The use of ivacaftor in CFTR mutations resulting in residual functioning protein.

INTRODUCTION: Ivacaftor, a cystic fibrosis transmembrane regulator (CFTR) potentiator is currently approved for use in individuals with class III gating mutations and the R117H mutation, a non-gating mutation with residual functioning CFTR. Nevertheless, ivacaftor may also be effective in individuals who have CF mutations giving rise to a residual functioning protein. However, aside from case reports involving a single patient, little data exist on the use of ivacaftor in such individuals. METHODS: A real life pragmatic report wherein seven adults with mutations resulting in a CFTR with residual function were prescribed ivacaftor. Four individuals with similar mutations acted as comparison. We assessed lung function, body mass index, sweat chloride; the number of acute respiratory exacerbations and health related quality of life. RESULTS: Patients with residual functioning CFTR showed significant improvement or stabilization in all parameters up to 3 years following the start of ivacaftor. Those with similar mutations and who did not receive ivacaftor worsened. CONCLUSION: We report the use of ivacaftor in seven adults with various Class IV and V non-gating CFTR mutation with residual functioning protein and we demonstrate improvement in several clinical parameters.

Carbachol stimulates c-fos expression and proliferation in oligodendrocyte progenitors.

To determine if muscarinic receptor-activation plays a role in oligodendrocyte development, the effect of carbachol a stable acetylcholine analog, on gene expression and proliferation was investigated. Using Northern blot analysis we showed that carbachol caused a time and concentration-dependent increase in c-fos mRNA. This effect was blocked by atropine, a non-selective muscarinic antagonist. In addition, the muscarinic-stimulated c-fos increase was inhibited by 1-(5-isoquinoline-sulfonyl)-2-methylpiperazine (H-7), a potent inhibitor of protein kinase C (PKC), but not by N-2-(p-bromocinnamylamino)-ethyl-5-isoquinoline-sulfonamide (H-89), a potent inhibitor of protein kinase A, suggesting the involvement of PKC in mediating the response. Down-regulation of PKC by overnight pre-treatment with 12-O-tetradecanoylphorbol 13-acetate (TPA) blocked only the phorbol ester-stimulated c-fos accumulation while no effect was observed in the carbachol-induced response. These results suggested that carbachol stimulated an H-7 sensitive PKC pathway which may be different than that activated by TPA. Further evidence for two separate mechanisms of proto-oncogene induction was provided by the additive effect of carbachol and TPA. Induction of c-fos mRNA by carbachol was dependent on both influx of extracellular Ca2+ and release from intracellular stores, as both EDTA and BAPTA blocked the response. Since activation of muscarinic receptors can affect cell division in other cellular systems, the effect of carbachol on [3H]thymidine and bromodeoxyuridine incorporation into oligodendrocyte DNA was measured. Carbachol stimulated DNA synthesis in oligodendrocyte progenitors. This effect was mediated by muscarinic receptors as [3H]thymidine incorporation was prevented or significantly reduced by the addition of atropine. In conclusion, the present findings suggest that, the neurotransmitter, acetylcholine may act as a trophic factor in developing oligodendrocytes, regulating their growth and development in the central nervous system.

Norepinephrine-stimulated PI hydrolysis in oligodendrocytes is mediated by alpha 1A-adrenoceptors.

Oligodendrocyte progenitors were labelled with [3H]-myo-inositol in order to determine the effect of adrenergic agents on the accumulation of [3H]-inositol phosphates (InsP). Both norepinephrine and phenylephrine, a selective alpha 1-adrenoceptor agonist, increased the formation of [3H]-InsP, while isoproterenol, a beta-adrenoceptor agonist, did not. Propranolol (beta) and yohimbine (alpha 2), two adrenoceptor antagonists, had no significant effect on the NE-stimulated [3H]-InsP formation. By contrast, the response to NE was significantly blocked by phenoxybenzamine and the alpha 1-receptor antagonist, prazosin. Pretreatment with chloroethylclonidine, which selectively inactivates alpha 1B receptors, had no effect on NE-induced [3H]-InsP formation, while WB4101 had high potency in inhibiting this response. Pertussis toxin, which inactivates certain G-proteins, caused a approximately 60% reduction. NE-stimulated formation of [3H]-InsP depended on extracellular calcium influx, because it was decreased by 55% and 75% by chelation with EGTA or the addition of 1 mM CdCl2, respectively. These results suggest that oligodendrocyte progenitors express alpha 1-adrenoceptors characteristic of the alpha 1A subtype.

Single- and multiple-dose pharmacokinetics of dezocine in patients with acute or chronic pain.

The pharmacokinetic properties of dezocine were examined in 15 patients with acute or chronic pain. In 3 groups of 5 patients each, serum levels were determined at various intervals after single intravenous doses of 5, 10, and 20 mg. After these single doses, dezocine was very rapidly distributed (mean t1/2 alpha less than 2 minutes), and then rather rapidly eliminated (mean t1/2 beta about 4 hours); the apparent volume of distribution was large (mean Vz beta about 6 L/kg) as was the total clearance (mean CL about 1.5 L/h/kg). In 2 groups of 5 patients each, serum levels were determined after the first and third of 3 intravenous doses of 5 or 20 mg given at 3-hour intervals. The pharmacokinetic parameters after these multiple doses were consistent with those after the single doses. Although some observations were suggestive, there was no unequivocal evidence that the pharmacokinetics were dose-related. In 7 serum samples containing dezocine at concentrations ranging from 12.8 to 522 ng/mL, the mean (+/- SE) proportion of dezocine bound to protein was 91.6 +/- 0.8%.

The effects of high dose NG-nitro-L-arginine-methyl ester on myocardial blood flow and left ventricular function in dogs.

PURPOSE: Nitric oxide (NO) synthase inhibition has been reported to cause elevation in mean arterial pressure (MAP) and a decrease in cardiac index (CI), the cause of which is not completely understood. It has been shown that increased concentrations of NO synthase inhibitors cause a further drop in cardiac output without a corresponding increase in arterial pressure, prompting the conclusion that NO inhibition results in direct myocardial depression. However, myocardial ischemia was not completely ruled out as a cause for myocardial dysfunction in these studies. The purpose of this study was to examine the effects of 30 mg/kg of the NO synthase inhibitor NG-nitro-L-arginine-methyl ester (L-NAME) to those of 300 mg/kg and assess the effects on coronary ischemia and myocardial function. MATERIALS AND METHODS: Eight anesthetized dogs underwent median sternotomy and pericardiectomy. L-NAME 30 mg/kg was administered and the effects were recorded at 5, 15, and 30 minutes. Thereafter, 300 mg/kg was administered and the effects were observed for 5, 15, and 30 minutes. We measured MAP, heart rate (HR), CI, left ventricle (LV) and systolic and diastolic pressures, the first derivative of LV pressure (dP/dt), left anterior descending artery blood flow, regional LV contraction, gas tensions, and lactates. A coronary sinus catheter allowed for measurements of coronary sinus pressure, lactate, and gas tensions. Stroke volume, percent myocardial shortening (dL/dt) myocardial oxygen consumption, and net lactate myocardial production were calculated. RESULTS: Whereas 30 mg/kg had minimal effects on coronary blood flow and LV function, 300 mg/kg resulted in profound hypotension, drop in CI, and acidocsis. CONCLUSIONS: L-NAME at 30 mg/kg caused a rise in MAP and systemic vascular resistance; however, it had no effect on ventricular function. High dose NO synthase inhibition causes myocardial depression not related to increased afterload, coronary vasoconstriction, or myocardial ischemia.

A comparison between the acute effects of nitric oxide synthase inhibition and fluid resuscitation on myocardial function and metabolism in entotoxemic dogs.

PURPOSE: Nitric oxide (NO) synthase inhibitors increase mean arterial pressure (MAP) and systemic vascular resistance (SVR) in animal models of sepsis and in humans with septic shock. However, NO synthase inhibitors may cause coronary vessel constriction leading to myocardial ischemia and increased mortality in endotoxemic animals. This study was designed to test the acute effect of NG-nitro-L-arginine (L-NAME) on left ventricular (LV) function and coronary blood flow in a dog model of endotoxemia. METHODS: In open chest, anesthetized dogs endotoxemia was induced intravenously (IV) by Escherichia coli lipopolysaccharide at 2 mg/kg for 60 minutes. This resulted in hypotension, acidosis, and decreased SVR while cardiac index (CI) was maintained. When MAP was < or = 60 mm Hg, animals were resuscitated with either dextran (group I), or L-NAME 30 mg/kg IV bolus (group II). Group III received L-NAME only. A fourth group of dogs was given endotoxin and not resuscitated. Animals were followed up for 30 minutes after intervention. Animals in the fourth group were followed up until the MAP was approximately 30 mm Hg. Heart rate, CI, MAP, LV end systolic and diastolic pressures, dP/dt at a pressure of 40 mm Hg, left anterior descending artery coronary blood flow, regional LV contraction (sonomicrometer crystals), coronary pressures, gas tension, and lactates were continuously recorded. A catheter placed in the coronary sinus allowed measurement of coronary sinus pressure, as well as coronary sinus lactate and gas tensions. Stroke volume index, stroke work index, systemic vascular resistance index (SVRI), coronary vascular resistance, percent myocardial shortening, myocardial oxygen consumption (Mvo2) and net myocardial lactate production were calculated. RESULTS: In Group I, fluid administration increased MAP, stroke work index, coronary blood flow, percent myocardial shortening, and Mvo2. In Group II, L-NAME increased MAP to the same extent as fluid administration without evidence of coronary ischemia or myocardial dysfunction. L-NAME did not alter Mvo2 in either endotoxemic or nonendotoxemic animals. In group III, L-NAME alone resulted in a significant increase in MAP and SVRI, but its effects on coronary blood flow and LV function were not significant. We did not observe net lactate production in any of the groups. Coronary blood flow increased out of proportion to Mvo2 in group I animals. CONCLUSIONS: We conclude that although L-NAME at 30 mg/kg causes vasoconstriction, its effects on coronary blood flow and LV function were not significant.

Guide to conservative, medical, and procedural therapies.

For patients without a specific diagnosis, treatment of low back pain begins with strategies to avoid re-injury and exacerbation. Most patients benefit from some form of medical therapy, guided by the three-step World Health Organization analgesic ladder. Opioid therapy is appropriate when needed for low back pain, especially in the acute period. Adjuvant medication (eg, an anticonvulsant or antidepressant) may help reduce or eliminate the need for opioid therapy. Side effects are common with opioid medications, although many resolve with time. Patient education in exercise, back protection, nutrition, and sexual concerns is an important component of treatment. Some patients may benefit from referral to a pain center for multidisciplinary management. Those with a structural or mechanical cause of pain may do well with surgery.

Admission decisions to a medical intensive care unit are based on functional status rather than severity of illness. A single center experience.

BACKGROUND: Few data exist on Medical Intensive Care Unit (MICU) triage practices. We assessed MICU triage practices in our medical center. METHODS: We collected data on all MICU consultations for one year, including each patient's APACHE II score at time of consultation. We assessed functional impairment at baseline and at time of MICU consultation. RESULTS: A total of 54% out of 572 consultations resulted in admission. Patients were less likely to be admitted if baseline functional status was poor (OR, 0.29; 95% CI 0.17-0.50), if a do-not-resuscitate order was present (OR, 0.44; 95% CI, 0.21-0.89), and if the MICU attending spent more than 25% of professional time in MICU (OR, 2.44; 95% CI, 1.37-4.32). Patients were more likely to be admitted if functional status at time of MICU consultation was poor (OR, 2.30; 95% CI 1.46-3.48). Patients' age, insurance, ethnicity, severity of illness, presence of malignancy, or whether patient's primary physician was on staff were not independently associated with MICU admission decisions. MICU attendings rarely cited functional status as reason for MICU refusal on the consult forms. CONCLUSION: MICU admission decisions are implicitly based on patients' baseline functional status rather than severity of illness.

Exploring oligodendrocyte guidance: 'to boldly go where no cell has gone before'.

Oligodendrocytes, the myelinating cells of the central nervous system (CNS), originate early in the formation of the brain in specific foci, and migrate throughout the parenchyma. The instructional cues guiding the migration of these progenitor cells must be encoded into their developing environment. Soluble factors as well as membrane-bound cues most likely synergize to create a complex thoroughfare needed to sculpt and organize the brain into a functional organ with white and gray matter. Classically, the focus of many guidance related studies in the CNS has been limited to neuron physiology. However, It is becoming increasingly clear that their lifelong partners, oligodendrocytes, express both ligands and receptors able to both present and respond to these classical cues. In this short review, some recent findings in the Semaphorin and Eph fields will be presented with respect to oligodendrocyte expression and function.

Rat oligodendrocytes express muscarinic receptors coupled to phosphoinositide hydrolysis and adenylyl cyclase.

Muscarinic receptors expressed by rat oligodendrocyte primary cultures were examined by measuring changes in second messengers following exposure to carbachol, an acetylcholine analog, and by polymerase chain reaction. Inositol phosphate levels were measured in [3H]myo-inositol-labelled young oligodendrocyte cultures following stimulation with carbachol. Atropine, a specific muscarinic antagonist, prevented the carbachol-induced accumulation of inositol phosphates. The formation of inositol trisphosphate was concentration- and time-dependent, with the peak at 100 microM carbachol and 10 min. Carbachol increased intracellular calcium levels, which were dependent both on the mobilization of intracellular stores and influx of extracellular calcium. In initial experiments with more selective antagonists, the mobilization of intracellular calcium was preferentially inhibited by pirenzepine, a selective M1 antagonist, but not methoctramine, a selective M2 antagonist, suggesting M1 muscarinic receptor involvement. A role for protein kinase C in the regulation of carbachol-stimulated inositol phosphate formation and intracellular calcium mobilization was demonstrated, as acute pretreatment with phorbol-12,13-myristate acetate abolished the formation of both second messengers. Pretreatment with 100 microM carbachol abolished the 40% increase in the cyclic AMP accumulation stimulated by isoproterenol, a specific beta-adrenergic agonist. In turn, the inhibition was alleviated by pretreatment with atropine, suggesting muscarinic receptor involvement. Polymerase chain reaction carried out with specific m1 and m2 muscarinic receptor oligonucleotide primers, confirmed that these cells express, at least, the two muscarinic receptor subtypes. Without excluding the expression of other subtypes, these results suggest that developing oligodendrocytes express m1 (M1) and m2 (M2) muscarinic receptors capable of mediating phosphoinositide hydrolysis, mobilization of intracellular calcium and the attenuation of beta-adrenergic stimulation of cyclic AMP formation.

Fibroblast growth factor-9 modulates the expression of myelin related proteins and multiple fibroblast growth factor receptors in developing oligodendrocytes.

The effect of fibroblast growth factor (FGF)-9 on the expression of FGF receptors (FGFR) and the major myelin proteins was examined in cultures of developing rat brain oligodendrocytes (OLs), using immunological techniques. FGFR-1, -3, and -4 were expressed at all developmental stages but were not present in isolated myelin fractions. By contrast, FGFR-2 protein was predominantly localized to differentiating cells and myelin. FGF-9 altered FGFR and myelin protein levels during OL differentiation; there was increased expression of FGFR-1 and decreased levels of both FGFR-2 and myelin proteins. Further, FGF-9 stimulated mitogen-associated protein kinase (MAPK) phosphorylation. The effect of FGF-9 on MAPK, however, was transient and less robust in progenitor cells than in differentiated oligodendrocytes. The effects of FGF-9 and FGF-2 on FGFR and myelin protein levels were comparable; both up-regulated FGFR-1, and down-regulated FGFR-2, CNP, PLP and MBP. These findings suggest that FGF-9 may be important for glial cell development.

Adult Still's disease and respiratory failure in a 74 year old woman.

A case of adult onset Still's disease in an elderly woman, that was associated with severe respiratory failure and multiorgan dysfunction, is reported. Histopathology was confirmed on open lung biopsy.

Cyclic AMP regulates PDGF-stimulated signal transduction and differentiation of an immortalized optic-nerve-derived cell line.

To facilitate the study of the molecular events underlying the development of optic-nerve-derived oligodendrocytes and their growth-factor-related signal transduction events, we immortalized perinatal rat optic nerve cells with a temperature-sensitive simian virus 40 large T-antigen, carrying the tsA58 and U19 mutations, via a retrovirus vector. The line, tsU19-9, was selected on the basis of the expression of the neural precursor marker nestin. At the permissive temperature, 33 degreesC, tsU19-9 cells had a flat epithelial morphology. In contrast, following exposure to platelet-derived growth factor (PDGF), a factor important in the lineage progression of oligodendrocytes, or in the presence of dibutyryl cyclic AMP at 39 degreesC (the non-permissive temperature), the cells underwent morphological and antigenic differentiation to cells characteristic of the oligodendrocyte lineage. We used this cell line to investigate the binding characteristics of PDGF and related signalling cascades. Competition binding, phosphoinositide hydrolysis and intracellular Ca2+ mobilization assays all demonstrated that the three different isoforms of PDGF (AA, AB and BB) bound to and acted on the cell line. Overnight exposure to forskolin, a treatment that initiated morphological and phenotypic progression into an oligodendrocyte lineage, decreased PDGF-BB-induced intracellular Ca2+ mobilization and inhibited basal and PDGF-stimulated [3H]thymidine incorporation. Our results demonstrate that tsU19-9 may serve as a resource to study early optic-nerve oligodendrocyte development.

Cavitary lung masses in SLE patients: an unusual manifestation of CMV infection.

The typical radiographical findings of cytomegalovirus pneumonitis are bilateral interstitial infiltrates. In this study, the current authors describe two patients on corticosteroid treatment for systemic lupus erythematosus, complicated by histologically confirmed cytomegalovirus pneumonitis, presenting as cavitary masses. This rare presentation of cytomegalovirus pneumonitis broadens the differential diagnosis of cavitary lesions to include cytomegalovirus infection in immunocompromised individuals.

Nerve growth factor and neurotrophin-3 differentially regulate the proliferation and survival of developing rat brain oligodendrocytes.

There is increasing evidence that the neurotrophins, particularly nerve growth factor (NGF) and neurotrophin-3 (NT-3), play a role in the regulation of glial development in the CNS. Recent studies have shown that the proliferation of optic nerve-derived O2A progenitors (OLPs) is potentiated by NT-3 in combination with platelet-derived growth factor, whereas NT-3 alone supports the survival of their differentiated progeny (Barres et al., 1994). In this study, we have examined the expression of the high-affinity neurotrophin receptors (trks) and the low-affinity nerve growth factor receptor p75 in developing oligodendrocytes (OLs). In addition, we have examined the effects of NGF and NT-3 on proliferation and survival of OLPs and OLs, respectively. TrkC, the high-affinity NT-3 receptor, and trkA, the high-affinity NGF receptor, are both expressed from the early OLP through the mature OL stage. The truncated form of trkB, lacking the tyrosine kinase domain, and the low-affinity neurotrophin receptor p75 are expressed at low levels in OLPs and are upregulated in mature OLs. NGF and NT-3 both induced the phosphorylation of mitogen-activated protein kinase (MAPK) in OLPs and in OLs. In both OLPs and OLs, NT-3 sustained the activation of MAPK more than NGF. NT-3 enhanced the proliferation of OLPs and supported the survival of OLs. By contrast, unless coadministered with FGF-2, NGF did not exhibit mitogenic effects on OLPs but did enhance the survival of differentiated OLs. Our data demonstrate the presence of functional trkA and trkC in developing OLs and indicate that both NGF and NT-3 have a broad spectrum of developmental actions on cells of the OL lineage.

Right ventricular overload causes the decrease in cardiac output after nitric oxide synthesis inhibition in endotoxemia.

OBJECTIVE: To determine whether the decrease in cardiac output after nitric oxide synthase inhibition in endotoxemia is due to increased left ventricular afterload or right ventricular afterload. DESIGN: Prospective, randomized, unblinded study. SETTING: Research laboratory at an academic, university medical center. SUBJECTS: Nonanesthetized, sedated, mechanically ventilated pigs. INTERVENTIONS: Pigs were infused with 250 microg/kg of endotoxin over 30 mins. Normal saline was infused to maintain pulmonary artery occlusion pressure (PAOP) at a value not exceeding 1.5 times the baseline value. Left ventricular dimensions and function were studied using echocardiography. Right ventricular volumes and ejection fraction were determined via a rapid thermistor pulmonary artery catheter. We also measured mean arterial pressure (MAP), cardiac output, pulmonary arterial pressure, and calculated pulmonary and systemic resistances. Gastric tonometry was used as an index of gastric mucosal oxygenation and peripheral oxygenation. When MAP had decreased to < or =60 mm Hg or had decreased 30 mm Hg from baseline, nine animals received NG-nitro-L-arginine methyl ester (L-NAME) at 15 mg/kg to restore MAP to baseline. A second group of animals (n = 6) continued to receive normal saline, ensuring that PAOP did not exceed 1.5 times its baseline value. A third group of pigs (n = 5) did not receive endotoxin and served as the time control. In this group, a balloon was used to occlude the descending thoracic aorta and to increase MAP by approximately the same amount as in the L-NAME group. MEASUREMENTS AND MAIN RESULTS: Endotoxin caused an increase in pulmonary arterial pressure and right ventricular volumes, and a decrease in gastric mucosal pH. Cardiac output was maintained in the animals receiving the saline infusion. By 2 hrs, pulmonary arterial pressure had decreased but was still notably higher than baseline. However, by this time, MAP had decreased to < or =60 mm Hg. L-NAME administration restored MAP to its baseline value but resulted in worsening pulmonary hypertension, increased right ventricular volumes, and decreased cardiac output, compared with the saline group. Three animals that received L-NAME died of right ventricular failure. We did not observe any evidence of left ventricular dysfunction with increased left ventricular afterload. Moreover, the restoration of MAP with L-NAME infusion did not correct gastric mucosal acidosis. No changes were noted in the time-control group. Occlusion of the thoracic aorta increased MAP but did not change cardiac output. This finding demonstrates that increases in left ventricular afterload of the magnitude seen with the infusion of L-NAME do not lead to decreases in cardiac output. CONCLUSION: The decrease in cardiac output after nitric oxide synthase inhibition in endotoxemia is due to increased right ventricular afterload and not to left ventricular afterload.

Selective NOS inhibition restores myocardial contractility in endotoxemic rats; however, myocardial NO content does not correlate with myocardial dysfunction.

The role of nitric oxide (NO) in lipopolysaccharide (LPS)-induced myocardial dysfunction remains controversial as some investigators concluded that inhibition of NO synthesis improves left ventricular (LV) contractility, whereas others did not. We investigated the relationship between LPS-induced LV dysfunction and LV NO production. We postulated that high myocardial NO concentrations would correspond to decreased contractility and low NO concentrations would correspond to recovery. In a rat model of endotoxemia, we used the isolated papillary preparation to assess inotropic dysfunction. We measured LV NO content and hemodynamics at baseline, 4, 16, and 48 h after LPS administration. LPS caused a decrease in LV contractility at 16 h with recovery at 48 h. Myocardial NO levels were elevated at all time periods. However, at 48 h in spite of normalization of LV contractility, myocardial NO content remained elevated. Pretreatment of LPS animals with the nonselective nitric oxide synthase (NOS) inhibitor N (G)-nitro-L-arginine methyl ester (L-NAME) worsened LV contractility, decreased LV NO content, and increased mortality. However, pretreatment with the relatively selective inducible NOS (iNOS) inhibitor S-methylisothiourea sulfate (SMT) restored LV contractility. Myocardial NO content in the SMT was lower than that of the LPS only group, but higher than the L-NAME group. We conclude that SMT is beneficial to myocardial contractility in this model of endotoxemia, whereas pretreatment with L-NAME is associated with further deterioration of contractility and increased mortality. Moreover, our data indicate that high myocardial NO concentrations do not necessarily correlate with decreased contractility.