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1.
Sci Rep ; 14(1): 5109, 2024 03 01.
Article in English | MEDLINE | ID: mdl-38429349

ABSTRACT

Fibrolamellar carcinoma (FLC) is a rare liver tumor driven by the DNAJ-PKAc fusion protein that affects healthy young patients. Little is known about the immune response to FLC, limiting rational design of immunotherapy. Multiplex immunohistochemistry and gene expression profiling were performed to characterize the FLC tumor immune microenvironment and adjacent non-tumor liver (NTL). Flow cytometry and T cell receptor (TCR) sequencing were performed to determine the phenotype of tumor-infiltrating immune cells and the extent of T cell clonal expansion. Fresh human FLC tumor slice cultures (TSCs) were treated with antibodies blocking programmed cell death protein-1 (PD-1) and interleukin-10 (IL-10), with results measured by cleaved caspase-3 immunohistochemistry. Immune cells were concentrated in fibrous stromal bands, rather than in the carcinoma cell compartment. In FLC, T cells demonstrated decreased activation and regulatory T cells in FLC had more frequent expression of PD-1 and CTLA-4 than in NTL. Furthermore, T cells had relatively low levels of clonal expansion despite high TCR conservation across individuals. Combination PD-1 and IL-10 blockade signficantly increased cell death in human FLC TSCs. Immunosuppresion in the FLC tumor microenvironment is characterized by T cell exclusion and exhaustion, which may be reversible with combination immunotherapy.


Subject(s)
Carcinoma, Hepatocellular , Interleukin-10 , Liver Neoplasms , Programmed Cell Death 1 Receptor , Humans , Carcinoma, Hepatocellular/pathology , Carcinoma, Hepatocellular/therapy , Immunosuppression Therapy , Interleukin-10/antagonists & inhibitors , Interleukin-10/metabolism , Liver Neoplasms/pathology , Programmed Cell Death 1 Receptor/antagonists & inhibitors , Programmed Cell Death 1 Receptor/metabolism , Receptors, Antigen, T-Cell , Tumor Microenvironment
3.
Tech Coloproctol ; 25(4): 401-411, 2021 04.
Article in English | MEDLINE | ID: mdl-32671661

ABSTRACT

BACKGROUND: Acute appendicitis (AA) is the most common general surgical emergency. Early laparoscopic appendicectomy is the gold-standard management. SARS-CoV-2 (COVID-19) brought concerns of increased perioperative mortality and spread of infection during aerosol generating procedures: as a consequence, conservative management was advised, and open appendicectomy recommended when surgery was unavoidable. This study describes the impact of the first weeks of the pandemic on the management of AA in the United Kingdom (UK). METHODS: Patients 18 years or older, diagnosed clinically and/or radiologically with AA were eligible for inclusion in this prospective, multicentre cohort study. Data was collected from 23rd March 2020 (beginning of the UK Government lockdown) to 1st May 2020 and included: patient demographics, COVID status; initial management (operative and conservative); length of stay; and 30-day complications. Analysis was performed on the first 500 cases with 30-day follow-up. RESULTS: The patient cohort consisted of 500 patients from 48 sites. The median age of this cohort was 35 [26-49.75] years and 233 (47%) of patients were female. Two hundred and seventy-one (54%) patients were initially treated conservatively; with only 26 (10%) cases progressing to an operation. Operative interventions were performed laparoscopically in 44% (93/211). Median length of hospital stay was significantly reduced in the conservatively managed group (2 [IQR 1-4] days vs. 3 [2-4], p < 0.001). At 30 days, complications were significantly higher in the operative group (p < 0.001), with no deaths in any group. Of the 159 (32%) patients tested for COVID-19 on admission, only 6 (4%) were positive. CONCLUSION: COVID-19 has changed the management of acute appendicitis in the UK, with non-operative management shown to be safe and effective in the short-term. Antibiotics should be considered as the first line during the pandemic and perhaps beyond.


Subject(s)
Appendectomy/statistics & numerical data , Appendicitis/surgery , COVID-19/prevention & control , Communicable Disease Control , Adult , Appendicitis/epidemiology , Cohort Studies , Female , Humans , Length of Stay , Male , Middle Aged , Pandemics , Postoperative Complications/epidemiology , Prospective Studies , SARS-CoV-2 , United Kingdom/epidemiology
4.
Langenbecks Arch Surg ; 404(7): 831-840, 2019 Nov.
Article in English | MEDLINE | ID: mdl-31748872

ABSTRACT

PURPOSE: Total pancreatectomy may improve symptoms in patients with severe end-stage chronic pancreatitis. This might be achieved whilst preserving both the duodenum- and spleen-(DPSPTP). Mature clinical outcomes of this approach are presented. METHODS: Single-centre prospective cohort study performed between September 1996 and May 2016. Demographic, clinical details, pain scores and employment status were prospectively recorded during clinic attendance. RESULTS: Fifty-one patients (33 men, 18 women) with a median (interquartile range) age of 40.8 (35.3-49.4) years, a median weight of 69.8 (61.0-81.5) Kg and a median body mass index of 23.8 (21.5-27.8), underwent intended duodenum-and spleen-preserving near-total pancreatectomy for end-stage chronic pancreatitis. Aetiology was excess alcohol in 25, idiopathic (no mutation) in 15, idiopathic (SPINK-1/CFTR mutations) in two, hereditary (PRSS1 mutation) in seven and one each post-necrotising pancreatitis and obstructive pancreatic duct divisum in 1. The main indication for surgery was severe pain. Findings included parenchymal calcification in 79% and ductal calculi in 24%, a dilated main pancreatic duct in 57% and a dilated main bile duct in 17%, major vascular involvement in 27% and pancreato-peritoneal fistula in 2%. Postoperative complications occurred in 20 patients with two deaths. Median pain scores were 8 (7-8) preoperatively and 3 (0.25-5.75) at 5 years (p = 0.013). Opiate analgesic use was significantly reduced postoperatively (p = 0.048). Following surgery, 22 (63%) of 38 patients of working age re-entered employment compared with 12 (33%) working preoperatively (p = 0.016). CONCLUSION: Duodenum-and spleen-preserving near-total pancreatectomy provided long-term relief in adult patients with intractable chronic pancreatitis pain, with improved employment prospects.


Subject(s)
Duodenum/surgery , Palliative Care/methods , Pancreatectomy/methods , Pancreatitis, Chronic/surgery , Spleen/surgery , Adult , Cohort Studies , Female , Follow-Up Studies , Humans , Male , Middle Aged , Pancreatitis, Chronic/diagnosis , Prospective Studies , Treatment Outcome
5.
World J Surg ; 43(6): 1604-1611, 2019 06.
Article in English | MEDLINE | ID: mdl-30815742

ABSTRACT

BACKGROUND: Autoimmune pancreatitis (AIP) is an uncommon form of chronic pancreatitis. Whilst being corticosteroid responsive, AIP often masquerades radiologically as pancreatic neoplasia. Our aim is to appraise demographic, radiological and histological features in our cohort in order to differentiate AIP from pancreatic malignancy. METHODS: Clinical, biochemical, histological and radiological details of all AIP patients 1997-2016 were analysed. The initial imaging was re-reviewed according to international guidelines by three blinded independent radiologists to evaluate features associated with autoimmune pancreatitis and pancreatic cancer. RESULTS: There were a total of 45 patients: 25 in type 1 (55.5%), 14 type 2 (31.1%) and 6 AIP otherwise not specified (13.3%). The median (IQR) age was 57 (51-70) years. Thirty patients (66.6%) were male. Twenty-six patients (57.8%) had resection for suspected malignancy and one for symptomatic chronic pancreatitis. Three had histologically proven malignancy with concurrent AIP. Two patients died from recurrent pancreatic cancer following resection. Multidisciplinary team review based on radiology and clinical history dictated management. Resected patients (vs. non-resected group) were older (64 vs. 53, p = 0.003) and more frequently had co-existing autoimmune pathologies (22.2 vs. 55.6%, p = 0.022). Resected patients also presented with less classical radiological features of AIP, which are halo sign (0/25 vs. 3/17, p = 0.029) and loss of pancreatic clefts (18/25 vs. 17/17, p = 0.017). There were no differences in demographic features other than age. CONCLUSION: Despite international guidelines for diagnosing AIP, differentiation from pancreatic cancer remains challenging. Resection remains an important treatment option in suspected cancer or where conservative treatment fails.


Subject(s)
Autoimmune Diseases/diagnosis , Pancreatic Neoplasms/diagnosis , Pancreatitis, Chronic/diagnosis , Adult , Aged , Antigens, Tumor-Associated, Carbohydrate/blood , Autoimmune Diseases/therapy , Biomarkers/blood , Cohort Studies , Diagnosis, Differential , Female , Glucocorticoids/therapeutic use , Humans , Immunoglobulin G/blood , Male , Middle Aged , Pancreas/diagnostic imaging , Pancreatic Neoplasms/therapy , Pancreatitis, Chronic/therapy , Retrospective Studies , Tomography, X-Ray Computed
7.
Am Fam Physician ; 63(12): 2413-20, 2001 Jun 15.
Article in English | MEDLINE | ID: mdl-11430456

ABSTRACT

Acute osteomyelitis is the clinical term for a new infection in bone. This infection occurs predominantly in children and is often seeded hematogenously. In adults, osteomyelitis is usually a subacute or chronic infection that develops secondary to an open injury to bone and surrounding soft tissue. The specific organism isolated in bacterial osteomyelitis is often associated with the age of the patient or a common clinical scenario (i.e., trauma or recent surgery). Staphylococcus aureus is implicated in most patients with acute hematogenous osteomyelitis. Staphylococcus epidermidis, S. aureus, Pseudomonas aeruginosa, Serratia marcescens and Escherichia coli are commonly isolated in patients with chronic osteomyelitis. For optimal results, antibiotic therapy must be started early, with antimicrobial agents administered parenterally for at least four to six weeks. Treatment generally involves evaluation, staging, determination of microbial etiology and susceptibilities, antimicrobial therapy and, if necessary, debridement, dead-space management and stabilization of bone.


Subject(s)
Anti-Bacterial Agents/therapeutic use , Osteomyelitis , Acute Disease , Adolescent , Adult , Age Distribution , Child , Humans , Infant , Magnetic Resonance Imaging , Osteomyelitis/diagnosis , Osteomyelitis/microbiology , Osteomyelitis/physiopathology , Osteomyelitis/therapy , Staphylococcus aureus/isolation & purification
8.
Ann Pharmacother ; 35(5): 636-40, 2001 May.
Article in English | MEDLINE | ID: mdl-11346071

ABSTRACT

OBJECTIVE: To describe prescribing practices of family physicians in a staff model health maintenance organization at a university health center in Lebanon and estimate costs of such practices for common diseases. METHODS: All prescriptions issued between July 1, 1997, and June 30, 1998, were prospectively collected. The diagnoses made by physicians at each encounter were recorded, and the total price of medications prescribed was calculated. The core prescribing indicators as defined by the World Health Organization and the mean annual prescription price per person for the 25 most common diagnoses were calculated. RESULTS: Prescribing occurred in 27.1% of encounters, with a mean of 1.6 medications per encounter; 17.5% of all prescriptions included an antibiotic. Generic drugs and essential drugs each accounted for 2.9% of all medications. Approximately 50% of the consultations for either respiratory or ear infections resulted in a prescription. Cervical spine syndromes and lipid metabolism disorders cost most among recorded diagnoses, with mean annual prescription prices per person of US $2016 and $1128, respectively. CONCLUSIONS: The low rate of generic and essential drug prescribing, as well as the frequency of prescribing in respiratory infections, highlight the need for initiatives to help rationalize prescribing in primary care in Lebanon. Together with the diagnostic categories incurring high cost per person, these issues can be part of physician education or treatment guideline development. These measures may aid the government in its subsidy of primary health care centers.


Subject(s)
Academic Medical Centers/statistics & numerical data , Ambulatory Care Facilities/statistics & numerical data , Ambulatory Care/economics , Drug Prescriptions/statistics & numerical data , Economics, Pharmaceutical , Adolescent , Adult , Aged , Child , Female , Humans , Lebanon , Male , Middle Aged
9.
J ECT ; 17(1): 50-2, 2001 Mar.
Article in English | MEDLINE | ID: mdl-11281516

ABSTRACT

OBJECTIVE: The components of a pre-ECT consultation have been well-described, but the outcome has not been described. We describe the outcome of 369 consecutive ECT consultations. METHODS: We performed a retrospective review of ECT consultations performed at Wake Forest University School of Medicine between January 23, 1992, and October 22. 1998. Each consultation was coded as either recommending against ECT, unenthusiastic about ECT, or recommending ECT. RESULTS: Thirteen percent of the patients at their first consultation needed clarification of their capacity to consent to ECT. Additional testing was recommended in 34%, and additional medical consultation was recommended for 11% of the patients. The ECT consultation recommended against ECT for 4% of patients, was unenthusiastic for an additional 15% of patients, and was enthusiastic for 81%. Likelihood of receiving ECT was strongly influenced by the consulting physician's level of enthusiasm for ECT. Enthusiasm for ECT, in turn, was highly related to diagnosis. CONCLUSIONS: The recommendations from an ECT consultation appeared influential in the likelihood of receipt of ECT. The consultation's enthusiasm for ECT, in turn, was related to the patient's diagnosis. Furthermore, the consultation revealed the need for additional testing, medical consultation, or clarification of capacity to consent in a substantial number of patients.


Subject(s)
Depressive Disorder/therapy , Electroconvulsive Therapy , Outcome Assessment, Health Care , Referral and Consultation , Adolescent , Adult , Aged , Aged, 80 and over , Attitude , Female , Humans , Informed Consent , Male , Middle Aged , Patient Education as Topic , Retrospective Studies
10.
J Med Liban ; 49(5): 246-56, 2001.
Article in English | MEDLINE | ID: mdl-12243418

ABSTRACT

Antibiotic resistance has increased dramatically over the past 10 years. In many countries, penicillin resistance to Streptococcus pneumoniae is nearly 50% with resistance to other drugs rising as well. One of the mechanisms responsible for the development of resistance is the widespread use of antibiotics in the primary care setting, chiefly for the treatment of respiratory disorders. Reduction in antibiotic prescribing for respiratory diseases in primary care has been associated with decreases in drug resistance in Streptococcus pneumoniae. This article will review common reasons for overuse of antibiotics in primary care settings and some strategies for reducing injudicious antibiotic prescribing.


Subject(s)
Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/therapeutic use , Bacteria/drug effects , Drug Resistance, Bacterial , Anti-Bacterial Agents/administration & dosage , Anti-Bacterial Agents/adverse effects , Bronchitis/drug therapy , Common Cold/drug therapy , Escherichia coli/drug effects , Humans , Medical Audit , Otitis Media/drug therapy , Penicillin Resistance , Practice Guidelines as Topic , Respiratory Tract Infections/drug therapy , Risk Factors , Sinusitis/drug therapy , Staphylococcus aureus/drug effects , Streptococcus pneumoniae/drug effects , Time Factors , Urinary Tract Infections/drug therapy
11.
J Toxicol Clin Toxicol ; 38(4): 421-8, 2000.
Article in English | MEDLINE | ID: mdl-10930059

ABSTRACT

STUDY OBJECTIVE: To evaluate the potential utility of sodium bicarbonate in an established model of acute propranolol toxicity. METHODS: Two minutes after the completion of a propranolol infusion (10 mg/kg), a bolus of 1.5 mEq/kg of sodium bicarbonate solution (1 mEq/mL) followed by an infusion of 1.5 mEq/kg over the next 26 minutes (n = 6) or an equivalent timing and volume of 5% dextrose solution (n = 6) was administered in each dog. Targeted cardiovascular parameters included heart rate, mean arterial pressure, left ventricular dP/dtmax, and QRS interval. RESULTS: Propranolol infusion significantly depressed heart rate (p < 0.0001), mean arterial pressure (p < 0.0001), dP/dtmax (p < 0.0001) and prolonged the QRS interval (p < 0.0001). Sodium bicarbonate failed to significantly improve these targeted parameters when compared to control animals. CONCLUSION: In this canine model of propranolol toxicity, intravenous sodium bicarbonate appears to be an ineffective single therapy. Furthermore, these results may suggest a different mechanism of sodium channel blockade for propanolol than that of type IA antiarrhythmic agents.


Subject(s)
Cardiovascular Diseases/chemically induced , Cardiovascular Diseases/drug therapy , Propranolol/toxicity , Sodium Bicarbonate/administration & dosage , Animals , Bicarbonates/blood , Blood Pressure/drug effects , Disease Models, Animal , Dogs , Electrocardiography , Heart Conduction System/drug effects , Heart Rate/drug effects , Infusions, Intravenous , Poisoning/drug therapy , Propranolol/administration & dosage , Sodium/blood , Treatment Outcome , Ventricular Function, Left/drug effects
13.
Pharmacotherapy ; 20(6): 711-23, 2000 Jun.
Article in English | MEDLINE | ID: mdl-10853627

ABSTRACT

Optimal use of antimicrobials is essential in the face of escalating antibiotic resistance, and requires cooperation from all sectors of the health care system. Although antibiotic-restriction policies in the hospital setting are important in altering microbial susceptibility patterns, an overall reduction in antibiotic prescriptions in the outpatient setting is more likely to significantly impact antibiotic resistance. Education of providers, application of clinical practice guidelines, audit and feedback activities, and multifaceted interventions all have had an effect in altering antibiotic prescribing in a research setting. Clinicians must alter antibiotic prescribing for the treatment of infectious diseases, and patients must change their perception of the need for these drugs. Pharmacists can play a major role through clinician education and focused clinical services. With cooperation of health care teams, the effectiveness of available antibiotics may be sustained and the threat of resistance minimized.


Subject(s)
Anti-Bacterial Agents/therapeutic use , Pharmacists , Delivery of Health Care , Drug Resistance, Microbial , Humans , Medical Audit , Vaccination
14.
Am Fam Physician ; 61(7): 2131-8, 2143, 2000 Apr 01.
Article in English | MEDLINE | ID: mdl-10779254

ABSTRACT

Obesity is a common health problem in the United States, and effective treatment is challenging. Obesity is associated with an increased mortality rate and risk factors such as hypertension, hyperlipidemia and diabetes mellitus. Numerous treatments are available for obesity. Behavioral therapy, surgery and pharmacologic treatment have been used with varying degrees of success. Older anorectic agents have significant side effects and limited benefit, and some have even been withdrawn from the U.S. market because of a possible association with cardiovascular complications. The safety of newer agents must be extensively evaluated before widespread use is recommended. Therefore, behavioral therapy, including regular exercise and the development of healthy eating habits, continues to be the best treatment for long-term weight loss.


Subject(s)
Anti-Obesity Agents/therapeutic use , Obesity/drug therapy , Anti-Obesity Agents/pharmacology , Body Mass Index , Humans , Obesity/complications , Patient Education as Topic , Teaching Materials , Weight Loss
16.
Drugs ; 57(6): 883-904, 1999 Jun.
Article in English | MEDLINE | ID: mdl-10400403

ABSTRACT

The pharmacological management of obesity has gained increasing attention as new weight loss treatments are approved and a significant proportion of the public strives to lose weight. Obesity is associated with a high mortality rate, multiple chronic medical conditions, and carries an enormous financial burden. Obesity is a multifactorial condition, most often due to an imbalance in energy intake and expenditure. Despite the greater focus on management of obesity, weight loss remains a difficult goal to achieve. Obesity is a chronic medical condition that may require long term treatment, therefore the risks and benefits of all pharmacological agents must be carefully considered. Noradrenergic appetite suppressants (ie. phenyl-propanolamine, phentermine) result in weight loss but stimulatory effects limit their use. The serotonergic agents (fenfluramine, dexfenfluramine) were effective weight loss drugs, but were voluntarily withdrawn from the US market last year because of cardiovascular and pulmonary complications. The combination noradrenergic/serotonergic agent sibutramine is indicated for the management of obesity, particularly in the presence of other cardiovascular risk factors. Modest weight loss is achieved with sibutramine, although weight gain is significant after discontinuation. In addition, long term safety data are not yet available. The thermogenic combination of ephedrine plus caffeine is minimally effective, and adverse effects are usually transient. Other thermogenic agents, such as beta3-agonists, are still under investigation. Agents may alter digestion through lipase inhibition (orlistat) or fat substitution (olestra). Orlistat decreases systemic absorption of dietary fat, decreasing body weight and cholesterol. Olestra is a fat substitute that has been incorporated into snack foods. Olestra substitution for dietary fat has not been studied as a weight loss strategy, although olestra has no caloric value and may be beneficial. The use of orlistat and olestra may be limited by gastrointestinal adverse effects. Finally, the manipulation of leptin and neuropeptide Y are under investigation for the treatment of obesity. Pharmacological agents should be used as an aid to a structured diet and exercise regimen in the treatment of obesity. Weight loss agents may result in initial weight loss, but sustained weight loss is not always achieved even with continuation of treatment. The effect of weight loss obtained while using pharmacotherapeutic agents on morbidity and mortality has not been established. Therefore, diet and exercise should be the focus of any weight loss programme. There is a continued need for safe and effective pharmacotherapeutic agents for the treatment of obesity.


Subject(s)
Appetite Depressants/therapeutic use , Hyperthermia, Induced/methods , Obesity/drug therapy , Digestion/drug effects , Hormones/metabolism , Humans , Leptin , Neuropeptide Y/agonists , Neuropeptide Y/antagonists & inhibitors , Obesity/etiology , Proteins/agonists , Proteins/antagonists & inhibitors
17.
Brain Lang ; 66(1): 61-88, 1999 Jan.
Article in English | MEDLINE | ID: mdl-10080865

ABSTRACT

The standard methods for decomposition and analysis of evoked potentials are bandpass filtering, identification of peak amplitudes and latencies, and principal component analysis (PCA). We discuss the limitations of these and other approaches and introduce wavelet packet analysis. Then we propose the "single-channel wavelet packet model," a new approach in which a unique decomposition is achieved using prior time-frequency information and differences in the responses of the components to changes in experimental conditions. Orthogonal sets of wavelet packets allow a parsimonious time-frequency representation of the components. The method allows energy in some wavelet packets to be shared among two or more components, so the components are not necessarily orthogonal. The single-channel wavelet packet model and PCA both require constraints to achieve a unique decomposition. In PCA, however, the constraints are defined by mathematical convenience and may be unrealistic. In the single-channel wavelet packet model, the constraints are based on prior scientific knowledge. We give an application of the method to auditory evoked potentials recorded from cats. The good frequency resolution of wavelet packets allows us to separate superimposed components in these data. Our present approach yields estimates of component waveforms and the effects of experiment conditions on the amplitude of the components. We discuss future extensions that will provide confidence intervals and p values, allow for latency changes, and represent multichannel data.


Subject(s)
Brain/physiology , Evoked Potentials , Models, Biological , Animals , Cats , Electroencephalography
18.
J Cardiovasc Pharmacol ; 33(1): 36-42, 1999 Jan.
Article in English | MEDLINE | ID: mdl-9890394

ABSTRACT

It has been suggested that cocaine acts directly in the brain to enhance central sympathetic outflow. However, some studies suggested that the cardiovascular effects of cocaine are related to a peripheral action. To characterize further the site of cocaine's cardiovascular effect, we compared the hemodynamic effects of cocaine (2 mg/kg, i.v. bolus) with those observed after administration of an equimolar dose (2.62 mg/kg, i.v. bolus) of cocaine methiodide, a quaternary derivative of cocaine that does not penetrate the blood-brain barrier, by using sufentanil-sedated dogs. Cocaine produced significant (p < 0.05) increases in heart rate (+37+/-11 beats/min), mean arterial pressure (+55+/-11 mm Hg), left ventricular end-diastolic pressure (+5.3+/-1.0 mm Hg), and cardiac output (+2.4+/-0.9 L/min). Cocaine methiodide produced increases in heart rate (+57+/-11 beats/min), mean arterial pressure (+45+/-11 mm Hg), left ventricular end-diastolic pressure (+3.4+/-1.0 mm Hg), and cardiac output (1.1+/-0.9 L/min), which were not significantly different from those observed with cocaine. Because opiate sedation potentially might have attenuated central sympathetic outflow, we further confirmed the qualitative similarity of the actions of cocaine and cocaine methiodide on heart rate and blood pressure in unsedated, conscious dogs. Our data suggest that the cardiovascular effects of cocaine result primarily from a peripheral site of action.


Subject(s)
Blood Pressure/drug effects , Central Nervous System/drug effects , Cocaine/analogs & derivatives , Heart Rate/drug effects , Anesthetics, Intravenous , Animals , Cocaine/pharmacology , Dogs , Electrocardiography/drug effects , Male , Sufentanil , Vasoconstrictor Agents/pharmacology
19.
Brain Res ; 810(1-2): 251-6, 1998 Nov 09.
Article in English | MEDLINE | ID: mdl-9813353

ABSTRACT

Previous research from this laboratory has shown that substance P-immunoreactive (SP) terminals synapse upon negative chronotropic vagal preganglionic neurons (VPNs), but not upon negative dromotropic VPNs, of the ventrolateral nucleus ambiguus (NA-VL). Moreover, SP agonists injected into NA-VL cause bradycardia without decreasing AV conduction. In the current study, we have: (1) defined the electron microscopic characteristics of the SP neurons of NA-VL in dog; and (2) tested the hypothesis that SP nerve terminals synapse upon negative inotropic VPNs of NA-VL, retrogradely labeled from the cranial medial ventricular (CMV) ganglion. Numerous SP terminals and a few SP neurons were observed in the vicinity of retrogradely labeled neurons. SP terminals were observed forming synapses with unlabeled dendrites and with SP dendrites, but never with the retrogradely labeled neurons. Together, these results and earlier findings suggest that SP agonists may be able to induce bradycardia without decreasing AV conduction or ventricular contractility.


Subject(s)
Heart/innervation , Medulla Oblongata/physiology , Myocardial Contraction/physiology , Neurons, Afferent/physiology , Neurons/physiology , Presynaptic Terminals/physiology , Substance P/physiology , Animals , Atrioventricular Node/physiology , Dogs , Female , Male , Medulla Oblongata/cytology , Medulla Oblongata/ultrastructure , Microscopy, Electron , Neurons/ultrastructure , Neurons, Afferent/ultrastructure , Presynaptic Terminals/ultrastructure , Vagus Nerve/cytology , Vagus Nerve/physiology
20.
Brain Res ; 802(1-2): 205-20, 1998 Aug 17.
Article in English | MEDLINE | ID: mdl-9748580

ABSTRACT

Recent physiological evidence indicates that vagal postganglionic control of left ventricular contractility is mediated by neurons found in a ventricular epicardial fat pad ganglion. In the dog this region has been referred to as the cranial medial ventricular (CMV) ganglion [J.L. Ardell, Structure and function of mammalian intrinsic cardiac neurons, in: J.A. Armour, J.L. Ardell (Eds.). Neurocardiology, Oxford Univ. Press, New York, 1994, pp. 95-114; B.X. Yuan, J.L. Ardell, D.A. Hopkins, A.M. Losier, J.A. Armour, Gross and microscopic anatomy of the canine intrinsic cardiac nervous system, Anat. Rec., 239 (1994) 75-87]. Since activation of the vagal neuronal input to the CMV ganglion reduces left ventricular contractility without influencing cardiac rate or AV conduction, this ganglion contains a functionally selective pool of negative inotropic parasympathetic postganglionic neurons. In the present report we have defined the light microscopic distribution of preganglionic negative inotropic neurons in the CNS which are retrogradely labeled from the CMV ganglion. Some tissues were also processed for the simultaneous immunocytochemical visualization of tyrosine hydroxylase (TH: a marker for catecholaminergic neurons) and examined with both light microscopic and electron microscopic methods. Histochemically visualized neurons were observed in a long slender column in the ventrolateral nucleus ambiguus (NA-VL). The greatest number of retrogradely labeled neurons were observed just rostral to the level of the area postrema. TH perikarya and dendrites were commonly observed interspersed with vagal motoneurons in the NA-VL. TH nerve terminals formed axo-dendritic synapses upon negative inotropic vagal motoneurons, however the origin of these terminals remains to be determined. We conclude that synaptic interactions exist which would permit the parasympathetic preganglionic vagal control of left ventricular contractility to be modulated monosynaptically by catecholaminergic afferents to the NA-VL.


Subject(s)
Heart Conduction System/physiology , Myocardial Contraction/physiology , Ventricular Function, Left/physiology , Animals , Brain Mapping , Dogs , Female , Male , Medulla Oblongata/cytology , Medulla Oblongata/physiology , Microscopy, Electron , Neurons/physiology , Synapses/physiology , Tyrosine 3-Monooxygenase/metabolism , Vagus Nerve/cytology , Vagus Nerve/physiology
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