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.

Congenital absence of a lumbar pedicle presenting as back pain in children

Four children with back pain were shown to have a congenital absence of a lumbar pedicle. Computed tomography scanning was the most helpful diagnostic test. A modification of the classification of Tiyaworabun et al. for congenital absence of a pedicle in the cervical spine is suggested.

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.

Estimation of the lumbar curve magnitude with correction of the right thoracic curve in idiopathic scoliosis

A simple formula was proposed to estimate the magnitude of the postoperative uninstrumented lumbar curve with correction of the right thoracic curve in idiopathic scoliosis. This formula is as follows: PLC < or = LC - 0.5(TC - BTC) (PLC, predicted postoperative standing lumbar Cobb angle; LC, preoperative standing lumbar Cobb angle; TC, preoperative standing thoracic Cobb angle; BTC, preoperative supine lateral bending thoracic Cobb angle). Sixty-five patients' preoperative and postoperative radiographic measurements were taken, and of these 45 had measurements taken after > or = 12 months of follow-up. Multiple regression (R) value for the proposed formula postoperatively was 0.8048 and at > or = 1 year follow-up was 0.6869.

Age of closure of the neurocentral cartilage in the thoracic spine

We reviewed magnetic resonance images (MRIs) of 91 patients to estimate the chronologic age of closure of the neurocentral cartilage in the thoracic spine. The neurocentral cartilage on MRI appeared low signal in both T1- and T2-weighted images. It was thick and clearly identified in younger patients but was thin and vague in older patients. The neurocentral cartilage closed at 11-16 years in female patients and at 12-16 years in male patients.

Occult fracture of the calcaneus in toddlers

Five children 14-33 months of age were treated for calcaneal fractures. All had a history of trauma with limping or refusal to walk. Physical examination could not localize the fracture. Initial radiographs were negative. There were no signs of systemic illness. They were treated with long-leg casts. Radiographs after 2 weeks revealed an arc of sclerosis across the tuberosity of the calcaneus. In no case was a bone scan instrumental in making the diagnosis. Awareness of calcaneal fractures in the child younger than 36 months can prevent the routine use of bone scans to make the diagnosis.

Posterior spinal arthrodesis for atlantoaxial instability in Down syndrome

Nine children with Down syndrome who had atlantoaxial instability underwent posterior spinal fusion. At follow-up, all patients had stabilization or improvement of their neurologic symptoms. Evaluation of the spine using flexion and lateral radiographs, as well as selective cineradiography, showed no instability over the fused area or adjacent motion segments. Stable fibrous union with no clinical significance was noted in three of the nine patients. We recommend posterior spinal fusion in situ with external immobilization as the safest and most effective means of surgical stabilization in the patient with Down syndrome who has symptomatic atlantoaxial instability.

Blood gas values during intermittent positive pressure ventilation and spontaneous ventilation in 160 anesthetized horses positioned in lateral or dorsal recumbency

One hundred sixty horses were anesthetized with xylazine, guaifenesin, thiamylal, and halothane for elective soft tissue and orthopedic procedures. Horses were randomly assigned to one of four groups. Group 1 (n = 40): Horses positioned in lateral (LRG1; n = 20) or dorsal (DRG1; n = 20) recumbency breathed spontaneously throughout anesthesia. Group 2 (n = 40): Intermittent positive pressure ventilation (IPPV) was instituted throughout anesthesia in horses positioned in lateral (LRG2; n = 20) or dorsal (DRG2; n = 20) recumbency. Group 3 (n = 40): Horses positioned in lateral (LRG3; n = 20) or dorsal (DRG3; n = 20) recumbency breathed spontaneously for the first half of anesthesia and intermittent positive pressure ventilation was instituted for the second half of anesthesia. Group 4 (n = 40): Intermittent positive pressure ventilation was instituted for the first half of anesthesia in horses positioned in lateral (LRG4; n = 20) or dorsal (DRG4; n = 20) recumbency. Spontaneous ventilation (SV) occured for the second half of anesthesia. The mean time of anesthesia was not significantly different within or between groups. The mean time of SV and IPPV was not significantly different in groups 3 and 4. Variables analyzed included pH, PaCO2, PaO2, and P(A-a)O2 (calculated). Spontaneous ventilation resulted in significantly higher PaCO2 and P(A-a)O2 values and significantly lower PaO2 values in LRG1 and DRG1 horses compared with LRG2 and DRG2 horses. Intermittent positive pressure ventilation resulted in normocarbia and significantly lower P(A-a)O2 values in LRG2 and DRG2 horses. In LRG2 the PaO2 values significantly increased from 20 minutes after induction to the end of anesthesia. The PaO2 and P(A-a)O2 values were not significantly different from the beginning of anesthesia after IPPV in DRG2 or DRG3. The PaO2 values significantly decreased and the P(A-a)O2 values significantly increased after return to SV in horses in LRG4 and DRG4. The PaO2 values were lowest and the P(A-a)O2 values were highest in all horses positioned in dorsal recumbency compared with lateral recumbency and in SV horses compared with IPPV horses. The pH changes paralleled the changes in PaCO2. Blood gas values during right versus left lateral recumbency in all groups were also evaluated. The PaO2 values were significantly lower and the P(A-a)O2 values were significantly higher during SV in horses positioned in left lateral (LRLG1) compared with right lateral (LRRG1) recumbency.(ABSTRACT TRUNCATED AT 400 WORDS)

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.

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.

Excision of herniated nucleus pulposus in children and adolescents

Eighty-eight patients were treated at the Alfred I. duPont Institute for disc disease from 1940 to 1989. Forty-eight patients, with an average age of 16 years, underwent discectomy. Twenty-three patients were followed for an average of 6 years after initial presentation. Thirteen patients, with an average age of 15 years, and who had radiographic documentation of disc disease, were treated nonoperatively. Eight patients were followed for an average of 6.3 years. The results of discectomy were rated as excellent or good in 91% of the patients, and poor in 9% at follow-up. In the patients treated nonoperatively, the results were rated as excellent or good in 25%, and poor in 75%. Our 6 year follow-up study suggests that discectomy yields excellent to good long-term results in children and adolescents.

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)

Dysplasia epiphysealis hemimelica: diagnosis and treatment

Clinical features and radiographic findings of eight patients with dysplasia epiphysealis hemimelica are described. In all patients, a single lower extremity was involved. The most common sites of involvement were the distal tibia and the distal femur. Magnetic resonance imaging was beneficial in determining a plane of separation between the accessory ossification center and the normal epiphysis. If the lesion is extraarticular, simple excision of the mass yields favorable results. If the lesion is intraarticular, an osteotomy may be needed to correct an angular deformity. Recurrence of the deformity is common.

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.

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.

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)

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.

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.

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.

Innervation of crab-eating monkey trachealis muscle determined in vitro

Strips of smooth muscle from the cervical tracheae of six adult male crab-eating monkeys (Macaca fascicularis) were studied in jacketed 25 ml organ baths filled with Krebs-bicarbonate solution maintained at 37 degrees C and gassed with 5% CO2 in oxygen. Isometric tissue tension increased in response to electrical field stimulation (18 V, 25 Hz, 0.5 msec), norepinephrine in the presence of propranolol, acetylcholine and histamine. Atropine abolished the contractile response to electrical stimulation. Tissues that were contracted with acetylcholine or pretreated with atropine then contracted with histamine relaxed when stimulated electrically. The relaxation was unaffected by propranolol but was abolished by tetrodotoxin. Isoproterenol relaxed tissues that were contracted with histamine, but failed to relax histamine-contracted tissues that had been pretreated with propranolol. Norepinephrine did not change isometric tension in untreated tissues or tissues pretreated with phentolamine. These results demonstrate the presence of excitatory and inhibitory nerves and noninnervated beta-adrenergic receptors in macaque trachealis. The excitatory nerves appear to be cholinergic. The inhibitory response to electrical stimulation is not mediated through muscarinic cholinergic or beta-adrenergic receptors. The inhibitory response to electrical field stimulation was likely mediated through nonadrenergic noncholinergic nerves.

Arterial blood gas tensions in the horse during recovery from anesthesia

The effects of body position and postoperative oxygen supplementation on arterial blood gas tensions (PaO2 and PaCO2) and pH were examined in clinically normal adult horses during recovery from halothane anesthesia. Hypoxemia developed during recovery from anesthesia in spite of adequate alveolar ventilation in horses without postanesthetic oxygen supplementation. Hypoxemia developed in horses positioned in left lateral or right lateral recumbency, and in horses that were rolled to the opposite side during the recovery period. Arterial blood gas tensions were not significantly (P greater than 0.05) different between horses insufflated with 100% oxygen at the rate of 10 L/min during recovery and horses that did not receive oxygen supplementation during the recovery period. Horses that received 100% oxygen at the rate of 50 L/min through a demand valve had arterial blood gas tensions similar to those in standing awake horses.