Dexamethasone reverses monocrotaline-induced pulmonary arterial hypertension in rats.

Pulmonary arterial hypertension (PAH) is associated with dysregulated bone morphogenetic protein receptor (BMPR)-II signaling and pulmonary vascular inflammation. We evaluated the effects of dexamethasone on monocrotaline (MCT)-induced PAH in rats for potential reversal of PAH at late time-points. Saline-treated control, MCT-exposed, MCT-exposed and dexamethasone-treated rats (5 mg·kg⁻¹·day⁻¹, 1.25 mg·kg⁻¹ and 2.5 mg·kg⁻¹·48 h⁻¹) were evaluated at day 28 and day 35 following MCT for haemodynamic parameters, right ventricular hypertrophy, morphometry, immunohistochemistry, and IL6 and BMPR2 expression. Dexamethasone improved haemodynamics and pulmonary vascular remodelling, preventing PAH development at early (day 1-14 and 1-28) and reversing PAH at late (day 14-28 and 21-35) time-points following MCT, as well as improving survival in MCT-exposed rats compared with controls. Both MCT-induced pulmonary IL6 overexpression and interleukin (IL)-6-expressing adventitial inflammatory cell infiltration were reduced with dexamethasone. This was associated with pulmonary BMPR2 downregulation following MCT, which was increased with dexamethasone, in whole lung and control pulmonary artery smooth muscle cells. Dexamethasone also reduced proliferation of rat pulmonary artery smooth muscle cells in vitro. Experimental PAH can be prevented and reversed by dexamethasone, and survival is improved. In this model, mechanisms may involve reduction of IL-6-expressing inflammatory cells, restoration of pulmonary BMPR2 expression and reduced proliferation of vascular smooth muscle cells.

Two new frog species from the Litoria rubella species group from eastern Australia.

The bleating tree frog (Litoria dentata) is one of the more prominent pelodryadid frogs of eastern Australia by virtue of its extremely loud, piercing, male advertisement call. A member of the Litoria rubella species group, L. dentata has a broad latitudinal distribution and is widespread from coastal and subcoastal lowlands through to montane areas. A recent mitochondrial DNA analysis showed a deep phylogeographic break between populations of L. dentata on the mid-north coast of New South Wales. Here we extended the mitochondrial survey with more geographically comprehensive sampling and tested the systematic implications of our findings with nuclear genome wide single-nucleotide polymorphism, morphological and male advertisement call datasets. While similar in appearance and in male advertisement call, our integrative analysis demonstrates the presence of three species which replace each other in a north-south series. We redescribe Litoria dentata, which is restricted to coastal north-eastern New South Wales, and formally describe Litoria balatus sp. nov., from south-eastern Queensland, and Litoria quiritatus sp. nov., from the mid-coast of New South Wales to north-eastern Victoria.

Noncardiothoracic nonobstetric surgery in mild-to-moderate pulmonary hypertension.

The anaesthetic management and follow-up of well-characterised patients with pulmonary arterial hypertension presenting for noncardiothoracic nonobstetric surgery has rarely been described. The details of consecutive patients and perioperative complications during the period January 2000 to December 2007 were reviewed. Repeat procedures in duplicate patients were excluded. Longer term outcomes included New York Heart Association (NYHA) functional class, 6-min walking distance and invasive haemodynamics. A total of 28 patients were identified as having undergone major (57%) or minor surgery under general (50%) and regional anaesthesia. At the time of surgery, 75% of patients were in NYHA functional class I-II. Perioperative deaths occurred in 7%. Perioperative complications, all related to pulmonary hypertension, occurred in 29% of all patients and in 17% of those with no deaths during scheduled procedures. Most (n = 11, 92%) of the complications occurred in the first 48 h following surgery. In emergencies (n = 4), perioperative complication and death rates were higher (100 and 50%, respectively; p<0.005). Risk factors for complications were greater for emergency surgery (p<0.001), major surgery (p = 0.008) and a long operative time (193 versus 112 min; p = 0.003). No significant clinical or haemodynamic deterioration was seen in survivors at 3-6 or 12 months of post-operative follow-up. Despite optimal management in this mostly nonsevere pulmonary hypertension population, perioperative complications were common, although survivors remained stable. Emergency procedures, major surgery and long operations were associated with increased risk.

Prognostic factors of acute heart failure in patients with pulmonary arterial hypertension.

Acute right ventricular failure in the setting of pulmonary arterial hypertension (PAH) often requires hospitalisation in intensive care units (ICU) to manage the subsequent low cardiac output and its consequences. There are very few data on these acute events. We recorded demographic, clinical and biological data and therapy in consecutive patients suffering from acute right heart failure requiring catecholamine treatment in the ICU of the French referral centre for pulmonary hypertension. These variables were analysed according to the survival status in ICU. 46 patients were included, the mean age was 50.3 yrs. ICU mortality was 41%. We found no difference in terms of demographics, clinical data, last haemodynamic measurements at admission. Systemic arterial pressure was significantly lower in the subgroup of patients whose clinical course was fatal. Plasma brain natriuretic peptide (BNP), C-reactive protein (CRP), serum sodium and creatinine at admission correlated with survival. Demonstration of an infection during the ICU stay was associated with a worse prognosis. These preliminary results underline the importance of some simple clinical and biological parameters in the prognostic evaluation of acute heart failure in the setting of PAH. Whether these parameters can guide therapy needs to be further investigated.

Pulmonary veno-occlusive disease.

Pulmonary veno-occlusive disease (PVOD) is currently classified as a subgroup of pulmonary arterial hypertension (PAH) and accounts for 5-10% of cases initially considered to be idiopathic PAH. PVOD has been described as idiopathic or complicating other conditions, including connective tissue diseases, HIV infection, bone marrow transplantation, sarcoidosis and pulmonary Langerhans cell granulomatosis. PVOD shares broadly similar clinical presentation, genetic background and haemodynamic characteristics with PAH. Compared to PAH, PVOD is characterised by a higher male/female ratio, higher tobacco exposure, lower arterial oxygen tension at rest, lower diffusing capacity of the lung for carbon monoxide, and lower oxygen saturation nadir during the 6-min walk test. High-resolution computed tomography (HRCT) of the chest can be suggestive of PVOD in the presence of centrilobular ground-glass opacities, septal lines and lymph node enlargement. Similarly, occult alveolar haemorrhage is associated with PVOD. A noninvasive diagnostic approach using HRCT of the chest, arterial blood gases, pulmonary function tests and bronchoalveolar lavage could be helpful for the detection of PVOD patients and in avoiding high-risk surgical lung biopsy for histological confirmation. PVOD is characterised by a poor prognosis and the possibility of developing severe pulmonary oedema with specific PAH therapy. Lung transplantation is the treatment of choice. Cautious use of specific PAH therapy can, however, be helpful in some patients.

Cautious epoprostenol therapy is a safe bridge to lung transplantation in pulmonary veno-occlusive disease.

Pulmonary veno-occlusive disease (PVOD) carries a poor prognosis and lung transplantation is the only curative treatment. In PVOD, epoprostenol therapy is controversial, as this condition may be refractory to specific therapy with an increased risk of pulmonary oedema. We retrospectively reviewed clinical, functional and haemodynamic data of 12 patients with PVOD (10 with histological confirmation) treated with continuous intravenous epoprostenol and priority listed for lung transplantation after January 1, 2003. All PVOD patients had severe clinical, functional and haemodynamic impairment at presentation. Epoprostenol was used at low dose ranges with slow dose increases and high dose diuretics. Only one patient developed mild reversible pulmonary oedema. After 3-4 months, improvements were seen in the New York Heart Association functional class (class IV to III in seven patients), cardiac index (1.99+/-0.68 to 2.94+/-0.89 L x min(-1) x m(-2)) and indexed pulmonary vascular resistance (28.4+/-8.4 to 17+/-5.2 Wood units x m(-2); all p<0.01). A nonsignificant improvement in the 6-min walk distance was also observed (+41 m, p = 0.11). Two patients died, one patient was alive on the transplantation waiting list on December 1, 2008 and nine patients were transplanted. Cautious use of continuous intravenous epoprostenol improved clinical and haemodynamic parameters in PVOD patients at 3-4 months without commonly causing pulmonary oedema, and may be a useful bridge to urgent lung transplantation.

Natural marine oil seepage.

The probable range of seepage into the marine environment is 0.2 x 10(6) to 6.0 x 10(6) metric tons per year. Within this range the best estimate for the present marine seepage worldwide is on the order of 0.6 x 10(6) metric tons per year. This estimate is based on the presumption that only a few other areas around the world are as seepage-prone as southern California. Measurements of seeps and seepage rates are too few to allow an accurate estimation by observation and measurement techniques alone. Seepage potential can, however, be related to geologic criteria, and these provide sound bases for marine seepage assessment. On the basis of this estimate, areas of high seepage potential contribute about 45 percent of the worldwide seepage, areas of moderate seepage about 55 percent, and areas of low seepage less than 1 percent. The situation varies somewhat from ocean to ocean. In the Pacific Ocean, areas of high seep potential are by far the major contributors. In the Atlantic, Indian, Arctic, and Southern oceans, areas of moderate seep potential are most significant because areas of high seep potential are relatively rare in these realnis. The circum-Pacific area is the area of greatest seepage; it contributes about 40 percent of the world's total.

Fatal rupture of pulmonary arteriovenous malformation in hereditary haemorrhagic telangiectasis and severe PAH.

A 29-yr-old patient with hereditary haemorrhagic telangiectasia was referred to the present authors' centre with progressive exertional dyspnoea. Pulmonary arterial hypertension (PAH) was suspected on Doppler echocardiography and confirmed by right heart catheterisation demonstrating severe PAH. Genetic analysis found an activin receptor-like kinase-1 gene missense mutation. Chest radiography and computed tomodensitometry of the chest revealed a pulmonary arteriovenous malformation with a 5-mm diameter feeding artery in the right lower lobe. Embolisation of the arteriovenous malformation was discussed, but was considered a very high-risk procedure that could aggravate PAH and was therefore not performed. Haemodynamics were improved by dual endothelin receptor antagonist and inhaled iloprost but the patient subsequently died suddenly of a rupture of the arteriovenous malformation into the pleural cavity. Severe PAH is generally considered a contraindication to performing pulmonary arteriovenous malformation embolisation because of the risk of worsening of PAH. However, given the significant risk of rupture, paradoxical embolism and haemoptysis, and the lack of data regarding the evolution of pulmonary pressure after embolisation in PAH, pulmonary arteriovenous malformation embolisation should not be absolutely contraindicated and might be considered in patients with stable PAH.

Use of vasopressin after Caesarean section in idiopathic pulmonary arterial hypertension.

We report the successful use of vasopressin in the management of hypotension in association with severe right ventricular (RV) failure in two patients with advanced idiopathic pulmonary arterial hypertension. Both patients were pregnant and developed systemic hypotension after delivery by Caesarean section. Placental autotransfusion and possibly oxytocin use were thought to be the major contributing factors in worsening RV function. After the use of vasopressin in both patients, cardiovascular variables improved without untoward effect on RV function, and provided rescue therapy for systemic hypotension in this setting. Vasopressin, a direct vasopressor acting via V1 receptors on the vascular endothelium, has been shown to cause pulmonary vasodilatation experimentally and in animal models of pulmonary hypertension. Its synthetic analogue, terlipressin, has been shown to reduce pulmonary vascular resistance in humans with cirrhosis. Vasopressin may therefore have differential effects on the pulmonary and systemic circulations, allowing systemic pressure to be supported without detrimental effects on the pulmonary circulation.

UK National COPD Audit 2003: Impact of hospital resources and organisation of care on patient outcome following admission for acute COPD exacerbation.

BACKGROUND: Acute chronic obstructive pulmonary disease (COPD) exacerbations use many hospital bed days and have a high rate of mortality. Previous audits have shown wide variability in the length of stay and mortality between units not explained by patient factors. This study aimed to explore associations between resources and organisation of care and patient outcomes. METHODS: 234 UK acute hospitals each prospectively identified 40 consecutive acute COPD admissions, documenting process of care and outcomes from a retrospective case note audit. Units also completed a resources and organisation of care proforma. RESULTS: Data for 7529 patients were received. Inpatient mortality was 7.4% and mortality at 90 days was 15.3%; the readmission rate was 31.4%. Mean length of stay for discharged patients was 8.7 days (median 6 days). Wide variation was observed in all outcomes between hospitals. Both inpatient mortality (odds ratio (OR) 0.67, CI 0.50 to 0.90) and 90 day mortality (OR 0.75, CI 0.60 to 0.94) were associated with a staff ratio of four or more respiratory consultants per 1000 hospital beds. The length of stay was reduced in units with more respiratory consultants, better organisation of care scores, an early discharge scheme, and local COPD management guidelines. CONCLUSIONS: Units with more respiratory consultants and better quality organised care have lower mortality and reduced length of hospital stay. This may reflect unit resource richness. Dissemination of good organisational practice and recruitment of more respiratory specialists offers the potential for improved outcomes for hospitalised COPD patients.

Special housing needs of the elderly patient.

The physician is increasingly asked to play a role in relocating elderly patients to special housing. The goal is to find the housing that is best suited to the patient's needs. Important factors to be considered are building design, sponsorship, financing and nonshelter services. Proper housing, with appropriate support services, enables the elderly to remain independent longer and contributes to their physical and mental health.

Constraints on the origins of hydrocarbon gas from compositions of gases at their site of origin

It is widely accepted that natural gas is formed from thermal decomposition of both oil in reservoirs and, to a lesser extent, the organic matter in shales from which the oil was derived. But laboratory pyrolysis experiments on shales do not reproduce the methane-rich composition typical of most gas reservoirs, leading to suggestions that other mechanisms, such as transition-metal catalysis, may be important. The discrepancy might, however, instead arise because gas (and oil) deposits have migrated from their source rocks, so that the reservoir composition might not be representative of the composition in the source rocks where the hydrocarbons were generated. To address this question, we have analysed gas samples coproduced with oils directly from a source rock (the Bakken shales, North Dakota, USA) where the local geology has prevented significant hydrocarbon migration. The methane contents of these Bakken-shale gases are much lower than that of conventional gas reservoirs, but are consistent with that from pyrolysis experiments on these shales. Thus, because these Bakken gases form with (rather than from) oils, we argue that compositional differences between gases from source rocks and conventional gas deposits result from fractionation processes occurring after hydrocarbon expulsion from the source rock.