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Harrison W Farber

Publications and source records attributed to Harrison W Farber.

At least 19 recordsLinked to original sources
PubMed2006

Pulmonary hypertension and beta-thalassemia major: report of a case, its treatment, and a review of the literature.

Pulmonary hypertension is a common complication of beta-thalassemia major. We report a case of successful treatment of pulmonary hypertension in a patient with beta-thalassemia major and review the literature on pulmonary hypertension and beta-thalassemia major. A 28-year-old man with beta-thalassemia major, splenectomy, hepatitis C, and hemosiderosis who presented with increasing dyspnea on exertion was diagnosed with pulmonary hypertension. After receiving continuous epoprostenol infusion and desferoxamine, his functional capacity and hemodynamic status improved. To our knowledge, this is the first case of pulmonary hypertension associated with beta-thalassemia treated with continuous epoprostenol infusion and desferoxamine. Epoprostenol, beneficial in the treatment of other types of pulmonary hypertension, may ameliorate the morbidity and mortality of pulmonary hypertension associated with thalassemia.

Adult↗
PubMed2006

Pulmonary hemodynamic responses to brain natriuretic peptide and sildenafil in patients with pulmonary arterial hypertension.

STUDY OBJECTIVES: Brain natriuretic peptide (BNP) blunts hypoxic pulmonary hypertension in animal models, but its acute hemodynamic effects in patients with pulmonary arterial hypertension (PAH) are not known. The aim of this study was to determine if human B-type natriuretic peptide is a safe and efficacious pulmonary vasodilator in patients with PAH and if the pulmonary hemodynamic effects are potentiated by phosphodiesterase inhibition. DESIGN: Open-label study. SETTING: Medical ICUs of three tertiary care hospitals in New England. PATIENTS: Thirteen consecutive adult patients undergoing right-heart catheterization and a pulmonary vasodilator trial for the initial evaluation of PAH. INTERVENTIONS: Patients were administered inhaled nitric oxide (iNO), i.v. epoprostenol, and a 3-h infusion of BNP alone and 1 h after an oral dose of the phosphodiesterase-5 inhibitor sildenafil. RESULTS: iNO and sildenafil alone decreased mean pulmonary artery pressure (mPAP) without a significant fall in pulmonary vascular resistance (PVR). Epoprostenol decreased both mPAP and PVR. BNP alone had no significant effect on pulmonary hemodynamics, but the combination of sildenafil plus BNP decreased mPAP and PVR for up to 6 h after stopping BNP. The decrease in mPAP with sildenafil plus BNP (+/- SE) was greater than after 1 h of sildenafil alone (44.6 +/- 3.8 to 40.6 +/- 3.9 mm Hg, p = 0.027). An acute vasodilator response, defined as a decrease in mPAP > 10 mm Hg and end mPAP < 40 mm Hg, was seen in 0 of 8 patients with iNO, 1 of 13 patients with epoprostenol, 0 of 13 patients with BNP, and 4 of 12 patients with sildenafil plus BNP. BNP decreased mean systemic arterial pressure (5.6 +/- 2.8 mm Hg) but had no effect on cardiac output or systemic vascular resistance. CONCLUSIONS: A 3-h BNP infusion does not significantly improve pulmonary hemodynamics in most patients with PAH but is well tolerated and augments the acute pulmonary vasodilator effect of sildenafil.

Administration, Inhalation↗
PubMed2006

Conversion to bosentan from prostacyclin infusion therapy in pulmonary arterial hypertension: a pilot study.

STUDY OBJECTIVES: We assessed the efficacy of bosentan in transitioning from prostacyclin infusions in patients with pulmonary arterial hypertension (PAH). METHODS: Twenty-two PAH patients were recruited from five PAH centers if they had been clinically stable while receiving therapy with IV epoprostenol or subcutaneous treprostinil for at least 3 months. Patients were observed in an open-label prospective trial while bosentan was added to therapy, and then epoprostenol or treprostinil were tapered after 2 months. RESULTS: Ten of the 22 patients were transitioned off prostacyclin infusion therapy after a mean (+/- SEM) duration of 6.1 +/- 1.2 months. Of those patients, seven patients have continued not receiving prostacyclin infusion therapy for a mean duration of 17.7 +/- 5.3 months, with no significant changes in pulmonary artery (PA) pressure estimated by echocardiography, World Health Organization (WHO)/New York Heart Association (NYHA) functional class, 6-min walk distance (6MWD), or Borg dyspnea score. The conditions of three patients deteriorated, necessitating the resumption of prostacyclin therapy, and two patients subsequently died. Twelve patients failed to transition or even lower the prostacylin infusion rate and had worsening of their WHO/NYHA functional class and estimated systolic PA pressures, and had a trend toward deterioration in their mean 6MWD (294 +/- 41 to 198 +/- 34 m, respectively; p = 0.2). Of these, two patients subsequently died. The baseline characteristics of those who transitioned successfully vs those who transitioned unsuccessfully were a lower prostacyclin infusion rate, and less severe elevations in the mean and estimated systolic PA pressures. CONCLUSION: Transitioning from therapy with prostacyclin to bosentan is possible in some PAH patients, mainly in those receiving lower prostacyclin doses and having less pulmonary hypertension at baseline. Careful patient selection and close interim monitoring is needed because the conditions of patients can deteriorate, and they may not respond to the resumption of therapy with prostacyclin.

Administration, Oral↗
PubMed2006

Sarcoidosis-associated pulmonary hypertension: outcome with long-term epoprostenol treatment.

RATIONALE: Pulmonary hypertension is a known complication of sarcoidosis and is associated with increased mortality. Little is known about the outcome of sarcoidosis-associated pulmonary hypertension, including response to treatment. OBJECTIVE: To determine the characteristics and outcome of patients with sarcoidosis-associated pulmonary hypertension treated with IV epoprostenol. DESIGN: Retrospective chart review of all cases of pulmonary hypertension with a concomitant diagnosis of sarcoidosis evaluated in the Boston University Pulmonary Hypertension Center from 2000 to 2004. MEASUREMENTS: Data collected included patient demographics, sarcoidosis stage, pulmonary function, echocardiography results, treatment, baseline and posttreatment hemodynamic measurements, and clinical outcome. RESULTS: Eight patients were identified; four of the patients had stage IV pulmonary sarcoidosis. Pulmonary function test results were notable for severe diffusion impairment (mean diffusion capacity of the lung for carbon monoxide, 30% of predicted), with only mild-to-moderate restrictive physiology (mean FVC, 59% of predicted). Seventy-five percent of patients required supplemental oxygen at the time of presentation. All patients had moderate or severe pulmonary hypertension and were New York Heart Association (NYHA)/World Health Organization (WHO) class III or IV. A vasodilator trial with epoprostenol was performed in seven of the eight patients; six of the seven patients had a significant hemodynamic response (> 25% reduction in pulmonary vascular resistance). All but one of the responders (five of six patients) continued on therapy. Average clinical improvement was one to two NYHA/WHO classes at a mean follow-up of 29 months (range, 15 to 49 months). CONCLUSIONS: In patients with sarcoidosis-associated pulmonary hypertension, the severity of pulmonary vascular disease occurs out of proportion to lung function abnormalities. The majority of our patients responded to epoprostenol; survival may be improved in this group.

Adult↗
PubMed2005

Synthesis and biological properties of the fluorescent ether lipid precursor 1-O-[9'-(1''-pyrenyl)]nonyl-sn-glycerol.

The synthesis of an omega-pyrene-labeled 1-O-alkyl-sn-glycerol was performed using a chirospecific method starting from R-(-)-2,3-O-isopropylidene-sn-glycerol. The product, 1-O-[9'-(1''-pyrenyl)]nonyl-sn-glycerol (pAG), is a fluorescent ether lipid that has a pyrene moiety covalently attached at the alkyl chain terminus. pAG was taken into CHO-K1 cells and a plasmalogen-deficient variant of CHO-K1, NRel-4. This variant is defective in dihydroxyacetonephosphate acyltransferase, which catalyzes the first step in plasmenylethanolamine (PlsEtn) biosynthesis. pAG was incorporated primarily into ethanolamine and choline phospholipids as well as a neutral lipid fraction tentatively identified as alkyldiacylglycerol. NRel-4 accumulated more fluorescence in the phospholipid fraction than CHO-K1, specifically in the ethanolamine phospholipids. Analysis of the fluorescent lipids showed that 93% of the pAG was incorporated into glycerolipids with the ether bond intact. Although the addition of 20 microM 1-O-hexadecyl-sn-glycerol to the medium fully restored PlsEtn biosynthesis in NRel-4 cells, pAG only partially restored PlsEtn synthesis. Incubation of cells with pAG followed by irradiation with long-wavelength (>300 nm) ultraviolet light resulted in cytotoxicity. NRel-4 cells displayed an increased sensitivity to this treatment compared with CHO-K1 cells. This photodynamic cytotoxicity approach could be used to select for mutants that are defective in downstream steps in ether lipid biosynthesis.

Animals↗
PubMed2005

Differential gene expression in pulmonary artery endothelial cells exposed to sickle cell plasma.

Clinical variability in sickle cell disease (SCD) suggests a role for extra-erythrocytic factors in the pathogenesis of vasoocclusion. We hypothesized that endothelial cell (EC) dysfunction, one possible modifier of disease variability, results from induction of phenotypic changes by circulating factors. Accordingly, we analyzed gene expression in cultured human pulmonary artery ECs (HPAEC) exposed to plasma from 1) sickle acute chest syndrome (ACS) patients, 2) SCD patients at steady state, 3) normal volunteers, and 4) serum-free media, using whole genome microarrays (U133A-B GeneChip, Affymetrix). Data were analyzed by Bayesian analysis of differential gene expression (BADGE). Differential expression was defined by the probability of >1.5 fold change in signal intensity greater than 0.999 and a predicted score of 70-100, measured by cross-validation. Compared with normal plasma, plasma from SCD patients (steady state) resulted in differential expression of 50 genes in HPAEC. Of these genes, molecules involved in cholesterol biosynthesis and lipid transport, the cellular stress response, and extracellular matrix proteins were most prominent. Another 58 genes were differentially expressed in HPAEC exposed to plasma from ACS patients. The pattern of altered gene expression suggests that plasma from SCD patients induces an EC phenotype which is anti-apoptotic and favors cholesterol biosynthesis. An altered EC phenotype elicited by SCD plasma may contribute to the pathogenesis of sickle vasoocclusion.

Anemia, Sickle Cell↗
PubMed2005

Sickle cell vaso-occlusive crisis induces the release of circulating serum heat shock protein-70.

Inflammation may play an important role in the pathophysiology of sickle cell disease (SCD), and recent studies have identified the 70-kDa heat shock protein (Hsp70) as an important mediator of inflammatory responses. Here we demonstrate a significant increase in circulating serum Hsp70 level in SCD during vaso-occlusive crisis (VOC) as compared with baseline steady-state levels (P <0.05) and a significant increase in Hsp70 levels in SCD at baseline compared with normal controls (P <0.05). Taken together, these results indicate that circulating serum Hsp70 might be a marker for VOC in SCD.

Anemia, Sickle Cell↗
PubMed2005

Acute and chronic effects of sildenafil in patients with pulmonary arterial hypertension.

Sildenafil and inhaled nitric oxide (iNO) relax smooth muscle by inhibiting the degradation and stimulating the production of cyclic guanosine monophosphate, respectively. We compared the acute pulmonary vasodilator effects of sildenafil, iNO, and epoprostenol and asked whether the combination of iNO with sildenafil had additive pulmonary vasodilator effects. We assessed the effects of extended use of sildenafil in a small cohort of patients. Twenty patients with pulmonary arterial hypertension underwent an acute vasodilator trial with sildenafil (all patients), iNO and iNO plus sildenafil (11), and epoprostenol (19). We also provided sildenafil to patients who were ineligible for, or had clinical deterioration on epoprostenol, treprostinil, or bosentan. Mean+/-se pulmonary artery pressure dropped by 13+/-3%, 19+/-4%, 14+/-3%, and 26+/-4% with epoprostenol, iNO, sildenafil, and iNO+sildenafil, respectively. Cardiac index increased with epoprostenol and sildenafil. A correlation was found between the effects of iNO and epoprostenol. Nine out of ten patients who were started on long-term sildenafil treatment alone or in combination with other vasodilators had symptomatic improvement. Three died of right heart failure. In conclusion, sildenafil is a potent acute pulmonary vasodilator, an effect that is potentiated by combination with iNO. Long-term therapy of pulmonary hypertension with sildenafil alone or in combination with other agents appears to be safe and well tolerated.

Administration, Inhalation↗
PubMed2005

Propylene glycol toxicity: a severe iatrogenic illness in ICU patients receiving IV benzodiazepines: a case series and prospective, observational pilot study.

STUDY OBJECTIVES: Benzodiazepines are commonly administered to medical ICU (MICU) patients. Propylene glycol (1,2-propanediol) is the solvent used to deliver lorazepam and diazepam IV. Although propylene glycol toxicity is increasingly recognized and reported, its incidence is unknown. Herein, we describe five MICU patients who acquired severe propylene glycol toxicity due to IV lorazepam or diazepam administration. Additionally, we evaluate the incidence of propylene glycol toxicity in MICU patients receiving IV lorazepam or diazepam. DESIGN: Case series and prospective, observational study. SETTING: Eighteen-bed MICU in a 550-bed urban academic hospital. PATIENTS AND METHODS: MICU patients administered IV benzodiazepines during a 3-month period were enrolled. Patients were categorized according to the IV benzodiazepine that they received. Laboratory data and highlights of their clinical course were recorded daily. The incidence of propylene glycol toxicity was determined and the groups compared. RESULTS: Forty-four patients were enrolled. Twenty-one patients received a benzodiazepine delivered in propylene glycol (lorazepam or diazepam), and 23 patients received a benzodiazepine delivered in an alternative solvent (midazolam). We found that four patients (19%) who received IV lorazepam or diazepam had metabolic evidence of propylene glycol toxicity. None of the patients had clinical deterioration. Neither metabolic abnormality nor clinical deterioration suggestive of propylene glycol toxicity were identified in subjects receiving IV midazolam. CONCLUSION: Propylene glycol toxicity is a potentially life-threatening iatrogenic complication that is common and preventable. It should be considered whenever a patient has an unexplained anion gap, unexplained metabolic acidosis, hyperosmolality, and/or clinical deterioration. Close monitoring of all patients receiving IV lorazepam or diazepam for early evidence of propylene glycol toxicity is warranted.

Adult↗
PubMed2002

Outcome after cardiopulmonary resuscitation in patients with pulmonary arterial hypertension.

Patients with pulmonary arterial hypertension (PAH) often die from right heart failure or sudden cardiac death. Cardiopulmonary resuscitation (CPR) may be instituted in these patients but there are no data in the medical literature about the outcome of CPR in this group of patients. We conducted a retrospective multicenter international study on the frequency and results of CPR in patients with PAH. A total of 3,130 patients with PAH were treated between 1997 and 2000 in 17 referral centers in Europe and in the United States. During this period, 513 patients had circulatory arrest and CPR was attempted in 132 (26%) of these patients. Although 96% of the CPR attempts took place in hospitalized patients (74% in intensive care units or equally equipped facilities) and although there was only minimal delay between collapse and initiation of CPR, resuscitation efforts were primarily unsuccessful in 104 patients (79%). Only eight patients (6%) survived for more than 90 d; these patients had no residual neurologic deficit. Hemodynamics obtained within 3 mo before CPR did not show any significant differences between the survivors and nonsurvivors. Except for one patient, all long-term survivors had identifiable causes of circulatory arrest that were rapidly reversible. Our data indicate that CPR for circulatory arrest in patients with PAH is rarely successful unless the cause of the cardiopulmonary decompensation can be corrected.

Aged↗