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Biomedical subjects

T M Murphy

Publications and source records attributed to T M Murphy.

At least 55 records · Page 3Linked to original sources
PubMed1987

Aerosolized ribavirin in the treatment of patients with respiratory syncytial virus disease.

Thirty children 1 to 33 months of age were enrolled in a study of aerosolized ribavirin therapy for respiratory syncytial virus lower respiratory tract illness. Twenty patients received ribavirin and 10 received placebo. There were no significant differences between the groups in chronologic or gestational age or in days of illness prior to admission. Among patients with pneumonia 17% of 6 placebo patients vs. 64% of 11 ribavirin patients had radiographic evidence that multiple lung lobes were affected (P = 0.06). Placebo patients received 42.5 to 94.7 hours (mean, 58.6) of aerosol therapy, whereas ribavirin patients received 36.3 to 95.6 hours (mean, 55.7). Seventy-seven percent of all study patients were discharged within 5 days of starting treatment. Severity of illness was evaluated daily using a scale of 0 (normal) to 4+ (most severe). Ribavirin patients initially had a mean severity score 0.5 higher than placebo patients. By Day 2, their rate of improvement was significantly greater than that of placebo patients (P = 0.001). By Day 5, 36% of ribavirin patients with rales showed improvement, whereas rales persisted in 100% of placebo patients. The rate of improvement of oxygen saturation from first to last day of treatment was statistically significant only for ribavirin patients (P = 0.02). On Day 3, 65% of ribavirin patients (13) vs. 50% (5) placebo patients shed 10(-0.5) 50% tissue culture infective dose virus per 0.2 ml of nasal wash. No side effects or toxicity were associated with aerosol therapy. A short course of ribavirin treatment (approximately 3 days) proved safe and beneficial.

Administration, Inhalation↗
PubMed1987

Homeostatic regulation of airway smooth muscle tone by catecholamine secretion in swine.

We studied the homeostatic secretory response of catecholamine secretion elicited by progressive bronchoconstriction in 18 swine in vivo. The potential reserve of the sympathetic nervous system (SNS) was first assessed by exogenous nicotinic stimulation with 1,1-dimethyl-4-phenylpiperazinium iodide (DMPP). A dose of 250 micrograms/kg iv DMPP caused an increase in plasma norepinephrine (NE) concentration from 207 +/- 86 (basal) to 2,625 +/- 448 pg/ml (P less than 0.02) and in plasma epinephrine (EPI) from 10 +/- 5.0 to 1,410 +/- 432 pg/ml (P less than 0.05) in four swine. In four other swine, bronchoconstriction induced by aerosolized prostaglandin F2 alpha caused approximately a fivefold increase in airway resistance without hemodynamic changes. No increase in plasma EPI was observed. However, plasma NE increased from 330 +/- 131 to 1,540 +/- 182 pg/ml (P less than 0.02). In five swine receiving aerosolized acetylcholine (ACh), similar changes in airways resistance were not associated with significant changes in catecholamine concentration when mean arterial blood pressure (MAP) was unchanged. However, inhalation of sufficient ACh to cause a greater than 10% decrease in MAP caused progressive increase in catecholamine secretion. Plasma EPI increased from 32 +/- 16 (MAP = 124 +/- 7 Torr) to 1,165 +/- 522 pg/ml (MAP = 94 +/- Torr). Hypoxemia that occurred with bronchoconstriction (greater than or equal to 50 Torr) did not cause catecholamine secretion. However, severe hypoxemia (PO2 less than 30 Torr) caused large increases in plasma EPI concentrations from 84 +/- 27 to 1,463 +/- 945 pg/ml (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1987

Mechanisms of airway hypercontractility in basenji-greyhound dogs.

The comparative effects of contractile agonists and physiological stimulation of the tracheal and bronchial smooth muscle (BSM) response were studied isometrically in situ in five Basenji-greyhound (BG) and six mongrel dogs. Frequency-response curves generated by bilateral stimulation of the vagus nerves (0-20 Hz, 15-20 V, 2-ms duration) elicited greater maximal contraction in mongrel trachea (36.8 +/- 8.1 vs. 26.9 +/- 4.0 g/cm; P less than 0.02) and exhibited greater responsiveness in mongrel BSM (half-maximal response to electrical stimulation 3.0 +/- 1.1 vs. 7.0 +/- 0.5 Hz; P less than 0.05) compared with BG dogs. However, muscarinic sensitivity to intravenous methacholine (MCh) was substantially greater in BG dogs; MCh caused contraction greater than 1.5 g/cm at a mean dose of 3.0 X 10(-10) mol/kg for BG dogs compared with 5.1 X 10(-9) mol/kg for mongrel controls (P less than 0.03, Mann-Whitney rank-sum test). In contrast to the muscarinic response, the contractile response elicited by intravenous norepinephrine after beta-adrenergic blockade was similar in trachea and bronchus for both mongrel and BG dogs. Our data confirm previous in vitro demonstration of tracheal hyporesponsiveness in BG dogs and demonstrate that the contraction resulting from efferent parasympathetic stimulation is less in the BG than mongrel dogs. However, postsynaptic muscarinic responsiveness of BG BSM is substantially increased. We conclude that a component of airway responsiveness in BG dogs depends directly on contractile forces generated postsynaptically that are nongeometry dependent, postjunctional, and agonist specific.

Airway Resistance↗
PubMed1987

Treatment of intractable pain.

The mechanism of acute pain is believed to be mainly a neurophysiological event involving the transmission along A delta and fibers to the neuraxis and then via discrete paths to higher cortical levels. This incoming signal can undergo modification at a levels, either by other incoming signals, or by descending inhibition. In its refractory form chronic pain probably represents a complex balance of a nociceptive stimulus and its interaction with the co-existing psychological state, and behavioral factors. To successfully treat chronic pain it is necessary to direct therapy at the tissue damage (if any), the psychological state of the patient, and the environment in which the pain complaint is made, This often needs a multidisciplinary therapeutic environment to effect change.

Analgesics, Opioid↗
PubMed1986

Use of a colouring agent in approved dips as an aid in identifying dipped sheep.

A fat soluble dye was identified as a suitable colourant for mixing with approved dips during the statutory winter dipping period. The optimum concentration of the dye was 0.4 per cent. It uniformly dyed the sheep and depending on the breed persisted on the fleece for three to six months. Any dye that remained on the wool at shearing (six to eight months after dipping) was washed out by scouring solutions containing non-ionic and anionic detergents. The dye did not alter the efficacy of the commonly used insecticides.

Animal Identification Systems↗
PubMed1986

Pulmonary function abnormalities in long-term survivors of childhood cancer.

Pulmonary function testing (PFT) was performed on 29 long-term survivors of childhood cancer. The patients, whose mean age was 11.7 years and whose mean age at diagnosis was 3.7 years, included 12 females and 17 males. Original diagnoses included 15 patients with leukemia and 14 individuals with solid tumors. Nine patients had received cyclophosphamide and 20 had received radiation therapy. Included in this latter group were five patients who had received radiation therapy to the thorax. Eight patients had acquired pneumonia during their treatment. Physical examination was normal in all the patients, and none had a history of acute or chronic pulmonary disease. PFT demonstrated an incidence of abnormalities in forced vital capacity (FVC) and/or total lung capacity (TLC) in 48% of the patients. Patients who were under 3 years of age at the time of diagnosis or who had received radiation to the thorax were more likely to demonstrate PFT abnormalities, but these differences did not reach statistical significance. The natural history of pulmonary function and subsequent respiratory disease in survivors of childhood cancer requires further definition.

Adolescent↗
PubMed1986

Effectiveness of continuous positive airway pressure in the treatment of bronchomalacia in infants: a bronchoscopic documentation.

Continuous positive airway pressure (CPAP) was used to treat severe respiratory distress in four infants with bronchomalacia. Fiberoptic bronchoscopy diagnosed the area of bronchomalacia, documented the effects of CPAP on the airway, and helped determine an effective level of CPAP. CPAP immediately decreased respiratory distress, and was correlated with improved airway patency in the formerly collapsed airways. All four infants, including three who had required prolonged mechanical ventilation, maintained spontaneous ventilation on CPAP.

Bronchial Diseases↗
PubMed1986

Potentiation of vagal contractile response by thromboxane mimetic U-46619.

We studied the effect of the thromboxane mimetic U-46619 on tracheal smooth muscle contraction caused by bilateral stimulation of the vagus nerves in 14 mongrel dogs in situ. The parasympathetic contractile response was studied isometrically after beta-adrenergic blockade with 2 mg/kg iv propranolol plus 20 micrograms X kg-1 X min-1 continuous intravenous infusion and blockade of endogenous prostaglandin synthesis with 5 mg/kg iv indomethacin. An initial frequency-response curve was generated by electrical stimulation of the caudal ends of cut cervical vagi over the range of frequencies 2-25 Hz (constant 25 V) at 15-s intervals. In five dogs, 10(-10) to 10(-8) mol of the thromboxane mimetic (15S)-hydroxyl-11 alpha,9 alpha-(epoxymethano)prosta-5Z,13E-dienoic acid (U-46619) was injected selectively into the tracheal arterial circulation, causing a transient contractile response (less than or equal to 10 g/cm). Additional frequency response studies were generated 7 min before and 1, 15, 30, 45, and 60 min after U-46619. Substantial augmentation of tracheal contraction to efferent vagal stimulation was observed after U-46619 for all frequencies greater than 4 Hz (P less than 0.02). Augmentation of vagally mediated contraction was not observed in four other dogs after equivalent tracheal contraction was elicited without U-46619. Similarly, in four separate dogs, augmentation of tracheal contraction was not observed when acetylcholine was given instead of vagal stimulation after U-46619. We conclude that the thromboxane analogue, U-46619, causes augmentation of tracheal contractile response induced by efferent vagus nerve stimulation. Potentiation is caused by a prejunctional action of U-46619 and is not induced by nonspecific precontraction with another agonist.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1986

Effects of rapid passage in the gerbil (Meriones unguiculatus) on the course of infection of the bovine piroplasm Babesia divergens in splenectomised calves.

The antigenicity and virulence of the cattle piroplasm Babesia divergens was compared in splenectomised calves before and after adaptation to the gerbil. It was apparent that adaptation of B divergens to the gerbil did not result in attenuation of the parasite in cattle. The gerbil-adapted parasite had a shorter prepatent period, produced higher parasitaemias, and more severe haematological and biochemical changes than the initial bovine strain. The antigenicity of the parasite was unchanged by gerbil passage. The changes in the virulence of the gerbil-adapted parasite were attributed to selection of a rapidly replicating parasite.

Animals↗
PubMed1985

Morphological comparisons of the bovine piroplasm, Babesia divergens, in cattle and jird (Meriones unguiculatus) erythrocytes.

In comparative studies of Babesia divergens in jirds and splenectomized calves several differences in the appearance of the parasite were found. Pyriform pairs of the parasite grew larger in jirds than in calves and also were larger than those of the original isolate when calves were infected after multiple jird passage. The parasites usually occupied a central intraerythrocytic position in jirds whereas in cattle they mainly occurred peripherally. The majority of pairs formed an obtuse angle relative to each other in both host species. The main difference in morphological types was found to be the rarity of single pyriforms in jirds and this, together with other small differences, was attributed to a faster replication rate of B. divergens in this host. Intraerythrocytic death of B. divergens was observed in both jirds and calves indicating similar defence mechanisms against primary infections in the 2 host species.

Animals↗
PubMed1984

Solubilization and partial purification of ATPase from a rose cell plasma membrane fraction.

The K(+)-stimulated ATPase was partially purified from a plasma membrane fraction of suspension cultured cells of rose (Rosa damascena) by two different solubilization procedures. Solubilization with 30 mm octyl-beta-d-glucopyranoside followed by precipitation with ammonium sulfate increased the specific activity of the enzyme about 6-fold. Solubilization with 1% cholate removed all but 1% of the phospholipids and resulted in an almost total loss of ATPase activity. The subsequent addition of polar lipids restored >90% of the ATPase activity with a doubling in specific activity. Fractionation of the cholate-solubilized ATPase activity on a Sephadex G-150 column resulted in 88% of the ATPase activity being recovered in two discrete, approximately equal peaks. Both ATPase activities were similar to plasma membrane ATPase activities in pH optimum, substrate specificity, ion stimulation, and inhibitor sensitivity. Assays of marker enzymes for Golgi apparatus, endoplasmic reticulum, and mitochondria revealed only a low contamination (<7%) from other membranes in the plasma membrane-enriched preparations. Lacking an unequivocal marker for the tonoplast, intact vacuoles were isolated, and their membrane density and ATPase activity were characterized and shown not to correspond to those of the putative plasma membrane preparation. These results suggest that there are two forms of ATPase separable by size in the plasma membrane of rose.

Journal Article↗
PubMed1984

Photoinactivation of Detergent-Solubilized Plasma Membrane ATPase from Rosa damascena: Action Spectra.

The photochemistry of vesicular and detergent-solubilized preparations of plasma membrane-associated ATPase was investigated in Rosa damascena. The cholate-solubilized ATPase activity fractionated into two peaks on a Sephadex G-150 column with simple, but different ultraviolet (UV) sensitivities. The larger enzyme was UV sensitive; the smaller enzyme was relatively insensitive. The activity of both ATPase fractions depended on environment: both were inactive in cholate, relatively inactive in phosphatidylcholine, phosphatidylethanolamine and phosphatidylinositol, and active in phosphatidylglycerol and phosphatidylserine. The UV sensitivities of both fractions also depended on their environment. For the UV sensitive fraction, the action spectrum differed in the 300 to 400 nanometers range when the fraction was irradiated with and without lipids. For the resistant fraction, UV sensitivity at 290 nanometers differed (up to 6-fold) in different lipids. The resistant fraction solubilized in octylglucoside had an action spectrum very different from that in cholate or in lipid vesicles. The absorption spectra of the different preparations reflected the action spectra. For both UV sensitive and insensitive fractions, the action spectra for photoinactivation had peaks at 290 nanometers, suggesting that the chromophores were tryptophanyl residues. The loss of ATPase activity was strictly correlated with the loss of fluorescence from tryptophan in the partially purified enzymes. Cs(+) protected the UV sensitive activity but not the insensitive one. We propose a model which explains the difference in UV sensitivities based on the positions of the tryptophan residues in the two proteins.

Journal Article↗
PubMed1984

Effect of sulfhydryl reagents on k efflux from rose cells: relationship to ultraviolet-stimulated efflux.

N-Ethylmaleimide causes a rapid efflux of K(+) from suspension-cultured cells of Rosa damascena. This efflux shows many characteristics of the ultraviolet-induced efflux of K(+), including the appearance of HCO(3) (-) together with the K(+) and inhibition by respiratory inhibitors. Cysteine inhibits the ultraviolet-induced efflux of K(+). These results are interpreted to mean that ultraviolet induces K(+) efflux through an alteration of sulfhydryl residues.

Journal Article↗