Psychological impact of medical evacuation for ICU saturation in Covid-19-related ARDS patients.

PURPOSE: Psychological impact of Medical Evacuation (MEDEVAC) in Covid-19 patients is undetermined. The objectives were to evaluate: Post-traumatic Stress Disorder (PTSD) in MEDEVAC patients hospitalized in ICU for Covid-19-related acute respiratory distress syndrome (ARDS) compared to control group; anxiety, depression rates and outcomes in patients and PTSD in relatives. MATERIAL AND METHODS: This is a retrospective multicentric 1/1 paired cohort performed in 10 ICUs in the West of France. Evaluation was performed 18 months after discharge. Patients and closest relatives performed IES-R (Impact and Event Scale-Revised) and/or HADS (Hospital Anxiety and Depression Scale) scales. RESULTS: Twenty-six patients were included in each group. Patients were 64 ± 11 years old, with 83% male. We report 12 vs 20% of PTSD in control vs MEDEVAC groups (p = 0.7). Anxiety disorder affected 43.5 vs 28.0% (p = 0.26) and depression 12.5 vs 14.3% (p > 0.99) in control vs MEDEVAC groups. PTSD affects 33.3 vs 42.1% of closest relatives (p = 0.55). Ways of communication were adapted: video calls were more frequent in MEDEVAC patients (8.7 vs 60.9%, p < 0.01) whereas physical visits concerned more control group (45.8 vs 13.0%, p = 0.01). CONCLUSIONS: PTSD rate were similar between groups. Adaptive ways of communication, restricted visits and global uncertainties could explain the absence of differences.

Nationwide survey on training and device utilization during tracheal intubation in French intensive care units.

BACKGROUND: Intubation is a lifesaving procedure that is often performed in intensive care unit (ICU) patients, but leads to serious adverse events in 20-40% of cases. Recent trials aimed to provide guidance about which medications, devices, and modalities maximize patient safety. Videolaryngoscopes are being offered in an increasing range of options and used in broadening indications (from difficult to unremarkable intubation). The objective of this study was to describe intubation practices and device availability in French ICUs. MATERIALS AND METHODS: We conducted an online nationwide survey by emailing an anonymous 26-item questionnaire to physicians in French ICUs. A single questionnaire was sent to either the head or the intubation expert at each ICU. RESULTS: Of 257 ICUs, 180 (70%) returned the completed questionnaire. The results showed that 43% of intubators were not fully proficient in intubation; among them, 18.8% had no intubation training or had received only basic training (lectures and observation at the bedside). Among the participating ICUs, 94.4% had a difficult intubation trolley, 74.5% an intubation protocol, 92.2% a capnography device (used routinely to check tube position in 69.3% of ICUs having the device), 91.6% a laryngeal mask, 97.2% front-of-neck access capabilities, and 76.6% a videolaryngoscope. In case of difficult intubation, 85.6% of ICUs used a bougie (154/180) and 7.8% switched to a videolaryngoscope (14/180). Use of a videolaryngoscope was reserved for difficult intubation in 84% of ICUs (154/180). Having a videolaryngoscope was significantly associated with having an intubation protocol (P = 0.043) and using capnography (P = 0.02). Airtraq® was the most often used videolaryngoscope (39.3%), followed by McGrath®Mac (36.9%) then by Glidescope® (14.5%). CONCLUSION: Nearly half the intubators in French ICUs are not fully proficient with OTI. Access to modern training methods such as simulation is inadequate. Most ICUs own a videolaryngoscope, but reserve it for difficult intubations.

Prognosis of autoimmune hemolytic anemia in critically ill patients.

Patients with autoimmune hemolytic anemia (AIHA) may require intensive care unit (ICU) admission. In order to describe the characteristics of AIHA patients in ICU and identify prognosis factors, clinical and biological data from 44 patients admitted in one ICU between 2002 and 2015 were retrospectively analyzed. The main reasons for ICU admission were profound anemia without any organ failure in 19 patients (either for safer transfusion or continuous monitoring only). Twenty-five (57%) patients had a past history of hemopathy. Twenty patients presented with a direct anti-globulin test (DAT) positive for immunoglobulin G (DAT-IgG) only (46%), 8 with a DAT positive for both IgG and complement (DAT-IgG+C) (36%), and 16 with a DAT positive for complement only (DAT-IgG+C) (18%). Corticosteroids and rituximab were administered to respectively 44 (100%) and 12 (25%) patients. Red blood cell transfusion was required in 28 (64%) patients. Ten (23%) patients received vasopressors. Renal replacement therapy was necessary in 14 (31.8%) patients. Thirteen (30%) patients died in the ICU. There was no difference between survivors and non-survivors regarding associated comorbidities like hemopathy (18/31 [58%] vs. 7/13 [54%], p = 0.80). In decedents, age was higher (72 years [57.8-76.3] vs. 50 years [34.3-64], p < 0.01) and organ dysfunctions were more severe at day 1 (SOFA 8 [7-11] vs. 5.5 [3-7], p < 0.01). Patients with a DAT-IgG displayed poorer outcome in comparison with patients with DAT-IgG+C/C (hospital mortality 69% vs. 36%, p = 0.04). Mortality rate of AIHA patients requiring ICU admission is consequential and appears to be impacted by age, organ failures, and DAT-IgG.

[Hyperviscosity syndrome]. / Syndrome d'hyperviscosité plasmatique.

Hyperviscosity syndrome is a life-threatening complication. Clinical manifestations include neurological impairment, visual disturbance and bleeding. Measurement of plasma or serum viscosity by a viscometer assesses the diagnosis. Funduscopic examination is a key exam because abnormalities are well-correlated with abnormal plasma viscosity. Etiologies are various but symptomatic hyperviscosity is more common in Waldenström's macroglobulinemia and multiple myeloma. Prompt treatment is needed: treatment of the underlying disease should be considered, but generally not sufficient. Symptomatic measures aim to not exacerbate blood viscosity while urgent plasmapheresis effectively reduces the paraprotein concentration and relieves symptoms.

Life-threatening complications and outcomes in patients with malignancies and severe pulmonary embolism.

BACKGROUND: Data are scarce about ICU patients with malignancy and severe pulmonary embolism. Here, our main objective was to identify risk factors for life-threatening complications, organ failures, and death in ICU patients with severe pulmonary embolism, with special attention to the impact of malignancy. We also described the clinical features of PE in patients with and without malignancies. METHODS: Data from consecutive adults admitted to our ICU in 2002-2011 with severe pulmonary embolism were collected retrospectively. Multivariate analysis was performed to look for factors associated with death, organ failures, or life-threatening complications (major bleeding, recurrent PE, and cardiac arrest). RESULTS: Of 119 included patients (42 [35%] with bilateral pulmonary embolism), 41 had solid malignancies, 27 hematological malignancies, and 51 no malignancies. The most common symptoms were syncope (40%) and hemoptysis (18%) in patients with solid and hematological malignancies, respectively. Life-threatening complications occurred in 23 (19%) patients; risk factors were obesity (OR, 13.22; 1.93-90.70), disseminated intravascular coagulation/ischemic hepatitis (OR, 27.06; 5.14-142.46), fluid load ≥1000 mL/24 h (OR, 6.42; 1.60-25.76), and solid malignancy (OR, 5.45; 1.15-25.89). Inhospital mortality was 27/119 (23%) and respiratory or circulatory failure developed in 36 (30%) patients. Risk factors for these adverse outcomes were older age (OR, 1.04/year; 1.01-1.07), higher oxygen flow rate (OR, 1.28/L; 1.13-1.45); and renal failure (OR, 8.08; 2.50-26.11); whereas chest pain was protective (OR, 0.13; 0.04-0.48). CONCLUSION: In this study, solid malignancy was a risk factor for life-threatening complications but not for death.

Acute renal failure is prevalent in patients with thrombotic thrombocytopenic purpura associated with low plasma ADAMTS13 activity.

BACKGROUND: Among patients with thrombotic microangiopathies, acute kidney injury (AKI) is the hallmark of hemolytic uremic syndrome (HUS) and is largely underestimated in patients with thrombotic thrombocytopenic purpura (TTP). OBJECTIVE: We sought to report AKI features and outcomes in patients with TTP. METHODS: We conducted a retrospective study of 92 patients with TTP assessed by low ADAMTS13 activity (< 10%) between 2001 and 2013. A logistic regression identified variables independently associated with AKI. RESULTS: Among the 92 patients, 54 (58.7%) presented with AKI, including 25 (46.3%) with stage 3 AKI. Fourteen (27.4%) patients had a nephrotic-range proteinuria and 21 (45.6%) had hemoglobinuria. Hematuria and leucocyturia were detected in 19 (41.3%) and 16 patients (36.4%), respectively. Renal replacement therapy (RRT) was required in 14 patients (25.9%). Six months after TTP remission, RRT-free patients had median (IQR) MDRD (Modification of Diet in Renal Disease formula estimating the glomerular filtration rate) of 93 mL min(-1) per 1.73 m(2) (68.8-110) and three patients required long-term dialysis. Mild or moderate chronic renal disease occurred in 23/54 (42.6%) AKI patients. By multivariate analysis, serum level of complement component 3 at admission was the only factor independently associated with AKI (OR per 0.25 unit decrease of C3, 0.85; CI, 1.82-8.33; P = 0.001). CONCLUSIONS: In patients with TTP, AKI is present in more than half the patients, and half of those will have lasting renal effects. Further studies to better understand the pathophysiology of renal involvement in patients with TTP and to identify a subset of patients with TTP syndrome overlapping HUS are warranted.

Severe infections requiring intensive care unit admission in kidney transplant recipients: impact on graft outcome.

BACKGROUND: Kidney transplant recipients are at risk for life-threatening infections, which may affect the long-term prognosis. METHODS: We retrospectively included all kidney transplant recipients admitted for sepsis, severe sepsis, or septic shock to the medical intensive care unit (ICU) of the Saint-Louis Hospital, Paris, France, between 2000 and 2010. The main objective was to identify factors associated with survival without graft impairment 90 days after ICU discharge. RESULTS: Data were available for 83 of 100 eligible patients. The main sites of infection were the lungs (54%), urinary tract (24%), and bloodstream (22%). Among documented infections (55/83), 80% were bacterial. Fungal infections were more common among patients transplanted after 2005 (5% vs. 23%, P = 0.02). Mechanical ventilation was used in 46 (56%) patients, vasopressors in 39 (47%), and renal replacement therapy (RRT) in 34 (41%). In-hospital and day-90 mortality rates were 20% and 22%, respectively. On day 90, among the 65 survivors, 39 (47%) had recovered their previous graft function and 26 (31%) had impaired graft function, including 16 (19%) who were dependent on RRT. Factors independently associated with day-90 survival and graft function recovery were baseline serum creatinine (odds ratio [OR] for a 10 µmol/L increase 0.94, 95% confidence interval [CI] 0.88-1.00) and cyclosporine therapy (OR 0.30, 95% CI 0.11-0.79). CONCLUSION: Sepsis was chiefly related to bacterial pneumonia or urinary tract infection. Pneumocystis jirovecii was the leading opportunistic agent, with a trend toward an increase over time. Infections often induced severe graft function impairment. Baseline creatinine and cyclosporine therapy independently predicted the outcome.

Diagnostic contribution from pulmonary biopsies in hematology patients with acute respiratory failure from undetermined etiology.

BACKGROUND: In about 20% of patients with malignancies with acute respiratory failure (ARF), no etiology can be determined, whatever the diagnostic strategy used. Lung biopsy could then be a precious diagnostic tool leading to therapeutic adaptations and increasing chances for cure. The aim of this study was to assess the diagnostic contribution of lung biopsy in patients for whom a complete diagnosis strategy failed to identify ARF etiology. METHODS: All hematology patients admitted for ARF to our ICU between 1995 and 2011, and for whom lung biopsy was performed were included in the study. Lung biopsies were surgical, CT guided, or post-mortem. Histological findings were compared to prebiopsy diagnosis and classified into specific or non-specific diagnosis. Therapeutic impact (or Goldman-class in post-mortem biopsies) was also recorded. RESULTS: Among the 1440 hematology patients with ARF managed during the study period, 21 (1%) biopsies were performed, including 10 post-mortem biopsies. Histological diagnoses were specific in 10 biopsies, non specific in 8 biopsies and lung parenchyma was normal in three patients. In 8/11 (72.7%) alive patients, lung biopsy had lead to therapeutic modifications, including treatment implementation in 5 patients and treatment withdrawal in 3 patients. One out of 10 (10%) patients had minor complications. For the 10 dead patients, only one Goldman-type 1 error was found. CONCLUSION: Diagnostic lung biopsy is rarely needed in hematology patients with ARF. But, it has a 73% therapeutic impact and has overall no major complications. Contribution from post-mortem biopsies seems less relevant.

Kidney biopsy in the critically ill patient, results of a multicentre retrospective case series.

BACKGROUND: The impact of a contributive result of kidney biopsy on the management of patients in the intensive care unit (ICU) has not been extensively investigated yet. METHODS: This was a retrospective study conducted between 2000 and 2011 in five French ICUs. The study included 56 patients. They had at least one non-renal organ failure, as defined by a Sequential Organ Failure Assessment (SOFA) score ≥3 on ICU admission, and kidney biopsy was performed during ICU stay. Kidney samples were obtained by percutaneous (N.=55) or transjugular biopsy (N.=1). RESULTS: The mean Simplified Acute Physiology Score II and total SOFA scores on ICU admission were 52±19 years and 10.3±3.6, respectively. ICU mortality was 23%. The median (interquartile range) time between ICU admission and kidney biopsy was 9 days (5-21). Pathologic findings in the 54 analyzable kidney biopsies were acute tubular necrosis (N.=26), glomerulonephritis (N.=14), acute vascular nephritis (N.=11), acute interstitial nephritis (N.=6), and deposit disease (N.=3). Kidney biopsy was contributive to the management of 40 patients. In 23 of these, new treatments were started, in 13 ongoing treatments were stopped, including four life-sustaining therapies, and in 13 it was decided to start chronic renal replacement. Severe bleeding was observed in 7 patients, with fatal outcome in one case. CONCLUSION: Kidney biopsy may have a significant impact on the management of critically ill patients. Further studies should be done to identify the groups of ICU patients likely to benefit from the procedure with minimum risk.

Dexamethasone in patients with acute lung injury from acute monocytic leukaemia.

The use of steroids is not required in myeloid malignancies and remains controversial in patients with acute lung injury (ALI) or acute respiratory distress syndrome (ARDS). We sought to evaluate dexamethasone in patients with ALI/ARDS caused by acute monocytic leukaemia (AML FAB-M5) via either leukostasis or leukaemic infiltration. Dexamethasone (10 mg every 6 h until neutropenia) was added to chemotherapy and intensive care unit (ICU) management in 20 consecutive patients between 2005 and 2008, whose data were compared with those from 20 historical controls (1994-2002). ICU mortality was the primary criterion. We also compared respiratory deterioration rates, need for ventilation and nosocomial infections. 17 (85%) patients had hyperleukocytosis, 19 (95%) had leukaemic masses, and all 20 had severe pancytopenia. All patients presented with respiratory symptoms and pulmonary infiltrates prior to AML FAB-M5 diagnosis. Compared with historical controls, dexamethasone-treated patients had a significantly lower ICU mortality rate (20% versus 50%; p = 0.04) and a trend for less respiratory deterioration (50% versus 80%; p = 0.07). There were no significant increases in the rates of infections with dexamethasone. In conclusion, in patients with ALI/ARDS related to AML FAB-M5, adding dexamethasone to conventional chemotherapy seemed effective and safe. These results warrant a controlled trial of dexamethasone versus placebo in AML FAB-M5 patients with noninfectious pulmonary infiltrates.

Role of glycolysis in the energy production for the non-mechanical myocardial work in isolated pig hearts.

BACKGROUND: The dissociation of mechanical from non-mechanical energy utilisation can be studied using BDM (2,3-butanedione monoxime), which inhibits the actin-myosin interaction without inhibiting Ca2+ transport. The objective of the present study was to establish if increasing the non-mechanical energy demand of perfused isolated pig hearts by dobutamine stimulation requires glycolysis with increased exogenous glucose uptake. METHODS: Five isolated pig hearts (CTRL) were perfused for 90 min at constant flow (1 ml g(-1) min(-1)) with non-recirculating blood containing 30 mM BDM and 26 MBq/l of fluorine-18 2-fluoro-2-deoxyglucose (IFDG). This was compared with five hearts (DOBU) subjected to the same protocol for the first 30 min and then to dobutamine (1.5 microM) for the following 30 min and dobutamine (4 microM) for the last 30 min. Five other isolated hearts were perfused as for the DOBU group but without BDM (CTRLDOBU). Using a clinical PET scanner, glucose uptake was assessed by estimating 18FDG uptake using linear regression. The slope variations were compared using a global test of coincidence. RESULTS: Heart rate was at 100 +/- 2 b.p.m. in the CTRL group and at 180 +/- 7 b.p.m. in the DOBU group. 18FDG uptake was homogeneous within the whole myocardium and we observed a linear and regular increase in both the CTRL and DOBU groups (p, NS). In the CTRLDOBU group, 18FDG uptake was also homogeneous within the whole myocardium, but slopes of 18FDG uptake during dobutamine perfusion were higher than without dobutamine. CONCLUSION: In blood-perfused isolated pig hearts, exogenous glucose is not necessarily required when non-mechanical energy is increased by dobutamine stimulation. These findings suggest that ATP derived from glycolysis is not necessary to preserve myocardial Ca2+ transport during beta-adrenergic stimulation.

Slaughterhouse blood as a perfusate for studying myocardial function under ischemic conditions.

Metabolic studies using the in vitro non-recirculating blood-perfused isolated heart model require large volumes of blood. The present study was designed to determine whether heterologous pig blood collected from a slaughterhouse can be used as perfusate for isolated pig hearts perfused under aerobic and constant reduced flow conditions. Eight isolated working pig hearts perfused for 90 min at a constant flow of 1.5 ml g(-1) min(-1) with non-recirculated blood diluted with Krebs-Henseleit bicarbonate buffer at a hematocrit of 23% were compared to eight hearts subjected to the same protocol but perfused only with Krebs-Henseleit bicarbonate buffer solution. Hearts were paced at 100 bpm and subjected to aerobic perfusion at 38 degrees C. Hearts were weighed before perfusion and at the end of the experiment and the results are reported as percent weight gain (mean +/- SD). Comparisons between groups were performed by the Student t-test (P<0.05). After 90 min of perfusion with modified Krebs-Henseleit, perfused hearts presented a larger weight gain than blood-perfused hearts (39.34 +/- 9.27 vs 23.13 +/- 5.42%, P = 0.003). Left ventricular end-diastolic pressure was higher in the modified Krebs-Henseleit-perfused group than in the blood group (2.8 +/- 0.4 vs 2.3 +/- 0.3 mmHg, respectively, P = 0.01). We conclude that heterologous blood perfusion, by preserving a more physiological myocardial water content, is a better perfusion fluid than modified Krebs-Henseleit solution for quantitative studies of myocardial metabolism and heart function under ischemic conditions.

Slaughterhouse blood as a perfusate for studying myocardial function under ischemic conditions

Metabolic studies using the in vitro non-recirculating blood-perfused isolated heart model require large volumes of blood. The present study was designed to determine whether heterologous pig blood collected from a slaughterhouse can be used as perfusate for isolated pig hearts perfused under aerobic and constant reduced flow conditions. Eight isolated working pig hearts perfused for 90 min at a constant flow of 1.5 ml g-1 min-1 with non-recirculated blood diluted with Krebs-Henseleit bicarbonate buffer at a hematocrit of 23 percent were compared to eight hearts subjected to the same protocol but perfused only with Krebs-Henseleit bicarbonate buffer solution. Hearts were paced at 100 bpm and subjected to aerobic perfusion at 38ºC. Hearts were weighed before perfusion and at the end of the experiment and the results are reported as percent weight gain (mean ± SD). Comparisons between groups were performed by the Student t-test (P<0.05). After 90 min of perfusion with modified Krebs-Henseleit, perfused hearts presented a larger weight gain than blood-perfused hearts (39.34 ± 9.27 vs 23.13 ± 5.42 percent, P = 0.003). Left ventricular end-diastolic pressure was higher in the modified Krebs-Henseleit-perfused group than in the blood group (2.8 ± 0.4 vs 2.3 ± 0.3 mmHg, respectively, P = 0.01). We conclude that heterologous blood perfusion, by preserving a more physiological myocardial water content, is a better perfusion fluid than modified Krebs-Henseleit solution for quantitative studies of myocardial metabolism and heart function under ischemic conditions

CT pulmonary angiography with a macromolecular contrast medium: a comparative study versus iobitridol in rabbits.

RATIONALE AND OBJECTIVES: To compare the pharmacokinetics of a new macromolecular iodinated contrast medium, prototype P743, with a standard contrast agent (iobitridol) for spiral computed tomography pulmonary angiography in rabbits. METHODS: Manual injection was first used to test the performance of P743 even in cases of nonoptimal bolus timing. Then a protocol was designed to compare vessel enhancement in both first-pass and delayed scans for the two contrast agents with the help of a power injector. RESULTS: With manual fast injection, the first pass of iobitridol was observed only on proximal scans. Conversely, opacification of vessels was maintained during three spiral scans with P743 under the same injection conditions. When optimal bolus timing was performed, higher vessel enhancement was observed during bolus first pass with iobitridol (iodine dosage 250 mg I/kg) compared with P743 (150 mg I/kg). However, during the postbolus phase, the decrease in attenuation values was markedly faster with iobitridol than with P743. CONCLUSIONS: This study confirmed that P743 remains more intravascular than iobitridol, which may have clinical implications for the diagnosis of pulmonary embolism, for example.

MR perfusion imaging using encapsulated laser-polarized 3He.

In this work, the use of a new carrier agent for intravascular laser-polarized 3He imaging is reported. Lipid-based helium microbubbles were investigated. Their average diameter of 3 microm, which is smaller than that of the capillaries, makes it possible to conduct in vivo studies. The NMR relaxation parameters T1, T2, and T2* of a microbubble suspension were measured as 90 s, 300 ms, and 4.5 ms, respectively, and in vivo images of encapsulated 3He with signal-to-noise ratios (SNRs) larger than 30 were acquired. Dynamic cardiac images and vascular images of encapsulated 3He were obtained in rats using intravenous injections of microbubble suspensions. Excellent preservation of 3He polarization through the lung capillaries and heart cavities was observed. The first images of 3He microbubble distributions in the lungs were obtained. Additionally, the potential of this technique for lung perfusion assessment was validated through an experimental embolism model with the visualization of perfusion defects.

SLC-1 receptor mediates effect of melanin-concentrating hormone on feeding behavior in rat: a structure-activity study.

Several studies have shown that melanin-concentrating hormone (MCH) is an orexigenic peptide in rat. In the present study, a structure-activity relationship with MCH analogs was performed in rat, both in vitro and in vivo. On rat recombinant SLC-1 receptor, both cAMP inhibition and [(125)I]S36057 binding were measured. In vivo, these analogs were injected intracerebroventricularly in rats and their effects were evaluated upon food intake. First, data obtained with the rat recombinant receptor were highly correlated with those obtained from its human counterpart. Second, agonist potencies in the cAMP assay were also highly correlated with binding affinities. These peptides could be classified into several groups according to their potency at the SLC-1 receptor (from subnanomolar activity to complete inactivity). Indeed, there was a strong correlation between their effects upon food intake and the results obtained at the rat SLC-1 receptor. The present report describes for the first time the rat SLC-1 receptor pharmacology and clearly establishes the relevance of the SLC-1 receptor in feeding behavior.

Regulation of murine airway responsiveness by endothelial nitric oxide synthase.

Nitric oxide (NO) is a potent vasodilator, but it can also modulate contractile responses of the airway smooth muscle. Whether or not endothelial (e) NO synthase (NOS) contributes to the regulation of bronchial tone is unknown at present. Experiments were designed to investigate the isoforms of NOS that are expressed in murine airways and to determine whether or not the endogenous release of NO modulates bronchial tone in wild-type mice and in mice with targeted deletion of eNOS [eNOS(-/-)]. The presence of neuronal NOS (nNOS), inducible NOS (iNOS), and eNOS in murine trachea and lung parenchyma was assessed by RT-PCR, immunoblotting, and immunohistochemistry. Airway resistance was measured in conscious unrestrained mice by means of a whole body plethysmography chamber. The three isoforms of NOS were constitutively present in lungs of wild-type mice, whereas only iNOS and nNOS were present in eNOS(-/-) mice. Labeling of nNOS was localized in submucosal airway nerves but was not consistently detected, and iNOS immunoreactivity was observed in tracheal and bronchiolar epithelial cells, whereas eNOS was expressed in endothelial cells. In wild-type mice, treatment with N-nitro-L-arginine methyl ester, but not with aminoguanidine, potentiated the increase in airway resistance produced by inhalation of methacholine. eNOS(-/-) mice were hyperresponsive to inhaled methacholine and markedly less sensitive to N-nitro-L-arginine methyl ester. These results demonstrate that the three NOS isoforms are expressed constitutively in murine lung and that NO derived from eNOS plays a physiological role in controlling bronchial airway reactivity.

Localization of the melatonin-related receptor in the rodent brain and peripheral tissues.

Previous studies have provided a limited examination of the expression of the orphan melatonin-related receptor in the pituitary and hypothalamus of human and sheep and retinal tissue in the sheep. The present study reports evidence of conservation of expression in regions of the hypothalamus (dorsal medial hypothalamus, lateral hypothalamus, arcuate nucleus), the epithelial layer lining the third ventricle and the paraventricular thalamic nucleus of the mouse, rat and hamster. An extensive and detailed analysis of melatonin-related receptor mRNA expression in the mouse central nervous system and peripheral tissues is presented. Mapping the distribution throughout the entire mouse brain has revealed new sites of expression in a number of brain nuclei, including preoptic areas, parabrachial nuclei and widespread distribution in the olfactory bulb. Reverse transcriptase-polymerase chain reaction was performed with RNA isolated from peripheral tissues revealing expression of the melatonin-related receptor mRNA in the mouse kidney, adrenal gland, intestine, stomach, heart, lung, skin, testis and ovary. These results suggest a conserved function in neuroendocrine regulation and a potential role in coordinating physiological responses in the central nervous system and peripheral tissues.