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Biomedical subjects

D C Morris

Publications and source records attributed to D C Morris.

At least 73 records · Page 4Linked to original sources
PubMed1992

Immunolocalization of alkaline phosphatase in osteoblasts and matrix vesicles of human fetal bone.

A monoclonal antibody raised against alkaline phosphatase (ALP) of human osteosarcoma was used to localize this enzyme in human fetal bone tissue. For light microscopy, the presence of alkaline phosphatase in osteoblasts and osteocytes was demonstrated by use of an avidin-biotin immunoperoxidase procedure. Electron microscopic immunolocalization was accomplished with an indirect immunoperoxidase method which revealed a concentration of the enzyme on matrix vesicle and osteoblast plasma membranes. In addition, many vesicular protrusions arising from areas of plasma membrane on the lateral surfaces of adjacent osteoblasts were strongly immunolabeled. Immunostaining for ALP was absent in vesicles which contained fine crystallites. Alkaline-phosphatase-rich matrix vesicles may play a significant role in the mineralization of the extracellular matrix.

Alkaline Phosphatase↗
PubMed1992

Anistreplase versus alteplase in acute myocardial infarction: comparative effects on left ventricular function, morbidity and 1-day coronary artery patency. The TEAM-3 Investigators.

OBJECTIVES: This double-blind, randomized, multicenter trial was designed to compare the effects of treatment with anistreplase (APSAC) and alteplase (rt-PA) on convalescent left ventricular function, morbidity and coronary artery patency at 1 day in patients with acute myocardial infarction. BACKGROUND: Anistreplase (APSAC) is a new, easily administered thrombolytic agent recently approved for treatment of acute myocardial infarction. Alteplase (rt-PA) is a rapidly acting, relatively fibrin-specific thrombolytic agent that is currently the most widely used agent in the United States. METHODS: Study entry requirements were age less than or equal to 75 years, symptom duration less than or equal to 4 h, ST segment elevation and no contraindications. The two study drugs, APSAC, 30 U/2 to 5 min, and rt-PA, 100 mg/3 h, were each given with aspirin (160 mg/day) and intravenous heparin. Prespecified end points were convalescent left ventricular function (rest/exercise), clinical morbidity and coronary artery patency at 1 day. A total of 325 patients were entered, stratified into groups with anterior (37%) or inferior or other (63%) acute myocardial infarction, randomized to receive APSAC or rt-PA and followed up for 1 month. RESULTS: At entry, patient characteristics in the two groups were balanced. Convalescent ejection fraction at the predischarge study averaged 51.3% in the APSAC group and 54.2% in the rt-PA group (p less than 0.05); at 1 month, ejection fraction averaged 50.2% versus 54.8%, respectively (p less than 0.01). In contrast, ejection fraction showed similar augmentation with exercise at 1 month after APSAC (+4.3% points) and rt-PA (+4.6% points), and exercise times were comparable. Coronary artery patency at 1 day was high and similar in both groups (APSAC 89%, rt-PA 86%). Mortality (APSAC 6.2%, rt-PA 7.9%) and the incidence of other serious clinical events, including stroke, ventricular tachycardia, ventricular fibrillation, heart failure within 1 month, recurrent ischemia and reinfarction were comparable in the two groups; and mechanical interventions were applied with equal frequency. A combined clinical morbidity index was determined and showed a comparable overall outcome for the two treatments. CONCLUSIONS: Convalescent rest ejection fraction was high after both therapies but higher after rt-PA; other clinical outcomes, including exercise function, morbidity index, and 1-day coronary artery patency, were favorable and comparable after APSAC and rt-PA.

Anistreplase↗
PubMed1992

Osseous expansion of the cranial vault by craniotasis.

A study of cranial vault lengthening using a custom expandable fixation-distraction (craniotatic) appliance was performed in the young-adult rabbit model. Ten 24-week-old rabbits underwent circumferential suturectomy plus expansion (expanded group), 10 underwent circumferential suturectomy without expansion (sham control group), and 10 served as normal controls. The appliance was lengthened at a rate of 2.5 mm per week for 5 weeks. Serial lateral cephalometry, comparative dry-skull anthropometric measurements, and histologic examinations were performed. The expanded group demonstrated a significantly longer skull, cranial vault, anterior cranial base, posterior face, and orbit as compared with the control groups (p less than 0.05). Callus bone filled the distracted suturectomy and united the frontofacial complex to the posterior cranium. In conclusion, skull lengthening by distraction osteogenesis is possible in the rabbit model and offers a new technique for future investigation in the treatment of coronal synostosis.

Analysis of Variance↗
PubMed1991

Cocaine heart disease.

Unlike neurologic toxicity, myocardial infarction appears to be an idiosyncratic response to the drug, unrelated to dose, duration of use, or route of administration. There is no marker to identify the person who may have life-threatening cardiac effects after taking cocaine, but those who experienced myocardial ischemia once are at risk of recurrence if they use the drug again.

Cocaine↗
PubMed1991

Effects of time required for reperfusion (thrombolysis or angioplasty, or both) and location of acute myocardial infarction on left ventricular functional reserve capacity several months later.

The purpose of this study was to determine whether reperfusion of acute myocardial infarction (AMI) by recombinant tissue-type plasminogen activator (rt-PA) or percutaneous transluminal coronary angioplasty, or both, would improve left ventricular (LV) function when it is measured several months later at rest or maximal bicycle exercise, or both. Radionuclide angiography was performed in 44 patients 5 months (range 6 weeks to 9 months) after AMI to assess function, and tomographic myocardial thallium-201 imaging was performed at maximal exercise and delayed rest to determine whether there was any evidence of myocardial ischemia. As expected, no patient had chest pain or redistribution of a thallium defect during the exercise test, because patients had undergone angioplasty (n = 28) or coronary bypass graft surgery (n = 5) where clinically indicated for revascularization. The LV ejection fraction was plotted as a function of the time elapsed between the onset of chest pain and the time when coronary angiography confirmed patency of the infarct-related artery (achieved in 91% of 44 patients by rt-PA [n = 31] or percutaneous transluminal coronary angioplasty [n = 9] ). Functional responses differed markedly between patients with anterior (n = 20) versus inferior (n = 24) wall AMI. LV ejection fraction during exercise correlated with time to reperfusion in patients with an anterior wall AMI (r = -0.58; standard error of the estimate = 11.9%; p less than 0.02) but not in patients with an inferior AMI (r = 0.10; standard error of the estimate = 13.1%; difference not significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon, Coronary↗
PubMed1991

Monoclonal antibody against human bone alkaline phosphatase.

A monoclonal antibody which reacts preferentially with human bone alkaline phosphatase (AP) has been developed using human osteosarcoma bone AP as an immunogen. The antibody with the highest selectivity shows about three- and a-half fold greater binding to bone than to liver AP. The selectivity was confirmed using mixtures of authentic samples of the bone and liver isoenzymes. Its selectivity was also shown by measurements of bone AP in sera from patients with either bone or liver diseases. Such a selective antibody could lead to the development of a monoclonal antibody highly specific for bone AP which can be used for a more sensitive approach for quantitative analysis of the isoenzyme.

Alkaline Phosphatase↗
PubMed1991

Increased matrix vesicle protein in rachitic rat epiphyseal growth plates.

Extracellular, membrane-bound vesicles are widely regarded to be the initial site of calcification in a variety of tissues under normal and pathological conditions. Alkaline phosphatase is believed to play a vital role in this process by hydrolysing ester phosphates or mineral inhibitors, e.g. inorganic phosphates. In the present study, matrix vesicles from normal and rachitic rat growth plates were compared with regard to specific activity of alkaline phosphatase, total vesicle protein and ultrastructural distribution of alkaline phosphatase activity. Matrix vesicles were released from normal or rachitic growth plates by collagenase digestion and isolated by differential centrifugation. Enzyme cytochemical localization involving a cerium capture method was performed on vesicles collected by vacuum filtration on Millipore filters. SDS gels and Western blots on fractions of both normal and rachitic matrix vesicles showed major proteins to be almost identical and confirmed the presence of alkaline phosphatase in both. Total matrix vesicle protein ((mg total matrix vesicle protein/rat) x 10(2)) per rat was significantly greater for the rachitic animals (9.0 +/- 2.0 vs. 4.0 +/- 1.0), P less than 0.0001. Alkaline phosphatase specific activity (units alkaline phosphatase/mg vesicle protein) in the rachitic and normal matrix vesicles was 25.29 +/- 9.36 and 18.78 +/- 3.37, respectively (0.05 less than P less than 0.1). Electron dense cerium phosphate deposits were localized to the outer membrane surface of matrix vesicles derived from both types of rats. This data, the first to quantify the relationship between rickets, matrix vesicle protein and alkaline phosphatase specific activity, suggests that matrix vesicles from rachitic and normal rats have biochemical and morphological similarity.(ABSTRACT TRUNCATED AT 250 WORDS)

Alkaline Phosphatase↗
PubMed1991

LGM (Vena Tech) vena cava filter: clinical experience in 64 patients.

LG-Medical (LGM) vena cava filters were inserted percutaneously in 64 patients. Each case was followed after the filter insertion. Clinical follow-up was available in all patients; in 11 patients it was the only form of follow-up. Findings were available from autopsies in seven patients, plain abdominal radiographs in 42, and duplex sonograms of the insertion vein and inferior vena cava (IVC) in 46. A filter was inserted without major complication in all patients. The filter failed to open fully in four patients and was tilted in the IVC in 15. Recurrent pulmonary embolism was found in two patients (fatal in one), and inconsequential filter migration occurred in 11. Introduction vein thrombosis occurred in four patients. IVC thrombosis, demonstrated at autopsy or sonography, was found in 14 patients (22%) and was symptomatic in six (9%). This report suggests that the LGM filter is easy to introduce, and few complications are associated with insertion. The rate of caval thrombosis, however, may be higher than previously reported.

Adult↗
PubMed1991

Clinical implications of late proven patency after successful coronary angioplasty.

BACKGROUND: The introduction of percutaneous transluminal coronary angioplasty (PTCA) has changed the pattern of intervention in coronary artery disease. However, the long-term results in patients undergoing successful, elective, native-vessel PTCA are not yet fully characterized. Because the healing and subsequent proliferative response after angioplasty are time related, it was the purpose of the present study to determine the long-term outcome in patients whose dilated arteries have been demonstrated to be patent 4-12 months after successful, uncomplicated PTCA. METHODS AND RESULTS: The patients were grouped on the basis of the 4-12 month catheterization into those whose vessels were angiographically "normal" or had luminal irregularities only at the PTCA sites (396 patients), those whose vessels also had luminal irregularities elsewhere with or without PTCA site luminal irregularities (680 patients), and those with significant obstructive disease (more than 50% diameter narrowing) at sites other than the PTCA sites (426 patients). Of 1,502 such patients, long-term follow-up was available in 1,491. At the time of the original angioplasty, the normal patients had a 1.8% incidence of multivessel disease; luminal irregularity patients, 9.4%; and obstructive disease patients, 58.7%. At angiographic restudy, 16.4% of the obstructive disease patients continued to have multivessel disease. The patients were followed for the events of death, myocardial infarction, coronary surgery, and repeat PTCA. The 6-year survival rate was 95%; cardiac survival, 96%; and freedom from all events, 65%. The strongest correlate of events during follow-up was the angiographic status of the undilated segments. At 6 years, freedom from cardiac events was noted in 77% of the normal group, 61% of the luminal irregularity group, and 55% of the obstructive disease group. Diabetes and hypertension were also independent correlates of events. CONCLUSIONS: Results from the present study show that associated disease in undilated segments is a strong predictor of late events in patients after successful, uncomplicated, reatenosis-free PTCA. However, the need for further revascularization was frequent even in patients without obstructive disease. Completeness of revascularization is appropriate when possible, and limiting progression of coronary disease at sites remote from those dilated should improve on these late results.

Aged↗
PubMed1991

You may be a target for business reengineering.

Over the past 20 years, the complexity of hospital evolution has resulted in executive and mid-level management losing touch with the details of the operation. Business reengineering involves restructuring the business to conform to the most efficient operation model for delivering the service or product.

Commerce↗
PubMed1991

Reengineering the hospital: making change work for you.

Two of the industry's prominent management experts and authors explain that the Information Systems Department can take a leading role in reengineering the management infrastructure of a healthcare organization. Change is no longer the enemy of management if the infrastructure is set up to accommodate and promote change from within.

Cost Control↗
PubMed1990

Balloon embolization of latrogenic aortocoronary arteriovenous fistula.

A detachable latex balloon was used to occlude an iatrogenic aortocoronary arterio-venous fistula. The aim of providing retrograde myocardial perfusion was not achieved to any significant degree because of rapid recruitment of collateral venous routes to the coronary sinus. This may have implications for the effectiveness of deliberate grafting of the coronary venous system with proximal venous ligation, as has been recommended when the coronary arterial system is small and diffusely diseased.

Angioplasty, Balloon, Coronary↗
PubMed1990

Inhibition of mediator release in systemic mastocytosis is associated with reversal of bone changes.

A 59-year-old male presented with systemic mastocytosis with extensive skeletal involvement resulting in vertebral compression fractures and bone pain. Histomorphometric analysis of bone revealed increased mast cells, elevated static parameters of bone resorption, and low bone formation. Serum calcium, phosphorus, and alkaline phosphatase were normal; however, serum 1,25-dihydroxyvitamin D3 and osteocalcin levels were low. Histamine levels in plasma and urine were elevated. Following therapy with ketotifen, the patient had resolution of bone pain along with decreased flushing and pruritus. Elevated plasma and urine histamine levels normalized, as did 1,25-dihydroxyvitamin D3 and osteocalcin levels. Indices of low bone formation improved on therapy. Eroded surfaces improved but remained elevated. This case is the first demonstration that bone symptoms and histomorphometric change in systemic mastocytosis are reversed with inhibition of mast cell degranulation. The role of mast cells and their products in bone metabolism is poorly understood, but the therapy of bone disease in systemic mastocytosis should include inhibition of the release of mast cell products along with the use of histamine antagonist.

Bone Resorption↗
PubMed1990

Catastrophic thrombosis of porcine aortic bioprostheses.

Hemodynamically critical thrombotic stenosis of porcine bioprosthetic valves in the aortic position without thrombotic predisposition is rare. Two patients at our institution abruptly manifested thrombotic stenosis of porcine bioprosthetic valves in the aortic position within 3 months of implantation without apparent predisposing factors. Clinicians should consider this rare but catastrophic complication in the appropriate setting.

Adult↗
PubMed1990

Matrix vesicle calcification of ectopically induced osteoid tissue in 1-hydroxethylidene-1,1-bisphosphonate (HEBP)-treated mice.

The effects of 1 hydroxethylidene-1, 1-bisphosphonate (HEBP) on the mineralization of osteoid induced ectopically by a murine, osteosarcoma-derived, bone-inducing substance was examined at the ultrastructural level. Samples of Dunn osteosarcoma were chemically processed, lyophilized into pellets of uniform dimensions and protein content, and implanted into the back muscles of male, 4 week old, ddY mice. In control animals injected intraperitoneally (i.p.) with saline each day for 30 days, the pellets exhibited ectopic cartilage and bone formation in a sequential manner consistent with endochondral ossification. Daily administration of HEBP (30 mg/kg i.p. per day) to animals over the same period produced wide anastomosing strands of osteoid and haematopoietic marrow in the pellets. Electron microscopical examination revealed a tightly packed organization of collagen fibrils with many membrane bounded organelles or matrix vesicles (0.05-0.3 micron diameter) dispersed throughout this nonmineralized matrix. After withdrawal of HEBP, mineralization proceeded initially within matrix vesicles and secondarily by involvement of the surrounding collagen fibrils. In pellets retrieved at 30 days after HEBP withdrawal, most of the matrix had been mineralized and remodeled to reveal thin bony trabeculae and an overall histologic appearance similar to that seen in the control pellets. This model of ectopic bone formation permits clear visualization of the sequence of mineral nucleating events in osteoid in the absence of an established mineralizing front. The results add further support to the hypothesis that matrix vesicles are directly responsible for the initiation of mineralization in bone.

Animals↗
PubMed1990

Enzyme cytochemical localization of alkaline phosphatase in cultures of chondrocytes derived from normal and rachitic rats.

Epiphyseal growth plate cartilages were removed from rats which had been maintained on normal laboratory chow or a rachitogenic diet. Chondrocytes were released from the growth plates by collagenase digestion and cultured in tissue chamber slides. After 7, 10 and 12 days of culture, the chondrocytes were removed as intact multilayers and processed for electron microscopical enzyme cytochemical studies. Alkaline phosphatase activity in the cultures was visualized by means of a cerium based capture method. Electron-dense cerium phosphate deposits were localized on the membrane of matrix vesicles and plasma membranes of chondrocytes derived from normal and rachitic animals. The appearance of first crystals within matrix vesicles was characterized by a concomitant decrease in alkaline phosphatase activity in the membrane of these structures. Calcification was initiated at approximately the same time in cultures of chondrocytes derived from normal or rachitic animals. The results suggest that rickets has no serious effects on the capacity of chondrocytes to support matrix calcification in vitro. Additionally, the evidence indicates that alkaline phosphatase-positive matrix vesicles play a significant role in the initiation of this process.

Alkaline Phosphatase↗
PubMed1990

Epiphora: treatment by means of dacryocystoplasty with balloon dilation of the nasolacrimal drainage apparatus.

A new interventional radiologic procedure was developed for treatment of epiphora. A small-bore, soft-tipped guide wire was introduced through the superior canaliculus and guided under fluoroscopic control through the nasolacrimal drainage system for retrieval through the nasal aperture. A small-bore angioplasty catheter was then introduced in a retrograde direction into the nasolacrimal drainage apparatus and dilated under fluoroscopic control. The procedure was attempted in 18 eyes of 17 patients with moderate to severe epiphora and was technically completed in 16; 13 of these cases demonstrated improvement, with 11 patients showing complete resolution of symptoms. In the three patients whose epiphora did not improve, no worsening of symptoms occurred. These results are preliminary; follow-up ranged from 7 weeks to 6 months. The authors believe that this technique may hold promise in the treatment of epiphora and may obviate the use of more invasive procedures.

Catheterization↗