Regulation of Luteinizing Hormone and Catecholamine Release

These studies tested the interrelated hypotheses that the ovarian hormones produce their positive feedback effects on luteinizing hormone (LH) secretion through activation of noradrenergic and adrenergic systems in specific hypothalamic regions. Furthermore, the ovarian hormones may alter the activity of opioid neuropeptide and Gamma-Aminobutyric Acid (GABA) systems to produce these alterations in catecholamine transmission and gonadotropin secretion. Radioimmunoassays were utilized to determine plasma LH and median eminence LHRH, and hypothalamic catecholamine concentrations were measured by radioenzymatic assay. The first two studies tested whether epinephrine (EPI) synthesis inhibition blocks the accumulation of median eminence LHRH that precedes the ovarian hormone-induced LH surge and also to test whether the stimulatory ovarian hormone regimen enhances the activity of hypothalamic EPI systems. Ovariectomized rats were primed with estradiol (EB), followed 2 days later by progesterone (Prog.). Animals were treated before Prog, administration with saline, one of the EPI synthesis inhibitors SKF 64139 or LY 78335, or the norepinephrine (NE) synthesis inhibitor, FLA-63. The catecholamine synthesis inhibitors blocked or delayed the LH surge. FLA-63 completely prevented the accumulation of LHRH in the median eminence that preceded the rise in LH release. However, selective reduction in EPI levels with SKF 64139 only partially prevented this increase in LHRH. A second EPI synthesis inhibitor, LY 78335, delayed both the LH surge and the rise in LHRH. In a second experiment, the administration of EB plus Prog, to ovariectomized rats increased the alpha-methyltyrosine (aMT) induced depletion of EPI in the medial basal hypothalamus (MBH). The depletion of NE after synthesis inhibition was enhanced in both the MBH and preoptic-anterior hypothalamus (POA). Experiments 3 and 4 examined a possible mechanism underlying these ovarian hormone effects on LH release and catecholamine activity. These studies tested whether the opiate antagonist, naloxone, which increases LH release, enhances the activity of NE and EPI neurons in the hypothalamus, and also tested whether morphine, an opiate agonist which decreases LH release, depresses the activity of hypothalamic NE and EPI activity. Administration of naloxone to EB-primed rats increased LH release and potentiated the depletion of NE in the POA and MBH, and enhanced the decline of EPI and dopamine (DA) in the MBH, suggesting increased catecholamine activity in these regions. Administration of the opiate agonist, morphine, to rats pretreated with EB and Prog., decreased LH and decreased the depletion of the catecholamines in the POA and MBH, suggesting reduced activity. In most cases, naloxone antagonized the inhibitory effect of morphine. Experiments 3, 6, and 7 examined the involvement of (GABA) systems in the positive feedback effects of EB and Prog, on LHRH and LH release. These studies tested 1) the effects of GABAergic drugs on the LH surge induced by EB and Prog., 2) whether GABA agonists reduce NE and EPI activity in the hypothalamus, and 3) whether a GABA agonist prevents the accumulation of median eminence LHRH induced by EB and Prog. Ovariectomized rats received the stimulatory EB plus Prog, treatment. Simultaneously with Prog., rats received either saline, the barbiturate, phenobarbital, the GABAg agonist, baclofen, the GABA^ agonist, muscimol, or either the GABA^ antagonist, bicuculline, or the putative GABAg antagonist, 5-aminovalerate. Additional experiments tested the effects of the GABA drugs on LH release in ovariectomized, hormonally untreated rats and in response to exogenous LHRH. The LH surge induced by EB+Prog. was blocked by treatment with either baclofen, muscimol, or phenobarbital. Bicuculline was ineffective in preventing the effect of baclofen and phonobarbital but partially prevented the effect of muscimol. Neither baclofen nor muscimol significantly affected LH release in hormonally untreated, ovariectomized rats or in rats receiving LHRH administration. In the results of Experiment 6, in EB plus Prog.-treated rats, baclofen and muscimol significantly reduced the concentrations of EPI and NE in the POA and MBH and prevented their decline after administration of otMT, suggesting decreased catecholamine transmission. In Experiment 7, rats were primed with the ovarian hormones and received, concurrently with Prog., either saline, or baclofen. The GABAg agonist, baclofen, blocked the LH surge and selectively increased LHRH concentrations. Experiment 8 tested 1) whether baclofen reverses the enhancement of LH release and catecholamine activity produced by naloxone, and 2) whether the opiate antagonist, nalmefene, prevents the blockade of the LH surge produced by baclofen. In the first study of Experiment 8, naloxone increased LH release and enhanced catecholamine activity in EB-primed rats. Baclofen was unable to reverse these effects. In the second study, baclofen administration to EB plus P treated rats blocked the LH surge and concomitant administration of nalmefene was unable to prevent this effect of baclofen. These results suggest that: 1) the ovarian hormones activate both NE and EPI systems to stimulate the early afternoon rise of LHRH in the median eminence and to induce the subsequent LH surge, 2) the ovarian hormones may produce their positive feedback effects on LH secretion by removing an inhibitory GABA or opioid neuropeptide influence on catecholamine transmission, allowing NE and EPI to stimulate LHRH, and subsequently, LH release, and 3) these modulatory actions of GABA and opiates may represent effects of two parallel, yet independent hypothalamic systems which regulate catecholamine neurotransmission and subsequently LH secretion

Segmentation and Alignment of Speech and Sketching in a Design Environment

Sketches are commonly used in the early stages of design. Our previous system allows users to sketch mechanical systems that the computer interprets. However, some parts of the mechanical system might be too hard or too complicated to express in the sketch. Adding speech recognition to create a multimodal system would move us toward our goal of creating a more natural user interface. This thesis examines the relationship between the verbal and sketch input, particularly how to segment and align the two inputs. Toward this end, subjects were recorded while they sketched and talked. These recordings were transcribed, and a set of rules to perform segmentation and alignment was created. These rules represent the knowledge that the computer needs to perform segmentation and alignment. The rules successfully interpreted the 24 data sets that they were given

Multimodal Interactive DialOgue System

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2009.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (p. 239-243).Interactions between people are typically conversational, multimodal, and symmetric. In conversational interactions, information flows in both directions. In multimodal interactions, people use multiple channels. In symmetric interactions, both participants communicate multimodally, with the integration of and switching between modalities basically effortless. In contrast, consider typical human-computer interaction. It is almost always unidirectional { we're telling the machine what to do; it's almost always unimodal (can you type and use the mouse simultaneously?); and it's symmetric only in the disappointing sense that when you type, it types back at you. There are a variety of things wrong with this picture. Perhaps chief among them is that if communication is unidirectional, it must be complete and unambiguous, exhaustively anticipating every detail and every misinterpretation. In brief, it's exhausting. This thesis examines the benefits of creating multimodal human-computer dialogues that employ sketching and speech, aimed initially at the task of describing early stage designs of simple mechanical devices. The goal of the system is to be a collaborative partner, facilitating design conversations. Two initial user studies provided key insights into multimodal communication: simple questions are powerful, color choices are deliberate, and modalities are closely coordinated. These observations formed the basis for our multimodal interactive dialogue system, or Midos. Midos makes possible a dynamic dialogue, i.e., one in which it asks questions to resolve uncertainties or ambiguities.(cont.) The benefits of a dialogue in reducing the cognitive overhead of communication have long been known. We show here that having the system able to ask questions is good, but for an unstructured task like describing a design, knowing what questions to ask is crucial. We describe an architecture that enables the system to accept partial information from the user, then request details it considers relevant, noticeably lowering the cognitive overhead of communicating. The multimodal questions Midos asks are in addition purposefully designed to use the same multimodal integration pattern that people exhibited in our study. Our evaluation of the system showed that Midos successfully engages the user in a dialogue and produces the same conversational features as our initial human-human conversation studies.by Aaron Daniel Adler.Ph.D

A Method for Fast, High-Precision Characterization of Synthetic Biology Devices

Engineering biological systems with predictable behavior is a foundational goal of synthetic biology. To accomplish this, it is important to accurately characterize the behavior of biological devices. Prior characterization efforts, however, have generally not yielded enough high-quality information to enable compositional design. In the TASBE (A Tool-Chain to Accelerate Synthetic Biological Engineering) project we have developed a new characterization technique capable of producing such data. This document describes the techniques we have developed, along with examples of their application, so that the techniques can be accurately used by others

Identifying the clinical domains of fibromyalgia: Contributions from clinician and patient delphi exercises

Objective In evaluating the effectiveness of fibromyalgia (FM) therapies, it is important to assess the impact of those therapies on the full array of domains considered important by both clinicians and patients. The objective of this research was to identify and prioritize the key clinically relevant and important domains impacted by FM that should be evaluated by outcome assessment instruments used in FM clinical trials, and to approach consensus among clinicians and patients on the priority of those domains to be assessed in clinical care and research. Methods Group consensus was achieved using the Delphi method, a structured process of consensus building via questionnaires together with systematic and controlled opinion feedback. The Delphi exercises involved 23 clinicians with expertise in FM and 100 patients with FM as defined by American College of Rheumatology criteria. Results The Delphi exercise revealed that the domains ranked most highly by patients were similar to the domain rankings by clinicians. Pain was consistently ranked highest by both panels. Fatigue, impact on sleep, health-related quality of life, comorbid depression, and cognitive difficulty were also ranked highly. Stiffness was ranked highly by patients but not clinicians. In contrast, side effects was important to clinicians but was not identified as important in the patient Delphi exercise. Conclusion The clinician and patient Delphi exercises identified and ranked key domains that need to be assessed in FM research. Based on these results, a conceptual framework for measuring patient-reported outcomes is proposed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/60452/1/23826_ftp.pd

Soil Aggregates as a Source of Dissolved Organic Carbon to Streams: An Experimental Study on the Effect of Solution Chemistry on Water Extractable Carbon

Over the past two decades, headwater streams of the northern hemisphere have shown increased amounts of dissolved organic carbon (DOC), coinciding with decreased acid deposition. The exact nature of the mechanistic link between precipitation composition and stream water DOC is still widely debated in the literature. We hypothesize that soil aggregates are the main source of stream water DOC and that DOC release is greater in organic rich, riparian soils vs. hillslope soils. To test these hypotheses, we collected soils from two main landscape positions (hillslope and riparian zones) from the acid-impacted Sleepers River Research Watershed in northeastern Vermont. We performed aqueous soil extracts with solutions of different ionic strength (IS) and composition to simulate changes in soil solution. We monitored dynamic changes in soil particle size, aggregate architecture and composition, leachate DOC concentrations, dissolved organic matter (DOM) characteristics by fluorescence spectroscopy and trends in bioavailability. In low IS solutions, extractable DOC concentrations were significantly higher, particle size (by laser diffraction) was significantly smaller and organic material was separated from mineral particles in scanning electron microscope observations. Furthermore, higher DOC concentrations were found in Na+ compared to Ca2+ solutions of the same IS. These effects are attributed to aggregate dispersion due to expanding diffuse double layers in decreased IS solutions and to decreased bridging by divalent cations. Landscape position impacted quality but not quantity of released DOC. Overall, these results indicate that soil aggregates might be one important link between Critical Zone inputs (i.e., precipitation) and exports in streams

NilD CRISPR RNA contributes to Xenorhabdus nematophila colonization of symbiotic host nematodes

The bacterium Xenorhabdus nematophila is a mutualist of entomopathogenic Steinernema carpocapsae nematodes and facilitates infection of insect hosts. X. nematophila colonizes the intestine of S. carpocapsae which carries it between insects. In the X. nematophila colonization-defective mutant nilD6::Tn5, the transposon is inserted in a region lacking obvious coding potential. We demonstrate that the transposon disrupts expression of a single CRISPR RNA, NilD RNA. A variant NilD RNA also is expressed by X. nematophila strains from S. anatoliense and S. websteri nematodes. Only nilD from the S. carpocapsae strain of X. nematophila rescued the colonization defect of the nilD6::Tn5 mutant, and this mutant was defective in colonizing all three nematode host species. NilD expression depends on the presence of the associated Cas6e but not Cas3, components of the Type I-E CRISPR-associated machinery. While cas6e deletion in the complemented strain abolished nematode colonization, its disruption in the wild-type parent did not. Likewise, nilD deletion in the parental strain did not impact colonization of the nematode, revealing that the requirement for NilD is evident only in certain genetic backgrounds. Our data demonstrate that NilD RNA is conditionally necessary for mutualistic host colonization and suggest that it functions to regulate endogenous gene expression

Association of postnatal age with neonatal hospital-onset bacteremia in a multicenter, retrospective cohort

Background: Prevention of hospital-onset bacteremia (HOB) in all settings is a healthcare priority. The CDC is developing a neonatal-specific HOB quality metric, but the epidemiology of neonatal HOB is poorly understood. Our objective was to validate a prior single-center finding that HOB risk varies by birthweight and postnatal age in a multicenter cohort. Methods: We performed a multicenter, retrospective cohort study of neonates admitted to 4 neonatal intensive care units (NICUs) for ≥4 days between July 1, 2016, and July 1, 2021. HOB was defined as a positive blood culture for bacteria or fungi on day ≥4 of admission. The first HOB event in the hospitalization was counted per neonate. Repeat HOB events during a neonate’s admission were excluded. Poisson regression models with robust variance estimates were used to estimate the incidence rate (IR) of HOB, expressed as HOB events per 1,000 patient days and IR ratios (IRRs), within strata defined by CDC birthweight categories and 4-week postnatal age intervals, adjusting for central venous catheter (CVC) presence at time of HOB and study site. Results: The analysis included 9,267 neonates, contributing 191,295 patient days and 470 HOB events, with an unadjusted IR of 2.46 per 1,000 patient days (Table 1). Of 477 infants born ≤750 g, 153 (30.1%) had a HOB with an IR of 13.3 (95% CI, 10.5–16.0) events per 1,000 patient days in the first 4 weeks after birth (Fig. 1). After adjusting for CVC presence and study site, infants ≤750 g had a higher HOB rate in the first 4 weeks of life (IRR, 7.45; 95% CI, 3.81–14.56) compared to infants ≥2,500 g. After 8 weeks of life, there was no difference in HOB rate in the 2 groups (IRR, 0.8, 95% CI, 0.3–2.7). Conclusions: Neonates born ≤750 g were at highest risk for HOB within the first 4 weeks after birth; however, risk for HOB was not consistent over time. Postnatal age should be considered in a neonatal HOB quality metric