Dietary pulmonary hypertension

1,2-Dehydropyrrolizidine Alkaloids: Their Potential as a Dietary Cause of Sporadic Motor Neuron Diseases

Sporadic motor neuron diseases (MNDs), such as amyotrophic lateral sclerosis (ALS), can be caused by spontaneous genetic mutations. However, many sporadic cases of ALS and other debilitating neurodegenerative diseases (NDDs) are believed to be caused by environmental factors, subject to considerable debate and requiring intensive research. A common pathology associated with MND development involves progressive mitochondrial dysfunction and oxidative stress in motor neurons and glial cells of the central nervous system (CNS), leading to apoptosis. Consequent degeneration of skeletal and respiratory muscle cells can lead to death from respiratory failure. A significant number of MND cases present with cancers and liver and lung pathology. This Perspective explores the possibility that MNDs could be caused by intermittent, low-level dietary exposure to 1,2-dehydropyrrolizidine alkaloids (1,2-dehydroPAs) that are increasingly recognized as contaminants of many foods consumed throughout the world. Nontoxic, per se, 1,2-dehydroPAs are metabolized, by particular cytochrome P450 (CYP450) isoforms, to 6,7-dihydropyrrolizines that react with nucleophilic groups (-NH, -SH, -OH) on DNA, proteins, and other vital biochemicals, such as glutathione. Many factors, including aging, gender, smoking, and alcohol consumption, influence CYP450 isoform activity in a range of tissues, including glial cells and neurons of the CNS. Activation of 1,2-dehydroPAs in CNS cells can be expected to cause gene mutations and oxidative stress, potentially leading to the development of MNDs and other NDDs. While relatively high dietary exposure to 1,2-dehydroPAs causes hepatic sinusoidal obstruction syndrome, pulmonary venoocclusive disease, neurotoxicity, and diverse cancers, this Perspective suggests that, at current intermittent, low levels of dietary exposure, neurotoxicity could become the primary pathology that develops over time in susceptible individuals, along with a tendency for some of them to also display liver and lung pathology and diverse cancers co-occurring with some MND/NDD cases. Targeted research is recommended to investigate this proposal.

Pulmonary Arterial Hypertension Secondary to Drugs and Toxins

Pulmonary arterial hypertension secondary to drugs and toxins is an important subgroup of group 1 pulmonary hypertension associated with significant morbidity and mortality. Many drugs and toxins have emerged as risk factors for pulmonary arterial hypertension, which include anorexigens, illicit agents, and several US Food and Drug Administration-approved therapeutic medications. Drugs and toxins are classified as possible or definite risk factors for pulmonary arterial hypertension. This article reviews agents that have been implicated in the development of pulmonary arterial hypertension, their pathologic mechanisms, and methods to prevent the next deadly outbreak of drug- and toxin-induced pulmonary arterial hypertension.

DARK Classics in Chemical Neuroscience: Aminorex Analogues

Aminorex (5-phenyl-4,5-dihydro-1,3-oxazol-2-amine) and 4-methylaminorex (4-methyl-5-phenyl-4,5-dihydro-1,3-oxazol-2-amine) are psychostimulants that have long been listed in Schedules IV and I of the UN Convention on Psychotropic Substances of 1971. However, a range of psychoactive analogues exist that are not internationally controlled and therefore often classified as new psychoactive substances (NPS). Aminorex analogues encompass failed pharmaceuticals that reemerged as drugs of abuse, and newly synthesized substances that were solely designed for recreational use by clandestine chemists. NPS, sometimes also referred to as "designer drugs" in alignment with a phenomenon arising in the early 1980s, serve as alternatives to controlled drugs. Aminorex and its derivatives interact with monoaminergic neurotransmission by interfering with the function of monoamine transporters. Hence, these compounds share pharmacological and neurochemical similarities with amphetamines and cocaine. The consumption of aminorex, 4-methylaminorex and 4,4'-dimethylaminorex (4-methyl-5-(4-methylphenyl)-4,5-dihydro-1,3-oxazol-2-amine) has been associated with adverse events including death, bestowing an inglorious fame on aminorex-derived drugs. In this Review, a historical background is presented, as well as an account of the pharmacodynamic and pharmacokinetic properties of aminorex and various analogues. Light is shed on their misuse as drug adulterants of well-established drugs on the market. This Review not only provides a detailed overview of an abused substance-class, but also emphasizes the darkest aspect of the NPS market, i.e., deleterious side effects that arise from the ingestion of certain NPS, as knowledge of the pharmacology, the potency, or the identity of the active ingredients remains obscure to NPS users.

Cardiac Pharmacology and Cardiomyopathy in Friedreich's Ataxia

Friedreich's ataxia is almost always associated with a cardiomyopathy. The cardiomyopathy and its attendant cardiopulmonary sequelae is the usual cause of death in this disease. The author reviews the known pharmacology of the heart, particularly as it applies to hypertrophic cardiomyopathy. The important role played by calcium and the possible role of taurine is stressed. Therapeutic possibilities are mentioned.

Pyrrolizidine Alkaloids: Potential Role in the Etiology of Cancers, Pulmonary Hypertension, Congenital Anomalies, and Liver Disease

Large outbreaks of acute food-related poisoning, characterized by hepatic sinusoidal obstruction syndrome, hemorrhagic necrosis, and rapid liver failure, occur on a regular basis in some countries. They are caused by 1,2-dehydropyrrolizidine alkaloids contaminating locally grown grain. Similar acute poisoning can also result from deliberate or accidental consumption of 1,2-dehydropyrrolizidine alkaloid-containing herbal medicines, teas, and spices. In recent years, it has been confirmed that there is also significant, low-level dietary exposure to 1,2-dehydropyrrolizidine alkaloids in many countries due to consumption of common foods such as honey, milk, eggs, salads, and meat. The level of 1,2-dehydropyrrolizidine alkaloids in these foods is generally too low and too intermittent to cause acute toxicity. However, these alkaloids are genotoxic and can cause slowly developing chronic diseases such as pulmonary arterial hypertension, cancers, cirrhosis, and congenital anomalies, conditions unlikely to be easily linked with dietary exposure to 1,2-dehydropyrrolizidine alkaloids, especially if clinicians are unaware that such dietary exposure is occurring. This Perspective provides a comprehensive review of the acute and chronic toxicity of 1,2-dehydropyrrolizidine alkaloids and their potential to initiate certain chronic diseases, and suggests some associative considerations or indicators to assist in recognizing specific cases of diseases that may have resulted from dietary exposure to these hazardous natural substances. If it can be established that low-level dietary exposure to 1,2-dehydropyrrolizidine alkaloids is a significant cause of some of these costly and debilitating diseases, then this should lead to initiatives to reduce the level of these alkaloids in the food chain.

Pyrrolizidine alkaloids in food: a spectrum of potential health consequences

Contamination of grain with 1,2-dehydropyrrolizidine ester alkaloids (dehydroPAs) and their N-oxides is responsible for large incidents of acute and subacute food poisoning, with high morbidity and mortality, in Africa and in central and south Asia. Herbal medicines and teas containing dehydroPAs have also caused fatalities in both developed and developing countries. There is now increasing recognition that some staple and widely consumed foods are sometimes contaminated by dehydroPAs and their N-oxides at levels that, while insufficient to cause acute poisoning, greatly exceed maximum tolerable daily intakes and/or maximum levels determined by a number of independent risk assessment authorities. This suggests that there may have been cases of disease in the past not recognised as resulting from dietary exposure to dehydroPAs. A review of the literature shows that there are a number of reports of liver disease where either exposure to dehydroPAs was suspected but no source was identified or a dehydroPA-aetiology was not considered but the symptoms and pathology suggests their involvement. DehydroPAs also cause progressive, chronic diseases such as cancer and pulmonary arterial hypertension but proof of their involvement in human cases of these chronic diseases, including sources of exposure to dehydroPAs, has generally been lacking. Growing recognition of hazardous levels of dehydroPAs in a range of common foods suggests that physicians and clinicians need to be alert to the possibility that these contaminants may, in some cases, be a possible cause of chronic diseases such as cirrhosis, pulmonary hypertension and cancer in humans.

Hepatotoxicity associated with herbal products

A significant number of herbal products have been associated with hepatotoxicity. Attribution of liver injury to a specific herbal pro-duct may be difficult. There are few clinical or laboratory manifestations that specifically suggest that liver injury is the result of aspecific herbal. Compounding this difficulty is that the patient may have liver disease from another cause, may be consuming other potentially hepatotoxic products, or may be using a contaminated herbal product. The most important clue often is the temporal relationship between initiation of the herbal product and the appearance of liver injury; of equal importance is the resolution of the injury following withdrawal of the herbal product.

Hemodynamics and survival of patients with portopulmonary hypertension

It is not known whether patients with pulmonary arterial hypertension associated with portal hypertension (portopulmonary hypertension (PPHTN) have different disease characteristics from those of patients with other forms of pulmonary arterial hypertension. We performed a retrospective cohort study of patients with PPHTN and patients with pulmonary arterial hypertension that was idiopathic, familial, or associated with anorexigen use (IPAH) to determine whether hemodynamics or survival were different between these groups. We included consecutive patients who underwent initial pulmonary artery catheterization and vasodilator testing at our center between January 1997 and May 2001 and who were followed until January 2004. Patients with PPHTN (N = 13) had a higher cardiac index and lower pulmonary vascular resistance than patients with IPAH (N = 33) (P < or = 0.001). Right atrial pressure and pulmonary artery pressure were similar between the groups. Patients with PPHTN had a higher risk of death in multivariate analysis (hazard ratio: [HR] = 2.8, 95% CI 1.04-7.4; P = 0.04). These findings were not affected by adjustment for differences in laboratory values, hemodynamics, or therapy. In conclusion, patients with PPHTN have a higher risk of death than that of patients with IPAH, despite having a higher cardiac index and lower pulmonary vascular resistance. Future studies of the specific mechanisms of and therapy for pulmonary arterial hypertension should focus on the distinctions between the different forms of this disease.

Medical therapy for pulmonary arterial hypertension: ACCP evidence-based clinical practice guidelines

Pulmonary arterial hypertension (PAH) is often difficult to diagnose and challenging to treat. Untreated, it is characterized by a progressive increase in pulmonary vascular resistance leading to right ventricular failure and death. The past decade has seen remarkable improvements in therapy, driven largely by the conduct of randomized controlled trials. Still, the selection of most appropriate therapy is complex, and requires familiarity with the disease process, evidence from treatment trials, complicated drug delivery systems, dosing regimens, side effects, and complications. This chapter will provide evidence-based treatment recommendations for physicians involved in the care of these complex patients. Due to the complexity of the diagnostic evaluation required, and the treatment options available, it is strongly recommended that consideration be given to referral of patients with PAH to a specialized center.

Clinical classification of pulmonary hypertension

Pulmonary hypertension is a prevalent disease of multiple etiologies. Over the years, different attempts at nomenclature and classification, largely based on morphologic findings at autopsy, have met with limited success. Recent advances in medical and surgical treatment, and the promise of effective approaches to prevention, have prompted the development of a clinical classification designed to take advantage of the new promising interventions. This article traces the growth of understanding of the pulmonary hypertensive diseases that has enabled the development of a clinical classification oriented towards prevention and treatment.

Primary pulmonary hypertension in Israel: a national survey

OBJECTIVES

To characterize the incidence of patients with primary pulmonary hypertension (PPH) in Israel and their outcomes.

METHODS

We have evaluated retrospectively all the patients in Israel in whom PPH was diagnosed between the years 1988 and 1997. We looked at medical history, hemodynamic data, pulmonary function and gas exchange, and demographic variables. Patients were followed up for survival until November 1997. Life table analysis and Kaplan-Meier statistics were used to estimate the overall survival distribution. Regression analysis was used to examine the relations between survival and selected variables.

RESULTS

Overall, we found 44 patients with PPH. The estimated incidence of PPH in Israel is 1.4 new cases per year per million population. The mean (+/- SD) age at diagnosis was 43 +/- 13 years. In the Jewish population, PPH was more frequent among immigrants from Europe and the United States. The mean interval from the onset of symptoms to diagnosis was 3 years (median, 2 years). The median survival time was 4 years. The 1-year, 3-year, and 5-year survival rates were 82%, 57%, and 43%, respectively. The major variables influencing the survival rate were the following: interval from symptom onset to diagnosis; and hemodynamic measurements (ie, mean pulmonary artery pressure, mean right atrial pressure, and cardiac index). In comparison to rates discerned from the National Institutes of Health registry data, the survival rate in Israel is somewhat better and prognosis is influenced by similar hemodynamic variables.

CONCLUSION

PPH is a rare and fatal disease in Israel. New therapeutic modalities such as prostacyclin therapy and lung transplantation may improve survival among patients with this malignant disease.

Pulmonary vascular sclerosis in an albino rat with leukemia

The animal investigated was a two years old male control Sprague-Dawley rat which died spontaneously during a carcinogenicity study. Post-mortem examination disclosed hepatic and splenic enlargement. At microscopical examination, massive leucaemic infiltration was observed in many tissues/organs, including bone marrow, spleen, liver and renal blood vessels. A very unusual finding was observed in the lung, consisting of scattered micronodules which replaced most of the lung parenchyma. They contained collagen, displaying a somewhat circular distribution at the periphery of the lesions, fibrin, leukemic cells and fibroblasts. Immunostaining for desmin revealed the presence of smooth muscle fibers within the nodules, while staining for elastic fibers showed clearly that the internal and external elastic membranes were identifiable within the nodules. The diagnosis of pulmonary vascular sclerosis was made on the basis of microscopical and immunohistochemical findings.

Primary pulmonary hypertension

Primary pulmonary hypertension (PPH) is a progressive disease characterised by raised pulmonary vascular resistance, which results in diminished right-heart function due to increased right ventricular afterload. PPH occurs most commonly in young and middle-aged women; mean survival from onset of symptoms is 2-3 years. The aetiology of PPH is unknown, although familial disease accounts for roughly 10% of cases, which suggests a genetic predisposition. Current theories on pathogenesis focus on abnormalities in interaction between endothelial and smooth-muscle cells. Endothelia-cell injury may result in an imbalance in endothelium-derived mediators, favouring vasoconstriction. Defects in ion-channel activity in smooth-muscle cells in the pulmonary artery may contribute to vasoconstriction and vascular proliferation. Diagnostic testing primarily excludes secondary causes. Catheterisation is necessary to assess haemodynamics and to evaluate vasoreactivity during acute drug challenge. Decrease in pulmonary vascular resistance in response to acute vasodilator challenge occurs in about 30% of patients, and predicts a good response to chronic therapy with oral calcium-channel blockers. For patients unresponsive during acute testing, continuous intravenous epoprostenol (prostacyclin, PGI2) improves haemodynamics and exercise tolerance, and prolongs survival in severe PPH (NYHA functional class III-IV). Thoracic transplantation is reserved for patients who fail medical therapy. We review the progress made in diagnosis and treatment of PPH over the past 20 years.

Pulmonary hypertension in chronic liver disease

Pulmonary hypertension develops in approximately 2% of patients with portal hypertension. Diagnosis is often difficult and requires a high degree of clinical suspicion. Treatment of patients with portal and pulmonary hypertension is limited, and mean survival following diagnosis is approximately 15 months. The effect of liver transplantation on the natural history of disease is discussed.

Pulmonary vasculitis with hypereosinophilia and episodic pulmonary hypertension: report of three siblings

Three siblings with eosinophilia who developed pulmonary hypertension are reported. They consisted of a 3 year old boy (case 1), a 9 year old boy (case 2) and a 13 year old girl (case 3), all of whom died within an 18 month period of severe episodic attacks of pulmonary hypertension and the resultant low cardiac output. Marked peripheral eosinophilia was found in cases 1 and 2, and mild eosinophilia in case 3. Open lung biopsy of case 1 revealed pulmonary arteritis with massive eosinophilic infiltration and intimal thickening of muscular arteries of 300-1500 microns in diameter. At autopsy, cases 2 and 3 showed almost similar findings, comprising widespread obliteration of the pulmonary arteries by concentric intimal thickening, medial hypertrophy and recanalized thrombi of arterioles. Rarely, there were foci of granulomas in the thickened intima surrounding birefringent foreign bodies. There were small areas of infarction in the lungs and heart due to arterial thrombi. Vascular lesions other than those in the lungs were mild and almost limited to the branches of the coronary arteries. Therefore, the present cases appear to be a single disease of pulmonary hypertension secondary to endothelial injury and the resultant intimal fibrosis probably evoked by toxic substances, although such agents were not confirmed.

Dietary pulmonary hypertension

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Exploration of the pulmonary circulation. Festschrift to Professor Donald Heath

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Pulmonary hypertension associated with portal hypertension in a child with Williams syndrome--a case report

A 14-year-old white female with Williams syndrome and portal hypertension presented in shock; at autopsy she was found to have grade II to VI vascular changes of pulmonary hypertension. This case demonstrates the association of portal hypertension and pulmonary hypertension in a pediatric patient.

Primary idiopathic pulmonary hypertension complicated by pulmonary arterial thrombosis. Association with antiphospholipid antibodies

OBJECTIVE

We report an unusual case of primary pulmonary hypertension and review the pertinent literature.

METHODS

A 25-year-old Caucasian woman presented with progressive dyspnea and was found to have pulmonary hypertension. Antiphospholipid antibodies were present. The patient had a prolonged hospital course, was unresponsive to therapy, and died suddenly.

RESULTS

Postmortem examination revealed a large thrombus affecting the right main pulmonary artery, with plexogenic arteriopathy bilaterally.

CONCLUSION

This appears to be the first reported case of primary pulmonary hypertension complicated by thrombosis of a main pulmonary artery in association with antiphospholipid antibodies.

Pulmonary hypertension associated with portal hypertension in childhood. Case report of a 6-year-old child and review of the literature

Pulmonary hypertension is a rare complication of portal hypertension. Reports of childhood cases especially rare. This report describes an autopsy case of a 6-year-old boy with congenital biliary atresia followed by liver cirrhosis in whom severe hypertensive pulmonary arterial changes, including medial hypertrophy, intimal fibrosis and plexiform lesions were demonstrated. Fresh and organizing fibrin-platelet thrombi as well as probable organized thrombi with recanalization were occasionally found in the pulmonary vasculature, but it was thought that they had probably been formed locally as a late complication rather than being of thromboembolic origin. Retrospectively, the chest roentgenograms had revealed abnormalities suggestive of pulmonary hypertension since infancy, but the patient showed no apparent symptoms of it during life. Previously reported childhood cases of pulmonary hypertension associated with portal hypertension were briefly reviewed. Although the mechanism is presently not known, it is suggested that patients with portal hypertension, even in early childhood, are at risk of developing this unusual complication.

Polymorphic debrisoquine and mephenytoin hydroxylation in patients with pulmonary hypertension of vascular origin after aminorex fumarate

During the period 1967 to 1971 an increase in the incidence of pulmonary hypertension of vascular origin (PHVO) was observed in Austria, Federal Republic of Germany, and Switzerland. Most patients had been given aminorex fumarate and a possible link was suspected. We therefore investigated the possibility of genetically-determined drug hydroxylation deficiencies (debrisoquine or mephenytoin type) in these patients as an explanation for the development of PHVO. Seventeen patients took 10 mg debrisoquine and 100 mg mephenytoin orally. Sixteen PHVO patients were classified as extensive metabolizers of debrisoquine with logarithmic metabolic ratios of -0.35 +/- 0.11 (mean +/- SEM), whereas one patient was a poor metabolizer with a logarithmic metabolic ratio of 1.82. For the mephenytoin hydroxylation sixteen patients with PHVO were extensive metabolizers, with logarithmic hydroxylation indices of 0.27 +/- 0.05. One poor metabolizer of mephenytoin had a logarithmic hydroxylation index of 1.59. Deficient hydroxylation of debrisoquine and mephenytoin was found in two different patients. The prevalence of poor metabolizers among patients with PHVO after aminorex fumarate was therefore approximately 9% for both debrisoquine and mephenytoin. This corresponds closely to the data of our reference population study where genetic debrisoquine and mephenytoin hydroxylation deficiencies occurred independently, with a prevalence of 10% and 5% respectively. Thus, the normal prevalence of extensive drug hydroxylation phenotypes in patients with PHVO is not consistent with the hypothesis that the development of PHVO after aminorex fumarate might be related to a pharmacogenetically determined impairment of polymorphic drug oxidation.

An epidemic of pulmonary hypertension after toxic rapeseed oil ingestion in Spain

The cardiac profile of 38 patients readmitted to the hospital with the clinical and radiologic findings of pulmonary artery hypertension and right ventricular failure 2 months after ingestion of toxic rapeseed oil was determined with M-mode and two-dimensional echocardiography, pulsed Doppler flow studies and right and left heart catheterization and ventriculography. The echocardiogram and pulsed Doppler recordings revealed right ventricular enlargement in 84% of the patients, indirect evidence of pulmonary artery hypertension in 76% and tricuspid insufficiency in 13%. At cardiac catheterization (n = 11) the mean (+/- standard deviation) pulmonary artery pressure was 40 +/- 9 mm Hg, mean pulmonary systemic vascular resistance ratio was 0.45 +/- 0.12 and mean right ventricular end-diastolic pressure was 13 +/- 4 mm Hg. Pulmonary artery hypertension was sustained after the acute administration of 100% oxygen and persisted in six patients who were restudied within 6 months. Cardiac index and left heart pressures were normal in all but one patient. The contrast ventriculographic studies revealed right ventricular dilation in all patients, tricuspid regurgitation in three patients and a normal left ventricular contraction pattern in all but one patient. The data confirm that symptomatic pulmonary artery hypertension and associated right ventricular dysfunction can complicate toxic rapeseed oil ingestion and that these findings persist for at least 6 months.

Estimated intakes of pyrrolizidine alkaloids by humans. A comparison with dose rates causing tumors in rats

Pyrrolizidine alkaloid poisoning in humans is associated with the consumption of plants containing the alkaloids, either as contaminants of grains or as infusions for medicinal purposes. The alkaloids are carcinogenic in rats but have not been associated, so far, with tumors in humans. For the known instances of human intake of pyrrolizidine alkaloids, the main alkaloids involved and estimated consumption rates have been tabulated. These rates are compared with the dose rates of the same or similar alkaloids that lead to a significant tumor incidence in experimental rats. In the more chronic poisoning outbreaks, the intake rate is comparable with a carcinogenic dose in rats. The long-term observation of survivors of these outbreaks would offer an opportunity for determining whether pyrrolizidine alkaloids are carcinogenic in humans.

Determination of serotonin, its precursors, metabolites and [3H] serotonin in lung by high-performance liquid chromatography with fluorescence detection

A rapid, simple, sensitive method for the determination of serotonin, its precursors, metabolites and [3H] serotonin in lung is described. Tissue preparation requires only homogenization in dilute perchloric acid and centrifugation prior to separation by high performance liquid chromatography using a reversed-phase column. Detection is based on the native fluorescence of indole compounds and detection limits ranged between 30-90 pg injected. The method has been used to determine these compounds in mouse lung and plasma.

Severe pulmonary hypertension associated with macronodular (postnecrotic) cirrhosis and autoimmune phenomena

The clinical and pathologic findings are reported in seven consecutive patients with progressive and fatal pulmonary hypertension which was not explained by predisposing cardiac or pulmonary diseases. Pulmonary arterial lesions consisted of atherosclerosis of the elastic pulmonary arteries, and medial hypertrophy and concentric laminar fibrosis of the muscular pulmonary arteries in seven patients, plexiform lesions in six patients and necrotizing vasculitis in one patient. Pulmonary emboli were not identified. Five patients had manifestations of autoimmune disease, including laboratory abnormalities (positive antinuclear antibody, positive latex agglutination for rheumatoid factor, hypergammaglobulinemia or antimitochondrial antibody) in four, necrotizing vasculitis in one, Raynaud's phenomenon in two and clinical evidence of multisystem collagen vascular disease in two. Five patients had liver disease which developed prior to or concomitant with the onset of pulmonary hypertension. At autopsy, one patient had prominent periportal fibrosis and four had macronodular (postnecrotic) cirrhosis (active in three and inactive in one). Four of these five patients with liver disease and pulmonary hypertension had evidence of autoimmune phenomena. The findings in the seven patients suggest an association between autoimmune disease, plexogenic pulmonary hypertension and liver disease of the chronic active hepatitis-postnecrotic cirrhosis type.

Plexogenic pulmonary arteriopathy and liver cirrhosis

Primary pulmonary hypertension with plexiform vascular changes in the lungs and liver cirrhosis is a rare combination of unclear pathogenesis. Until now, the real prevalence has not been known. The diagnosis of this association is usually made retrospectively. The criteria are morphological--that is, right ventricular hypertrophy and the characteristic pulmonary arterial lesions, as well as clinical--based on ECG and chest radiography. Between 1970 and 1977, two such cases have been found among a total of 11988 necropsies performed on adults. In the same necropsy series, 765 cases of liver cirrhosis were found. The prevalence of this combination is 0.26% of the cirrhosis and 0.016% of all necropsies of adults. This low prevalence raises serious doubts as to whether the association is more than coincidental.

Pulmonary heart disease: pathophysiology, diagnostic signs, and therapy

The anatomy and physiology of the pulmonary vasculature has been described with emphasis on several types of pulmonary hypertension and their pathophysiology. Treatment of pulmonary hypertension may be successful, especially when disease is related to emboli which respond to anticoagulant therapy. Relief of mitral valve obstruction is usually beneficial. Patients with abnormalities of blood PO2 and pH (especially in chronic obstructive lung disease) may be spared increased pulmonary pressure or may reverse existing pulmonary hypertension by giving up smoking, learning more efficient ventilatory methods, and when indicated, using supplemental oxygen, bronchodilators, digitalis, diuretics, or a combination of these.

Long term effects of the anorectic agent fenfluramine alone and in combination with aminorex on pulmonary and systemic circulation in the pig

We have investigated the effects of chronic oral administration of two anorectic substances, fenfluramine and aminorex, especially on the pulmonary circulation in young pigs with one ligated pulmonary artery. The pulmonary vascular reactivity was tested by alveolar hypoxia, alveolar hyperoxia and infusion of prostaglandin F2ALPHA. No elevation of pulmonary arterial pressures or resistances were found due to the intake of fenfluramine or aminorex over a three month period. The responses to the vasoconstrictor stimuli, hypoxia and prostaglandin F2alpha, and to the vasodilator stimulus, hyperoxia, were equal and not augmented in the drug groups. Fenfluramine or aminorex could therefore could therefore not be shown to have an adverse effect on the pulmonary circulation or on the reactivity of the pulmonary vascular bed in the pig, but fenfluramine elevated systemic arterial pressure.