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1.
Ann Oncol ; 30(12): 1902-1913, 2019 12 01.
Article in English | MEDLINE | ID: mdl-31566658

ABSTRACT

Adoptive cell therapy (ACT) using autologous tumor-infiltrating lymphocytes (TIL) has been tested in advanced melanoma patients at various centers. We conducted a systematic review and meta-analysis to assess its efficacy on previously treated advanced metastatic cutaneous melanoma. The PubMed electronic database was searched from inception to 17 December 2018 to identify studies administering TIL-ACT and recombinant interleukin-2 (IL-2) following non-myeloablative chemotherapy in previously treated metastatic melanoma patients. Objective response rate (ORR) was the primary end point. Secondary end points were complete response rate (CRR), overall survival (OS), duration of response (DOR) and toxicity. Pooled estimates were derived from fixed or random effect models, depending on the amount of heterogeneity detected. Analysis was carried out separately for high dose (HD) and low dose (LD) IL-2. Sensitivity analyses were carried out. Among 1211 records screened, 13 studies (published 1988 - 2016) were eligible for meta-analysis. Among 410 heavily pretreated patients (some with brain metastasis), 332 received HD-IL-2 and 78 LD-IL-2. The pooled overall ORR estimate was 41% [95% confidence interval (CI) 35% to 48%], and the overall CRR was 12% (95% CI 7% to 16%). For the HD-IL-2 group, the ORR was 43% (95% CI 36% to 50%), while for the LD-IL-2 it was 35% (95% CI 25% to 45%). Corresponding pooled estimates for CRR were 14% (95% CI 7% to 20%) and 7% (95% CI 1% to 12%). The majority of HD-IL-2 complete responders (27/28) remained in remission during the extent of follow-up after CR (median 40 months). Sensitivity analyses yielded similar results. Higher number of infused cells was associated with a favorable response. The ORR for HD-IL-2 compared favorably with the nivolumab/ipilimumab combination following anti-PD-1 failure. TIL-ACT therapy, especially when combined with HD-IL-2, achieves durable clinical benefit and warrants further investigation. We discuss the current position of TIL-ACT in the therapy of advanced melanoma, particularly in the era of immune checkpoint blockade therapy, and review future opportunities for improvement of this approach.


Subject(s)
Interleukin-2/therapeutic use , Lymphocytes, Tumor-Infiltrating/transplantation , Melanoma/therapy , Recombinant Proteins/therapeutic use , Skin Neoplasms/therapy , Combined Modality Therapy , Disease-Free Survival , Dose-Response Relationship, Drug , Humans , Interleukin-2/genetics , Melanoma/immunology , Melanoma/pathology , Remission Induction , Skin Neoplasms/immunology , Skin Neoplasms/pathology , Transplantation, Autologous , Melanoma, Cutaneous Malignant
2.
Br J Anaesth ; 123(2): e284-e292, 2019 Aug.
Article in English | MEDLINE | ID: mdl-30916038

ABSTRACT

OBJECTIVE: Pain undertreatment, or oligoanalgesia, is frequent in the emergency department (ED), with major medical, ethical, and financial implications. Across different hospitals, healthcare providers have been reported to differ considerably in the ways in which they recognise and manage pain, with some prescribing analgesics far less frequently than others. However, factors that could explain this variability remain poorly understood. Here, we used neuroscience approaches for neural signal modelling to investigate whether individual decisions in the ED could be explained in terms of brain patterns related to empathy, risk-taking, and error monitoring. METHODS: For 15 months, we monitored the pain management behaviour of 70 ED nurses at triage, and subsequently invited 33 to a neuroimaging study involving three well-established tasks probing relevant cognitive and affective dimensions. Univariate and multivariate regressions were used to predict pain management decisions from neural activity during these tasks. RESULTS: We found that the brain signal recorded when empathising with others predicted the frequency with which nurses documented pain in their patients. In addition, neural activity sensitive to errors and negative outcomes predicted the frequency with which nurses denied analgesia by registering potential side-effects. CONCLUSIONS: These results highlight the multiple processes underlying pain management, and suggest that the neural representations of others' states and one's errors play a key role in individual treatment decisions. Neuroscience models of social cognition and decision-making are a powerful tool to explain clinical behaviour and might be used to guide future educational programs to improve pain management in ED.


Subject(s)
Brain/physiopathology , Clinical Decision-Making/methods , Emergency Service, Hospital , Empathy , Pain Management/methods , Pain Measurement/methods , Adult , Analgesics , Diagnostic Errors/prevention & control , Emergency Nursing/methods , Female , Hospitals , Humans , Male , Pain , Triage
3.
Rev Epidemiol Sante Publique ; 66(1): 75-80, 2018 Feb.
Article in English | MEDLINE | ID: mdl-29310987

ABSTRACT

OBJECTIVE: Patient complaints are a valuable resource for monitoring and improving patient safety and quality of care. The purpose of this study was to analyze the complaint letters received at a Swiss academic emergency department (ED) over six years. METHODS: A retrospective study of all complaint letters sent to a Swiss academic ED between 2009 and 2014 was conducted. The following data were extracted: epidemiology items, reasons for complaints, hospital responses, follow-up, and severity of the events mentioned in the complaints. All complaint letters related to adult patients evaluated in the ED between 2009 and 2014 were included and a qualitative evaluation was performed based on a systematic taxonomy. Context, patient characteristics, mode of resolution and clinical severity of the related adverse event were evaluated. RESULTS: A total number of 156 complaints were recorded, corresponding to an annual complaint rate of 5.5 to 8.8 per 10,000 visits. The complaints concerned mostly three domains (clinical care, management and patient or caregiver relationship) with a slight predominance for organisation and logistics (39%) compared with 31.4% for standard of care and 29.6% for communication/relational complaints. The majority of complaints were sent within one month of the ED visit. Most complaints were resolved with written apologies or explanations. The consequences of 73.5% of the events in question were considered minor or negligible, 19% moderate, and 6.5% major. Only 1% (two cases) was related to situations with catastrophic consequences. CONCLUSION: Complaint incidence in our ED was low and remained stable over the six-year observation period. Most of the complaints pertained to incidents that entailed negligible or minor consequences. As most complaints were due to inadequate communication, interventions targeting improvement of the doctor/patient communication are required.


Subject(s)
Correspondence as Topic , Dissent and Disputes , Emergency Service, Hospital , Professional-Patient Relations , Adolescent , Adult , Aged , Aged, 80 and over , Communication , Emergency Service, Hospital/standards , Emergency Service, Hospital/statistics & numerical data , Female , Health Care Surveys , Humans , Male , Middle Aged , Patient Harm/statistics & numerical data , Patient Safety/standards , Patient Safety/statistics & numerical data , Patient Satisfaction/statistics & numerical data , Physician-Patient Relations , Retrospective Studies , Switzerland/epidemiology , Triage/standards , Young Adult
4.
Rev Med Suisse ; 9(394): 1465-70, 1472, 2013 Aug 14.
Article in French | MEDLINE | ID: mdl-24024391

ABSTRACT

Mushroom poisoning is a regular complaint for consultation in emergency facilities. These situations are usually benign and symptomatic treatment is sufficient. However, severe damage can occur, potentially life-threatening. We review the various syndromes associated with the toxins involved, their management and the major signs that are suggestive of serious injury and requiring hospitalization.


Subject(s)
Emergency Service, Hospital , Mushroom Poisoning/therapy , Diagnosis, Differential , Humans , Mushroom Poisoning/epidemiology , Mushroom Poisoning/physiopathology , Severity of Illness Index
5.
Rev Med Suisse ; 9(368): 57-61, 2013 Jan 09.
Article in French | MEDLINE | ID: mdl-23367706

ABSTRACT

We review some of the most influential papers from 2012 in the different aspects of emergency medicine, such as prehospital medicine, resuscitation, early diagnosis and timely ED discharge and treatment. In particular, intramuscular benzodiazepines have been shown to be efficient in prehospital status epilepticus, epinephrines usefulness in cardiopulmonary resuscitation has been challenged, colloids have been shown to be deleterious in the treatment of severe sepsis and septic shock, the time window for thrombolysis in acute stroke will probably be extended, acute pyelonephritis treatment duration can be decreased, new D-dimers thresholds for older patients may prevent further diagnosis tests, and hs-Troponin may allow earlier discharge of low coronary risk patients.


Subject(s)
Emergency Medical Services/trends , Anti-Bacterial Agents/therapeutic use , Critical Care/methods , Critical Care/trends , Emergency Medical Services/methods , Epinephrine/therapeutic use , Heart Arrest/drug therapy , Humans , Pyelonephritis/drug therapy , Stroke/therapy , Troponin/therapeutic use , Vasoconstrictor Agents/therapeutic use
7.
Praxis (Bern 1994) ; 94(1-2): 31-4, 2005 Jan 12.
Article in French | MEDLINE | ID: mdl-15697148

ABSTRACT

A 83 years old woman presents to our hospital with fatigue and dyspnea since 2 weeks, followed by a painless icterus. On laboratory we discover a pancytopenia with severe haemolytic anaemia, thrombopenia and schistocytosis. This association suggest a thrombotic microangiopathy. In the presence of macrocytes, hypersegmented neutrophils and a low reticulocytes count, a vitamin screening was performed witch leads to the discovery of a vitamin B12 and folic acid deficiency. After initiation of a vitamin therapy we observe a reticulocytic crisis and thereafter the normalisation of the haematological parameters.


Subject(s)
Anemia, Hemolytic/etiology , Erythrocytes, Abnormal , Folic Acid Deficiency/diagnosis , Pancytopenia/etiology , Vitamin B 12 Deficiency/diagnosis , Aged , Aged, 80 and over , Anemia, Hemolytic/pathology , Diagnosis, Differential , Erythrocyte Count , Erythrocytes, Abnormal/pathology , Folic Acid Deficiency/blood , Folic Acid Deficiency/pathology , Humans , Male , Pancytopenia/pathology , Reticulocytes/pathology , Vitamin B 12 Deficiency/blood , Vitamin B 12 Deficiency/pathology
8.
Praxis (Bern 1994) ; 93(50): 2093-7, 2004 Dec 08.
Article in French | MEDLINE | ID: mdl-15646676

ABSTRACT

Hyperhomocysteinemia represents an independent risk factor for atherothrombotic disease. Physiopathological mechanisms of accelerated progression of atherosclerosis in presence of hyperhomocysteinemia are complex. Herein we report a clinical case which emphasis the importance of screening elevated homocystein in the absence of conventional risk factors in patients who suffer from premature atherosclerosis.


Subject(s)
Coronary Artery Disease/blood , Homocysteine/blood , Myocardial Infarction/blood , Adult , Coronary Artery Disease/diagnosis , Coronary Artery Disease/genetics , DNA Mutational Analysis , Genetic Carrier Screening , Humans , Male , Methylenetetrahydrofolate Reductase (NADPH2)/genetics , Myocardial Infarction/diagnosis , Myocardial Infarction/genetics , Protein S Deficiency/blood , Protein S Deficiency/diagnosis , Protein S Deficiency/genetics , Prothrombin/genetics , Recurrence , Risk Factors , Thrombophilia/blood , Thrombophilia/diagnosis , Thrombophilia/genetics
9.
Schweiz Med Wochenschr ; 130(11): 385-9, 2000 Mar 18.
Article in English | MEDLINE | ID: mdl-10774001

ABSTRACT

High altitude pulmonary oedema (HAPE) is a paradigm of pulmonary oedema that occurs in otherwise healthy subjects and thereby allows us to study underlying mechanisms in the absence of damning factors. Exaggerated pulmonary hypertension, which is related at least in part to endothelial dysfunction, is a hallmark of high-altitude pulmonary oedema. It is thought to play an important part in the pathogenesis of HAPE, but the predisposing factors are not clear. In rats, transient exposure to hypoxia during the first few days of life predisposes to exaggerated hypoxic pulmonary vasoconstriction in adulthood. We hypothesised that a similar mechanism may operate in humans, and if so may predispose to high-altitude pulmonary oedema. To test this hypothesis we studied the effects of high-altitude exposure (4559 m) on pulmonary-artery pressure and incidence of pulmonary oedema in 10 healthy young adults who had suffered from transient hypoxic pulmonary hypertension during perinatal period, and compared these effects with those observed in 10 controls of similar age and sex distribution, and in 14 HAPE-prone mountaineers. We found that at high altitude, the subjects who had suffered from transient perinatal hypoxic pulmonary hypertension had exaggerated pulmonary hypertension compared to controls (62 +/- 7 vs 50 +/- 11 mm Hg, p < 0.01). Despite exaggerated pulmonary vasoconstriction of similar magnitude to that observed in HAPE-prone subjects (59 +/- 10 mm Hg), none of the young adults developed HAPE. In contrast, 8 of the 14 HAPE-prone subjects had radiographic evidence of lung oedema (p < 0.001 for the comparison with the other 2 groups). These data challenge previous concepts and indicate that exaggerated hypoxic pulmonary vasoconstriction, while consistently associated with HAPE, is not sufficient to trigger pulmonary oedema. This suggests that additional mechanisms play a role.


Subject(s)
Altitude Sickness/physiopathology , Hypertension, Pulmonary/complications , Hypertension, Pulmonary/physiopathology , Pulmonary Edema/physiopathology , Adult , Altitude Sickness/complications , Animals , Carbon Dioxide/blood , Disease Susceptibility , Echocardiography , Female , Forced Expiratory Flow Rates , Humans , Male , Oxygen/blood , Pulmonary Edema/diagnostic imaging , Pulmonary Edema/etiology , Radiography , Rats , Reference Values , Retrospective Studies
10.
J Morphol ; 243(1): 75-104, 2000 Jan.
Article in English | MEDLINE | ID: mdl-10629097

ABSTRACT

The adult osteology of the direct-developing pipid frog, Pipa pipa, is described based on cleared-and-stained and dry skeletal specimens. Observations on skeletal development are based on cleared-and-stained embryos and young removed from the backs of preserved females. Osteologically, P.pipa is distinguished from its congeners and other pipid anurans by its large size and peculiar skull, which is extremely depressed and hyperossified. Skulls of the smallest individuals are not significantly different from those of other basal anurans at a similar stage of development; comparisons are made with Bombina orientalis, Discoglossus sardus, Spea bombifrons, Rhinophrynus dorsalis, and Xenopus laevis. The general sequence of chondrification and ossification resembles that of X.laevis; however, there is evidence that the mandible forms earlier in Pipa than in Xenopus. The major allometric transformations that result in the morphologically bizarre skull of adult P.pipa commence after the embryo has resorbed its tail, an event interpreted as marking the end of metamorphic climax in this taxon. In addition, ontogenetic comparisons reveal that the sacrum forms differently in Discoglossus sardus,Silurana tropicalis, and P.pipa. The development of the sphenethmoid region of the skull is the same in P.pipa and X.laevis, and distinctly different from the development of this region of the skull in other non-pipid basal anurans and neobatrachians for which ontogenetic descriptions exist.


Subject(s)
Bone Development/physiology , Bone and Bones/anatomy & histology , Pipidae/anatomy & histology , Animals , Bone and Bones/embryology , Female , Pipidae/embryology , Pipidae/growth & development , Skull/anatomy & histology , Skull/embryology , Skull/growth & development
11.
Hypertension ; 34(4 Pt 1): 586-9, 1999 Oct.
Article in English | MEDLINE | ID: mdl-10523331

ABSTRACT

Insulin exerts cardiovascular actions by stimulating nitric oxide (NO) release and sympathetic neural outflow. It is unclear, however, whether insulin stimulates muscle blood flow (and NO release) by a direct action at the vasculature and/or by stimulating neural vasodilator mechanisms. In these studies we used patients with regional sympathectomy to examine the vascular actions of insulin in the presence and absence of sympathetic vasoconstrictor and vasodilator innervation. A 2-hour insulin (6 pmol/kg per minute)/glucose clamp increased muscle blood flow in both innervated and denervated limbs by roughly 40% (P<0.01 versus baseline for both limbs). The vasodilation reached its maximum within the first 30 to 45 minutes of insulin/glucose infusion in sympathetically denervated limbs, but only at the end of the infusion in innervated limbs (P<0. 01, denervated versus innervated limb). Infusion of a NO synthase inhibitor (N(G)-monomethyl-L-arginine [L-NMMA]) increased baseline arterial pressure, abolished the vasodilation in the denervated limb, and led to a significant additional increase in arterial pressure during the clamp, but did not alter whole body glucose uptake. Our data indicate that insulin stimulates blood flow in sympathectomized limbs by a direct action at the vasculature. This effect is mediated by stimulation of NO release and appears to be masked by the sympathetic vasoconstrictor tone in innervated limbs.


Subject(s)
Glucose/pharmacology , Insulin/pharmacology , Nitric Oxide Synthase/antagonists & inhibitors , Sympathectomy , Vasodilation/drug effects , omega-N-Methylarginine/pharmacology , Adult , Blood Glucose/drug effects , Blood Pressure/drug effects , Enzyme Inhibitors/pharmacology , Female , Forearm/blood supply , Glucose/administration & dosage , Glucose Clamp Technique , Humans , Insulin/administration & dosage , Insulin/blood , Leg/blood supply , Male , Plethysmography , Vascular Resistance/drug effects
12.
Lancet ; 353(9171): 2205-7, 1999 Jun 26.
Article in English | MEDLINE | ID: mdl-10392986

ABSTRACT

BACKGROUND: Adverse environmental events occurring early in life have received little attention as predictors of disease in the later stages of life. At birth, the transition from gas exchange by the placenta to gas exchange by the lungs requires dramatic changes in the pulmonary circulation, which during this period is particularly vulnerable to noxious stimuli. We measured pulmonary-artery pressure responses to high-altitude exposure, a stimulus that causes pronounced pulmonary vasoconstriction, in young adults who had had transient perinatal hypoxic pulmonary hypertension and in controls of similar age and sex distribution. METHODS: Review of neonatal-care records at the Lausanne University Hospital for Children identified 15 individuals who met the eligibility criteria (birth at > or = 34 weeks of gestation, persistence of hypoxaemia during ventilation with oxygen during the first week of life, and persistence of fetal circulation). Ten of these individuals agreed to take part; the control group was ten volunteers without any history of perinatal complications. Systolic pulmonary-artery pressure (by echocardiography) and arterial oxygen saturation were measured at baseline and at high altitude (4559 m). FINDINGS: The mean increase in pulmonary-artery pressure at high altitude was significantly greater (p=0.01) in the participants who had had perinatal pulmonary hypertension (from 26.2 mm Hg [SD 2.1] to 62.3 mm Hg [7.3]) than in the controls (from 25.8 mm Hg [2.3] to 49.7 mm Hg [11.3]). The fall in arterial oxygen saturation was similar in the two groups. INTERPRETATION: These findings suggest that a transient perinatal insult to the pulmonary circulation leaves a persistent and potentially fatal imprint, which when activated in adult life predisposes to a pathological response. Survivors of perinatal pulmonary hypertension may be at risk of developing this disorder in later life.


Subject(s)
Altitude , Hypertension, Pulmonary/etiology , Hypoxia/complications , Pulmonary Wedge Pressure , Adult , Case-Control Studies , Female , Humans , Hypoxia/physiopathology , Infant, Newborn , Male , Nitric Oxide , Pulmonary Circulation/physiology , Vasoconstriction
13.
Adv Exp Med Biol ; 474: 93-107, 1999.
Article in English | MEDLINE | ID: mdl-10634996

ABSTRACT

High-altitude pulmonary edema (HAPE) is a form of lung edema which occurs in otherwise healthy subjects, thereby allowing the study of underlying mechanisms of pulmonary edema in the absence of confounding factors. Exaggerated pulmonary hypertension is a hallmark of HAPE and is thought to play an important part in its pathogenesis. Pulmonary vascular endothelial dysfunction and augmented hypoxia-induced sympathetic activation may be underlying mechanisms contributing to exaggerated pulmonary vasoconstriction in HAPE. Recent observations by our group suggest, however, that pulmonary hypertension itself may not be sufficient to trigger HAPE. Based on studies in rats, indicating that perinatal exposure to hypoxia predisposes to exaggerated hypoxic pulmonary vasoconstriction in adulthood, we examined effects of high-altitude exposure on pulmonary-artery pressure in a group of young adults who had suffered from transient perinatal pulmonary hypertension. We found that these young adults had exaggerated pulmonary vasoconstriction of similar magnitude to that observed in HAPE-susceptible subjects. Surprisingly, however, none of the subjects developed lung edema. These findings strongly suggest that additional mechanisms are needed to trigger pulmonary edema at high-altitude. Observations in vitro, and in vivo suggest that a defect of the alveolar transepithelial sodium transport could act as a sensitizer to pulmonary edema. The aim of this article is to review very recent experimental evidence consistent with this concept. We will discuss data gathered in mice with targeted disruption of the gene of the alpha subunit of the amiloride-sensitive epithelial sodium channel (alpha ENaC), and present preliminary data on measurements of transepithelial sodium transport in vivo in HAPE-susceptible and HAPE-resistant mountaineers.


Subject(s)
Altitude Sickness/physiopathology , Altitude , Hypertension, Pulmonary/physiopathology , Pulmonary Edema/physiopathology , Respiratory Mucosa/physiopathology , Sodium/metabolism , Adult , Animals , Humans , Mice , Pulmonary Alveoli/physiology , Pulmonary Alveoli/physiopathology , Pulmonary Circulation , Pulmonary Edema/etiology , Rats , Respiratory Mucosa/physiology , Sympathetic Nervous System/physiopathology , Vasoconstriction
14.
Clin Physiol ; 18(6): 562-9, 1998 Nov.
Article in English | MEDLINE | ID: mdl-9818162

ABSTRACT

The effects of a sympathetic activation elicited by a lower body negative pressure (LBNP) (at -15 mmHg for 75 min) were assessed in 7 healthy subjects on two occasions: (i) in post-absorptive conditions, and (ii) during glucose infusion (22.2 mumol kg-1 min-1). LBNP increased plasma norepinephrine concentration and heart rate. It did not alter whole-body glucose metabolism (measured with [6,6-2H]glucose) and glycerol turnover (measured with [1,1,2,3,3-2H]glycerol). Interstitial glycerol concentrations were monitored with microdialysis in subcutaneous adipose tissue and in skeletal muscle. LBNP increased dialysate glycerol concentrations in muscle by 16% (P < 0.03) but not in adipose tissue in post-absorptive conditions, and by 37% in adipose tissue (P < 0.05) but not in muscle during glucose infusion. These results indicate that an LBNP-induced sympathetic activation (i) does not increase endogenous glucose production, and (ii) induces only a slight stimulation of lipolysis in adipose tissue during glucose infusion.


Subject(s)
Glucose/metabolism , Lipid Metabolism , Lower Body Negative Pressure , Sympathetic Nervous System/physiology , Adolescent , Adult , Blood Glucose/analysis , Extracellular Space/metabolism , Glucose/pharmacology , Glycerol/metabolism , Glycerol/pharmacology , Heart Rate/drug effects , Heart Rate/physiology , Humans , Infusions, Intravenous , Insulin/blood , Leg/blood supply , Male , Norepinephrine/blood , Postprandial Period , Regional Blood Flow/drug effects , Regional Blood Flow/physiology
15.
J Hypertens ; 16(4): 519-23, 1998 Apr.
Article in English | MEDLINE | ID: mdl-9797197

ABSTRACT

BACKGROUND: In several animal species, nitric oxide (NO) buffers central neural sympathetic outflow, but data concerning humans are sparse and conflicting. We hypothesized that these conflicting results could be related to large differences in the dose of N(G)-monomethyl-L-arginine, a stereospecific inhibitor of NO synthase, infused in these human studies. OBJECTIVE: To investigate the haemodynamic and sympathetic effects of systemic inhibition of NO synthase by intravenous infusion of two different doses of N(G)-monomethyl-L-arginine into healthy humans and compare these effects with those of an equipressor dose of the non-endothelium-dependent vasoconstrictor phenylephrine. METHODS: Muscle sympathetic nerve activity was measured by microneurography and blood flow by venous occlusion plethysmography. N(G)-monomethyl-L-arginine was infused over 15 min at a rate of 50 microg/kg per min into members of one group (n = 8) and at a rate of 450 microg/kg per min into members of another group (n = 7). An equipressor dose of phenylephrine was infused into four subjects from each group. RESULTS: Infusions of N(G)-monomethyl-L-arginine and of phenylephrine at the higher dose similarly suppressed sympathetic activity. In contrast, infusions of N(G)-monomethyl-L-arginine and of an equipressor dose of phenylephrine at the lower dose had different sympathetic effects. Burst frequency of muscle sympathetic nerve activity remained unchanged during infusion of N(G)-monomethyl-L-arginine but decreased by roughly 50% during infusion of phenylephrine. Infusion of N(G)-monomethyl-L-arginine at both doses did not alter forearm blood flow. Only infusion of N(G)-monomethyl-L-arginine at the higher dose increased forearm vascular resistance. CONCLUSIONS: Haemodynamic and sympathetic effects of inhibition of NO synthase by infusion of N(G)-monomethyl-L-arginine into humans are dose dependent. At higher doses, N(G)-monomethyl-L-arginine exerts sympathoinhibitory effects that are comparable to those evoked by a non-specific vasoconstrictor drug, whereas at lower doses, it exerts sympatho-excitatory effects.


Subject(s)
Enzyme Inhibitors/administration & dosage , Hemodynamics/drug effects , Nitric Oxide Synthase/physiology , Sympathetic Nervous System/drug effects , omega-N-Methylarginine/administration & dosage , Adult , Dose-Response Relationship, Drug , Hemodynamics/physiology , Humans , Infusions, Intravenous , Male , Muscle, Skeletal/blood supply , Muscle, Skeletal/innervation , Nitric Oxide Synthase/antagonists & inhibitors , Regional Blood Flow/drug effects , Regional Blood Flow/physiology , Sympathetic Nervous System/physiology
16.
Circulation ; 96(11): 3897-903, 1997 Dec 02.
Article in English | MEDLINE | ID: mdl-9403613

ABSTRACT

BACKGROUND: Nitric oxide (NO) regulates vascular tone and blood pressure, and studies in animals suggest that it does so, at least in part, by modulating sympathetic neural outflow. Loss of NO-induced vasodilator tone and restraint on sympathetic vasoconstrictor outflow could lead to exaggerated vasoconstrictor and pressor responses to physical stress in humans. METHODS AND RESULTS: To determine the role of NO in the modulation of central sympathetic outflow and vascular tone at rest and during a physical stress, we tested effects of systemic inhibition of NO synthase by N(G)-monomethyl-L-arginine (L-NMMA) infusion (a stereospecific inhibitor of NO synthase) on sympathetic nerve activity (microneurography), regional vascular resistance, and blood pressure at rest and during static handgrip. The major new findings are that (1) under resting conditions, L-NMMA infusion, which increased mean arterial pressure by approximately 10%, did not have any detectable effect on muscle sympathetic nerve activity, whereas a similar increase in arterial pressure evoked by phenylephrine infusion (an NO-independent vasoconstrictor) decreased the rate of sympathetic nerve firing by approximately 50%; (2) during static handgrip, the exercise-induced sympathetic nerve responses were preserved during L-NMMA infusion but markedly attenuated during phenylephrine infusion; and (3) the L-NMMA-induced loss of vasodilator tone did not result in exaggerated exercise-induced pressor and calf vasoconstrictor responses. CONCLUSIONS: These findings indicate that NO is involved in the central regulation of sympathetic outflow in humans and suggest that both neuronal and endothelial NO synthesis may contribute to the regulation of vasomotor tone.


Subject(s)
Blood Pressure/physiology , Exercise/physiology , Nitric Oxide Synthase/antagonists & inhibitors , Rest/physiology , Sympathetic Nervous System/physiology , Vascular Resistance/physiology , Adrenergic alpha-Agonists , Adult , Blood Flow Velocity , Blood Pressure/drug effects , Enzyme Inhibitors , Forearm/blood supply , Humans , Male , Phenylephrine , Reference Values , Sympathomimetics , Vascular Resistance/drug effects , Vasoconstrictor Agents , omega-N-Methylarginine
19.
Science ; 264(5162): 1068, 1994 May 20.
Article in English | MEDLINE | ID: mdl-17744878
20.
J Morphol ; 214(1): 1-41, 1992 Oct.
Article in English | MEDLINE | ID: mdl-1433306

ABSTRACT

Postembryonic skeletal development of the pipid frog Xenopus laevis is described from cleared-and-stained whole-mount specimens and sectioned material representing Nieuwkoop and Faber developmental Stages 46-65, plus postmetamorphic individuals up to 6 months old. An assessment of variation of skeletogenesis within a single population of larvae and comparison with earlier studies revealed that the timing, but not the sequence, of skeletal development in X. laevis is more variable than previously reported and poorly correlated with the development of external morphology. Examination of chondrocranial development indicates that the rostral cartilages of X. laevis are homologous with the suprarostral cartilages of non-pipoid anurans, and suggests that the peculiar chondrocranium of this taxon is derived from a more generalized pattern typical of non-pipoid frogs. Derived features of skeletal development not previously reported for X. laevis include 1) bipartite formation of the palatoquadrate; 2) precocious formation of the adult mandible; 3) origin of the angulosplenial from two centers of ossification; 4) complete erosion of the orbital cartilage during the later stages of metamorphosis; 5) development of the sphenethmoid as a membrane, rather than an endochondral bone; and 6) a pattern of timing of ossification that more closely coincides with that of the pelobatid frog Spea than that recorded for neobatrachian species.


Subject(s)
Bone Development , Xenopus laevis/growth & development , Animals , Metamorphosis, Biological , Skull/growth & development
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