of PVF was repeated at Week 7 and 13. The VTD-fed dogs showed a significantly higher PVF at Week 7 (p < 0.001) and at Week 13 (p < 0.001) when compared to Baseline. From Baseline to Week 13, VTD-fed dogs had a mean (± SD) change in PVF recording of 3.5 ± 6.8% of body weight (%BW) compared with 0.5 ± 6.1%BW (p = 0.211) in CTR-fed dogs. This change in primary outcome was consistent with an effect size of 0.5. Conversely, dogs fed the CTR did not show significant change in PVF measurements. At the end of the study, the CSOM was significantly decreased (p = 0.047) only in VTD fed dogs. In lame OA dogs, a VTD that contains high level of omega-3 from fish origin improved the locomotor disability and the performance in activities of daily living. Such nutritional approach appears interesting for the management of OA.

The cost of quantum locality.

It has been more than 20 years since Deutsch and Hayden demonstrated that quantum systems can be completely described locally-notwithstanding Bell's theorem. More recently, Raymond-Robichaud proposed two other approaches to the same conclusion. In this paper, all these means of describing quantum systems locally are proved formally equivalent. The cost of such descriptions is then quantified by the dimensionality of their underlining space. The number of degrees of freedom of a single qubit's local description is shown to grow exponentially with the total number of qubits considered as a global system. This apparently unreasonable cost to describe such a small system in a large Universe is nonetheless shown to be expected. Finally, structures that supplement the universal wave function are investigated.

Rectal plasmacytoma with intracellular hemosiderin in a dog.

An 11-year-old female American Cocker Spaniel was presented with a rectal mass that protruded through the anus. Cytologically, the mass was composed of neoplastic round cells consistent with an extramedullary plasmacytoma. Histiocytic sarcoma, carcinoid tumor, and melanoma were also considered because of the presence of golden-brown cytoplasmic granules. Histopathologic findings and immunohistochemical reactivity for lambda light chains confirmed the cytologic diagnosis of plasmacytoma. Prussian blue staining identified the cytoplasmic granules as hemosiderin. The granules were negative by Fontana Masson and Grimelius histochemistry. To our knowledge, this is the first report of an extramedullary plasmacytoma containing hemosiderin in a dog.

N-acetyl-beta-D-glucosaminidase index as an early biomarker for chronic kidney disease in cats with hyperthyroidism.

BACKGROUND: Hyperthyroid cats are at risk of developing azotemic chronic kidney disease (CKD) and diagnostic tools currently used to screen for CKD in hyperthyroid cats are either unreliable or impractical. HYPOTHESIS: Urine N-acetyl-beta-D-glucosaminidase index (NAG(i)) is a good biomarker for azotemic CKD in hyperthyroid cats. ANIMALS: Twenty-four newly diagnosed nonazotemic hyperthyroid cats and 10 healthy cats. METHODS: All cats were evaluated for hyperthyroidism at baseline. Hyperthyroid cats were treated with methimazole and reevaluated once euthyroid. At the end of the study, cats were divided into 3 groups: healthy cats, nonazotemic, and azotemic euthyroid cats. Baseline group characteristics were compared to predict azotemic CKD. The influence of treatment on NAG(i) was evaluated. RESULTS: Baseline NAG(i) was significantly different among groups (P= .004). Azotemic cats had a higher median value (13.12 U/g) when compared with healthy cats (1.38 U/g). With NAG(i) >2.76 U/g, negative and positive predictive values for development of azotemia were 77.7 and 50%, whereas the combination of a urine specific gravity (USG) 7.80 microg/dL enhanced predictive values to 88.9 and 83.3%, respectively. NAG(i) values decreased significantly over time in treated nonazotemic cats. CONCLUSIONS AND CLINICAL RELEVANCE: Baseline NAG(i) did not differentiate azotemic from nonazotemic euthyroid cats. NAG(i) could be used to assess renal function during medical therapy allowing the clinician to adjust methimazole dosage accordingly. The combination of USG and T(4) could optimize identification of appropriate candidates for permanent treatment of hyperthyroidism.

Model of low-pass filtering of local field potentials in brain tissue.

Local field potentials (LFPs) are routinely measured experimentally in brain tissue, and exhibit strong low-pass frequency filtering properties, with high frequencies (such as action potentials) being visible only at very short distances (approximately 10 microm) from the recording electrode. Understanding this filtering is crucial to relate LFP signals with neuronal activity, but not much is known about the exact mechanisms underlying this low-pass filtering. In this paper, we investigate a possible biophysical mechanism for the low-pass filtering properties of LFPs. We investigate the propagation of electric fields and its frequency dependence close to the current source, i.e., at length scales in the order of average interneuronal distances. We take into account the presence of a high density of cellular membranes around current sources, such as glial cells. By considering them as passive cells, we show that under the influence of the electric source field, they respond by polarization. Because of the finite velocity of ionic charge movements, this polarization will not be instantaneous. Consequently, the induced electric field will be frequency-dependent, and much reduced for high frequencies. Our model establishes that this situation is analogous to an equivalent RC circuit, or better yet a system of coupled RC circuits. We present a number of numerical simulations of an induced electric field for biologically realistic values of parameters, and show the frequency filtering effect as well as the attenuation of extracellular potentials with distance. We suggest that induced electric fields in passive cells surrounding neurons are the physical origin of frequency filtering properties of LFPs. Experimentally testable predictions are provided allowing us to verify the validity of this model.

Brainstem auditory evoked response and subcortical abnormalities in autism.

Previous studies of the neurobiology of autism that have used the brainstem auditory evoked response have given contradictory results. The authors of this study considered two supplementary aspects; they added an ipsilateral masking procedure, and they compared the results for every subject to the values (corrected for age and sex) of a large number of normal children. Twenty autistic (according to DSM-III-R criteria) and 13 mentally retarded (nonverbal IQ less than 75) subjects were assessed. Eighty percent of the autistic subjects had abnormal interpeak latencies, compared to 15% of the mentally retarded subjects. The I-V and III-V prolonged interpeak latency values were seen only in the autistic subjects. The ipsilateral masking procedure doubled the rate of detection of higher-brainstem abnormalities in the autistic children.

Growth, nutrient consumption, and end-product accumulation in Sf-9 and BTI-EAA insect cell cultures: insights into growth limitation and metabolism.

Growth, nutrient consumption, and end-product accumulation were quantitated in shake-flask cultures of two insect cell lines, Sf-9 and BTI-EAA, in three different serum-supplemented media. Per cell consumption or production rates were calculated for most medium components analyzed. Glucose was growth-limiting in TNM-FH medium and was the most important single source of organic-C for the cells in all cultures. Cells utilized fructose and maltose but not sucrose. alpha-Ketoglutarate and malate contributed significantly to the carbon budget of cells in TNM-FH. Lactate generally did not accumulate during growth. Most of the amino acids were consumed by the cells, with the exception of alanine which was produced. Most of the amino acids appeared to be present in adequate supply in the cultures. Glutamate was generally the most rapidly consumed of the amino acids, followed closely by glutamine. Alanine accumulation was correlated with glucose consumption. In Sf-9 cultures, ammonia accumulated only slightly or not at all as long as glucose was present in the medium, and uric acid was detectable at the end of growth and in the stationary phase. Added ammonia up to a concentration of 10 mM did not affect the growth of either cell line. Ammonia and lactate may be of less importance in limiting growth in insect cell cultures than in mammalian cell cultures. A hypothetical outline of the major metabolic pathways of the cultured insect cells is presented on the basis of information obtained here and in the literature.

Family history of cognitive disabilities in first-degree relatives of autistic and mentally retarded children.

We compared with a family history method the rate of cognitive disabilities (CD) in 156 first-degree relatives of 49 autistic (AU) probands to that found in 55 first-degree relatives of 18 mentally retarded (MR) probands. Broadly defined CD were found in, respectively, 17 and 16% of the relatives of the AU and MR probands. However, the characteristics of the probands associated with a family history of CD are different in AU and MR: Female and low IQ AU probands have more first-degree relatives with CD. Our findings suggest that a positive family history of CD is not specific to autism when compared to mental retardation. The observation that female and low IQ probands have higher family history of CD may suggest heterogeneity within autistic children and provides leads for future family studies.

International Child Care Practices Study: infant sleeping environment.

BACKGROUND: The International Child Care Practices Study (ICCPS) has collected descriptive data from 21 centres in 17 countries. In this report, data are presented on the infant sleeping environment with the main focus being sudden infant death syndrome (SIDS) risk factors (bedsharing and infant using a pillow) and protective factors (infant sharing a room with adult) that are not yet well established in the literature. METHODS: Using a standardised protocol, parents of infants were surveyed at birth by interview and at 3 months of age mainly by postal questionnaire. Centres were grouped according to geographic location. Also indicated was the level of SIDS awareness in the community, i.e. whether any campaigns or messages to "reduce the risks of SIDS" were available at the time of the survey. RESULTS: Birth interview data were available for 5488 individual families and 4656 (85%) returned questionnaires at 3 months. Rates of bedsharing varied considerably (2-88%) and it appeared to be more common in the samples with a lower awareness of SIDS, but not necessarily a high SIDS rate. Countries with higher rates of bedsharing appeared to have a greater proportion of infants bedsharing for a longer duration (>5 h). Rates of room sharing varied (58-100%) with some of the lowest rates noted in centres with a higher awareness of SIDS. Rates of pillow use ranged from 4% to 95%. CONCLUSIONS: It is likely that methods of bedsharing differ cross-culturally, and although further details were sought on different bedsharing practices, it was not possible to build up a composite picture of "typical" bedsharing practices in these different communities. These data highlight interesting patterns in child care in these diverse populations. Although these results should not be used to imply that any particular child care practice either increases or decreases the risk of SIDS, these findings should help to inject caution into the process of developing SIDS prevention campaigns for non-Western cultures.

Effects of age and education on the lexico-semantic content of connected speech in adults.

One hundred and thirty-three subjects who considered themselves to be in good health described the bank robbery picture from an aphasia battery for French-speaking subjects. The subjects' connected speech was analyzed and various lexico-semantic measures were obtained. For the purposes of analysis, the subjects were grouped according to age and education level. Results demonstrated that subjects with fewer years of education produced less content than subjects with higher levels of education. Age also affected subjects' performance but only when considering efficiency, the number of content units as a function of time, and the number of different open-class words as a function of time. Older subjects tended to repeat the same content units (using mostly the same words) and comment on some word-finding difficulties they experienced. These behaviors may explain why older subjects were less efficient in the transmission of lexico-semantic information. The results emphasize how age can affect lexico-semantic performance, and add new data about the effects of education, which should be taken into consideration when assessing persons who may show signs of a language disorder.

Dopaminergic innervation of the human subventricular zone: a comparison between Huntington's chorea and Parkinson's disease.

The subventricular zone retains its neurogenic capacity throughout life and, as such, is often considered a potential source for endogenous repair in neurodegenerative disorders. Because dopamine is believed to stimulate adult neurogenesis, we looked for possible variations in the dopaminergic innervation of the subventricular zone between cases of Huntington's chorea and Parkinson's diseases. Antibodies against tyrosine hydroxylase (TH) and proliferating cell nuclear antigen (PCNA) were used as specific markers of dopaminergic axons and cell proliferating activity, respectively. The immunohistochemical approach was applied to postmortem tissue from 2 Parkinson's disease cases, 4 Huntington's disease cases, along with age-matched controls. The immunostaining was revealed with either diaminobenzidine or fluorescent-conjugated secondary antibodies. Optical density measurements were made along the entire dorso-ventral extent of the caudate nucleus. An intense TH+ zone was detected along the ventricular border of the caudate nucleus in Huntington's disease cases, but not in patients with Parkinson's disease or age-matched controls. This thin (287±38 µm) paraventricular zone was composed of numerous small and densely packed dopamine axon varicosities and overlapped the deep layers of the subventricular zone. Its immunoreactivity was 47±8% more intense than that of adjacent striatal areas. The dopamine innervation of the subventricular zone is strikingly massive in Huntington's chorea compared to Parkinson's disease, a finding that concurs with the marked increase in neurogenesis noted in the subventricular zone of Huntington's disease patients. This finding suggests that dopamine plays a crucial role in mechanisms designed to compensate for the massive striatal neuronal losses that occur in Huntington's disease.

Effect of canine hyperadrenocorticism on coagulation parameters.

BACKGROUND: Hyperadrenocorticism (HAC) has been associated with thrombotic disease in dogs. HYPOTHESIS: The purpose of this study was to use thromboelastography (TEG) and measurement of thrombin generation (TG) to characterize the hypercoagulable state in dogs with HAC. We hypothesized that dogs with HAC would have a hypercoagulable profile on TEG tracings and an increase in thrombin generation as measured by endogenous thrombin potential (ETP). ANIMALS: Sixteen dogs with HAC. Dogs were compared with a population of normal dogs used to obtain reference intervals. METHODS: TEG tracings on citrated whole blood were obtained from 15 dogs, and TG measurements on frozen-thawed platelet-poor plasma (PPP) were obtained from 15 dogs. RESULTS: For the TEG analysis, when results of individual dogs were compared with the reference interval, 12/15 dogs had at least 1 parameter associated with hypercoagulability. When the population of HAC dogs was compared with a population of healthy dogs, HAC dogs had decreases in R and K and increases in α and MA values. The ETP was increased when the HAC group was compared with a population of normal dogs. However, only 3/15 dogs had an ETP above reference interval, and 1/15 had a decreased lag time. CONCLUSION AND CLINICAL IMPORTANCE: Of 16 dogs with HAC, 12/15 had evidence of hypercoagulability when evaluated by TEG, 4/15 when evaluated by TG, and 2 dogs had increases in ETP and MA.

Intravenous injection of autologous amniotic fluid induces transient thrombocytopenia in a gravid rabbit model of amniotic fluid embolism.

BACKGROUND: Amniotic fluid embolism (AFE) is a rare but catastrophic complication of pregnancy characterized by severe hypotension, cardiovascular collapse, and massive consumptive coagulopathy. Several animal models of this syndrome have been proposed, but most have yielded inconclusive results. OBJECTIVES: The objective of this study was to develop a suitable animal model of AFE. METHODS: Twelve rabbits in late gestation (25 days) were used. Amniotic fluid was collected from the fetal amniotic sacs after laparotomy, and autologous fluid was injected into 6 rabbits via the left auricular vein. Six other rabbits received saline (control group). Blood pressure, platelet counts, and coagulation variables were measured at baseline and at various intervals for 60 minutes after injection. The in vitro effect of amniotic fluid on coagulation was assessed by thrombelastographic (TEG) analysis. RESULTS: Injection of amniotic fluid did not reproduce clinical signs of AFE and had no effect on activated partial thromboplastin time (aPTT), prothrombin time (PT), or Factor VIII activity. However, significant thrombocytopenia was observed 5 minutes after administration of amniotic fluid and resolved by 60 minutes. In vitro addition of amniotic fluid to blood resulted in accelerated clotting on TEG tracings. CONCLUSIONS: The syndrome of AFE was not reproduced in this rabbit model. However, injection of autologous amniotic fluid induced a transient and severe thrombocytopenia. Moreover, TEG analysis indicated that amniotic fluid could initiate the coagulation cascade. Other factors such as the presence of meconium in amniotic fluid may be needed to provoke more severe clinical signs.

Does the 1/f frequency scaling of brain signals reflect self-organized critical states?

Many complex systems display self-organized critical states characterized by 1/f frequency scaling of power spectra. Global variables such as the electroencephalogram, scale as 1/f, which could be the sign of self-organized critical states in neuronal activity. By analyzing simultaneous recordings of global and neuronal activities, we confirm the 1/f scaling of global variables for selected frequency bands, but show that neuronal activity is not consistent with critical states. We propose a model of 1/f scaling which does not rely on critical states, and which is testable experimentally.

Histiocytic sarcoma in the tarsus of a cat.

A 12-year-old Persian cat was examined for a firm swelling of the right tarsal region and enlargement of the corresponding right popliteal lymph node. Cytologic evaluation demonstrated a population of malignant cells consistent with large cell lymphoma. Necropsy revealed a multi-lobulated subcutaneous mass involving the tarsus with some extension into adjacent deep muscular tissue. Histologically, the mass was composed of round cells with eosinophilic cytoplasm and pleomorphic anisokaryotic nuclei. Evidence of articular and nodal infiltration by these cells was observed. Differential diagnoses included synovial sarcoma and histiocytic sarcoma. Neoplastic cells were negative for cytokeratin, CD79a, and CD3 and positive for CD18, vimentin, lysozyme, and alpha-1-antitrypsin, most consistent with a diagnosis of histiocytic sarcoma. This is the first report of a histiocytic sarcoma involving a joint of a cat. The final diagnosis was based on the light microscopic appearance in combination with the immunohistochemical stains.

Physiology, biochemistry, and specific inhibitors of CH4, NH4+, and CO oxidation by methanotrophs and nitrifiers.

Ammonia oxidizers (family Nitrobacteraceae) and methanotrophs (family Methylococcaceae) oxidize CO and CH4 to CO2 and NH4+ to NO2-. However, the relative contributions of the two groups of organisms to the metabolism of CO, CH4, and NH4+ in various environments are not known. In the ammonia oxidizers, ammonia monooxygenase, the enzyme responsible for the conversion of NH4+ to NH2OH, also catalyzes the oxidation of CH4 to CH3OH. Ammonia monooxygenase also mediates the transformation of CH3OH to CO2 and cell carbon, but the pathway by which this is done is not known. At least one species of ammonia oxidizer, Nitrosococcus oceanus, exhibits a Km for CH4 oxidation similar to that of methanotrophs. However, the highest rate of CH4 oxidation recorded in an ammonia oxidizer is still five times lower than rates in methanotrophs, and ammonia oxidizers are apparently unable to grow on CH4. Methanotrophs oxidize NH4+ to NH2OH via methane monooxygenase and NH4+ to NH2OH via methane monooxygenase and NH2OH to NO2- via an NH2OH oxidase which may resemble the enzyme found in ammonia oxidizers. Maximum rates of NH4+ oxidation are considerably lower than in ammonia oxidizers, and the affinity for NH4+ is generally lower than in ammonia oxidizers. NH4+ does not apparently support growth in methanotrophs. Both ammonia monooxygenase and methane monooxygenase oxidize CO to CO2, but CO cannot support growth in either ammonia oxidizers or methanotrophs. These organisms have affinities for CO which are comparable to those for their growth substrates and often higher than those in carboxydobacteria. The methane monooxygenases of methanotrophs exist in two forms: a soluble form and a particulate form. The soluble form is well characterized and appears unrelated to the particulate. Ammonia monooxygenase and the particulate methane monooxygenase share a number of similarities. Both enzymes contain copper and are membrane bound. They oxidize a variety of inorganic and organic compounds, and their inhibitor profiles are similar. Inhibitors thought to be specific to ammonia oxidizers have been used in environmental studies of nitrification. However, almost all of the numerous compounds found to inhibit ammonia oxidizers also inhibit methanotrophs, and most of the inhibitors act upon the monooxygenases. Many probably exert their effect by chelating copper, which is essential to the proper functioning of some monooxygenases. The lack of inhibitors specific for one or the other of the two groups of bacteria hampers the determination of their relative roles in nature.

Westermark's sign in the diagnosis of pulmonary emboli in patients with the adult respiratory distress syndrome.

Two patients with adult respiratory distress syndrome (ARDS) are described in which the development of localized areas of increased lucency on chest roentgenogram, Westermark's sign, aided in the rapid diagnosis of concurrent pulmonary emboli. Recognition of this radiological sign represents a noninvasive technique for diagnosing this complication.