Biomedical subjects

C L Hansen

Publications and source records attributed to C L Hansen.

At least 19 recordsLinked to original sources

PubMed2006

Short communication: Cultivation of Lentinus edodes mycelia using whey permeate as an alternative growth substrate.

The major objective of this research was to use whey permeate as an alternative growth medium for the cultivation of mycelia of the edible mushroom Lentinus edodes and to find an optimum condition for solid-state cultivation. Response surface analysis was applied to determine the combination of substrate concentration (40 to 60 g of lactose/L), temperature (20 to 30 degrees C), and pH (4 to 6) resulting in a maximal mycelial growth rate. The radial extension rates, estimated by measuring the diameters of growing colonies on the Petri dishes, were used as the growth rate of the mycelia at different conditions. The conditions predicted to maximize the mycelial growth of 6.41 +/- 0.47 mm/d were determined to be 40 g of lactose/L, temperature 23.6 degrees C, and pH 5.0. It was concluded that a partial cubic equation could accurately model the response surface of, and predict optimal growth conditions for, L. edodes mycelia using whey permeate because the model prediction agreed with the experimental growth rate, 6.39 +/- 0.22 mm/d. The results suggest that whey permeate could be utilized as a growth substrate for the cultivation of mycelia from the edible mushroom L. edodes, enhancing the use of this by-product by the cheese manufacturing industry.

Hydrogen-Ion Concentration↗

PubMed2003

Effect of salt on structure-function relationships of cheese.

Our objective was to determine the effect of salt on structural and functional properties of cheese. Unsalted Muenster cheese was obtained on 1 d, vacuum packaged, and stored for 10 d at 4 degrees C. The cheese was then cut into blocks that were vacuum packaged. After 4 d of storage at 4 degrees C, cheese blocks were high-pressure injected one, three, or five times, with a 20% (wt/wt) sodium chloride solution. Successive injections were performed 24 h apart. After 40 d of storage at 4 degrees C, cheese blocks were analyzed for chemical, structural, and functional attributes. Injecting sodium chloride increased the salt content of cheese, from 0.1% in the control, uninjected cheese to 2.7% after five injections. At the highest levels, salt injection promoted syneresis, and, after five injections, the moisture content of cheese decreased from 41 to 38%. However, the increased salt content caused a net weight gain. Cheese pH, soluble nitrogen, and total and soluble calcium content were unaffected. Cheese injected five times had a 4% increased area of cheese occupied by protein matrix compared with uninjected cheese. Hardness, adhesiveness, and initial rate of cheese flow increased, and cohesiveness decreased upon salt injection. However, the final extent of cheese flow, or melting was unaffected. We concluded that adding salt to cheese alters protein interactions, such that the protein matrix becomes more hydrated and expands. However, increasing the salt content of cheese did not cause an exchange of calcium with sodium. Therefore, calcium-mediated protein interactions remain a major factor controlling cheese functionality.

Calcium↗

PubMed2003

Effect of calcium and water injection on structure-function relationships of cheese.

Our objectives were to determine the effect of calcium and water injection on cheese structure and to relate changes in structure to changes in functional properties of cheese. Cheese with fat and moisture content similar to that of low-moisture part-skim Mozzarella was made according to a direct-acid, stirred/pressed-curd procedure. The cheese was then cut into blocks that were high-pressure-injected from one to five times, with either water or a 40% calcium chloride solution. Successive injections were performed 24 h apart. After 42 d of refrigerated storage, cheese microstructure and functionality were analyzed. When injected three or more times, water tended to increase cheese weight. The control, uninjected cheese, had the typical structure of a stirred/pressed-curd cheese: protein matrix interspersed with areas that originally contained fat and/or serum. Injecting water increased the area of cheese matrix occupied by protein, but it did not affect textural properties or melting of cheese. In contrast, when calcium was injected, a decrease in cheese weight was observed that was manifested through syneresis. The moisture content and pH of the cheese decreased as well. Calcium injection also decreased the area of cheese matrix occupied by protein. Cheese hardness increased, and cohesiveness and melting of cheese decreased upon calcium injection. We concluded that adding calcium to cheese alters how the proteins interact, which is manifested as changes in cheese microstructure. Such changes in cheese structure provide an understanding of changes in functional attributes of the cheese.

Calcium↗

PubMed2003

Effect of pH on the chemical composition and structure-function relationships of cheddar cheese.

The objectives of this study were to determine the effect of pH on chemical, structural, and functional properties of Cheddar cheese, and to relate changes in structure to changes in cheese functionality. Cheddar cheese was obtained from a cheese-production facility and stored at 4 degrees C. Ten days after manufacture, the cheese was cut into blocks that were vacuum-packaged and stored for 4 d at 4 degrees C. Cheese blocks were then high-pressure injected one, three, or five times with a 20% (wt/wt) glucono-delta-lactone solution. Successive injections were performed 24 h apart. Cheese blocks were then analyzed after 40 d of storage at 4 degrees C. Acidulant injection decreased cheese pH from 5.3 in the uninjected cheese to 4.7 after five injections. Decreased pH increased the content of soluble calcium and slightly decreased the total calcium content of cheese. At the highest level, injection of acidulant promoted syneresis. Thus, after five injections, the moisture content of cheese decreased from 34 to 31%, which resulted in decreased cheese weight. Lowered cheese pH, 4.7 compared with 5.3, also resulted in contraction of the protein matrix. Acidulant injection decreased cheese hardness and cohesiveness, and the cheese became more crumbly. The initial rate of cheese flow increased when pH decreased from 5.3 to 5.0, but it decreased when cheese pH was further lowered to 4.7. The final extent of cheese flow also decreased at pH 4.7. In conclusion, lowering the pH of Cheddar cheese alters protein interactions, which then affects cheese functionality. At pH greater than 5.0, calcium solubilization decreases protein-to-protein interactions. In contrast, at pH lower than 5.0, the acid precipitation of proteins overcomes the opposing effect caused by increased calcium solubilization and decreased calcium content of cheese, and protein-to-protein interactions increase.

Calcium↗

PubMed2003

Effect of sodium citrate on structure-function relationships of Cheddar cheese.

The objective of this study was to determine the effect of sodium citrate on the structure and functionality of Cheddar cheese. The hypothesis was that citrate (sodium citrate) injection would affect cheese properties mainly through its effect on bound calcium (calculated as the difference between total calcium and the water-soluble calcium content of a cheese extract). A 9-kg block of Cheddar cheese was made, vacuum-packaged, and then stored for 2 wk at 4 degrees C. After storage, the cheese was cut into 0.5- to 0.6-kg blocks that were vacuum-packaged and stored for 1 wk at 4 degrees C prior to injection. Cheese blocks were then high-pressure injected with a buffer solution (pH 5.27) containing 40% (wt/ wt) citric acid trisodium dihydrate and 6.25% (wt/wt) anhydrous citric acid, from zero (control) to five times (successive injections performed 24 h apart). Increased citric acid content of cheese from 0.22 (uninjected) to 1.39% (after five injections) caused phosphate solubilization. Thus, the calculated bound phosphate content of cheese decreased from 0.54 to 0.45 mmol/g of protein. However, unexpectedly, the soluble calcium content decreased from 0.34 (control) to 0.28 mmol/g of protein (after five injections), whereas the bound calcium content remained unchanged (0.42 mmol/g of protein). The decrease in soluble calcium probably resulted from the formation and concentration of crystals in the cheese surface, which was not included in samples for analysis, and from the expulsion of serum from within the cheese. Higher concentration of solutes in the water phase of cheese would increase the volume of serum, but the cheese had limited holding capacity and serum was expelled. Citrate injection increased the sodium content of cheese from 0.63 to 0.93%, but it had no effect on cheese pH (5.2). After five injections, the protein matrix expanded, occupying an increased area of cheese matrix (83 vs. 78%). Even though citrate injection had no effect on bound calcium, and thus the rate and extent of cheese flow were unaffected, increased phosphate solubilization, and possibly decreased ionic calcium content, resulted in expansion of the protein matrix and increased cheese hardness.

Calcium↗

PubMed2001

Complete genome sequence of a virulent isolate of Streptococcus pneumoniae.

The 2,160,837-base pair genome sequence of an isolate of Streptococcus pneumoniae, a Gram-positive pathogen that causes pneumonia, bacteremia, meningitis, and otitis media, contains 2236 predicted coding regions; of these, 1440 (64%) were assigned a biological role. Approximately 5% of the genome is composed of insertion sequences that may contribute to genome rearrangements through uptake of foreign DNA. Extracellular enzyme systems for the metabolism of polysaccharides and hexosamines provide a substantial source of carbon and nitrogen for S. pneumoniae and also damage host tissues and facilitate colonization. A motif identified within the signal peptide of proteins is potentially involved in targeting these proteins to the cell surface of low-guanine/cytosine (GC) Gram-positive species. Several surface-exposed proteins that may serve as potential vaccine candidates were identified. Comparative genome hybridization with DNA arrays revealed strain differences in S. pneumoniae that could contribute to differences in virulence and antigenicity.

Antigens, Bacterial↗

PubMed2000

Effect of patient obesity on the accuracy of thallium-201 myocardial perfusion imaging.

The effects of patient habitus (e.g., breast attenuation in women and diaphragmatic attenuation in men) have long been recognized as factors that reduce the accuracy of myocardial perfusion imaging. Although it has long been assumed that patient obesity effects accuracy, this has never been formally evaluated. We studied the effects of patient obesity, defined as a body mass index (BMI) > or = 30, on 607 patients who underwent exercise thallium-201 single-photon emission computed tomography (SPECT). Because the effects of obesity are most likely mediated through increased photon attenuation and scatter, we also evaluated the effects of other markers of patient size: body surface area (BSA) and patient weight. Accuracy was determined by performing quantitative analysis and measuring the area under the receiver operating characteristic curve (AUC). Obesity was associated with significantly lower accuracy (AUC 0.86 +/- 0.03 vs 0.92 +/- 0.02, p <0.05) despite similar estimates of maximal coronary blood flow (as estimated by heart rate and rate-pressure product at peak exercise) and severity of coronary disease. There were no significant differences attributable to either patient weight or BSA. Weight and BSA correlated significantly with left ventricular chamber size whereas BMI did not. We conclude that the accuracy of quantitative SPECT thallium-201 is significantly reduced by patient obesity and that although BSA and weight are also associated with increased attenuation, they have no effect on accuracy, which is most likely due to the compensating effects of increased chamber size.

Body Mass Index↗

PubMed2000

Attenuation smear: a 'paradoxical' increase in counts due to attenuation artifact.

BACKGROUND: Attenuation is a well recognized cause of reconstruction artifacts in SPECT imaging. Occasionally, we have noted an increase in activity extending from the apical septal portion of the ventricle in women with significant breast attenuation. Although the idea that attenuation can produce an increase in activity on the reconstructed images seems paradoxical at first, it is consistent with the process of filtered back projection. METHODS: We filled a cardiac phantom with 1 mCi of Technetium-99m, placed it in a water filled anthropomorphic torso phantom and imaged it over a 180 degree orbit. Next, a breast phantom designed to simulate a significant degree of breast attenuation was placed on the torso phantom and imaging was repeated. The images were reconstructed first using conventional filtered back projection then with maximum likelihood. RESULTS: When the phantoms with and without breast attenuation were reconstructed using filtered back projection and compared, the phantom with breast attenuation had a large 'smear' of activity extending anteriorly from the apical septal wall which was very similar to the abnormalities previously noted in clinical images; the phantom without breast attenuation had no such defect. This artifact was significantly less prominent when the images were reconstructed using the maximum likelihood technique. CONCLUSIONS: Attenuation artifact can also produce a seemingly paradoxical increase in counts on the reconstructed image but this phenomenon is consistent with the workings of filtered back projection.

Artifacts↗

PubMed2000

Topoisomerase II alpha: prognostic predictor and cell cycle marker in surface epithelial neoplasms of the ovary and peritoneum.

Immunohistochemistry for Topoisomerase II alpha (TopoIIa), a nuclear protein important for the separation of chromosomes and deoxyribonucleic acid replication, provides insight into the molecular events in the cell cycle and the response to chemotherapeutic agents, which target TopoIIa. We test the hypothesis that the percentage of TopoIIa immunoreactive nuclei (TopoIIaI) aids in the treatment and prognostic evaluation of ovarian and primary peritoneal surface epithelial neoplasms (SENs) and correlates with established cell cycle control markers: p53, p21WAF1/CIP1 (p21), and Ki67. Paraffin sections from a retrospective surgical series of 108 SENs were immunostained with anti-TopoIIa, anti-p53, anti-p21, and anti-Ki67. The TopoIIaI, the Ki67 proliferation index (Ki67PI), and the immunoreactivity score for p53 and p21 (IMS: S1, S2, S3 < 10%, 10 to 50%, > 50% of strong staining cells, respectively) were evaluated manually. TopoIIaI and Ki67PI ranged from 5 to 84% and 4 to 88% (mean/median: 31/30 and 44/46%), respectively, and were correlated (coefficient 0.62, p < 10(-11)). IMS of 108 SENs was as follows: p53 50% + (2S1, 52S3) and p21 66% + (38S1, 12S2, 21S3). The TopoIIaI associated directly with p53 (p < 10(-5) and inversely with p21 (p < 0.005) IMS. TopoIIaI correlated with SEN architectural/nuclear grade (p < 10(-5)/10(-7)), but not histologic type. Sixty-seven patients had disease at last follow-up, 55 were dead from disease at 2 to 67 months (mean/median 24/21), and 14 were alive with disease at 31 to 230 months (mean/median 73/59). Forty-one patients were disease free at 5 to 228 months (mean/median 75/54). TopoIIaI correlated with presence of disease (p < 0.01) and poor survival (p < 1 x 10(-9), even when only 93 invasive SEN cases are considered (p < 0.005). TopoIIaI correlates with poor prognosis and other cell cycle control markers. The patients in this retrospective series of SEN were treated primarily with platinum-based chemotherapy. These data may suggest further prospective studies in which patients with SENs exhibiting high TopoIIaI are treated with chemotherapy targeted against TopoIIa (e.g., etoposide). In this retrospective series, high SEN TopoIIaI predicted poor survival when treated with platinum-based chemotherapy, which does not target TopoIIa.

Adenocarcinoma↗

PubMed1999

Immunohistochemical markers of cell cycle control applied to ovarian and primary peritoneal surface epithelial neoplasms: p21(WAF1/CIP1) predicts survival and good response to platinin-based chemotherapy.

Immunohistochemistry for p53, p21(WAF1/CIP1), and Ki-67 provides insight into the molecular events controlling the cell cycle. We tested the hypothesis that these cell cycle markers will aid in the clinical evaluation of ovarian and primary peritoneal surface epithelial neoplasms (SENs). Paraffin sections from a retrospective surgical series of 117 SENs were immunostained with anti-p53 (clone DO7, Novacastra Laboratories, UK), anti-p21(WAF1/CIP1) (clone EA10, Oncogene Science, Cambridge, MA), and anti-Ki-67 (clone MIB-1, Immunotech, Westbrook, ME). The Ki-67 proliferation index (Ki-67PI) and immunoreactivity were evaluated. One hundred seventeen SENs reacted as follows: p53 50%+ and p21(WAF1/CIP1) 65%+. Ki-67PI ranged from 4% to 88% (mean/median = 44/46%). p53 reactivity associated with transitional cell histology, decreased p21(WAF1/CIP1) staining, increased Ki-67PI, architectural/nuclear grade, and stage (P < .05, 1 x 10(-7), .01, .05/.0001, .001,). p21(WAF1/CIP1) staining was associated with endometrioid/clear cell histology, decreased Ki-67PI, architectural/nuclear grade, and stage (P < 05/.05, .05, .01/1 x 10(-8), 1 x 10(-5)). Ki-67PI associated with increased architectural/nuclear grade but not mucinous histology (P < 1 x 10(-5)/1 x 10(-6), .01). Sixty-seven patients had disease at last follow-up; 53 were dead of disease at 0 to 67 months (mean/median, 21/18), and 14 were alive with disease at 12 to 224 months (mean/median, 56/40). Fifty patients were disease free at 5 to 214 months (mean/median, 59/41). Predictors of survival include decreased Ki-67PI, stage, architectural/nuclear grade (P < 1 x 10(-6), 1 x 10(-10), 1 x 10(-10)/.005) and p21(WAF1/CIP1) IMS (multivariate P < 1 x 10(-6)). p21(WAF1/CIP1), a potent inhibitor of cyclin-dependent kinases necessary for cell cycle progression, functions as a key checkpoint in cell cycle control. Immunoreactivity for p21(WAF1/CIP1) provides prognostic information independent of other histological and clinical predictors, p53 IMS, and Ki-67PI in this series of 117 PTs with SENs. Our preliminary data suggest an interrelationship between p21(WAF1/CIP1) expression and an effective clinical response to platinin-based chemotherapy, both associated with apoptosis. Further investigation seems warranted.

Adolescent↗

PubMed1999

Comparison of pulmonary uptake with transient cavity dilation after exercise thallium-201 perfusion imaging.

OBJECTIVES: The purpose of the study was to evaluate the relationship between elevated lung/heart ratio (LHR) and transient ischemic dilation (TID) after stress thallium-201 myocardial perfusion imaging and to provide further insight into the mechanism of cavity dilation. BACKGROUND: Because both LHR and TID have been identified as adjunctive markers of severe coronary disease they should be found in the same patients. Although the mechanism of LHR has been defined, that of transient dilation has not. METHODS: We identified 4,618 consecutive patients undergoing maximal exercise perfusion imaging with thallium-201. Lung/heart ratio and a dilation index were derived and compared to each other and to relevant clinical parameters. RESULTS: There was a very weak relationship between the LHR and dilation index (r = 0.15, p < 0.001). Defining a dilation index > or =1.10 and LHR > or =50% as abnormal revealed that 322 of the patients (7%) had TID only, 351 (7.8%) had LHR only and 40 (0.9%) had both. When compared to patients without these findings both TID and LHR had higher thallium stress defect and redistribution scores. When comparing subjects who had elevated LHR uptake to those who had TID, it was found that those with LHR were more likely to have had prior myocardial infarction (MI) (29% vs. 9%), coronary artery bypass grafting (22% vs. 8%), lower ejection fraction (34+/-17% vs. 55+/-11%) and had more evidence of ischemia based on thallium stress defect and redistribution scores. However, patients with cavity dilation had a higher frequency of positive electrocardiographic response (31% vs. 19%) despite lower scintigraphic markers. CONCLUSIONS: Although pulmonary uptake and transient cavity dilation have both been associated with severe coronary disease, they have a very weak correlation, which, in combination with the different clinical parameters associated with each, suggests that they represent different pathophysiologic responses to exercise-induced ischemia. Our data support the hypothesis that TID represents transient subendocardial ischemia rather than physical dilation from increased end-diastolic pressure.

Coronary Disease↗

PubMed1998

Severe transmural myocardial ischemia after dipyridamole administration implicating coronary steal.

Myocardial perfusion imaging with coronary vasodilators is routinely used for patients with suspected coronary disease who are unable to exercise. Since these agents work by increasing blood flow without significantly changing myocardial oxygen demand, they generally do not produce ischemia. A minority of patients show evidence of ischemia which some investigators suggest is due to a coronary steal phenomenon, but this has been challenged by several investigators. We present the case of a patient who developed severe transmural myocardial ischemia manifested by ST-segment elevation and severe perfusion defects which occurred after dipyridamole administration and which were reversed with aminophylline and nitroglycerin. This case supports the notion that coronary vasodilation with dipyridamole can induce a coronary steal.

Coronary Angiography↗

PubMed1996

Lower diagnostic accuracy of thallium-201 SPECT myocardial perfusion imaging in women: an effect of smaller chamber size.

OBJECTIVES: We attempted to formally compare the diagnostic accuracy of thallium-201 single-photon emission computed tomographic (SPECT) myocardial perfusion imaging in men and women and the effect of chamber size on accuracy. BACKGROUND: The diagnostic accuracy of conventional exercise testing has been shown to be lower in women. Less is known about the relative accuracy of perfusion imaging. Because of smaller body size, women have a smaller heart size than men, a factor that may reduce accuracy. METHODS: We identified 323 patients undergoing thallium-201 SPECT myocardial perfusion imaging who either had < 5% probability of coronary artery disease (CAD) by Bayesian analysis or who underwent cardiac catheterization within 60 days of stress testing. Patients with documented history of infarction, coronary artery bypass grafting, pathologic Q waves on the electrocardiogram, left bundle branch block or nonischemic cardiomyopathy were not included. We performed strict quantitative analysis, and receiver operating characteristic (ROC) curves were generated and the area under the curve was calculated for men and women. A size index was generated from the number of short-axis slices and average radius of each slice, and the group was classified as having a large or a small chamber size. The ROC areas of men and women with a large and a small chamber size were then compared. RESULTS: Diagnostic accuracy was lower in women than in men (ROC are 0.82 vs. 0.93, p < 0.05) despite similar values for peak heart rate and rate-pressure product and similar severity of CAD. There was a greater difference in accuracy between patients with a large versus a small chamber size (ROC area 0.94 vs. 0.73, p < 0.01) despite similar levels of exercise and severity of CAD. When we compared men and women in groups stratified by chamber size, we could not detect a significant difference between ROC area values of men and women (large: 0.94 men, 0.93 women, p = 0.77, power to detect difference in area of 0.15 = 91%; small: 0.79 men, 0.72 women, p = 0.58, power to detect difference in area of 0.15 = 35%). CONCLUSIONS: The diagnostic accuracy of thallium SPECT myocardial perfusion imaging is lower in women than in men. Most of the difference appears to be due to smaller left ventricular chamber size in women, although a small residual gender effect in smaller heart sizes cannot be entirely excluded. It is proposed that the most likely cause for this difference is the relatively greater effect of imaging blurring on smaller hearts.

Aged↗

PubMed1995

[Death under anesthesia. Definition, causes, risk factors and prevention].

Death associated with anaesthetic procedures is rare, 1-4 deaths per 10,000 anaesthesias. However, each case gives rise to discussion about causality and who is to blame. Prospective studies are few, and comparison between them is difficult because of the use of different definitions of anaesthesia related death. A critically ill patient with impaired function of multiple organs seems to be at a higher risk of anaesthesia related death than a more healthy patient. However, no study has so far identified preoperative risk factors of anaesthesia related death. This is probably due to the low incidence of anaesthesia related death. The most common causes of anaesthesia related deaths are: 1) circulatory failure due to hypovolaemia in combination with overdosage of anaesthetic agents such as thiopentone, opioids, benzodiazepines or regional anaesthesia; 2) hypoxia and hypoventilation after for instance undetected oesophageal intubation, difficult intubation, technical failure in the anaesthetic equipment, or aspiration of gastric content, 3) anaphylactoid reactions including malignant hyperthermia, and 4) human negligence such as lack of vigilance or errors in the administration of drugs and in the maintenance and control of the anaesthetic equipment. We discuss the importance of continuing education for anaesthesiologists, development of a standard for surveillance during anaesthesia and quality control of the anaesthetic procedure with registration of undesired incidents. National registration of serious incidents will make it possible to determine the incidence of serious complications and death associated with anaesthesia. Hopefully this registration will provide information about causality and thereby facilitate prevention and improve patient safety during anaesthesia.

Anesthesia↗

PubMed1995

Detection of alterations in left ventricular fatty acid metabolism in patients with acute myocardial infarction by 15-(p-123I-phenyl)-pentadecanoic acid and tomographic imaging.

15-(p-iodine 123-phenyl)-pentadecanoic acid (IPPA) is a synthetic radiolabeled fatty acid with kinetics similar to palmitate. Fourteen patients who had had an acute myocardial infarction 7 +/- 6 days earlier and 9 normal volunteers were studied after being injected with IPPA. The volunteers were remarkable for homogeneous uptake and metabolism of IPPA; 13 of 14 infarct patients showed areas of decreased uptake > 2 SDs below the mean of the volunteers. Metabolism was homogeneous in the volunteers (14.2% +/- 5.8%) and was significantly higher than in regions identified as infarcted (3.9% +/- 12.1%, p < 0.001). Noninfarcted regions in the patients demonstrated significantly increased rates of IPPA metabolism compared to rates in volunteers (23.0% +/- 9.6% p < 0.001). We conclude that patients with recent myocardial infarction have abnormalities of fatty acid metabolism such as decreased uptake and clearance of fatty acid in regions of infarction and normal uptake but relatively increased fatty acid clearance in unaffected regions of the myocardium.

Adult↗

PubMed1995

Prediction of improvement in left ventricular function with iodine-123-IPPA after coronary revascularization.

UNLABELLED: Iodine-123-phenylpentadecanoic acid (IPPA) is a synthetic fatty acid suitable for myocardial imaging. This study is the result of a Phase I/II trial to evaluate IPPA's ability to predict functional recovery in patients undergoing coronary revascularization. METHODS: Twenty-three patients with documented coronary disease underwent sequential SPECT imaging with IPPA before and radionuclide ventriculography both before and 8 wk after revascularization. Software was developed to evaluate myocardial IPPA metabolism and to determine the fraction of the left ventricle with intermediate metabolism. RESULTS: There was a significant correlation between initial IPPA uptake and final LVEF. The fractional area of the left ventricle demonstrating IPPA metabolism in the intermediate metabolic range was significantly higher in patients who demonstrated a 5% or greater increase in EF after revascularization (0.90 +/- 0.08 versus 0.78 +/- 0.17, p = 0.04). When only the patients who received complete revascularization were evaluated, there was a more significant difference (improved 0.92 +/- 0.05 versus 0.74 +/- 0.17, p = 0.011). Taking a lower limit of 1 s.d. from the mean, (87%) the six patients who had > or = 5% increase in LVEF after revascularization had more than 87% of the left ventricle in the intermediate metabolic range, whereas seven of ten patients whose change in LVEF was < 5% had less than 87% in the intermediate metabolic range (p = 0.011). CONCLUSION: In this initial experience, the amount of myocardium in the intermediate metabolic range is associated with improvement in LVEF after revascularization, especially in patients receiving complete revascularization.

Coronary Disease↗

PubMed1994

Prevention of hypotension during spinal anaesthesia for caesarean section.

Twenty-six parturients scheduled to receive spinal anaesthesia for caesarean section were randomized to receive either isotonic saline 750 ml plus 20 ml/kg (group A) or 750 ml plus 500 ml (group B) before subarachnoid administration of bupivacaine 13 mg. Ephedrine 0.15 mg/kg i.v. followed by an infusion 0.4 mg.kg(-1) h(-1) were then administered in group B. In both groups ephedrine 10 mg/min i.v. was given if the mean arterial blood pressure decreased more than 10 mmHg. Despite the fluid preload and large doses of ephedrine noted {median (range), group A 30 mg (10-80), group B 92 mg (25-194)}, hypotension, sometimes accompanied by nausea, still occurred. Mean maternal arterial was significantly lower in group A than in group B 5-10 min after induction of spinal anaesthesia (P < 0.05). There was no difference in the frequency of nausea or vomiting, Apgar score, or pH in umbilical cord blood. One neonate in group A and 2 in group B were acidotic. In conclusion, a reduced volume loading could be compensated with an increased ephedrine administration after induction of spinal anaesthesia, without increasing the incidence of hypotension or other maternal or neonatal complications. However, the fluid volumes and/or ephedrine doses used were not sufficient to prevent hypotension altogether.

Journal Article↗

PubMed1994

Preliminary report of an ongoing phase I/II dose range, safety and efficacy study of iodine-123-phenylpentadecanoic acid for the identification of viable myocardium.

An agent that can accurately and cost-effectively identify viable myocardium is needed to select the patients most likely to benefit from myocardial revascularization. Iodine-123-phenylpentadecanoic acid (IPPA) is a synthetic radiolabeled fatty acid that has shown promise in evaluating patients with coronary artery disease (CAD). IPPA has unique metabolic properties that may make it superior to other single-photon agents used for this task. A Phase I/II study is underway to evaluate safety, dose range and efficacy of IPPA in assessing viability and predicting functional recovery after revascularization. Patients between the ages of 21 and 75 with angiographically documented CAD, who were being referred for coronary revascularization, were recruited. The patients were randomized to receive 2, 4 or 6 mCi of IPPA and then underwent sequential SPECT imaging at 4, 12, 20, 28 and 36 min after injection. Radionuclide ventriculography and perfusion imaging were performed before and again 8 wk after revascularization. Myocardial metabolic activity of IPPA was analyzed and compared to the preinjection and postejection fractions. There were no significant adverse effects from the administration of IPPA. Image quality was dose-dependent; the 2-mCi dose was not consistently acceptable for quantitative analysis. These preliminary data show that IPPA is safe and can produce myocardial images of good quality when 4 mCi or more are used. Early results are encouraging but more experience will be needed to define the role of IPPA in identifying myocardial viability.

Adult↗