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1.
Am J Obstet Gynecol ; 229(2): B2-B9, 2023 08.
Article in English | MEDLINE | ID: mdl-37146704

ABSTRACT

Prophylactic low-dose aspirin reduces the rates of preeclampsia, preterm birth, fetal growth restriction, and perinatal death in patients with risk factors for preeclampsia. Despite recommendations from the US Preventive Services Task Force, the American College of Obstetricians and Gynecologists, and the Society for Maternal-Fetal Medicine, low-dose aspirin use is reported in <50% of patients with high-risk factors and <25% of patients with >1 moderate-risk factor. These low use rates represent an important "quality gap" and demonstrate the need for quality improvement activities. In this article, we outline the specifications for a process metric to standardize the measurement of the rate of aspirin use. Furthermore, we outline an approach to conducting a quality improvement project to increase the use of aspirin by patients with risk factors for preeclampsia.


Subject(s)
Pre-Eclampsia , Premature Birth , Pregnancy , Female , Humans , Infant, Newborn , Pre-Eclampsia/prevention & control , Pre-Eclampsia/etiology , Perinatology , Quality Improvement , Premature Birth/prevention & control , Aspirin/therapeutic use
2.
Am J Perinatol ; 40(4): 348-355, 2023 03.
Article in English | MEDLINE | ID: mdl-36427510

ABSTRACT

OBJECTIVE: Prior data suggest that there are racial and ethnic disparities in postpartum readmission among individuals, especially among those with hypertensive disorders of pregnancy. Existing reports commonly lack granular information on social determinants of health. The objective of this study was to investigate factors associated with postpartum readmission for individuals and address whether such risk factors differed by whether an individual had an antecedent diagnosis of a hypertensive disorder of pregnancy (HDP). STUDY DESIGN: This is a secondary analysis of a large, multicenter prospective cohort study of 10,038 nulliparous participants. The primary outcome of this analysis was postpartum readmission. A priori, participants were analyzed separately based on whether they had HDP. Participant characteristics previously associated with a greater risk of perinatal morbidity or readmission (including social determinants of health, preexisting and chronic comorbidities, and intrapartum characteristics) were compared with bivariable analyses and retained in multivariable models if p < 0.05. Social determinants of health evaluated in this analysis included insurance status, self-identified race and ethnicity (as a proxy for structural racism), income, marital status, primary language, and educational attainment. RESULTS: Of 9,457 participants eligible for inclusion, 1.7% (n = 165) were readmitted following initial hospital discharge. A higher proportion of individuals with HDP were readmitted compared with individuals without HDP (3.4 vs 1.3%, p < 0.001). Among participants without HDP, the only factors associated with postpartum readmission were chorioamnionitis and cesarean delivery. Among participants with HDP, gestational diabetes and postpartum hemorrhage requiring transfusion were associated with postpartum readmission. While the number of postpartum readmissions included in our analysis was relatively small, social determinants of health that we examined were not associated with postpartum readmission for either group. CONCLUSION: In this diverse cohort of nulliparous pregnant individuals, there was a higher frequency of postpartum readmission among participants with HDP. Preexisting comorbidity and intrapartum complications were associated with postpartum readmission among this population engaged in a longitudinal study. KEY POINTS: · Non-HDP patients had higher odds of PPR with chorioamnionitis or cesarean.. · HDP patients had higher odds of PPR if they had GDM or PPH.. · Characterizing PPR may identify and highlight modifiable factors..


Subject(s)
Chorioamnionitis , Diabetes, Gestational , Hypertension , Pregnancy , Female , Humans , Patient Readmission , Prospective Studies , Longitudinal Studies , Chorioamnionitis/epidemiology , Social Determinants of Health , Postpartum Period , Hypertension/epidemiology , Risk Factors , Retrospective Studies
3.
Neuroendocrinology ; 112(12): 1200-1213, 2022.
Article in English | MEDLINE | ID: mdl-35654013

ABSTRACT

INTRODUCTION: Angiotensin (Ang) II signalling in the hypothalamic paraventricular nucleus (PVN) via Ang type-1a receptors (AT1R) regulates vasopressin release and sympathetic nerve activity - two effectors of blood pressure regulation. We determined the cellular expression and function of AT1R in the PVN of a rodent model of polycystic kidney disease (PKD), the Lewis polycystic kidney (LPK) rat, to evaluate its contribution to blood pressure regulation and augmented vasopressin release in PKD. METHODS: PVN AT1R gene expression was quantified with fluorescent in situ hybridization in LPK and control rats. PVN AT1R function was assessed with pharmacology under urethane anaesthesia in LPK and control rats instrumented to record arterial pressure and sympathetic nerve activity. RESULTS: AT1R gene expression was upregulated in the PVN, particularly in corticotrophin-releasing hormone neurons, of LPK versus control rats. PVN microinjection of Ang II produced larger increases in systolic blood pressure in LPK versus control rats (36 ± 5 vs. 17 ± 2 mm Hg; p < 0.01). Unexpectedly, Ang II produced regionally heterogeneous sympathoinhibition (renal: -33%; splanchnic: -12%; lumbar: no change) in LPK and no change in controls. PVN pre-treatment with losartan, a competitive AT1R antagonist, blocked the Ang II-mediated renal sympathoinhibition and attenuated the pressor response observed in LPK rats. The Ang II pressor effect was also blocked by systemic OPC-21268, a competitive V1A receptor antagonist, but unaffected by hexamethonium, a sympathetic ganglionic blocker. DISCUSSION/CONCLUSION: Collectively, our data suggest that upregulated AT1R expression in PVN sensitizes neuroendocrine release of vasopressin in the LPK, identifying a central mechanism for the elevated vasopressin levels present in PKD.


Subject(s)
Paraventricular Hypothalamic Nucleus , Polycystic Kidney Diseases , Rats , Animals , Paraventricular Hypothalamic Nucleus/metabolism , Blood Pressure , Rodentia/genetics , Rodentia/metabolism , In Situ Hybridization, Fluorescence , Rats, Inbred Lew , Vasopressins/metabolism , Sympathetic Nervous System/metabolism , Angiotensin II , Receptor, Angiotensin, Type 1/genetics , Receptor, Angiotensin, Type 1/metabolism , Polycystic Kidney Diseases/metabolism , Kidney
4.
Am J Perinatol ; 2022 Dec 30.
Article in English | MEDLINE | ID: mdl-36584691

ABSTRACT

OBJECTIVE: Hypertensive disorders of pregnancy (HDP) impact 10% of pregnancies in the United States and cause adverse maternal and neonatal outcomes such as prematurity and low birth weight. Aspirin administration to at-risk individuals during pregnancy can reduce risk of HDP. STUDY DESIGN: Define-Measure-Assess-Improve-Control methodology was utilized to improve aspirin screening in an outpatient obstetric clinic. Retrospective cohort analysis compared outcome metrics pre- and postimplementation by using logistic regression models, adjusting for race and insurance. Key informant interviews and process mapping identified barriers to aspirin screening. A multidisciplinary team implemented low-cost strategies such as provider education, additional screening by ancillary staff, automated electronic reminders, and standardized patient counseling. RESULTS: Over 6 months, the screening rate improved from 62.5 to 92.0% (adjusted odds ratio [aOR] = 6.89, 95% confidence interval [CI]: 3.30-14.43). The prescription rate for patients correctly identified to be eligible for aspirin improved from 66.7 to 82.4% (aOR = 1.96, 95% CI: 0.88-4.35). CONCLUSION: Comprehensive, tailored quality improvement efforts can significantly increase aspirin screening and prescription, which may decrease maternal and neonatal morbidity due to HDP. KEY POINTS: · Initiative improved overall and correct screening rates.. · Initiative increased provider knowledge of eligibility.. · Low-cost interventions can have high impact over short time interval..

5.
J Neurosci ; 39(49): 9757-9766, 2019 12 04.
Article in English | MEDLINE | ID: mdl-31666354

ABSTRACT

Breathing results from sequential recruitment of muscles in the expiratory, inspiratory, and postinspiratory (post-I) phases of the respiratory cycle. Here we investigate whether neurons in the medullary intermediate reticular nucleus (IRt) are components of a central pattern generator (CPG) that generates post-I activity in laryngeal adductors and vasomotor sympathetic nerves and interacts with other members of the central respiratory network to terminate inspiration. We first identified the region of the (male) rat IRt that contains the highest density of lightly cholinergic neurons, many of which are glutamatergic, which aligns well with the putative postinspiratory complex in the mouse (Anderson et al., 2016). Acute bilateral inhibition of this region reduced the amplitudes of post-I vagal and sympathetic nerve activities. However, although associated with reduced expiratory duration and increased respiratory frequency, IRt inhibition did not affect inspiratory duration or abolish the recruitment of post-I activity during acute hypoxemia as predicted. Rather than representing an independent CPG for post-I activity, we hypothesized that IRt neurons may instead function as a relay that distributes post-I activity generated elsewhere, and wondered whether they could be a site of integration for para-respiratory CPGs that drive the same outputs. Consistent with this idea, IRt inhibition blocked rhythmic motor and autonomic components of fictive swallow but not swallow-related apnea. Our data support a role for IRt neurons in the transmission of post-I and swallowing activity to motor and sympathetic outputs, but suggest that other mechanisms also contribute to the generation of post-I activity.SIGNIFICANCE STATEMENT Interactions between multiple coupled oscillators underlie a three-part respiratory cycle composed from inspiratory, postinspiratory (post-I), and late-expiratory phases. Central post-I activity terminates inspiration and activates laryngeal motoneurons. We investigate whether neurons in the intermediate reticular nucleus (IRt) form the central pattern generator (CPG) responsible for post-I activity. We confirm that IRt activity contributes to post-I motor and autonomic outputs, and find that IRt neurons are necessary for activation of the same outputs during swallow, but that they are not required for termination of inspiration or recruitment of post-I activity during hypoxemia. We conclude that this population may not represent a distinct CPG, but instead may function as a premotor relay that integrates activity generated by diverse respiratory and nonrespiratory CPGs.


Subject(s)
Central Pattern Generators/physiology , Deglutition/physiology , Neurons/physiology , Respiratory Mechanics/physiology , Reticular Formation/physiology , Sympathetic Nervous System/physiology , Animals , Apnea/physiopathology , Choline O-Acetyltransferase/physiology , Female , Hypercapnia/physiopathology , Hypoxia/physiopathology , Larynx/physiology , Male , Mice , Nerve Net/physiology , Rats , Vagus Nerve/physiology
6.
J Neurosci ; 36(31): 8174-87, 2016 08 03.
Article in English | MEDLINE | ID: mdl-27488637

ABSTRACT

UNLABELLED: The activity of background potassium and sodium channels determines neuronal excitability, but physiological roles for "leak" Na(+) channels in specific mammalian neurons have not been established. Here, we show that a leak Na(+) channel, Nalcn, is expressed in the CO2/H(+)-sensitive neurons of the mouse retrotrapezoid nucleus (RTN) that regulate breathing. In RTN neurons, Nalcn expression correlated with higher action potential discharge over a more alkalized range of activity; shRNA-mediated depletion of Nalcn hyperpolarized RTN neurons, and reduced leak Na(+) current and firing rate. Nalcn depletion also decreased RTN neuron activation by the neuropeptide, substance P, without affecting pH-sensitive background K(+) currents or activation by a cotransmitter, serotonin. In vivo, RTN-specific knockdown of Nalcn reduced CO2-evoked neuronal activation and breathing; hypoxic hyperventilation was unchanged. Thus, Nalcn regulates RTN neuronal excitability and stimulation by CO2, independent of direct pH sensing, potentially contributing to respiratory effects of Nalcn mutations; transmitter modulation of Nalcn may underlie state-dependent changes in breathing and respiratory chemosensitivity. SIGNIFICANCE STATEMENT: Breathing is an essential, enduring rhythmic motor activity orchestrated by dedicated brainstem circuits that require tonic excitatory drive for their persistent function. A major source of drive is from a group of CO2/H(+)-sensitive neurons in the retrotrapezoid nucleus (RTN), whose ongoing activity is critical for breathing. The ionic mechanisms that support spontaneous activity of RTN neurons are unknown. We show here that Nalcn, a unique channel that generates "leak" sodium currents, regulates excitability and neuromodulation of RTN neurons and CO2-stimulated breathing. Thus, this work defines a specific function for this enigmatic channel in an important physiological context.


Subject(s)
Central Pattern Generators/physiology , Chemoreceptor Cells/physiology , Ion Channels/metabolism , Nerve Tissue Proteins/metabolism , Respiratory Mechanics/physiology , Sodium/metabolism , Superior Olivary Complex/physiology , Animals , Carbon Dioxide/metabolism , Cells, Cultured , Female , Ion Channel Gating/physiology , Male , Membrane Proteins , Mice
7.
J Physiol ; 594(6): 1529-51, 2016 Mar 15.
Article in English | MEDLINE | ID: mdl-26748771

ABSTRACT

We discuss recent evidence which suggests that the principal central respiratory chemoreceptors are located within the retrotrapezoid nucleus (RTN) and that RTN neurons are directly sensitive to [H(+) ]. RTN neurons are glutamatergic. In vitro, their activation by [H(+) ] requires expression of a proton-activated G protein-coupled receptor (GPR4) and a proton-modulated potassium channel (TASK-2) whose transcripts are undetectable in astrocytes and the rest of the lower brainstem respiratory network. The pH response of RTN neurons is modulated by surrounding astrocytes but genetic deletion of RTN neurons or deletion of both GPR4 and TASK-2 virtually eliminates the central respiratory chemoreflex. Thus, although this reflex is regulated by innumerable brain pathways, it seems to operate predominantly by modulating the discharge rate of RTN neurons, and the activation of RTN neurons by hypercapnia may ultimately derive from their intrinsic pH sensitivity. RTN neurons increase lung ventilation by stimulating multiple aspects of breathing simultaneously. They stimulate breathing about equally during quiet wake and non-rapid eye movement (REM) sleep, and to a lesser degree during REM sleep. The activity of RTN neurons is regulated by inhibitory feedback and by excitatory inputs, notably from the carotid bodies. The latter input operates during normo- or hypercapnia but fails to activate RTN neurons under hypocapnic conditions. RTN inhibition probably limits the degree of hyperventilation produced by hypocapnic hypoxia. RTN neurons are also activated by inputs from serotonergic neurons and hypothalamic neurons. The absence of RTN neurons probably underlies the sleep apnoea and lack of chemoreflex that characterize congenital central hypoventilation syndrome.


Subject(s)
Chemoreceptor Cells/metabolism , Medulla Oblongata/physiology , Protons , Respiration , Animals , Humans , Medulla Oblongata/cytology , Medulla Oblongata/metabolism , Potassium Channels, Tandem Pore Domain/genetics , Potassium Channels, Tandem Pore Domain/metabolism , Receptors, G-Protein-Coupled/genetics , Receptors, G-Protein-Coupled/metabolism , Reflex , Sleep, REM
9.
J Neurosci ; 33(41): 16033-44, 2013 Oct 09.
Article in English | MEDLINE | ID: mdl-24107938

ABSTRACT

Phox2b-expressing glutamatergic neurons of the retrotrapezoid nucleus (RTN) display properties expected of central respiratory chemoreceptors; they are directly activated by CO2/H(+) via an unidentified pH-sensitive background K(+) channel and, in turn, facilitate brainstem networks that control breathing. Here, we used a knock-out mouse model to examine whether TASK-2 (K2P5), an alkaline-activated background K(+) channel, contributes to RTN neuronal pH sensitivity. We made patch-clamp recordings in brainstem slices from RTN neurons that were identified by expression of GFP (directed by the Phox2b promoter) or ß-galactosidase (from the gene trap used for TASK-2 knock-out). Whereas nearly all RTN cells from control mice were pH sensitive (95%, n = 58 of 61), only 56% of GFP-expressing RTN neurons from TASK-2(-/-) mice (n = 49 of 88) could be classified as pH sensitive (>30% reduction in firing rate from pH 7.0 to pH 7.8); the remaining cells were pH insensitive (44%). Moreover, none of the recorded RTN neurons from TASK-2(-/-) mice selected based on ß-galactosidase activity (a subpopulation of GFP-expressing neurons) were pH sensitive. The alkaline-activated background K(+) currents were reduced in amplitude in RTN neurons from TASK-2(-/-) mice that retained some pH sensitivity but were absent from pH-insensitive cells. Finally, using a working heart-brainstem preparation, we found diminished inhibition of phrenic burst amplitude by alkalization in TASK-2(-/-) mice, with apneic threshold shifted to higher pH levels. In conclusion, alkaline-activated TASK-2 channels contribute to pH sensitivity in RTN neurons, with effects on respiration in situ that are particularly prominent near apneic threshold.


Subject(s)
Chemoreceptor Cells/metabolism , Potassium Channels, Tandem Pore Domain/metabolism , Respiratory Center/metabolism , Animals , Female , Hydrogen-Ion Concentration , Immunohistochemistry , Male , Mice , Mice, Knockout , Organ Culture Techniques , Patch-Clamp Techniques , Reverse Transcriptase Polymerase Chain Reaction
10.
Brain Struct Funct ; 229(5): 1121-1142, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38578351

ABSTRACT

In mammals, the ventral respiratory column (VRC) plays a pivotal role in integrating neurochemically diverse inputs from brainstem and forebrain regions to generate respiratory motor patterns. VRC microinjection of the neuropeptide galanin has been reported to dampen carbon dioxide (CO2)-mediated chemoreflex responses. Additionally, we previously demonstrated that galaninergic neurons in the retrotrapezoid nucleus (RTN) are implicated in the adaptive response to hypercapnic stimuli, suggesting a link between RTN neuroplasticity and increased neuronal drive to the VRC. VRC neurons express galanin receptor 1, suggesting potential regulatory action by galanin, however, the precise galaninergic chemoreceptor-VRC circuitry remains to be determined. This study aimed to identify sources of galaninergic input to the VRC that contribute to central respiratory chemoreception. We employed a combination of retrograde neuronal tracing, in situ hybridisation and immunohistochemistry to investigate VRC-projecting neurons that synthesise galanin mRNA. In an additional series of experiments, we used acute hypercapnia exposure (10% CO2, 1 h) and c-Fos immunohistochemistry to ascertain which galaninergic nuclei projecting to the VRC are activated. Our findings reveal that a total of 30 brain nuclei and 51 subnuclei project to the VRC, with 12 of these containing galaninergic neurons, including the RTN. Among these galaninergic populations, only a subset of the RTN neurons (approximately 55%) exhibited activation in response to acute hypercapnia. Our findings highlight that the RTN is the likely source of galaninergic transmission to the VRC in response to hypercapnic stimuli.


Subject(s)
Galanin , Hypercapnia , Neurons , Animals , Hypercapnia/metabolism , Hypercapnia/physiopathology , Male , Galanin/metabolism , Neurons/metabolism , Carbon Dioxide/metabolism , Proto-Oncogene Proteins c-fos/metabolism , Neural Pathways/metabolism , Neural Pathways/physiology , Respiratory Center/metabolism , Rats , Chemoreceptor Cells/metabolism , Rats, Sprague-Dawley , Brain Stem/metabolism
11.
eNeuro ; 2024 Feb 26.
Article in English | MEDLINE | ID: mdl-38408869

ABSTRACT

GPR4 is a proton-sensing G protein-coupled receptor implicated in many peripheral and central physiological processes. GPR4 expression has previously been assessed only via detection of the cognate transcript or indirectly, by use of fluorescent reporters. In this work, CRISPR/Cas9 knock-in technology was used to encode a hemagglutinin (HA) epitope tag within the endogenous locus of Gpr4 and visualize GPR4-HA in the mouse central nervous system using a specific, well characterized HA antibody; GPR4 expression was further verified by complementary Gpr4 mRNA detection. HA immunoreactivity was found in a limited set of brain regions, including in the retrotrapezoid nucleus (RTN), serotonergic raphe nuclei, medial habenula, lateral septum, and several thalamic nuclei. GPR4 expression was not restricted to cells of a specific neurochemical identity as it was observed in excitatory, inhibitory, and aminergic neuronal cell groups. HA immunoreactivity was not detected in brain vascular endothelium, despite clear expression of Gpr4 mRNA in endothelial cells. In the RTN, GPR4 expression was detected at the soma and in proximal dendrites along blood vessels and the ventral surface of the brainstem; HA immunoreactivity was not detected in RTN projections to two known target regions. This localization of GPR4 protein in mouse brain neurons corroborates putative sites of expression where its function has been previously implicated (e.g., CO2-regulated breathing by RTN), and provides a guide for where GPR4 could contribute to other CO2/H+ modulated brain functions. Finally, GPR4-HA animals provide a useful reagent for further study of GPR4 in other physiological processes outside of the brain.Significance Statement GPR4 is a proton-sensing G-protein coupled receptor whose expression is necessary for a number of diverse physiological processes including acid-base sensing in the kidney, immune function, and cancer progression. In the brain, GPR4 has been implicated in the hypercapnic ventilatory response mediated by brainstem neurons. While knockout studies in animals have clearly demonstrated its necessity for normal physiology, descriptions of GPR4 expression have been limited due to a lack of specific antibodies for use in mouse models. In this paper, we implemented a CRISPR/Cas9 knock-in approach to incorporate the coding sequence for a small epitope tag into the locus of GPR4. Using these mice, we were able to describe GPR4 protein expression directly for the first time.

12.
Indian J Ophthalmol ; 72(5): 653-658, 2024 May 01.
Article in English | MEDLINE | ID: mdl-38099390

ABSTRACT

PURPOSE: The study was undertaken to look into the clinicodemographic profile, management, and clinical outcomes of advanced retinoblastoma at a tertiary care center. METHODS: A prospective cohort study was conducted from Jan 2019 to Dec 2022. Forty-two patients of intraocular advanced retinoblastoma were assessed. The treatment protocol was formulated based on size, extension of tumor, and laterality. Primary outcome measure was response to the treatment in terms of regression of tumor and seeds and no evidence of recurrence after 12 month in enucleated eyes. Secondary outcome measures were complications like implant exposure, metastasis, and death associated with each treatment modality. RESULTS: The mean age of the study group was 13 months. The most common presentation was leukocoria with diminished vision. Most of the patients had group E retinoblastoma ( n = 40, 95%) as per the International Classification of Retinoblastoma. In 12 patients with group E retinoblastoma, primary enucleation was performed and in six patients, secondary enucleation was done, in which initially, globe salvage treatment was tried. In 30 patients, globe salvage treatment was attempted and we could manage to save 23 eyes. The most common treatment modality was intra-arterial chemotherapy using a triple-drug regimen. One patient developed intracranial spread and died due to systemic metastasis during the follow-up period. CONCLUSION: The current study showed that globe salvage is possible in advanced retinoblastoma if appropriate therapy is instituted depending upon the extent of the tumor and availability of latest treatment modalities. Intra-arterial chemotherapy using triple drugs can be offered as a first-line therapy in advanced unilateral retinoblastoma as it has been found to be very effective in the present study.

13.
Neuropeptides ; 107: 102454, 2024 Jul 03.
Article in English | MEDLINE | ID: mdl-38970907

ABSTRACT

Neuropeptide Y (NPY) plays a crucial role in controlling energy homeostasis and feeding behaviour. The role of NPY neurons located in the arcuate nucleus of the hypothalamus (Arc) in responding to homeostatic signals has been the focus of much investigation, but most studies have used AgRP promoter-driven models, which do not fully encompass Arc NPY neurons. To directly investigate NPY-expressing versus AgRP-expressing Arc neurons function, we utilised chemogenetic techniques in NPY-Cre and AgRP-Cre animals to activate Arc NPY or AgRP neurons in the presence of food and food-related stimuli. Our findings suggest that chemogenetic activation of the broader population of Arc NPY neurons, including AgRP-positive and AgRP-negative NPY neurons, has equivalent effects on feeding behaviour as activation of Arc AgRP neurons. Our results demonstrate that these Arc NPY neurons respond specifically to caloric signals and do not respond to non-caloric signals, in line with what has been observed in AgRP neurons. Activating Arc NPY neurons significantly increases food consumption and influences macronutrient selection to prefer fat intake.

14.
Eur J Neurosci ; 38(4): 2504-15, 2013 Aug.
Article in English | MEDLINE | ID: mdl-23651135

ABSTRACT

The activity of neurons in the rostral ventrolateral medulla (RVLM) is critical for the generation of vasomotor sympathetic tone. Multiple pre-sympathetic pathways converge on spinally projecting RVLM neurons, but the origin and circumstances in which such inputs are active are poorly understood. We have previously shown that input from the contralateral brainstem contributes to the baseline activity of this population: in the current study we investigate the distribution, phenotype and functional properties of RVLM neurons with commissural projections in the rat. We firstly used retrograde transport of fluorescent microspheres to identify neurons that project to the contralateral RVLM. Labelled neurons were prominent in a longitudinal column that extended over 1 mm caudal from the facial nucleus and contained hybridisation products indicating enkephalin (27%), GABA (15%) and adrenaline (3%) synthesis and included 6% of bulbospinal neurons identified by transport of cholera toxin B. Anterograde transport of fluorescent dextran-conjugate from the contralateral RVLM revealed extensive inputs throughout the RVLM that frequently terminated in close apposition with catecholaminergic and bulbospinal neurons. In urethane-anaesthetised rats we verified that 28/37 neurons antidromically activated by electrical stimulation of the contralateral pressor region were spontaneously active, of which 13 had activity locked to central respiratory drive and 15 displayed ongoing tonic discharge. In six tonically active neurons sympathoexcitatory roles were indicated by spike-triggered averages of splanchnic sympathetic nerve activity. We conclude that neurons in the RVLM project to the contralateral brainstem, form synapses with sympathetic premotor neurons, and have functional properties consistent with sympthoexcitatory function.


Subject(s)
Ganglia, Sympathetic/anatomy & histology , Medulla Oblongata/anatomy & histology , Medulla Oblongata/physiology , Neurons/physiology , Animals , Female , Male , Neural Pathways/physiology , Rats , Rats, Sprague-Dawley
15.
Anesthesiology ; 118(4): 785-95, 2013 Apr.
Article in English | MEDLINE | ID: mdl-23377220

ABSTRACT

BACKGROUND: Ketamine is a commonly used anesthetic, but the mechanistic basis for its clinically relevant actions remains to be determined. The authors previously showed that HCN1 channels are inhibited by ketamine and demonstrated that global HCN1 knockout mice are twofold less sensitive to hypnotic actions of ketamine. Although that work identified HCN1 channels as a viable molecular target for ketamine, it did not determine the relevant neural substrate. METHODS: To localize the brain region responsible for HCN1-mediated hypnotic actions of ketamine, the authors used a conditional knockout strategy to delete HCN1 channels selectively in excitatory cells of the mouse forebrain. A combination of molecular, immunohistochemical, and cellular electrophysiologic approaches was used to verify conditional HCN1 deletion; a loss-of-righting reflex assay served to ascertain effects of forebrain HCN1 channel ablation on hypnotic actions of ketamine. RESULTS: In conditional knockout mice, HCN1 channels were selectively deleted in cortex and hippocampus, with expression retained in cerebellum. In cortical pyramidal neurons from forebrain-selective HCN1 knockout mice, effects of ketamine on HCN1-dependent membrane properties were absent; notably, ketamine was unable to evoke membrane hyperpolarization or enhance synaptic inputs. Finally, the EC50 for ketamine-induced loss-of-righting reflex was shifted to significantly higher concentrations (by approximately 31%). CONCLUSIONS: These data indicate that forebrain principal cells represent a relevant neural substrate for HCN1-mediated hypnotic actions of ketamine. The authors suggest that ketamine inhibition of HCN1 shifts cortical neuron electroresponsive properties to contribute to ketamine-induced hypnosis.


Subject(s)
Analgesics/pharmacology , Cyclic Nucleotide-Gated Cation Channels , Hypnotics and Sedatives/pharmacology , Ketamine/pharmacology , Potassium Channels , Prosencephalon/drug effects , Animals , Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels , Mice , Mice, Transgenic
16.
Am J Obstet Gynecol MFM ; 5(2): 100831, 2023 02.
Article in English | MEDLINE | ID: mdl-36496115

ABSTRACT

BACKGROUND: The COVID-19 pandemic led to the rapid uptake of telemedicine services, which have been shown to be potentially cost-saving and of comparable quality to in-person care for certain populations. However, there are some concerns regarding the feasibility of implementation for marginalized populations, and the impact of widespread implementation of these services on health disparities has not been well studied. OBJECTIVE: This study aimed to assess the impact of telehealth implementation on postpartum care during the COVID-19 pandemic on racial disparities in visit attendance and completion of postpartum care goals. STUDY DESIGN: In this retrospective cohort study at a single tertiary care center, differences in outcomes between all Black and non-Black patients who had scheduled postpartum visits before and after telehealth implementation for postpartum care were compared. The primary outcome was postpartum visit attendance. The secondary outcomes included postpartum depression screening, contraception selection, breastfeeding status, completion of postpartum 2-hour glucose tolerance test, and cardiology follow-up for hypertensive disorders of pregnancy. In multivariable analysis, interaction terms were used to evaluate the differential impact of telehealth implementation by race. RESULTS: Of 1579 patients meeting the inclusion criteria (780 in the preimplementation group and 799 in the postimplementation group), 995 (63%) self-identified as Black. In the preimplementation period, Black patients were less likely to attend a postpartum visit than non-Black patients (63.9% in Black patients vs 88.7% in non-Black patients; adjusted odds ratio, 0.48; 95% confidence interval, 0.29-0.79). In the postimplementation period, there was no difference in postpartum visit attendance by race (79.1% in Black patients vs 88.6% in non-Black patients; adjusted odds ratio, 0.74; 95% confidence interval, 0.45-1.21). In addition, significant differences across races in postpartum depression screening during the preimplementation period became nonsignificant in the postimplementation period. Telehealth implementation for postpartum care significantly reduced racial disparities in postpartum visit attendance (interaction P=.005). CONCLUSION: Telehealth implementation for postpartum care during the COVID-19 pandemic was associated with decreased racial disparities in postpartum visit attendance.


Subject(s)
COVID-19 , Depression, Postpartum , Telemedicine , Female , Pregnancy , Humans , Pandemics , Retrospective Studies , COVID-19/diagnosis , COVID-19/epidemiology , COVID-19/prevention & control , Postpartum Period
17.
Curr Obstet Gynecol Rep ; 11(3): 159-168, 2022.
Article in English | MEDLINE | ID: mdl-35757523

ABSTRACT

Purpose of Review: Patients remain at risk for persistent and de novo postpartum hypertension related to pregnancy. This review aims to summarize the current definitions, clinical practices, and novel systems innovations and therapies for postpartum hypertension. Recent Findings: Recent changes to the definitions of hypertension outside of pregnancy have not yet impacted definitions or management of hypertensive disorders of pregnancy (HDP), though research examining the implications of these new definitions on risks of developing HDP and the resultant sequelae is ongoing. The administration of diuretics has been shown to reduce postpartum hypertension among women with HDP. Widespread implementation of telemedicine models and remote assessment of ambulatory blood pressures has increased data available on postpartum blood pressure trajectories, which may impact clinical management. Additionally, policy changes such as postpartum Medicaid extension and an increasing emphasis on building bridges to primary care in the postpartum period may improve long-term outcomes for women with postpartum hypertension. Prediction models utilizing machine learning are an area of ongoing research to assist with risk assessment in the postpartum period. Summary: The clinical management of postpartum hypertension remains focused on blood pressure control and primary care transition for cardiovascular disease risk reduction. In recent years, systemic innovations have improved access through implementation of new care delivery models. However, the implications of changing definitions of hypertension outside of pregnancy, increased data assessing blood pressure trajectories in the postpartum period, and the creation of new risk prediction models utilizing machine learning remain areas of ongoing research.

18.
Pregnancy Hypertens ; 30: 82-86, 2022 Dec.
Article in English | MEDLINE | ID: mdl-36067638

ABSTRACT

OBJECTIVE: In response to 2013 guidelines for hypertensive disorders of pregnancy (HDP), our study examined changes in antenatal management and postpartum readmission (PPR) over time. STUDY DESIGN: This is a retrospective cohort study of individuals diagnosed antenatally with HDP who delivered at a tertiary care center from 2012 to 2017. MAIN OUTCOME MEASURES: The primary outcome was postpartum readmission for HDP in 2012-2013 vs 2014-2017. Secondary outcomes included intravenous magnesium administration and prescription for oral (PO) antihypertensive medication during delivery admission. Multivariable logistic regression models assessed differences in outcomes over time, adjusted for age, race, and payer status, for HDP with and without severe features, defined by ACOG criteria. RESULTS: Of 5,300 eligible individuals, 73.5 % had HDP without severe features and 26.5 % had severe features. The PPR frequency in this cohort was 1.1 % (N = 59). There was no difference in PPR for individuals with HDP without severe features (aOR 0.73; 95 % CI 0.28-1.88) or with severe features (aOR 1.30; 95 % CI 0.50-3.39) by epoch. Magnesium administration for HDP with severe features remained below 80 % over time. Magnesium administration for HDP without severe features and discharge prescriptions for PO medications for HDP with severe features were lower after 2013. Neither magnesium administration nor discharge prescriptions were associated with decreased odds of PPR. CONCLUSION: Although there was no difference in PPR for HDP after 2013, there were changes in antenatal management of HDP, including decreased magnesium administration for individuals with HDP without severe features and PO medication for individuals with severe features.


Subject(s)
Hypertension, Pregnancy-Induced , Pre-Eclampsia , Pregnancy , Female , Humans , Hypertension, Pregnancy-Induced/diagnosis , Hypertension, Pregnancy-Induced/drug therapy , Retrospective Studies , Patient Readmission , Magnesium/therapeutic use , Postpartum Period
19.
Brain Commun ; 4(5): fcac215, 2022.
Article in English | MEDLINE | ID: mdl-36072647

ABSTRACT

Oxidative stress has been implicated in Alzheimer's disease, and it is potentially driven by the depletion of primary antioxidant, glutathione, as well as elevation of the pro-oxidant, iron. Present study evaluates glutathione level by magnetic resonance spectroscopy, iron deposition by quantitative susceptibility mapping in left hippocampus, as well as the neuropsychological scores of healthy old participants (N = 25), mild cognitive impairment (N = 16) and Alzheimer's disease patients (N = 31). Glutathione was found to be significantly depleted in mild cognitive impaired (P < 0.05) and Alzheimer's disease patients (P < 0.001) as compared with healthy old participants. A significant higher level of iron was observed in left hippocampus region for Alzheimer's disease patients as compared with healthy old (P < 0.05) and mild cognitive impairment (P < 0.05). Multivariate receiver-operating curve analysis for combined glutathione and iron in left hippocampus region provided diagnostic accuracy of 82.1%, with 81.8% sensitivity and 82.4% specificity for diagnosing Alzheimer's disease patients from healthy old participants. We conclude that tandem glutathione and iron provides novel avenue to investigate further research in Alzheimer's disease.

20.
J Vis Exp ; (172)2021 06 25.
Article in English | MEDLINE | ID: mdl-34251373

ABSTRACT

Fluorescent in situ hybridization (FISH) is a molecular technique that identifies the presence and spatial distribution of specific RNA transcripts within cells. Neurochemical phenotyping of functionally identified neurons usually requires concurrent labelling with multiple antibodies (targeting protein) using immunohistochemistry (IHC) and optimization of in situ hybridization (targeting RNA), in tandem. A "neurochemical signature" to characterize particular neurons may be achieved however complicating factors include the need to verify FISH and IHC targets before combining the methods, and the limited number of RNAs and proteins that may be targeted simultaneously within the same tissue section. Here we describe a protocol, using both fresh frozen and fixed mouse brain preparations, which detects multiple mRNAs and proteins in the same brain section using RNAscope FISH followed by fluorescence immunostaining, respectively. We use the combined method to describe the expression pattern of low abundance mRNAs (e.g., galanin receptor 1) and high abundance mRNAs (e.g., glycine transporter 2), in immunohistochemically identified brainstem nuclei. Key considerations for protein labelling downstream of the FISH assay extend beyond tissue preparation and optimization of FISH probe labelling. For example, we found that antibody binding and labelling specificity can be detrimentally affected by the protease step within the FISH probe assay. Proteases catalyze hydrolytic cleavage of peptide bonds, facilitating FISH probe entry into cells, however they may also digest the protein targeted by the subsequent IHC assay, producing off target binding. The subcellular location of the targeted protein is another factor contributing to IHC success following FISH probe assay. We observed IHC specificity to be retained when the targeted protein is membrane bound, whereas IHC targeting cytoplasmic protein required extensive troubleshooting. Finally, we found handling of slide-mounted fixed frozen tissue more challenging than fresh frozen tissue, however IHC quality was overall better with fixed frozen tissue, when combined with RNAscope.


Subject(s)
Brain , RNA , Animals , Immunohistochemistry , In Situ Hybridization, Fluorescence , Mice , RNA, Messenger
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