The isolation and characterization of a novel collagenolytic serine protease allergen (Der p 9) from the dust mite Dermatophagoides pteronyssinus.

BACKGROUND: Dust mites have been shown to contain a serine protease distinct from the previously reported trypsin and chymotrypsin. The latter enzymes have been shown to be allergens, but the allergenic importance of the former is unknown. OBJECTIVE: This study was performed to isolate and characterize the novel mite serine protease and determine its allergenicity. METHODS: The mite serine protease was isolated from feces-enriched extracts of Dermatophagoides pteronyssinus by ion-exchange chromatography and affinity chromatography, and its physicochemical properties were determined. The allergenicity of the protease was assessed by using the RAST. RESULTS: The protease was enzymatically similar to chymotrypsin and cathepsin G-like enzymes from a variety of sources and was shown to cleave collagen. It had a molecular mass of 23,780 d. N-terminal sequence analysis (18 residues) indicated homology with the mite tryptic allergen, Der p 3, and the chymotryptic allergen, Der p 6. RAST analyses showed that the frequencies of reactivity to the novel allergen and to Der p 1, Der p 2, Der p 3, and Der p 6 were 92%, 97%, 100%, 97%, and 65%, respectively (n = 35). RAST inhibition studies showed some cross-reactivity between the protease and Der p 3 but not Der p 6. CONCLUSIONS: A novel mite serine protease was isolated from D. pteronyssinus and found to be a major allergen. This allergen has been tentatively designated Der p 9.

Pretreatment of human myocardium with adenosine during open heart surgery.

BACKGROUND: Depressed myocardial performance after cardiac surgery can be contributed to ischemic reperfusion injury (IRI) incurred during and following the cardiopulmonary bypass (CPB). Myocardial preconditioning (PC) achieved by brief ischemia and subsequent reperfusion appears to be a clinically useful method of improved cardiac protection during surgery involving CPB by retarding IRI. Based on animal studies, activation of cardiac adenosine (ADO) receptors prior to the prolonged ischemic period appears to mimic this PC phenomenon. AIMS AND METHODS: We investigated whether the human myocardial PC can be mimicked with ADO in the setting of the coronary artery bypass graft (CABG). The specific proposed objective of this study was to determine whether ADO infusion just prior to starting the CPB can improve post-CPB myocardial hemodynamics. Patients undergoing elective CABG with poor ventricular function (ejection fraction approximately 30%), and with at least three-vessel disease were selected for this study (n = 7 ADO, and n = 7 control). RESULTS: Our results show that ADO infusion (250-350 micrograms/kg X 10 min) just prior to CPB resulted in an immediately improved postbypass cardiac index (CI) in the OR (CI increase of 41.5% +/- 11.1% for ADO vs 9.7% +/- 6.0% for control, p < 0.05). Forty hours postoperatively in the intensive care unit, ADO patients had improved CI (3.3 +/- 0.2 L/min per m2 for ADO, vs 2.6 +/- 4 L/min per m2 for control, p < 0.05). ADO patients maintained lowered resting heart rate (90 +/- 6 for ADO, vs 108 +/- 4 for control, p < 0.05) 40 hours after surgery. ADO patients also released significantly less CPK during the first 24 hours of the postoperative period. CONCLUSION: Based on these measurements, ADO pretreated patients had improved ventricular performance postoperatively. It also appears that ADO pretreatment results in lowered postoperative myocardial energy demand and less myocellular injury during CPB. To our knowledge, this is the first study to demonstrate that human myocardium can be hemodynamically improved with ADO pretreatment, and may be protected against IRI incurred during and following the CPB. We believe that a cardiac surgeon may now have the unique opportunity to confer myocardial protection during and after a cardiac surgical procedure.

Immediate-early gene expression in human saphenous veins harvested during coronary artery bypass graft operations.

Saphenous vein graft occlusion is a common late complication of coronary bypass grafting. Intimal smooth muscle cell hyperplasia is a component of this pathobiology, but the underlying molecular events are poorly understood. Immediate-early genes are activated shortly after growth stimulation and subserve cellular functions, which may contribute to intimal smooth muscle cell accumulation. In the present study, human saphenous vein grafts were harvested with minimal manipulation during coronary bypass and processed for isolation of total ribonucleic acid to examine change in immediate-early gene expression of messenger ribonucleic acid by Northern blotting techniques. Thirty saphenous vein grafts were incubated at 4 degrees C in Dulbecco's modified Eagle media from 30 minutes to 10 hours. The messenger ribonucleic acids for immediate-early genes c-fos and c-myc were weak or undetectable in controls but were increased (> 10 times controls) within 1 hour (c-fos) and persisted for at least 6 hours (c-myc) after harvest. Our results demonstrate, for the first time in human vascular tissue, incipient immediate-early gene induction. This information may lead to molecular therapies to control saphenous vein graft disease.

NF-Y activates mouse tryptophan hydroxylase transcription.

Tryptophan hydroxylase catalyses the rate-limiting step in the biosynthesis of serotonin, a neurotransmitter which has been implicated in the etiologies of clinically important psychiatric illnesses. Tryptophan hydroxylase is expressed in a tissue-specific manner, but little is known about its transcriptional regulation. By analysing transcriptional activities of a set 5'-deletion constructs of promoter-reporter plasmids in P815-HTR mastocytoma cells, we found that transcription was activated by sequences between nucleotides -343 and -21. DNase I footprint analysis, using nuclear protein extracts from P815-HTR cells, revealed a protein-DNA interaction between nucleotides -77 and -46. A double stranded oligonucleotide, representing this binding site, specifically bound nuclear protein in a gel shift assay. Methylation interference analysis of this complex revealed that nuclear protein interacted with an inverted GGCCAAT element, which is a high-affinity binding motif for the transcription factor NF-Y (also known as CP1 or CBF). An NF-Y specific antibody abolished protein binding in a gel shift assay. Mutagenesis of specific base pairs abolished protein binding in vitro, and mutagenesis of the same base pairs in a reporter gene construct resulted in a 65% decrease in transcriptional activity. Our results suggest that the transcription factor NF-Y binds to a GGCCAAT motif in the tph proximal promoter and activates transcription.

Experience with the Mitroflow aortic bioprosthesis.

From October 1985 to May 1990, the Mitroflow bovine pericardial valve was placed in the aortic position in 168 patients (97 men, 71 women) with a mean age of 69.7 years. Eighty-nine patients had isolated aortic valve replacement, and 79 had aortic valve replacement and additional procedures. Follow-up over 7 1/2 years includes 781 patient years (426 for isolated aortic valve replacement). Mean follow-up time is 56 months. Peak-to-peak gradients (in millimeters of mercury) measured in the intraoperative period averaged 11.0 +/- 8.7, 11.8 +/- 10.8, and 8.6 +/- 8.2 for 19 mm, 21 mm, and 23 mm valves, respectively. Hospital mortality was 7.3% (14 patients); all deaths were non-valve related. Late mortality of 20.1% in 31 patients resulted from cardiac failure (n = 8), sepsis (n = 4), valve reoperation (n = 1), non-cardiac causes (n = 15) and sudden, unknown causes (n = 3). Fifteen thromboembolic episodes occurred, but only three late thromboembolic episodes occurred in isolated aortic valve replacement without other risk factors. Four early and four late episodes of endocarditis occurred. Seven patients had clinical valve dysfunction, and five others required reoperation for structural deterioration, with one death. At 94 months, overall survival was 64% +/- 5%. Freedom from thromboembolic episode was 87% +/- 3% and 90% +/- 4% for isolated aortic valve replacement. Freedom from combined reoperation or clinical dysfunction was 75% +/- 8%: 64% +/- 15% for those under 70 years of age, and 87% +/- 7% for those 70 years of age and older. The valve has favorable hemodynamics. Durability begins to decline during the sixth year after implantation, possibly at a slower rate in patients older than 70 years of age.

Repair of coronary sinus rupture secondary to retrograde cardioplegia.

Coronary sinus injuries related to retrograde cardioplegia administration are uncommon, but can be a lethal complication of this technique. This report describes a major coronary sinus disruption during retrograde cardioplegia administration and details a method of repair with suggestions for possible prevention of this complication.

Safety and efficacy of autologous blood donation before elective aortic valve operation.

Although the use of preoperative autologous blood donations for patients undergoing elective cardiac operations has increased dramatically in recent years, patients awaiting elective aortic valve replacement have traditionally been denied access to preoperative autologous blood collection programs. We report our experience with 79 patients, each of whom donated 1 to 3 units of autologous blood before an aortic valve operation. All patients had serious aortic valve disease as evidenced by symptoms and preoperative catheterization data. The patients collectively made 129 blood donations. One patient had a syncopal episode within 2 hours of donation and recovered without difficulty. Of the patients who gave autologous blood preoperatively, 68% avoided any homologous blood donor exposure during their subsequent hospitalization for aortic valve replacement. In contrast, in a group of 298 patients who did not give autologous blood preoperatively, only 31% avoided homologous blood exposure during aortic valve replacement (p < 0.0001). Our experience suggests that preoperative autologous blood donation by patients awaiting elective aortic valve replacement is both safe and effective. Patients with aortic valve disease should not be routinely excluded from preoperative blood services.

Primary cardiac tumors. Diagnosis and management in 14 cases.

In our experience over a 10-year period at Westchester County Medical Center (Valhalla, NY), we diagnosed 11 left atrial myxomas and three primary cardiac malignancies in ten females and four males, aged 18-74 years. Two-dimensional echocardiography enabled the correct diagnosis of these lesions. Detailed characteristics of the cardiac tumors were provided by magnetic resonance imaging (MRI) scanning in five patients. Two of three malignancies were only biopsied; the myxomas were completely excised. We emphasized removal of tumor and its attachments to the atrial wall, accomplished by left or biatrial incision, full-thickness excision of the area of attachment, and pericardial patch closure of the atrial or free-wall defects. Associated procedures included mitral valve repair (three) and coronary artery bypass grafting (two). There was no mortality associated with the surgery. Two patients with malignancy died three and 36 months after surgery; a third is alive at 30 months after surgery. No patients with myxoma has had recurrence from 16 to 100 months. Preoperative diagnosis of cardiac tumors is enhanced by MRI scanning and may help in planning the surgical procedure. Complete and timely removal of these tumors contributes to long-standing patient survival.

Analysis of gunshot residue test results in 112 suicides.

The results of gunshot residue (GSR) tests in 112 suicide cases investigated by the U.S. Army Criminal Investigation Command over a ten-year period are described. Only suicide cases in which there was certainty that the victim fired a weapon were examined in an effort to reduce ambiguous results. Previous case work research by Rudzitis indicated that positive GSR test results were encountered in suicides 62% of the time using various combinations of neutron activation analysis (NAA) and atomic absorption spectrophotometry (AAS). Threshold values of 0.2-micrograms antimony and 0.3-micrograms barium (0.2-micrograms antimony and 0.5-micrograms barium after 1985) used by the U.S. Army Criminal Investigation Laboratory resulted in positive GSR results in suicide cases 38% of the time. The effects of time, location of body, handling of the body, weapon type, caliber, and condition of the hands on GSR results are examined. Case studies involving suicides by unit armorers are discussed.

Simplified method for reoperation on the mitral valve.

Reoperation on the mitral valve is becoming more common because of the degeneration of bioprosthetic valves, endocarditis, and malfunction or thrombosis of mechanical valves. We advocate a technique that transforms a technically difficult operation into one that is much less tedious, time-consuming, and dangerous than reopening a sternal-split operative site the second, third, or fourth time. Favorable experience in 11 patients using right anterolateral thoracotomy without aortic or right atrial cannulation and without aortic cross-clamping or cardioplegia is presented.

Prevention of ventricular fibrillation after aortic declamping during cardiac surgery.

Ventricular fibrillation is common after aortic declamping during cardiac surgery, and the metabolic demands of such fibrillation, or its treatment by means of countershock, may contribute to myocardial injury. To determine the effects of administering intravenous lidocaine just before aortic declamping, we randomly divided 194 cardiac surgery patients into 2 groups. One hundred patients (group A) received lidocaine, 200 mg intravenously, 3 minutes before aortic declamping; and 94 patients (group B) received no medication before declamping. Multiple baseline variables, including clamp times, medications, electrolyte values, ventricular function, and the extent and type of surgery, were similar for both groups. After aortic declamping, 31 of the 100 patients in group A had ventricular fibrillation, as did 57 of the 94 patients in group B (p < 0.001). Of those who fibrillated, the group-A patients required a mean of 1.76 countershocks, whereas the group-B patients required a mean of 2.68 countershocks (p < 0.05). Serum potassium level also affected the incidence of ventricular fibrillation, independently of lidocaine. Elevated serum potassium levels were associated with a lower incidence of ventricular fibrillation. Although lidocaine was independently protective at all potassium levels, the combination of lidocaine and a high serum potassium level had the greatest effect in preventing fibrillation. In patients who had potassium levels higher than 5.1 mEq/l and who were also given lidocaine, the incidence of ventricular fibrillation was lower than 15%.

Predictors, prevention, and long-term prognosis of atrial fibrillation after coronary artery bypass graft operations.

Multiple trials have suggested the use of digoxin, digoxin and propranolol, or timolol to prevent atrial fibrillation after coronary artery bypass grafting. No trial has evaluated the efficacy of digoxin verus propranolol. Furthermore, the predictors of postoperative atrial fibrillation and the long-term consequence of atrial fibrillation that reverts to sinus rhythm have not been established. One hundred fifty patients were randomized to receive no drug, propranolol (20 mg every 6 hours), or digoxin (0.5 mg followed by 0.25 mg daily). Twenty-seven patients were excluded from data analysis. In the remaining 123 patients, no preoperative parameter (age, sex, diabetes, hypertension, smoking, electrocardiographic p wave morphology, or preoperative digoxin or propranolol therapy), intraoperative parameter (bypass time, aortic cross-clamp time, or number of vessels bypassed), or postoperative parameter (peak creatinine kinase, congestive heart failure, or pericarditis) by univariate or multivariate analysis predicted patients at risk for atrial fibrillation. Sustained atrial fibrillation developed in 37.5% of control and 32.6% of digoxin-treated patients. Only 16.2% of propranolol-treated patients had sustained atrial fibrillation (p less than 0.03). There were no in-hospital complications in those patients with atrial fibrillation. After 26 +/- 7 months follow-up, those patients with postoperative atrial fibrillation had no increased incidence of angina, cerebral vascular accident, myocardial infarction, or sudden death. Therefore, in this select population, propranolol prophylaxis is effective but discretionary.

Early postoperative spasm in left internal mammary artery bypass grafts.

Two patients with early postoperative spasm of a left internal mammary artery bypass graft are described. To our knowledge, this entity has not been reported previously. Both patients were characterized by vasomotor collapse secondary to intractable spasm responsive only to local application of vasodilator agents. Although the mechanism of graft spasm is not clear, prophylactic nifedipine therapy in appropriate dose may be of some value. The profound hemodynamic effect of internal mammary artery spasm in the immediate postoperative period may allow no time for anything other than emergency reoperation to assess the nature of the problem and treat it appropriately.

Coronary revascularization in young patients.

From 1978 to 1982, 92 of our 1704 patients undergoing coronary bypass surgery were 40 years of age or younger. Eighty-six were male and six were female. The main indications for surgery were refractory angina and unstable angina. A family history of heart disease, smoking, and hypertension were major risk factors. The majority of patients had triple vessel disease, and six had left main lesions. Left ventricular function was moderately or severely impaired in 24. Coronary revascularization was performed with internal mammary and saphenous vein conduits, with a mean of 3.7 grafts per patient (range, 1 to 7). There was no operative mortality, but one patient required an intraaortic balloon pump. Perioperative infarction determined by Q waves occurred in one patient, while eight had enzymatic evidence of infarction. Late follow-up to 60 months showed three late deaths of cardiac origin. Eighty-three survivors were greatly improved, and 50 were asymptomatic. Sixty-five patients returned to work. Seventy percent of smokers stopped smoking; half the patients exercised regularly, and half maintained dietary modifications. Coronary bypass grafting is an effective rehabilitation procedure in the young. Long-term attention to risk factors and life style is required to maintain a beneficial outcome.

Delayed sternal closure as a safe adjunct to support biventricular failure after open heart surgery.

Over a four-year period, 22 patients of 2495 undergoing open heart surgery sustained severe biventricular failure (BVF) and would not tolerate primary sternal closure. Reasons for BVF included intraoperative injury, perioperative infarction, global dysfunction, cardiopulmonary edema, and intractable arrhythmia. Mechanical assist devices were required in nine patients. Average cardiac index fell to 1.1 L/min/m2 with attempts to close the chest, then stabilized at 1.9 with the sternum open and only soft tissue closed. After 3 to 11 days, cardiac index rose to 2.5 when assist devices were removed, inotropic agents decreased, and the sternum closed. Three early deaths (5-12 days) were caused by progressive biventricular failure. Five later deaths (19-64 days) were associated with renal and respiratory failure, superinfection, and sepsis. All of these required tracheostomy. Survival of 14 patients was not related to early low cardiac output, preoperative status, timing of sternal closure, or age, but was associated with early recovery of respiratory function without need for tracheostomy, avoidance of renal failure, and satisfactory alimentation. Sternal infection occurred in three patients, resulting in one death. The hospital stay ranged from 12 to 230 days. There was one death resulting from respiratory failure 14 months postoperatively. Our findings show that delayed sternal closure lessens early cardiac instability during BVF, helps allow recovery, and does not produce long-term disability.

Endothelial loss due to leukocytes in canine experimental vein-to-artery grafts.

Vein-to-artery grafts develop areas of endothelial loss with fibrin and leukocytes which lead to early thrombosis and may lead to subsequent atherosclerosis of the graft. En face monolayers were prepared which removed greater than 90% of vascular intima. Unevenly distributed leukocytes and endothelial cells were counted using a standardized sampling of calibrated oil immersion fields of 0.01 mm2. Nongrafted veins had 14 +/- 1 evenly arranged endothelial cells per field without gaps or leukocytes, while 10-min grafts had 13 +/- 2 with rare leukocytes. Four-hour grafts from normal dogs had 9 +/- 2 endothelial cells with gaps and 97 +/- 37 neutrophils and 44 +/- 25 monocytes. Leukopenic dogs (vinblastine-treated) had normal numbers of endothelial cells (14 +/- 1) with scanty leukocytes. We conclude that leukocytes cause endothelial loss in vein-to-artery grafts that can be prevented by intense leukopenia. This may lead to practical approaches to protecting such grafts in humans.

Coexisting carotid stenosis in patients undergoing cardiac surgery: indications and guidelines for simultaneous operations.

The coexistence of critical carotid stenosis with coronary artery or valvular heart disease occurs in a small percentage of patients requiring open heart surgical procedures. Recognition of such combined lesions by noninvasive carotid testing identifies patients at risk for neurologic events. Our experience with 62 patients having combined simultaneous carotid and cardiac operations among 2,400 open heart surgery patients was compared with the results in 110 patients with only carotid endarterectomy operations. The outcomes indicated that carotid endarterectomy can be performed simultaneously with open heart surgical procedures with morbidity and mortality rates similar to those of isolated cervical artery operations. Thus, patients with significant coexisting carotid artery disease defined with specific criteria and coronary artery disease need not be exposed to cerebral ischemic events or to myocardial infarctions that often accompany staged operations.