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C Beeder

Publications and source records attributed to C Beeder.

10 recordsLinked to original sources
PubMed1996

Pressure and Flow Characteristics of Various Resectoscopes

We evaluated the pressure and flow characteristics of four hysteroscopic resectoscopes using both gravity and suction. Each hysteroscope was introduced through a port into a sealed chamber of 150 ml volume. A pressure reading was made from the chamber and flow was measured. Using gravity feed, the mean maximum flow rate for the four devices was 512 ± 29 ml/minute, with a mean chamber pressure of 41 ± 24 mm Hg at maximum flow. Using suction, the mean maximum flow rate for the devices was 948 ± 74 ml/minute, with a mean chamber pressure of -65 ± 39 mm Hg at maximum flow. The gravity-fed maximum flow rate was very similar for all devices tested and virtually doubled under suction. More variability was apparent in chamber pressure data, especially during suction.

Journal Article↗
PubMed1992

Endoscopy of the lacrimal outflow system.

Management of obstructions in the lacrimal drainage system would be greatly aided by improvements in the ability to visualize the blockages. We describe a new method of observation using miniature fiberoptics to view the entire lacrimal excretory system. We employed flexible endoscopes of fiberoptic bundles with outside diameters of from 0.5 to 0.7 mm. These endoscopes were inserted through the puncta and canaliculi. Sixteen patients were examined. A range of pathologic conditions were found, including slightly stenosed passages and severely destroyed canalicular mucosal lining. Our results indicate that this technique is feasible and useful in the diagnosis of lacrimal excretory disease.

Endoscopes↗
PubMed1991

Excimer laser ablation of fibrocartilage: an in vitro and in vivo study.

To date, lasers have found only limited applications in orthopedics. We employed a 308 nm XeCl excimer laser for ablation of fibrocartilage, in order to investigate the feasibility of excimer laser assisted meniscectomy. Experiments were conducted both in vitro and in vivo. For the in vitro study, human menisci, obtained during surgery and autopsy, were irradiated via a 600 microns core fiber at radiant exposures ranging between 20 mj/mm2 and 80 mj/mm2, at 20 Hz. Ablation rate measurements and histological analysis of the samples were performed. The ablation rates were found to range from 3 microns/pulse to 100 microns/pulse depending on the radiant exposure and/or the applied pressure on the fiber delivery system. Thermographic analysis was also performed during pulsed excimer as well as CW Nd:Yag and CW CO2 laser irradiation. Temperatures were lower for excimer laser (Tmax less than 65 degrees) than CW ND: Yag (Tmax less than 210 degrees) or CW CO2 (Tmax less than 202 degrees) laser. For the in vitro study, medial meniscectomy was performed in 15 rabbits with the excimer laser and a CW Nd:Yag laser in the right and left knee respectively. Excimer laser irradiation was performed at 70 mj/mm2. Nd:Yag irradiation was performed via a 600 microns core fiber at power outputs between 20 to 40 W for 10 and 20 seconds duration. The healing response to injury was investigated by histological analysis of the menisci after 1 day, 1, 2, 4, and 8 weeks following the laser procedure. Excimer laser treated menisci showed less inflammatory reaction and noticeable repair with minimal inflammatory response.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Utility of echocardiography for the early assessment of patients with nondiagnostic chest pain.

A two-dimensional (2D) echocardiogram was recorded shortly after admission in 46 patients with nondiagnostic chest pain. Eighteen patients were studied during chest pain and 28 were studied following the resolution of chest pain. Of the 18 patients studied during chest pain, six of the eight patients who had a regional wall motion abnormality (RWMA) evolved an acute infarction and the remaining two patients had evidence of significant coronary artery disease. Only 1 of 10 patients without a RWMA evolved an infarction and none had significant coronary artery disease. Of the 28 patients studied following the resolution of chest pain, 8 of the 10 patients with a RWMA evolved an acute infarction and one patient had evidence of significant coronary artery disease, whereas of 18 patients without a RWMA, none evolved an acute infarction and five had evidence of significant coronary artery disease. These data suggest that in patients presenting with nondiagnostic chest pain, an early assessment of regional wall motion by 2D echocardiography can reliably differentiate patients with myocardial ischemia or early infarction from patients with nonischemic chest pain when performed during an episode of chest pain; can also identify those patients with early acute myocardial infarction, even when performed following the resolution of chest pain; but is not useful for the detection of patients with significant coronary artery disease without infarction when performed following the resolution of chest pain.

Adult↗
PubMed1984

Improvement in regional and global left ventricular function after intracoronary thrombolysis: assessment with two-dimensional echocardiography.

After acute myocardial infarction, 23 patients undergoing intracoronary thrombolysis and 10 patients receiving conventional medical treatment were studied by 2-dimensional echocardiography to determine changes in regional and global left ventricular (LV) performance. Both quantitative and qualitative analysis of echocardiographic studies showed improvement in regional and global LV function in 18 patients with successful reperfusion immediately after thrombolysis to 10 days later (p less than 0.0005). Eleven patients who were studied before thrombolysis demonstrated no change in regional or global LV function immediately after thrombolysis. LV function did not improve in the conventionally treated group. These data indicate that in patients with acute coronary artery occlusion successfully reperfused by intracoronary thrombolysis, regional and global LV function improved by day 10 but not immediately after reperfusion.

Adult↗
PubMed1983

Simultaneous assessment of segmental and global left ventricular function by two-dimensional echocardiography in acute myocardial infarction.

Both segmental and global left ventricular performance were assessed simultaneously in 29 patients with acute myocardial infarction using two-dimensional echocardiography. Comparisons were made between left ventricular wall motion versus peak CK-MB, site of infarction, and occurrence of heart failure. Two-dimensional echocardiography identified areas of dyssynergy which corresponded to electrocardiographic areas of infarction in 89% of all cases. Patients with heart failure had more dyssynergic segments, and these segments manifested more severe dyssynergy than patients without heart failure. Patients with severe global dysfunction manifested higher peak CK-MB values, and those with anterior infarction had more global dyssynergy than did those patients with inferior infarction. These observations suggest that two-dimensional echocardiography is a useful technique for localization and assessment of segmental and global dyssynergy in acute myocardial infarction. Information so derived correlates with the clinical status of patients with acute myocardial infarction, and may offer important insights into both prognosis and treatment.

Creatine Kinase↗
PubMed1982

Early diagnosis of nontransmural myocardial infarction by two-dimensional echocardiography.

Thirty patients with chest pain syndromes were studied on admission by two-dimensional echocardiography (2DE) to confirm or exclude acute myocardial infarction (AMI). Twelve patients suffered nontransmural AMI and 18 patients had no AMI. There was no significant difference between these groups in background characteristics. 2DE studies were analyzed quantitatively and qualitatively. The most sensitive and specific technique for detecting AMI was qualitative analysis, using the presence of severe hypokinesis as the criterion for an abnormal study. Using this technique, 10 of 12 patients (83%) with AMI and all 18 patients (100%) without AMI were correctly identified. This analysis technique was highly reproducible. These data indicate that in patients with chest pain syndromes without diagnostic ECG findings of AMI, 2DE may provide a rapid, sensitive, specific tool to aid in the establishment of the correct diagnosis. In patients with nontransmural AMI, the presence of severe hypokinesis appears to be the best discriminator of myocardial infarction.

Adult↗
PubMed1981

Relationship between segmental abnormalities and global left ventricular function in coronary artery disease: validation of a theoretical model.

A theoretical model of the heart, which suggests a direct relationship between segmental abnormalities of left ventricular (LV) wall motion (WM) and LV ejection fraction (EF), was tested using two-dimensional echocardiography (2DE) and multiple-gated equilibrium blood pool scintigraphy (MGES) in a population of 25 coronary artery disease patients. MGES was used to determine EF, and 2DE was used to develop a method of analysis of LV segmental WM abnormalities. Two orthogonal apical 2DE views were analyzed. The length of the end-diastolic segments in which normal contraction occurred during systole were measured in each view, summed and divided by the sum of the end-diastolic silhouette lengths. The fraction thus created was multiplied by 100 and defined as the percentage of normally contracting myocardium (%NCM). %NCM correlated well with EF determined by MGES (r = 0.94). Determination of %NCM was highly reproducible for the same observer (r = 0.98), as well as for two observers (r = 0.98), and the standard error of estimate was low in both cases (4%). These findings, in addition to confirming the theoretical model, provide a new technique to assess LV segmental WM abnormalities by 2DE.

Aged↗