Search PubMed⌕ Search

Biomedical subjects

D E Mason

Publications and source records attributed to D E Mason.

At least 19 recordsLinked to original sources
PubMed2001

SALSA: a pattern recognition algorithm to detect electrophile-adducted peptides by automated evaluation of CID spectra in LC-MS-MS analyses.

A pattern recognition algorithm called SALSA (scoring algorithm for spectral analysis) has been developed to rapidly screen large numbers of peptide MS-MS spectra for fragmentation characteristics indicative of specific peptide modifications. The algorithm facilitates sensitive and specific detection of modified peptides at low abundance in an enzymatic protein digest. SALSA can simultaneously score multiple user-specified search criteria, including product ions, neutral losses, charged losses, and ion pairs that are diagnostic of specific peptide modifications. Application of SALSA to the detection of peptide adducts of the electrophiles dehydromonocrotaline, benzoquinone, and iodoacetic acid permitted their detection in a complex tryptic peptide digest mixture. SALSA provides superior detection of adducted peptides compared to conventional tandem MS precursor ion or neutral loss scans.

Algorithms↗
PubMed2000

Characterization of benzoquinone-peptide adducts by electrospray mass spectrometry.

Benzoquinone adducts were prepared with model peptides to identify characteristic features of adduct fragmentation in tandem mass spectrometry (MS) experiments. Model peptides contained cysteine and had a molecular mass of less than 2 kDa to facilitate peptide fragmentation in tandem MS analyses. Peptides were adducted with an excess of benzoquinone, and the adducts were analyzed by LC/MS. Adducts were identified by addition of 108 Da to the monoisotopic mass of the peptide, except in the case of oxytocin, which formed a bis adduct with addition of 216 Da. Tandem MS experiments were performed on the [M + 2H](2+) ions and/or the [M + H](+) ions. Sequence information obtained from modified peptides was comparable to that of their unmodified counterparts. A unique ion pair separated by 141 or 142 Da corresponding to beta-elimination of benzoquinol-S or benzoquinol-SH from a b(n) or y(n) series ion indicated attachment at the sulfur of the cysteine residue. An alternate ion pair of 211 Da corresponded to fragmentation at the peptide bond on either side of the adducted cysteine. Enzymatic digestion of BSA and a 2560 Da frog peptide with trypsin yielded tryptic peptides, which were treated with benzoquinone. In addition to ion pairs of 142 and 211 Da, singly and doubly charged tryptic peptide adducts showed a neutral loss of 142 Da from the precursor. Either one or both ion pairs were present in more than half of all the peptides that were examined. The neutral loss of 142 Da was present in all singly charged tryptic peptide adducts and in 11 out of 14 doubly charged tryptic peptide adducts. The data indicate that reliable detection of benzoquinone-cysteinyl peptide adducts requires monitoring of multiple spectral characteristics.

Amino Acid Sequence↗
PubMed1996

[Sedation and anesthesia in dogs and cats with cardiovascular diseases. III. Ventilation, respiratory monitoring, treatment for postoperative pain].

The purpose of this study was to review ventilation and postoperative analgesic technics in 137 dogs and 13 cats with congenital or acquired heart disease. The animals were referred to the Department of Veterinary Clinical Sciences at The Ohio State University, U.S.A, for the following surgical interventions: correction of patent ductus arteriosus (PDA-ligation, 28%), cardiac catheterization with angiogram and angioplasty (22%), pacemaker implantation (18%), exploratory lateral thoracotomy (8.7%), correction of right aortic arch ring anomaly (3.3%), correction of subvalvular aortic stenosis (2.7%), correction of PDA with coil in patients with mitral regurgitation and congestive heart failure (2%), pericardectomy and removal of heart base tumor (2%), and palliative surgery for ventricular septal defect (VSD, 0.7%). Controlled ventilation was used in all animals during thoracotomy. Anesthesia was maintained over 2.3 +/- 1.3 hours by using either isoflurane, halothane, propofol, or diazepam-ketamine in 64%, 32%, 2%, and 0.7% of animals, respectively. Postoperative analgesia was necessary in 20% of animals and was provided by using different technics over several hours. The technics and respective percentages of animals in which they were used, were: intravenous buprenorphine (3.3%), intercostal nerve blocks (8.7%), epidural morphine (4%), and interpleural regional analgesia (4%).

Analgesia↗
PubMed1995

[Sedation and anesthesia in dogs and cats with cardiovascular diseases. I. Anesthesia plan considering risk assessment, hemodynamic effects of drugs and monitoring].

The purpose of this study was to review the effects of sedatives and anesthetics in 137 dogs and 13 cats with congenital or acquired heart disease which were referred for diagnostic, therapeutic, and surgical interventions: correction of patent ductus arteriosus (PDA-ligation, 28%), cardiac catheterization with angiogram and angioplasty (22%), pacemaker implantation (18%), exploratory lateral thoracotomy (8.7%), correction of right aortic arch (ring anomaly, 3.3%), correction of subvalvular aortic stenosis (2.7%), correction of PDA with coil in patients with mitral regurgitation and congestive heart failure (2%), pericardectomy and removal of heart-base tumors (2%), palliative surgery for ventricular septal defect (VSD, 0.7%), and sick patients with deleterious cardiac arrhythmias (0.7%). The anesthetic plan considered the risks of anesthesia based upon preoperative patient assessment, classification scheme for functional phases of heart failure, and anesthetic drug effects of the cardiovascular system. The effects of sedatives and anesthetic drugs on determinants of cardiac output are described. The most commonly used drugs for premedication, induction, and maintenance of anesthesia were midazolam-oxymorphone (20%), thiopental or etomidate (30%), and isoflurane (64%). Prompt therapy was given to control arrhythmias and provide organ perfusion, pain relief, muscle relaxation and renal diuresis, using lidocaine, dopamine, fentanyl, atracurium, and furosemide in 17.3% 14.7%, 12%, 10%, and 8.7% of animals, respectively. Methods of routine and advanced patient monitoring are described.

Anesthesia↗
PubMed1995

A 13-month-old boy with progressive genu valgum.

The following case illustrates the roentgenographic and clinical findings of a condition of interest to the orthopedic surgeon. Initial history, physical findings, and roentgenographic examinations are indicated below. The final clinical and differential diagnoses are presented on the following pages.

Bone Malalignment↗
PubMed1995

[Sedation and anesthesia in dogs and cats with cardiovascular disease. II. Anesthesia planning with respect to pathophysiology, heart arrhythmia].

The purpose of this study was to review the incidence of cardiac arrhythmias in 137 anesthetized dogs and 13 anesthetized cats with congenital or acquired heart disease that were referred for correction of following procedures: patent ductus arteriosus (PDA-ligation, 28%), cardiac catheterization with angiogram and angioplasty (22%), pacemaker implantation (18%), exploratory lateral thoracotomy (8.7%), correction of right aortic arch (ring anomaly, 3.3%), correction of subvalvular aortic stenosis (2.7%), correction of PDA with coil in patients with mitral regurgitation and congestive heart failure (2%), pericardectomy and removal of heart base tumor (2%), and palliative surgery for ventricular septal defect (VSD, 0.7%). The anesthetic plan considered the risks of anesthesia based upon the pathophysiology of cardiac lesions and the anesthetic drug effects on the cardiovascular system. Recommendations are made for dogs with decreased cardiac contractility, cardiac disease with volume overload, cardiac disease with pressure overload, and pericardial tamponade. The percentages of animals and their associated cardiac arrhythmias after premedication and during and after anesthesia were: sinus bradycardia (15.3%), sinus tachycardia (3.3%), atrial flutter (0.7%), atrial fibrillation (0.7%), premature ventricular contraction (14%), and ventricular tachycardia (1.3%). Prompt therapy was given to a percentage of animals in order to control arrhythmia and support cardiovascular system, by using atropine or glycopyrrolate (14%), lidocaine (17.3%), and dopamine (14.7%).(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia↗
PubMed1994

Respiratory emergencies in the adult horse.

Responding to an equine respiratory emergency requires rapid localization of the problem and appropriate choices for therapy. Localizing the cause of respiratory distress is aided by history and thorough physical examination. When examining the patient, one must focus on the presenting signs as indicators of URT or LRT dysfunction. Table 3 summarizes the characteristic presenting signs based on respiratory tract location and suggests the initial treatment course indicated. Respiratory distress in the absence of signs related to the pulmonary system suggests inadequate oxygen delivery secondary to a nonpulmonary problem such as shock or severe anemia, which is just as compromising to the animal but requires an entirely different therapeutic approach (see Allen and Schertel, this issue). Thus, localization of the source of respiratory distress is always the first step in determining successful treatment.

Animals↗
PubMed1993

Effects of diazepam, acepromazine, detomidine, and xylazine on thiamylal anesthesia in horses.

The cardiorespiratory effects of thiamylal (10 mg/kg of body weight, IV) and the effects of preanesthetic medication with diazepam, acepromazine, detomidine, or xylazine administered prior to a thiamylal dosage of 6 mg/kg, IV, were evaluated in 6 adult horses. The quality of recovery from thiamylal anesthesia also was evaluated. Intravenous administration of thiamylal at a dosage of 10 mg/kg increased heart rate, systemic arterial, pulmonary artery, and central venous blood pressures, as well as cardiac output and arterial partial pressure of CO2 (PaCO2). The maximal rate of right ventricular pressure increase (RVdP/dtmax), respiratory rate, and arterial partial pressure of O2 (PaO2) decreased, whereas arterial pH and systemic vascular resistance remained unchanged. Preanesthetic medication with diazepam prior to IV administration of thiamylal (6 mg/kg) did not change the pattern of this response, but diazepam did increase heart rate, cardiac output, and respiratory rate during the recovery period. Administration of acepromazine (0.1 mg/kg, IV) prior to administration of thiamylal increased heart rate and decreased systemic arterial and central venous blood pressures and systemic vascular resistance. Detomidine (10 micrograms/kg, IV), administered prior to thiamylal, decreased heart rate, cardiac output, and respiratory rate, and increased right atrial blood pressure. Administration of xylazine (0.5 and 1.0 mg/kg, IV) prior to thiamylal induced effects qualitatively similar to detomidine. Thiamylal decreased RVdP/dtmax and PaO2 in horses that received diazepam, acepromazine, detomidine, or xylazine.(ABSTRACT TRUNCATED AT 250 WORDS)

Acepromazine↗
PubMed1991

ECG of the month.

Explore the source record for details and available documents.

Anesthesia, Inhalation↗
PubMed1991

Spinal decompensation in Cotrel-Dubousset instrumentation.

Forty-one patients with idiopathic scoliosis having a primary right thoracic and a compensatory left lumbar curve underwent posterior spinal fusion of the primary curve only. Twenty-four patients had instrumentation with a Harrington rod or variant, and 17 patients underwent Cotrel-Dubousset instrumentation. Decompensation occurred postoperatively when the apex of the thoracic curve was located on or to the left of the center sacral line. There was no statistically significant change in the lumbosacral portion of the lumbar curve from the apex to the lumbosacral junction in both groups. Curve correction occurred cephalad to the apex of the lumbar curve, and not along the center sacral line. The decompensation rate was 4% for Harrington rod instrumentation and variants and 41% for Cotrel-Dubousset instrumentation. Cotrel-Dubousset instrumentation translated the apex of the thoracic curve 1.5 cm farther to the left than Harrington rod instrumentation and variants. When the apex of the lumbar curve is 2 cm or greater to the left of the center sacral line, the patient's spine will decompensate to the left, centered over the apex of the lumbar curve.

Arthrodesis↗
PubMed1990

Occipito-atlantal translation in Down's syndrome.

Several cases of occipito-atlantal instability have been reported in patients with Down's syndrome. However, standards for radiographic measurement and normal values for translational motion at the occiput-C1 level have not been established for the Down's patient. A retrospective analysis of 102 flexion and extension lateral cervical spine radiographs of 73 patients with Down's syndrome was performed. Patients with congenital cervical spine anomalies, C1-C2 instability, or previous neck surgery were excluded. Occiput-C1 translation was measured by the technique described by Wiesel and Rothman. In normal adult patients, occiput-C1 translation should be no more than 1 mm by this method. Analysis of the data demonstrated a range of 0 to 10 mm, with a mean of 2.62 mm and a standard deviation of +/- 1.94 mm. Only 30 sets of films (29%) representing 27 patients (37%) showed anteroposterior translation of 1 mm or less. This laxity was not dependent on patient age in the current study group. A review of these patients' medical records did not disclose any evidence of impaired neurologic function related to cervical spine instability. The authors' data suggest that the prevalence and magnitude of occipito-atlantal instability in Down's syndrome is greater than previously appreciated.

Adolescent↗
PubMed1989

Side effects of etomidate in dogs.

Intravenous administration of etomidate, a nonbarbiturate sedative hypnotic, induced excitement, myoclonus, pain on injection, vomiting, and apnea during induction of anesthesia in 20 experimental dogs and 70 hospitalized dogs. The dogs had excitement and purposeless muscle movements during recovery from anesthesia. The frequency and severity of the side effects were markedly attenuated or eliminated by the administration of diazepam, acepromazine, or morphine prior to etomidate administration.

Acepromazine↗
PubMed1989

Isoproterenol- and salbutamol-induced relaxation of acetylcholine- and histamine-induced contraction of equine trachealis muscle in vitro.

Strips of trachealis muscle were dissected from the midcervical portion of the trachea of horses that were free of respiratory tract disease, and the overlying epithelium and mucosa were removed. Muscle strips were suspended in tissue baths that were filled with Krebs-bicarbonate solution, aerated with 5% CO2 in oxygen and maintained at 37 C. Isometric tension was continuously recorded. The increase in active isometric tension was concentration dependent when acetylcholine (10(-9) to 10(-4) M) or histamine (10(-9) to 10(-4) M) was added to the tissue baths in 0.5-logarithmic increments. When the tissues were contracted with acetylcholine (3.1 x 10(-6) M) or histamine (10(-4) M), the decrease in active isometric tension was concentration dependent when isoproterenol (10(-9) to 10(-4) M) or salbutamol (10(-9) to 10(-4) M) was added to the tissue baths in 0.5-logarithmic increments. There was no difference between the response to isoproterenol and salbutamol when tissues from the same horses were compared whether the tissues were contracted in response to acetylcholine (3.1 x 10(-6) M) or histamine (10(-4) M). Relaxation was antagonized by 10(-6) M propranolol. The degree of relaxation obtained in these muscle strips was considerably less than that reported from other species' tracheal muscle strips that had the epithelium and mucosa intact. We concluded that equine tracheal smooth muscle contains beta-adrenoceptors that can be stimulated by either a mixed beta-1, beta-2 agonist or a selective beta-2 agonist.

Acetylcholine↗
PubMed1989

Epithelium- and mucosa-dependent relaxation and contraction of normal equine trachealis muscle in vitro.

Strips of trachealis muscle were dissected from the mid-cervical portion of the trachea from horses that were free of respiratory tract disease. The epithelium and mucosa were removed from one group of tissues and were left intact in a second group of tissues. Each tissue was suspended in a bath filled with Krebs-bicarbonate solution that was aerated with 5% CO2 in oxygen and maintained at 37 degrees C. Isometric tension was continuously recorded. The contractile response to square-wave electrical stimulations increased as frequency (3, 5, 10, 15, 20, 25, and 30 Hz), voltage (10, 15, 18, and 25 V), and pulse duration (0.2, 0.5, 1.0, 1.5, and 2.0 ms) increased in tissues with the epithelium and mucosa intact. A stimulus of 18 V, 20 Hz, and 0.5 ms induced maximal contraction. Atropine (10(-6) M) abolished the response to 18 V and 0.5 ms at all frequencies. The increase in active isometric tension was concentration dependent when acetylcholine (10(-9) to 10(-4) M) was added to the baths in 0.5-logarithmic increments. Tissues that were contracted in response to acetylcholine (10(-5) M) had a concentration-dependent decrease in active isometric tension when isoproterenol was added to the baths in 0.5-logarithmic increments (10(-9) to 10(-4) M). The contraction and relaxation curves were qualitatively similar, but quantitatively different in tissues with and without the epithelium and mucosa. Removing the epithelium and mucosa increased the contractile response to acetylcholine at bath concentrations of 3.1 x 10(-7) M and 10(-6) M. The presence of epithelium and mucosa enhanced the magnitude of isoproterenol-induced relaxations.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1989

Response of equine airway smooth muscle to acetylcholine and electrical stimulation in vitro.

Smooth muscle strips from the midcervical portion of the trachea and bronchial smooth muscle strips from third-generation airways of horses were placed in tissue baths, and isometric contractile force was measured. Active force was measured in response to electrical stimulation and exogenous acetylcholine. Square-wave electrical stimuli were applied at various voltages (10, 12, 15, 18, 20, 25 V), frequencies (3, 5, 10, 15, 20, 25, 30 Hz), and pulse durations (0.2, 0.5, 1.0, 1.5, 2.0 ms). Isometric contractile force increased as voltage, frequency, and pulse duration increased. Maximal contractile response to electrical stimulation was obtained at 18 V, 25 Hz, and 0.5 ms. Atropine (10(-6)M) or tetrodotoxin (3 x 10(-6)M) blocked the contraction, indicating that the contractile response was attributable to the release of neurotransmitter from cholinergic nerves. Cumulative concentration-response curves to acetylcholine (10(-9)M through 10(-4)M) were determined. Isometric contractile force increased as acetylcholine concentration increased. There was a significant (P less than 0.05) difference in the 50% effective dose for acetylcholine in tracheal smooth muscle and bronchial smooth muscle. The mean (+/- SD) contractile response to maximal electrical stimulus was 89% (+/- 7.4%) of that in response to 10(-4)M acetylcholine in tracheal smooth muscle and was 68% (+/- 10.4%) of the response to 10(-4)M acetylcholine in bronchial smooth muscle.

Acetylcholine↗