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Biomedical subjects

R Greene

Publications and source records attributed to R Greene.

At least 127 records · Page 7Linked to original sources
PubMed1987

99mTc-fibrinogen scanning in adult respiratory distress syndrome.

Fibrin is often seen occluding the lung vessels of patients dying from ARDS and is surrounded by regions of lung necrosis. To learn if we could observe increased or focal fibrin deposition and assess the kinetics of plasma fibrinogen turnover during severe acute respiratory failure, we injected technetium 99m-labeled human purified fibrinogen (Tc-HF) and used gamma camera scanning for as long as 12 h in 13 sequential patients as soon as possible after ICU admission. The fibrinogen uptake rates were determined by calculating the lung:heart radioactivity ratios at each time point. Slopes of the lung:heart ratio versus time were compared between ARDS and mild acute respiratory failure (ARF). The slope of the lung:heart Tc-HF ratio of the 9 patients with ARDS (2.9 +/- 0.4 units) was markedly higher (p less than 0.02) than the slope of the 4 patients with mild ARF (1.1 +/- 0.4) and the 3 patients studied 5 to 9 months after recovery from respiratory failure (0.7 +/- 0.07). In the 1 patient with ARDS and the 2 patients with mild ARF studied both during acute lung injury and after recovery, the lung:heart Tc-HF ratio had decreased at recovery. To compare the pulmonary uptake of Tc-HF to 99mTc-labeled human serum albumin (Tc-HSA), 5 patients were injected with 10 mCi of Tc-HSA, and scanning of the thorax was performed with a similar sequential imaging protocol 24 h after conclusion of the Tc-HF study.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1987

Pulmonary vascular obstruction in severe ARDS: angiographic alterations after i.v. fibrinolytic therapy.

IV streptokinase was infused to test the potential reversibility of adult respiratory distress syndrome (ARDS) associated pulmonary vascular thrombosis in five patients suffering from severe ARDS with elevated mean pulmonary artery pressure, increased pulmonary vascular resistance, and angiographically documented pulmonary vascular thrombosis. At 48 hr there was clearance of obstructions in arteries larger than 1 mm in diameter in all patients, increased filling of the microvasculature and small arteries less than 1 mm in diameter in four patients, a fall in pulmonary vascular resistance in all patients, a rise in cardiac output in four patients, improved oxygenation (PAO2/FlO2) in three patients, and variable changes in shunt fraction and ventilator pressures. Expressed as a mean fraction of the preinfusion controls, the postinfusion physiologic values were pulmonary artery pressure = 0.89 mm Hg, pulmonary vascular resistance = 0.68 mm Hg X min/L, cardiac output = 1.36 L/min, central venous pressure = 0.77 cm H2O, pulmonary capillary wedge pressure = 0.92 mm Hg, PAO2/FlO2 = 1.08, and shunt fraction = 0.95. Follow-up angiography showed no evidence of reocclusion. Postmortem studies of the three nonsurvivors confirmed recanalization of thrombosed pulmonary arteries. One documented bleeding episode occurred. We conclude that fibrinolytic infusion can lyse thrombi and possibly improve hemodynamics and oxygenation in ARDS-associated pulmonary vascular thrombosis.

Angiography↗
PubMed1987

CT-findings in ARDS.

The CT features of 28 patients with ARDS are described. Diffuse lung consolidation, multifocal patchy involvement and lobar or segmental disease were observed. Large lung cysts as well as small cysts producing a "swiss-cheese" appearance of the parenchyma, were detected. These findings were not regularly appreciated on chest radiographs. The overall mortality of our 28 patients was 72.7% (22 out of 28). Patients with lung cysts showed a trend toward higher mortality (87.5% or 13 out of 16). Other unexpected findings were basilar lung abscesses and an empyema. In 15 out of 28 patients, CT scans provided additional information, not obvious on bedside chest radiographs and led to a change in management in five patients.

Adult↗
PubMed1986

Doxorubicin/vinblastine and doxorubicin/cyclophosphamide combination chemotherapy by continuous infusion.

Fifty-two patients received one of two doxorubicin (DOX)-based admixtures; DOX plus cyclophosphamide (CTX) or DOX plus vinblastine (VBL) administered as a continuous 24-hour infusion for protracted periods. Compatibility and stability of the two-drug admixture was established for a minimum of 7 days. Twenty patients on the DOX/CTX admixture were infused for a median of 20 days (range, 7-56 days). DOX/VLB was infused in 32 patients for a median of 18 days (range, 5-48 days). Dose limiting toxicity was leukopenia observed in 14/52 patients; 4/20 on DOX/CTX and 10/32 on DOX/VLB. Additional toxicities observed included stomatitis (15%) and subclavian vein thrombosis (23%). Tumor responses were observed in 11 patients, including 6/13 breast cancer; 2/2 hepatoma; 2/4 sarcoma and 1/1 ovarian cancer. Responses were relatively short-lived and no responses were noted in known anthracycline resistant tumors. Admixtures of chemotherapeutic agents represents a novel, but feasible, mechanism for delivery of multiple drugs with an infusion schedule and can be considered for Phase III comparative clinical trials.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1986

Functional consequences and intracoronary localization of alpha-adrenergic stimulation of the canine coronary circulation.

Although alpha-adrenergic stimulation can increase coronary vascular resistance, it remains unknown whether the vasoconstriction can override intrinsic coronary regulatory influences to produce ischemia. Methoxamine, 2 to 4 mg, was infused into the circumflex coronary artery of 23 chloralose-anesthetized open chest dogs, and resulted in a 68% increase in coronary vascular resistance. The functional consequence of this increased coronary vascular resistance was assessed by gated radionuclide ventriculography and ST-T wave changes on the electrocardiogram. In six dogs (Group I), aortic pressure changed trivially (less than 5 mm Hg) to allow distinction between direct effects of the flow reduction and indirect effects of increased aortic pressure. In this group, coronary blood flow decreased 33% from a control value of 44 +/- 10 ml/min (p less than 0.001) and left ventricular ejection fraction decreased from 0.54 +/- 0.12 to 0.46 +/- 0.10 (p less than 0.025). In eight dogs (Group II) in which aortic pressure increased by more than 5 mm Hg, left ventricular ejection fraction decreased from 0.46 +/- 0.07 to 0.39 +/- 0.09 (p less than 0.002). Pressure gradients were measured between the aorta and a distal coronary artery branch to calculate small and large vessel resistances separately in four other dogs (Group III). The resistance of small coronary arteries accounted for 92% of the total increase in coronary vascular resistance produced by methoxamine. In five other dogs (Group IV), intracoronary methoxamine, 2 mg, produced ST-T wave changes suggestive of ischemia as it increased coronary vascular resistance by 33%.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic alpha-Agonists↗
PubMed1986

Pulmonary vascular obstruction in the adult respiratory distress syndrome.

Pulmonary vascular obstruction is most likely to occur in patients with the severest form of ARDS. Obstruction has been ascribed to fibrin thrombosis and to activation of the blood coagulation system, both well-documented in ARDS. The obstruction has been postulated to occur in two stages during post-traumatic ARDS: an initial transient pulmonary vasoconstriction, attributable to platelet and leukocyte aggregation and the release of vasoactive substances; and, two to five days post injury, a more malignant "delayed microembolism" stage, attributable to the development of protein-rich edema and fibrin deposition in the lungs. Bedside balloon occlusion pulmonary angiography, in a single exposure, allows identification of intraluminal filling defects and occlusions of arteries greater than or equal to 1.0 mm in diameter, irregularity and decreased filling of side branch arteries 0.5 to 1.0 mm in diameter, and decreased filling of the pulmonary microvascular background. Plain radiography findings correlate poorly with angiography results, but the mortality rate of patients who exhibit angiographic evidence of obstruction is twice as high as it is in patients with normal angiography.

Angiography↗
PubMed1986

Cross-sectional imaging of silent pulmonary venous anomalies.

An overview of the forms of partial anomalous pulmonary venous connections (PAPVC) and a discussion of the role of computed tomography (CT) in diagnosing this anomaly are offered. Although angiography remains the most sensitive technique for detection of anomalous pulmonary veins and other cardiac anomalies, the increased use of CT over the past decade has probably resulted in the detection of PAPVC that otherwise might have been missed. In the case of asymptomatic PAPVC, CT may provide positive identification and obviate the need for further studies.

Humans↗
PubMed1986

Interpretation of pulmonary artery wedge pressure and pullback blood gas determinations during positive end-expiratory pressure ventilation and after exclusion of the bronchial circulation in the dog.

Left atrial pressure (LAP) and pulmonary artery wedge pressure (PWP) were measured at different heights during graded increases in positive end-expiratory pressure (PEEP). Six healthy anesthetized dogs were placed in lateral decubitus positions with a balloon-tipped pulmonary artery catheter inserted in each lung. PWP in the gravitationally superior lung overestimated LAP at 15 and at 20 cm H2O PEEP (p less than 0.05). PWP in the dependent lung was virtually identical to LAP at all degrees of PEEP. Wedge blood could be aspirated through the distal lumen of the pulmonary artery catheters during balloon inflation at all degrees of PEEP except for 3 attempts. PCO2 in wedge blood in both the nondependent and dependent lungs at all degrees of PEEP was consistently lower than PCO2 in arterial blood (p less than 0.05). Wedge blood was arterialized, i.e., oxygen saturation greater than 95%, in all but 4 specimens. Surgical elimination of the bronchial artery supply to the lung in 3 dogs did not affect PWP or blood gas measurements. We conclude that in this animal model: (1) the tip of a pulmonary artery catheter must be below the level of the left atrium, Zone III location, to accurately reflect LAP at high degrees of PEEP; (2) arterialization of wedge blood samples does not guarantee that PWP reflects LAP; (3) bronchial artery blood supply does not affect PWP or wedge blood gas measurements, even at high degrees of PEEP.

Animals↗
PubMed1986

Vinblastine plus cisplatin in advanced non-small cell lung cancer: lack of advantage for vinblastine infusion schedule.

We have evaluated 31 patients with advanced non-small cell lung cancer treated by short-term 5-day vinblastine infusion combined with bolus cisplatin. Nine of 31 patients (29%) had partial and complete responses. Although five of nine (55%) of the responders were alive at greater than or equal to 1 year, three of the 31 patients experienced drug-related mortality. Our experience, as well as a review of previously reported trials in the literature, suggests that the infusion schedule of vinblastine offers no advantage over the bolus schedule.

Adenocarcinoma↗
PubMed1986

Protracted low-dose cisplatin infusion in advanced colorectal cancer.

Protracted, 24-hour, continuous-infusion cisplatin at a dose rate of 5 mg/m2/day was administered to 25 patients with advanced measurable colorectal cancer. All patients had previously received 5-FU administered on the same schedule. Sixteen patients received the infusion for greater than or equal to 14 days and were considered evaluable for response assessment. No patient achieved a response.

Ambulatory Care↗
PubMed1985

Randomized trial of estrogen vs. tamoxifen therapy for advanced breast cancer.

Forty-three postmenopausal females with advanced breast cancer were studied in a prospective comparative trial of estrogen vs. an anti-estrogen (tamoxifen) therapy with a crossover to the alternative hormone with progressive disease. Ten of 19 patients (53%) responded to primary tamoxifen therapy and six of 24 (25%) responded to primary estrogen therapy. Crossover responses were observed in seven of 19 (37%) on the secondary tamoxifen therapy and in two of 10 (20%) on secondary estrogen therapy, and were not related to the response to the primary hormonal maneuver. Responses were related to the presence of estrogen receptor protein (ERP), particularly for tamoxifen therapy, although responses were observed in three of six ERP negative patients receiving estrogen and in seven of 25 (28%) of patients with an unknown ERP status. Complications were observed in 35 instances with estrogen therapy and in only five instances with tamoxifen therapy. Initial hormonal therapy with tamoxifen in postmenopausal patients with advanced breast cancer and ERP status positive or unknown is superior to primary estrogen treatment. Secondary therapy and response to estrogen or tamoxifen is not necessarily predicted by the initial hormone response, and crossover to the alternative therapy is generally indicated.

Aged↗