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Volatility, Adsorption, and Degradation of Propargyl Bromide as a Soil Fumigant.

During the 1960s, propargyl bromide (3-bromopropyne, C(3)H(3)Br, or 3BP) was used in a soil fumigant Trizone, a combination of chloropicrin, methyl bromide, and propargyl bromide. Since a great deal of attention is being placed on finding replacements for methyl bromide (CH(3)Br, MeBr) in soil fumigation, there is a revived interest in developing propargyl bromide as an alternative fumigant. However, at present, no information exists for assessing its behavior and safety in the environment. In this study, several important parameters needed to determine its environmental fate are obtained. These include basic parameters such as solubility, saturated vapor density, the Henry's law constant, adsorption, and degradation. These parameters are compared to MeBr and 1,3-dichloropropene (1,3-D), a methyl bromide alternative. At 25 degrees C, the Henry's law constant, K(H), for 3-bromopropyne is 0.046, which is smaller than that for MeBr and similar in magnitude to that for 1,3-D. In water at 25 degrees C, the solubility is approximately 1.5% and 3BP slowly degrades with a hydrolysis half-life of 47 days. In soil, the degradation half-life ranged from 1.2 to 5 days, depending on the soil type. Under typical agricultural conditions, 3BP will move readily in soils, a desirable characteristic for fumigants, but, due to its short soil degradation time, should not pose a serious environmental risk.

Journal Article↗

Diverging Effects of Steric Congestion on the Reaction of Tributylstannyl Radicals with Areneselenols and Aryl Bromides and Their Mechanistic Implications.

The effects of bulky ortho,ortho' groups on the reactions of aryl bromides and areneselenols with tributylstannane have been studied. Bulky ortho,ortho' groups accelerate the reaction of the bromides with the stannane but retard the reactions of the selenols. On the other hand, ab initio and force field calculations show that introducing bulky ortho substituents into selenols causes a greater increase in strain than in the corresponding bromides. Two possible explanations for the divergent reactivity patterns are advanced. On one hand, it is possible that bromine abstraction by stannyl radicals from aryl bromides proceeds in a single step through a linear transition state whereas the abstraction of SeH from the selenols involves a T-shaped, hypervalent intermediate. Alternatively, it may be that both reactions are concerted with the bromine abstraction having a late transition state and the SeH abstraction an early one. Approximate second-order rate constants for the reaction of tributylstannane with a range of hindered aryl bromides are derived from competition reactions. 2,4,6-Tri-tert-butylbenzeneselenol is able to function moderately well as a catalyst for the stannane-mediated reactions of vinyl bromides. The X-ray crystal structure of bis(2,4,6-triisopropylphenyl) diselenide is presented.

Journal Article↗

Otilonium bromide in irritable bowel syndrome: a double-blind, placebo-controlled, 15-week study.

AIM: To evaluate the efficacy of otilonium bromide, a spasmolytic agent, in the treatment of irritable bowel syndrome using modern and validated diagnostic criteria. METHODS: Three hundred and seventy-eight patients with irritable bowel syndrome were enrolled in the study. At entry, endoscopy/barium enema, clinical examination and laboratory tests were used to rule out organic diseases. After a 2-week placebo run-in, 325 patients were randomly assigned to receive either otilonium bromide 40 mg t.d.s. or placebo for 15 weeks. Abdominal pain, abdominal distension and disturbed defecation were scored at the beginning of the study and every 5 weeks. A global determination of well-being by visual analogue scale and the tenderness of the sigmoid colon were also scored. RESULTS: The reduction in the number of abdominal pain episodes was significantly higher (P < 0.01) in otilonium bromide patients (55.3%) than in those taking placebo (39.9%) as was the severity of abdominal distension (42.0%, vs. 30.2%; P < 0.05). Bowel disturbance improved in both groups. but without any statistically significant difference. The visual analogue scale of well-being revealed a significant improvement (P < 0.05) in patients taking otilonium bromide. The investigators' global positive assessment was in favour of otilonium bromide (65.2%) compared with placebo (49.6%) (P < 0.01). CONCLUSIONS: Otilonium bromide may represent an effective treatment for irritable bowel syndrome because it reduces its predominant symptom (abdominal pain/ discomfort) more than placebo does.

Colonic Diseases, Functional↗

A time-dose study of the effect of topical ipratropium bromide on methacholine-induced rhinorrhoea in patients with perennial non-allergic rhinitis.

Intranasal application of the anticholinergic drug, ipratropium bromide, is used for the treatment of watery rhinorrhoea. We have performed a time-dose study of ipratropium bromide in patients with perennial non-allergic rhinitis, using rhinorrhoea, induced by nasal methacholine challenge, as a laboratory model. Two doses of ipratropium bromide, 40 microg and 80 microg, delivered from a pressurized aerosol, were both very effective, reducing the volume of methacholine-induced secretion by 85 to 95%. The maximum effect lasted for at least 4 h and then slowly diminished. A significant effect was demonstrable for 12 h with 40 microg and for 18 h with 80 microg ipratropium bromide. These results from a laboratory challenge study indicate that the presently used frequency of ipratropium bromide, namely four times daily, may not be necessary in many patients. Perhaps once in the morning, followed by an as-needed medication, will be a better way to use intranasal ipratropium bromide in perennial non-allergic rhinitis.

Administration, Intranasal↗

Dose-response relationships for edrophonium and neostigmine antagonism of rocuronium bromide (ORG 9426)-induced neuromuscular blockade.

BACKGROUND: Rocuronium bromide (ORG 9426) is a new nondepolarizing muscle relaxant with a rapid onset but an intermediate duration of action. The dose-response relationships for neostigmine and edrophonium were studied during antagonism of neuromuscular block induced by rocuronium bromide. METHODS: Sixty-four ASA physical status 1 or 2 adults were given 0.6 mg/kg rocuronium bromide during thiopental-fentanyl-nitrous oxide-isoflurane anesthesia. Train-of-four (TOF) stimulation was applied to the ulnar nerve every 10 s, and the force of contraction of the adductor pollicis muscle was recorded. When spontaneous recovery of first twitch height reached 10% of its initial control value, edrophonium (0.1, 0.2, 0.4, or 1 mg/kg) or neostigmine (0.005, 0.01, 0.02, or 0.05 mg/kg) was administered by random allocation. Neuromuscular function in another eight subjects was allowed to recover spontaneously. Assisted recovery was defined as actual recovery minus mean spontaneous recovery in patients who were not given antagonists. RESULTS: The dose-response curves for neostigmine- and edrophonium-assisted antagonism of rocuronium bromide neuromuscular blockade for the single twitch and TOF ratio were not parallel. The doses of neostigmine required to achieve 50% and 80% recovery (ED50 and ED80, respectively) of the first twitch after 10 min were 0.017 (0.001) and 0.033 (0.001) mg/kg (mean (standard error of estimate for the mean)), respectively. Corresponding ED50 and ED80 values for edrophonium were 0.161 (0.001) and 0.690 (0.001) mg/kg, respectively. These values corresponded to neostigmine:edrophonium potency ratios of 9.5 (0.56) and 21 (0.67) for first twitch ED50 and ED80 height, respectively. The calculated doses producing ED50 of the TOF ratio at 10 min were 0.017 (0.001) and 0.469 (0.001) mg/kg for neostigmine and edrophonium, respectively. These values corresponded to a potency ratio of 27.5 (1.66). CONCLUSIONS: Under the conditions described in this study, if reversal was attempted at 10% first twitch recovery, edrophonium was less capable than neostigmine of reversing fade (potency ratio of 19.2 and 27.5 at 5 and 10 min, respectively) than first twitch (potency ratio of 6.7 and 9.5 at 5 and 10 min, respectively) during antagonism of rocuronium bromide-induced blockade. Edrophonium was found to be less effective than neostigmine at reversing rocuronium bromide-induced TOF fade.

Adult↗

Extended analysis of a double-blind, placebo-controlled, 15-week study with otilonium bromide in irritable bowel syndrome.

BACKGROUND/OBJECTIVE: In order to follow the most recent developments and recommendations in trial methodology for drug evaluation in patients with irritable bowel syndrome, we performed an extended analysis of a large clinical trial from a previously published study of otilonium bromide, using an assessment that integrates the key symptoms of irritable bowel syndrome. MATERIALS AND METHODS: A large-scale clinical trial with a double-blind, placebo-controlled, parallel-group study design was conducted in 378 patients, treated for 15 weeks with the recommended standard dose of 40 mg otilonium bromide or placebo three times daily. The study was based on the collection of 12 single efficacy endpoints. The new efficacy assessment was based on the data reported by the patients. Rather than demonstrating score differences between the treatment groups of the study, we carried out an assessment that integrates the most frequent symptoms reported (pain frequency and intensity, presence of meteorism and distension) by the patient. RESULTS: The rate of response to treatment within 2-4 months (the primary efficacy outcome measure) was significantly higher in the otilonium bromide group (36.9%) than in the placebo group (22.5%; P = 0.007). In each month of treatment, the rate of monthly response was higher in the otilonium bromide group as compared to the placebo group (P < 0.05). The total monthly and weekly responses to the single endpoints (intensity and frequency of pain and discomfort, meteorism/abdominal distension, severity of diarrhoea or constipation and mucus in the stool) were significantly more frequent in the group treated with otilonium bromide than in the placebo-treated group, with differences ranging from 10% to 20%. The subgroup analysis of the intestinal habits endpoint indicates that patients with diarrhoea have an additional benefit. CONCLUSION: The present re-evaluation of a previously published study confirms that otilonium bromide is more effective than placebo for the treatment of irritable bowel syndrome, being very efficient in relieving pain and discomfort.

Adult↗

Vagal activity and airway response to ipratropium bromide before and after exercise in ambient and cold conditions in healthy cross-country runners.

OBJECTIVE: To determine whether the variability in the effect of ipratropium bromide on the bronchial response to exercise among endurance athletes depends on their vagal activity. The hypothesis was that this would be the case. DESIGN: Participants served as their own controls in a double-blind, repeated-measures investigation. SETTING: Climatic chamber in an exercise laboratory. PARTICIPANTS: Six well-trained healthy adult cross-country runners (three women and three men). INTERVENTIONS: Four exercise provocation tests at ambient temperature of 22 or -5 degrees C after inhalation of ipratropium bromide or placebo. MAIN OUTCOME MEASURES: Vagal activity was assessed in each visit by a 4-second cycling test; airway response to exercise was measured by periodic pulmonary function testing. RESULTS: With ipratropium bromide, forced expiratory volume in 1 second (FEV1) increased by 5.3+/-1.4% at 22 degrees C and by 7.5+/-1.5% at -5 degrees C. The beneficial response of the large airways to ipratropium bromide versus placebo was positively related to vagal activity for FEV1 at -5 degrees C, for peak expiratory flow (PEF) at -5 degrees C, and for PEF at 22 degrees C. CONCLUSION: The findings suggest that the beneficial large-airways response to ipratropium bromide may be related to vagal activity. CLINICAL RELEVANCE: Information about vagal activity may help to determine whether an athlete is a suitable candidate for treatment with ipratropium bromide. This may offer more therapeutic possibilities, especially for those individuals who have a high vagal activity, such as endurance athletes.

Adult↗

Effects of cimetropium bromide on gastrointestinal transit time in patients with irritable bowel syndrome.

Cimetropium bromide is a new antimuscarinic compound with strong antispasmodic activity. The aim of this study was to evaluate the effects of oral cimetropium bromide on total gut transit time in patients with irritable bowel syndrome. Forty patients, divided according to their initial total gastrointestinal transit times and presenting symptoms, were treated with cimetropium bromide 50 mg t.d.s. or placebo for 1 month according to a double-blind, parallel group design. Before and after treatment all subjects ingested 24 radio-opaque markers. The total intestinal transit time was determined by evaluating the rate of disappearance of markers from plain X-ray films of the abdomen taken every 24 h for 4 days. Pain and bowel habits were also monitored. Seven patients did not complete the study. Cimetropium bromide significantly (P less than 0.01) shortened the whole gut transit time in patients with prolonged transit time (80.8 +/- 4.0 h before vs 60.8 +/- 6.7 h after treatment) and improved the global clinical condition significantly compared with placebo (P = 0.029). In patients with a short total intestinal transit time, cimetropium bromide had no effect on whole gut transit time and did not significantly improve symptoms. The results of this study indicate that oral cimetropium bromide is effective both objectively and subjectively in a subgroup of irritable bowel syndrome patients with constipation.

Adult↗

Ipratropium bromide nasal spray in non-allergic rhinitis: efficacy, nasal cytological response and patient evaluation on quality of life.

Intranasal fluorocarbon anticholinergic agents have been used to treat the nasal hypersecretion of perennial non-allergic rhinitis, but chronic use has been restricted either due to the potential for systemic anticholinergic adverse events or due to the irritating properties of the fluorocarbon metered dose formulations. This study evaluates a new aqueous nasal formulation of ipratropium bromide (Atrovent Nasal Spray 0.03%) in subjects with perennial non-allergic rhinitis in a double-blind, placebo-controlled trial. Two hundred and twenty-eight patients were randomized to receive two sprays per nostril of either ipratropium bromide (42 micrograms/nostril) or placebo-administered three times a day as an aqueous nasal spray over an 8-week interval. Patients were evaluated bi-weekly and maintained daily diaries for duration and severity of nasal symptoms. Ipratropium bromide reduced the mean severity and duration of rhinorrhoea within the first week and throughout the 8 weeks of active treatment compared with placebo (P < 0.05). Secondary endpoints of efficacy (patient and physician global assessments and a quality of life assessment) also supported the use of ipratropium bromide nasal spray for rhinitis symptom control. With the reduction in rhinorrhoea by the ipratropium bromide nasal spray, patients reported a marked improvement in daily moods vs placebo (P < 0.01). Both placebo and ipratropium bromide nasal spray induced a modest reduction of nasal congestion, sneezing and postnasal drip. This improvement in these other nasal symptoms was consistent with the known soothing effects of a nasal saline vehicle. There were no drug-related serious or systemic anticholinergic adverse events.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Intranasal↗

Respiratory depressant and skeletal muscle relaxant effects of low-dose pancuronium bromide in spontaneously breathing, isoflurane-anesthetized dogs.

OBJECTIVE: To assess and compare the respiratory depressant and skeletal muscle relaxant effects of two low doses of a nondepolarizing neuromuscular blocker, pancuronium bromide. To determine if a "low dose" of pancuronium bromide can produce selective skeletal muscle relaxation in extraocular muscles sufficient to perform intraocular surgery while sparing or minimizing depression of muscles of ventilation. STUDY DESIGN: Blinded, randomized crossover, placebo controlled study. ANIMALS: Six healthy, adult mongrel dogs weighing 20.8 +/- 1.9 kg. METHODS: Spontaneously breathing, isoflurane-anesthetized dogs received 0.02 mg/kg pancuronium bromide, intravenously (i.v.), (high dose [HD]), 0.01 mg/kg pancuronium bromide, i.v., (low dose [LD]), or saline placebo i.v. in a blinded, randomized crossover study. Indices of patient ventilation including tidal volume (Vt), respiratory rate (RR), and minute ventilation (VE) were recorded throughout the study period. Serial arterial blood gas analyses were performed at timed intervals. Neuromuscular blockade of skeletal muscle was assessed at timed intervals with train-of-four stimulus/response ratios. Eye position scores, based on the degree of ocular rotation from a neutral gaze axis, were assigned by an ophthalmologist who was blinded to the treatment given. RESULTS: VT and VE in HD dogs decreased by 82% from baseline after administration of pancuronium bromide. Similarly, Vt and VE in LD dogs decreased 40% and 55%, respectively. Decreased ventilation in HD dogs corresponded with significant (P< .05) neuromuscular blockade, as indicated by train-of-four ratio less than 75% between 0 and 60 minutes. Eye position scores in HD and LD dogs were suitable for intraocular surgery between 0 and 60 minutes. Eye position scores in five of six control dogs were unsuitable for intraocular surgery at any time period. CONCLUSIONS: LD dogs experienced only transient, mild to moderate respiratory depression compared with HD dogs, which experienced prolonged, moderate to severe respiratory depression. Both LD and HD dogs acquired and maintained eye position scores suitable for intraocular surgery between 0 to 60 minutes. A "low dose" of pancuronium bromide, which would provide adequate extraocular muscle relaxation while minimizing ventilatory depression, was not identified. CLINICAL RELEVANCE: All patients receiving any dose of neuromuscular blocking agents should be closely monitored and receive ventilatory assistance as needed.

Anesthesia, Inhalation↗

Sodium cromoglycate and ipratropium bromide in exercise-induced asthma.

In thirteen patients with extrinsic asthma the effects of placebo, sodium cromoglycate, ipratropium bromide, and ipratropium bromide plus sodium cromoglycate were studied in a random double-blind fashion to assess their inhibitory action in exercise-induced asthma (EIA). Exercise testing consisted of steady state running on an inclined treadmill for up to eight minutes. In eight of the 13 patients studied the baseline ratio of expiratory flow at 50% vital capacity (VC) breathing helium-oxygen (V50He) to V50air was over 1.20 and they were called responders; the remaining five patients were called non-responders. There was a significantly lower baseline maximum mid-expiratory flow rate (MMEF) in non-responders (P less than 0.02) as compared to responders but no difference in forced expiratory volume in one second (FEV1) or forced vital capacity (FVC). Sodium cromoglycate (P less than 0.02), ipratropium bromide (P less than 0.01), and ipratropium bromide plus spdium cromoglycate (P less than 0.01) all significantly inhibited the percentage fall in FEV1 after exercise in the responders. Ipratropium bromide had no preventive action on non-responders, unlike sodium cromoglycate (P less than 0.05) and ipratropium bromide plus sodium cromoglycate (P less than 0.02). It is postulated that mediator release is an important factor in development of EIA in most extrinsic asthmatics, whereas cholinergic mechanisms are relevant only in those patients in whom the main site of airflow obstruction is in the large central airways.

Adolescent↗

Ipratropium bromide increases the ability of the nose to warm and humidify air.

We have developed a method for measuring the temperature and relative humidity of air prior to and after nasal conditioning and used it to study the effect of treatment with ipratropium bromide on the ability of the nose to condition cold, dry air. We performed randomized, double-blind, placebo-controlled, two-way crossover studies and an open study in nonallergic subjects. The subjects were treated with ipratropium bromide (84 microgram) or normal saline solution sprayed into the nasal cavity 15 min before the measurement of nasal conditioning capacity. Cold, dry air was delivered to the nose via a nasal mask, and the temperature and humidity of air were measured before entering and after exiting the nasal cavity. The total water gradient across the nose was calculated and represents nasal conditioning capacity. Ipratropium bromide treatment significantly increased nasal conditioning capacity when compared with saline. Ipratropium bromide led to less reduction in the cold, dry air-induced decrease in the nasal volume (p < 0.05) without affecting the decrease in nasal surface temperature during cold, dry air exposure (p = 0.3). Our data show that ipratropium bromide increases the ability of the nose to condition cold, dry air. Thus, treating rhinitis with ipratropium bromide should not increase the burden for inspired air conditioning on the conducting pulmonary airways.

Administration, Intranasal↗

Reversed phase-high performance liquid chromatographic (RP-HPLC) method to measure migration of semi-volatile compound, vanillin, in ipratropium bromide inhalation solution.

Ipratropium bromide, a bronchodilator, is used as an inhalation solution. Commercial ipratropium bromide solution products are packaged in low-density polyethylene (LDPE) vials, through which semivolatile compounds are reported to migrate. In this article, a specific reversed phase-high performance liquid chromatographic method to assay vanillin, a semivolatile compound, in ipratropium bromide solution is described. The method was validated for a concentration range for vanillin from 30 ng/mL to 1,600 ng/mL. Migration of vanillin was assessed in two commercial preparations, ATROVENT (ipratropium bromide) Inhalation Solution packaged in a secondary foil pouch and a generic ipratropium bromide inhalation solution packaged in a carton. Levels of vanillin detected in ATROVENT after 6 months of storage at 40 degrees C and 75% RH were below the limit of detection (11 ng/mL). Significant migration of vanillin was observed after 1 month in the generic product and reached 165 ng/mL to 999 ng/mL in three months under the same storage conditions. It is concluded that this method can be readily used to measure vanillin in commercial preparations of ipratropium bromide inhalation solution. The results strongly indicate that a protective secondary packaging material is critical in preventing migration of semivolatile compounds. This study result is in agreement with the FDA's recommendation to consider even the secondary packaging components as potential sources of contamination and the use of an overwrap (typically aluminum foil) to decrease the overall permeability.

Administration, Inhalation↗

[Effects of flutropium bromide, a new antiasthma drug, on mediator release from mast cells and actions of mediators].

The effects of flutropium bromide (Ba598Br), a new antiasthma drug possessing the quarternary ammonium structure of atropine derivatives, on mediator release from mast cells and on actions of leukotriene (LT) D4 and serotonin were investigated. Flutropium bromide (3 and 10 mg/kg, i.v.) showed an inhibitory action on the 48 hr homologous PCA in guinea pigs. Atropine showed no inhibitory effect. Flutropium bromide also inhibited the release of histamine from isolated rat mast cells stimulated by antigen, although the inhibitory action was weaker than that of disodium cromoglycate. Atropine also had no inhibitory action in this case. Flutropium bromide and atropine showed no antagonistic action against LTD4-induced contraction of isolated tracheal smooth muscle of guinea pigs. Inhalation of flutropium bromide (0.3%) also showed no antagonistic action against serotonin-induced bronchoconstriction in dogs. From the above results, it is indicated that flutropium bromide has a weak mast cell stabilizing action, but no antagonistic action against LTD4 and serotonin.

Animals↗

Induction of parturition in bitches with minimal side effects by two injections of a low dose of fenprostalene, a prostaglandin F2alpha analogue, and pretreatment with prifinium bromide.

An experiment using 16 Beagle bitches (aged 11 months to 6 years and 2 months) in their 56th to 58th day of pregnancy was carried out to investigate the effects of two injections of a low dose of fenprostalene, a long-acting prostaglandin F2alpha analogue, and pretreatment with prifinium bromide, a parasympathetic nerve blocking agent, on the induction of parturition and severity of side effects. The bitches were divided into three treatment groups: one injection of 5 microg/kg of fenprostalene (group I, n=5); one injection of 7.5 mg/head of prifinium bromide followed by one injection of 5 microg/kg of fenprostalene at 5 min after prifinium bromide injection (group II, n=6); and one injection of 7.5 mg/head of prifinium bromide followed by two injections of 2.5 microg/kg of fenprostalene, one injection at 5 min after prifinium bromide injection and the next at 1 hr after the fenprostalene first injection (group III, n=5). Following the injection of fenprostalene, side effects such as salivation, vomiting, colic symptoms, and watery diarrhea occurred most frequently (80-100% of cases) in group I bitches. Apart from colic symptoms, no side effects were observed in group III bitches. Group III bitches also showed the smallest increase in plasma cortisol concentration. No significant difference in the time to initiation of parturition was found between the three groups. The one-week survival rate of newborn puppies was highest in group III. The results showed that pretreatment with prifinium bromide and two injections of 2.5 microg/kg of fenprostalene can alleviate side effects following fenprostalene administration and have no adverse effect on the survival of newborn puppies, indicating that this method is a reliable and safe way of inducing parturition in bitches.

Abortifacient Agents, Nonsteroidal↗

Effects of ipratropium bromide nebulizer solution with and without preservatives in the treatment of acute and stable asthma.

In a recent study, it was suggested that the preservatives in ipratropium bromide nebulizer solution may cause a paradoxic bronchoconstrictor response in 20 percent or more of patients with stable asthma. The frequency of this response in patients with acute asthma is unknown. The aim of this study was to examine the acute effects of the usual dose of nebulized ipratropium bromide (0.25 mg) in patients with either stable or acute asthma using formulations with and without added preservatives. Twenty-five patients with stable asthma and 25 patients with acute asthma were studied. Each subject was given preservative-containing ipratropium bromide, preservative-free ipratropium bromide, pH 7 preservative-free ipratropium bromide, and saline solution in random order using a double-blind crossover technique with at least 4 h between drug administrations. Very frequent measurements of FEV1 were made for 30 min after each drug administration and then 5 mg of albuterol was nebulized and the FEV1 was measured again after another 30 min. Changes in FEV1 were expressed as a percentage of the predicted FEV1. Paradoxic bronchoconstriction to ipratropium was detected in only one patient with acute asthma (12 percent fall in FEV1) but in none of the patients with stable asthma. A 6 percent fall in FEV1 change occurred with the saline solution in this subject suggesting that the response may have been a nonspecific one due to increased bronchial responsiveness. The mean response (+/- 1 SD) to albuterol plus either preservative-containing ipratropium, preservative-free ipratropium, or pH7 preservative-free ipratropium was significantly greater (p less than 0.05) than the response to albuterol alone both in the patients with acute asthma (25 +/- 12 percent, 27 +/- 15 percent, 26 +/- 15 percent, and 20 +/- 15 percent, respectively) and stable asthma (26 +/- 7 percent, 25 +/- 8 percent, 24 +/- 6 percent, and 22 +/- 9 percent) supporting the use of ipratropium bromide as an additional bronchodilator in patients with asthma who do not show a satisfactory response to nebulized beta-adrenergic agonist.

Aerosols↗

Effect of ipratropium bromide on airway and pulmonary muscarinic receptors in a rat model of chronic obstructive pulmonary disease.

OBJECTIVE: To observe the level of muscarinic receptors in airway and lung tissues, and the effect of inhaled ipratropium bromide on these receptors in a rat model of chronic obstructive pulmonary disease (COPD). METHODS: This model was developed by exposure of rats to 250 ppm SO2 gas, 5 h/d, 5 d/wk, for a period of 7 wk. The COPD rats inhaled 0.025% aerosolized iratropium bromide for 20 min, 2 times daily, in an airtight chamber. Muscarinic receptors in airway and lung tissues of normal rats, ipratropium bromide-treated COPD rats and the recovering COPD rats were measured by the radio-ligand binding assay. RESULTS: Airway/lung pathology and pulmonary function tests showed that chronic SO2 exposure caused pathophysiologic changes similar to those observed in human COPD. The density (0.038 +/- 0.011, pmol/mg protein) and affinity (Kd, 23 +/- 11 pmol/L) of muscarinic receptors in airway and lung tissues of COPD rats were not changed compared with those of normal control rats (0.030 +/- 0.008 and 29 +/- 19, respectively, P > 0.05). Densities of the muscarinic receptors were not changed after inhalation of ipratropium bromide for 5 days, but increased significantly after inhalation for 30 days, as compared with those of the untreated COPD rats. The muscarinic receptors returned the normal levels at day 6 after cessation of ipratropium bromide treatment. There were no differences among different groups of rats in equilibrium dissociation constants (Kd). CONCLUSION: A rat model of COPD with pathophysiologic changes similar to the human counterpart was developed using chronic SO2 exposure. There was no significant change in the number and function of muscarinic receptors in airway and lung tissues of the COPD rats, but upregulation of the muscarinic receptors was observed after long-term inhalation of ipratropium bromide.

Animals↗

Effects of ethidium bromide on the respiratory chain and oligomycin-sensitive adenosine triphosphatase in purified mitochondria from the cellular slime mold Dicyostelium discoideum.

Mitochondria were isolated from the cellular slime mold. Dictyoostelium discoideum, and partially purified by sucrose density gradient fractionation. The most purified mitochondrial fraction from the gradient contained essentially no contaminating lysosomes and minimal amounts of contaminating peroxisomes as determined by the marker enzymes N-acetyl-glucosaminidase and catalase. A mitochondrial fraction with the same amount of lysosomal and peroxisomal contamination was also isolated from cells which had been treated with ethidium bromide for 5 days. The most purified mitochondrial fraction from control and ethidium bromide-treated cells had an identical buoyant density of 1.181 to 1.182 g per ml, suggesting that treatment with the drug does not result in any drastic structural changes in the mitochondrial membrane which would affect its density. In the purified mitochondria from ethidium bromide-treated cells, the content of cytochromes a-a3 was decreased over 80% and that of cytochrome oxidase and oligomycin sensitive ATPase were reduced approximately 50%. By contrast, the specific activities of NADH and succinate dehydrogenases were identical in the purified mitochondria from control and ethidium bromide-treated cells. Previously, we had reported that the specific activities of these two enzymes had nearly doubled in whole cells maintained in ethidium bromide for a time equivalent to six or seven generations after growth had stopped (Stuchell, R. N., Weinstein, B. I., and Beattie, D. S. (1973) Fed. Eur. Biochem. Coc Lett. 37, 23-26). These results suggest that continued formation of new mitochondrial membranes, with an identical complement of succinate and NADH dehydrogenases, must occur despite the cessation of cell growth which occurs as a result of the ethidium bromide induced loss of mitochondrial enzymes. Consequently, the amount of mitochondria, or mitochondrial protein per cell, calculated from the activity of NADH and succinate dehydrogenases has increased nearly 50%. Possible models to explain the control of mitochondrial biogenesis are discussed to explain these results.

Adenosine Triphosphatases↗