Development of novel linkers to conjugate pharmacophores to a carrier antibody.

We have developed modified maleimide novel linkers with improved chemical stability that could potentially be used in conjugating various pharmacophores such as oligo nucleotides, peptides, and proteins to antibodies to afford novel biologics with well-defined therapeutic benefits and improved pharmacokinetic properties. These linkers expand the array of tools available for bioconjugation of pharmacophores to antibodies.

Inhibitors of ABL and the ABL-T315I mutation.

Chronic myelogenous leukemia (CML) is a hematological stem cell disorder caused by increased and unregulated growth of myeloid cells in the bone marrow, and the accumulation of excessive white blood cells. Abelson tyrosine kinase (ABL) is a non-receptor tyrosine kinase involved in cell growth and proliferation and is usually under tight control. However, 95% of CML patients have the ABL gene from chromosome 9 fused with the breakpoint cluster (BCR) gene from chromosome 22, resulting in a short chromosome known as the Philadelphia chromosome. This Philadelphia chromosome is responsible for the production of BCR-ABL, a constitutively active tyrosine kinase that causes uncontrolled cellular proliferation. An ABL inhibitor, imatinib, was approved by the FDA for the treatment of CML, and is currently used as first line therapy. However, a high percentage of clinical relapse has been observed due to long term treatment with imatinib. A majority of these relapsed patients have several point mutations at and around the ATP binding pocket of the ABL kinase domain in BCR-ABL. In order to address the resistance of mutated BCR-ABL to imatinib, 2(nd) generation inhibitors such as dasatinib, and nilotinib were developed. These compounds were approved for the treatment of CML patients who are resistant to imatinib. All of the BCR-ABL mutants are inhibited by the 2(nd) generation inhibitors with the exception of the T315I mutant. Several 3(rd) generation inhibitors such as AP24534, VX-680 (MK-0457), PHA-739358, PPY-A, XL-228, SGX-70393, FTY720 and TG101113 are being developed to target the T315I mutation. The early results from these compounds are encouraging and it is anticipated that physicians will have additional drugs at their disposal for the treatment of patients with the mutated BCR-ABL-T315I. The success of these inhibitors has greater implication not only in CML, but also in other diseases driven by kinases where the mutated gatekeeper residue plays a major role.

Inhibition of nuclear factor-kappaB in T cells suppresses lung fibrosis.

RATIONALE: Cytokines secreted by T cells play a pivotal role in the pathogenesis of lung injury and fibrosis, and the transcription factors nuclear factor (NF)-kappaB and activator protein (AP)-1 are involved in the expression of cytokines from T cells during lung injury. OBJECTIVES: We assessed the potential therapeutic effect of SP100030, a specific inhibitor of T-cell NF-kappaB and AP-1 in lung fibrosis. METHODS: The effect of SP100030 was evaluated using a mouse model of chronic lung fibrosis. MEASUREMENTS AND MAIN RESULTS: Mice treated with SP100030, as compared with untreated mice, had significantly less cachexia and less lung injury and had decreased levels of inflammatory cytokines and growth factors, decreased activation of coagulation activation, and decreased collagen deposition in the lung. The inhibitory activity of SP100030 was dose dependent and was effective in acute and chronic phases of lung fibrosis. SP100030 inhibited the activation of the protein kinase C-isoform in T-cell lines and suppressed NF-kappaB-driven cytokine expression in CD4(+) and CD8(+) T cells. CONCLUSIONS: These results suggest that the specific inhibition of NF-kappaB could be useful for the treatment of lung fibrosis.

Discovery of 3,3'-(2,4-diaminopteridine-6,7-diyl)diphenol as an isozyme-selective inhibitor of PI3K for the treatment of ischemia reperfusion injury associated with myocardial infarction.

In studies aimed toward identifying effective and safe inhibitors of kinase signaling cascades that underlie ischemia/reperfusion (I/R) injury, we synthesized a series of pteridines and pyridopyrazines. The design strategy was inspired by the examination of naturally occurring PI3K inhibitors such as wortmannin and quercetin, and building a pharmacophore-based model used for optimization. Structural modifications led to hybrid molecules which incorporated aminopyrimidine and aminopyridine moieties with ATP mimetic characteristics into the pharmacophore motifs to modulate kinase affinity and selectivity. Elaborations involving substitutions of the 2 and 4 positions of the pyrimidine or pyridine ring and the 6 and 7 positions of the central pyrazine ring resulted in in vivo activity profiles which identified potent inhibitors of vascular endothelial growth factor (VEGF) induced vascular leakage. Pathway analysis identified a diaminopteridine-diphenol as a potent and selective phosphatidylinositol-3-kinase (PI3K) inhibitor. The structure-activity relationship studies of various analogues of diaminopteridine-diphenol-based on biochemical assays resulted in potent inhibitors of PI3K.

Discovery of [7-(2,6-dichlorophenyl)-5-methylbenzo [1,2,4]triazin-3-yl]-[4-(2-pyrrolidin-1-ylethoxy)phenyl]amine--a potent, orally active Src kinase inhibitor with anti-tumor activity in preclinical assays.

We describe the identification of [7-(2,6-dichlorophenyl)-5-methylbenzo [1,2,4]triazin-3-yl]-[4-(2-pyrrolidin-1-ylethoxy)phenyl]amine (3), a potent, orally active Src inhibitor with desirable PK properties, demonstrated activity in human tumor cell lines and in animal models of tumor growth.

Discovery and preliminary structure-activity relationship studies of novel benzotriazine based compounds as Src inhibitors.

We report the discovery and preliminary SAR studies of a series of structurally novel benzotriazine core based small molecules as inhibitors of Src kinase. To the best of our knowledge, benzotriazine template based compounds have not been reported as kinase inhibitors. The 3-(2-(1-pyrrolidinyl)ethoxy)phenyl analogue (43) was identified as one of the most potent inhibitors of Src kinase.

Management of anesthesia in geriatric patients undergoing head and neck surgery.

Surgical outcomes of patients aged 65 and older depend in part on the patient's physiologic status and coexisting disease and whether the surgery is elective or urgent. As our overall population continues to grow older, more elderly patients with head and neck cancers are being scheduled for surgery. In addition to the usual problems of aging, older head and neck surgery patients have unique airway issues that must be addressed preoperatively. Likewise, thorough planning for perioperative management is imperative to reduce morbidity and mortality. Because pharmacokinetics and pharmacodynamics are different in older patients than in younger patients, the administration of anesthesia must be adjusted accordingly.

Significance of atrial septal aneurysm: report of a case.

Postoperative stroke can have many etiologies including cerebral thrombosis, embolism, and hemorrhage. If there is a right-to-left intracardiac shunt, paradoxical embolism may also occur. Atrial septal aneurysm has been diagnosed with increasing frequency because of the accuracy of transesophageal echocardiography (TEE). Atrial septal aneurysm is also associated with patent foramen ovale and atrial septal defects. We report a case of a patient who developed a postoperative stroke one day after coronary artery bypass surgery. TEE performed in the intensive care unit revealed an atrial septal aneurysm with a right-to-left interatrial shunt, which may have resulted in paradoxical systemic embolism.

Changes in intraocular pressure during low dose intravenous sedation with propofol before cataract surgery.

AIMS: This study examined the effects on intraocular pressure, pulse rate, and blood pressure of low dose intravenous sedation with propofol. METHODS: Twenty adult patients who were scheduled to undergo cataract surgery were given a single intravenous bolus (0.98 (SEM 0.4) mg/kg) of propofol for sedation before administering the local anaesthetic for cataract surgery. A small intravenous dose of lignocaine was the only other anaesthetic or sedative agent given. The intraocular pressure in the non-surgery eye, the pulse rate, and the blood pressure were measured before and after propofol induction. RESULTS: Compared with the preinduction baseline, there was a 17% to 27% (from 16.2 (0.7) mm Hg to 11.8 (0.7) mm Hg) decrease in intraocular pressure after propofol induction. A significant decrease in intraocular pressure occurred within the first minute and was still evident at 7 minutes when the measurements were stopped. There was also a 7%-12% increase in pulse rate during the first 4 minutes, a 12% decrease in mean systolic blood pressure, and a 7% decrease in mean diastolic blood pressure from baseline after propofol induction. CONCLUSION: A single low dose bolus of propofol used for sedation before cataract surgery caused a moderate reduction in intraocular pressure with minimal, easily managed side effects.

Increased cerebral and decreased femoral artery blood flow velocities during direct laryngoscopy and tracheal intubation.

Direct laryngoscopy and tracheal intubation may be associated with increased heart rate, arterial blood pressure, cardiac index, and systemic vascular resistance. These responses have been attributed to sympathoadrenal stimulation. However, the studies measuring distribution of blood flow to various organs are limited. We prospectively evaluated blood flow velocities in the common carotid, middle cerebral, and femoral arteries before induction of anesthesia, after induction but before direct laryngoscopy, at the conclusion of direct laryngoscopy and tracheal intubation, and 3 min after tracheal intubation in 13 adult patients. Direct laryngoscopy and tracheal intubation produced increases in the heart rate (from 76 +/- 13 to 91 +/- 10 bpm; chi +/- SD), systolic blood pressure (from 168 +/- 20 to 206 +/- 21 mmHg), common carotid and middle cerebral blood flow velocities, but produced decreases in femoral artery blood flow velocities. Common carotid artery blood flow velocity increased from 49.4 +/- 12.5 cm/s to 65.2 +/- 20.7 cm/s (P < 0.05) at the conclusion of tracheal intubation. Middle cerebral artery blood flow velocity, which could be measured only in seven patients due to technical difficulties secondary to movement during laryngoscopy, increased from 62.4 +/- 20.5 cm/s to 78.0 +/- 27.7 cm/s (P < 0.05). In contrast, femoral artery blood flow velocity decreased from 107.6 +/- 37.8 cm/s to 76.8 +/- 28.6 cm/s (P < 0.05). These responses suggest that the hypertensive response due to direct laryngoscopy and tracheal intubation is associated with redistribution of blood flow in the body.

Loss of hypoxic ventilatory response following bilateral neck dissection.

Modified radical neck or combined radical and modified radical neck surgery is performed for treatment of head and neck cancer. Because of the extensive nature of the surgery, including dissection around the carotid vessels, we prospectively evaluated hypoxic ventilatory responses preoperatively and postoperatively in five patients. The change in ventilation to percent desaturation varied between -0.22 and -0.60 L/min per percent desaturation in the five study patients. In the postoperative evaluation, two of five patients showed flattened responses compared with the preoperative measurements due to denervation of their carotid bodies. Two patients showed increased responses due to loss of upper airway resistance from tracheostomy. We conclude that after bilateral neck dissection for cancer surgery some patients may lose their hypoxic ventilatory responses due to carotid body denervation.

Noncardiac surgery in the patient with congenital heart disease.

The patient with congenital heart disease who presents for noncardiac surgery requires careful evaluation and planning to avoid adverse perioperative events. This chapter presents a physiological approach to the management of anesthesia for the most common congenital heart lesions. The various congenital heart defects are categorized into lesions resulting in: (1) left-to-right shunting; (2) right-to-left shunting; (3) complete mixing of pulmonary and systemic circulation; (4) complete separation of the pulmonary and systemic circulations; (5) increased myocardial work; and (6) mechanical obstruction of the airway.

Resistance to vecuronium in patients with cerebral palsy.

To determine the electromyographic response of patients with cerebral palsy to vecuronium, 10 children (mean age, 6 yr 10 mo) without cerebral palsy and 11 children with cerebral palsy (mean age, 10 yr 3 mo) were studied. All patients were undergoing abdominal or orthopedic surgery and were anesthetized with isoflurane and nitrous oxide. The time from intravenous administration of 0.1 mg/kg of vecuronium to 25% recovery of control twitch height was 43.9 +/- 5.3 and 18.9 +/- 1.7 min (mean +/- SEM) in children without and with cerebral palsy, respectively (P less than 0.01). The authors conclude that patients with cerebral palsy are either resistant to vecuronium or have a rapid clearance as evidenced by the rapid recovery from neuromuscular blockade.

Chest radiograph changes after cardiopulmonary bypass in children.

To determine the spectrum of pediatric chest radiograph changes after cardiopulmonary bypass, 98 children (mean age = 5.9 yr, range 4 wk-16 yr) were studied for 3 days postoperatively. Daily A-P radiographs were evaluated for atelectasis, cardiomegaly, pleural effusions, diaphragmatic elevation, mediastinal widening, and pulmonary infiltrates. The overall incidence of atelectasis was 82%, with left lower lobe atelectasis the most common (64%). Right upper lobe atelectasis occurred in 35% of patients, far more common than in the adult. Radiographic changes were then compared with independent variables including patient weight, age, duration of bypass, and fluid balance by multiple linear regression. Pleural effusion correlated with patient weight and duration of bypass. Diaphragmatic elevation correlated with patient weight. Cardiomegaly correlated with patient age. Net fluid balance was a poor predictor of postoperative chest radiograph changes. We conclude that radiographic changes are common after cardiopulmonary bypass in children, that the overall incidence is not markedly different from adults, and that right upper lobe atelectasis occurs more frequently in children.

Hypoglycemia following bilateral adrenalectomy for pheochromocytoma.

Severe hypoglycemia with delayed emergence occurred in a 12-yr-old boy following bilateral adrenalectomy for pheochromocytoma. Hypoglycemia after resection of pheochromocytoma may be due to release of insulin from the beta cells of the pancreas due to sudden withdrawal of catecholamines. Beta blockade with the use of propranolol impairs both hepatic glucose production and glucagon secretion mechanism. For early detection and treatment of hypoglycemia, perioperative blood glucose monitoring is important in patients undergoing adrenalectomy for pheochromocytoma.

Monitoring urinary bladder temperature.

We evaluated bladder, rectal, and esophageal temperatures compared with nasopharyngeal temperatures in 12 patients who underwent cardiac surgery that required CPB. Changes in bladder temperature lagged behind those of esophageal and nasopharyngeal temperature during rapid cooling and rewarming. Changes in rectal temperature were the slowest. Bladder and rectal temperatures were similar after surgery. Monitoring bladder temperature represents the core temperature in a steady state.

Postoperative phrenic nerve palsy in patients with open-heart surgery.

We prospectively studied patients undergoing open-heart surgical procedures to evaluate the role of phrenic nerve palsy in the causation of the high incidence of pulmonary complications reported in these patients. Although atelectasis, or infiltrates, or both developed in the left lower lobe of 98% of the patients (43 of 44) with or without similar changes on the right side, only 5 (11%) of the 44 patients had diaphragmatic dysfunction following operation. In 1, the left phrenic nerve became inexcitable; 2 had paresis of the left hemidiaphragm, and 2 had paresis of the right hemidiaphragm. Although damage to the phrenic nerve can occur during open-heart operations, a relatively low incidence of this complication does not support it as the major cause of postoperative pulmonary complications.

Monitoring of multimodality evoked potentials during open heart surgery under hypothermia.

Multimodality evoked responses (ERs) were monitored in 16 adults who had cardiac surgery under cardiopulmonary bypass and moderate hypothermia (19-25 degrees C). Cooling affected all sensory ERs by progressively increasing the latencies of the major components. The effect was more profound on the later than on the earlier ER components. Visual evoked responses (VERs) were most inconsistent and always disappeared at temperatures below 25 degrees C. The later components of the long latency somatosensory evoked responses (SERs) also attenuated or disappeared rather early during hypothermia. On the other hand, short latency SERs were more resistant to the effects of hypothermia. They were always recordable at temperatures of 25 degrees C or above; and usually persisted even at temperatures between 20 and 25 degrees C. Brain-stem auditory evoked responses (BAERs) were consistently present at temperatures above 25 degrees C, wave V was recordable in majority between 20 and 25 degrees C. All sensory ERs disappeared with severe hypothermia (20 degrees C or less) except the components generated more peripherally such as N10 of the short latency SERs. We feel that BAERs and short latency SERs may serve as useful intraoperative monitors of brain function during hypothermia.