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Biomedical subjects

G Kan

Publications and source records attributed to G Kan.

At least 19 recordsLinked to original sources
PubMed1999

Improved cardiovascular variables during acetate free biofiltration.

BACKGROUND AND AIM: Acetate free biofiltration (AFB) provides a well-tolerated and efficient renal replacement therapy. Replacement of most of the acetate by bicarbonate in standard hemodialysis has resulted in a decrease in intradialytic hypotensive episodes. This has been attributed to a decrease in the acetate-induced impairment of myocardial contractility. The aim of the present study was to investigate whether the total absence of acetate in AFB would further enhance dialysis stability and improve cardiovascular status. PATIENTS AND METHODS: In a long-term, randomized trial we included 11 patients on AFB and 9 patients on bicarbonate hemodialysis (HD) for one year. Patients were matched for age, sex and urea reduction rate, but not for the presence of hypertension or cardiovascular history. During each dialysis session blood pressure was measured automatically and the presence of significant hypotension was recorded. Antihypertensive medication was registered every three months. Before and at the end of the study M-mode echocardiography was performed and left ventricular mass index (LVMi) was calculated. Every six months serum lipids were measured. RESULTS: At baseline, mean arterial pressure (MAP) before and after dialysis, the percentage of hypotensive dialyses, LVMi and serum lipids did not differ between AFB and HD. Pre-dialysis MAP decreased in AFB (from 112.5 to 107 mmHg) and increased in HD (from 101.7 to 105.3 mmHg; p = 0.01, HD versus AFB). Postdialysis MAP remained stable in both groups (AFB 91.6 mmHg at 0 months and 90.6 mmHg at 12 months, for HD respectively 83.9 and 86.5 mmHg, NS). The percentage of hypotensive dialyses did not differ significantly between the groups during the study. LVMi decreased in AFB from 195.4 to 162.1 gr/m2 and increased in HD patients from 153.8 to 182.5 gr/m2 (p = 0.03 HD versus AFB). The number of antihypertensive medications per patient did not differ between groups. Serum lipids remained unchanged during the trial. CONCLUSION: In conclusion, AFB provided better control of pre-dialysis MAP compared to HD, and stable postdialysis MAP. The percentage of dialysis sessions with hypotension did not differ. LVMi decreased significantly in AFB, but rose in HD.

Acetates↗
PubMed1998

[Changes of bone cytokines and compensating regulation in tail suspended rats].

The aim of the study was to determine the relationship between the changes in bone metabolism and insulin-like growth factor--I(IGF-I) as well as epidermal growth factor (EGF). 10 Male S.D. rats were tail-suspended for 28 d with another 10 free active rats as control. The results showed that mineral content increased significantly, osteocalcin and albumin content had no significant change, but IGF-I and EGF content increased significantly in L3 in the suspended rats. The results suggest that although there are no change in osteocalcin and albumin content, the phenomenon of bone mineral loss still exists in the suspended rats. The increase in IGF-I and EGF content may be one of the compensation responses of the bone in the suspended rats.

Animals↗
PubMed1995

[Fifteen years' experience in reformed Beijing tuberculosis control programme].

Since 1978 a new tuberculosis control programme based on WHO recommended modern concept has been started in Beijing. A sound network of tuberculosis control service has been organized. Fully supervised intermittent chemotherapy with newly diagnosed cases of smear-positive pulmonary tuberculosis as top priority has achieved satisfactory high rates of compliance and sputum conversion in all 18 districts and counties of the city. Sputum examination was emphasized as the main tool for diagnosis and determination of criterion of cure. Drugs are provided free to those who are needy. On the basis of good implementation of fully supervised chemotherapy for newly diagnosed smear-positive cases, fully supervised retreatment for chronic infectious cases was started, and it resulted in a rapid reduction of the prevalence of chronic infectious tuberculosis from 69.9 in 1979 to 6 in 1985 per 100,000. The prevalence of smear-positive tuberculosis of Beijing during the 3 National Surveys of Tuberculosis was 127, 56 and 16 per 100,000 in 1979, 1985 and 1990 respectively, with an average annual reduction rate of 17%.

China↗
PubMed1994

Esophageal dysfunction as a cause of angina pectoris ("linked angina"): does it exist?

PURPOSE: The differentiation between cardiac and esophageal causes of retrosternal chest pain is notoriously difficult. Theoretically, cardiac and esophageal causes may coexist. It has also been reported that gastroesophageal reflux and esophageal motor abnormalities may elicit myocardial ischemia and chest pain, a phenomenon called linked angina pectoris. The aim of this study was to assess the incidence of esophageal abnormalities as a cause of retrosternal chest pain in patients with previously documented coronary artery disease. PATIENTS AND METHODS: Thirty consecutive patients were studied, all of whom had undergone coronary arteriography. The patients were studied after they were admitted to the coronary care unit with an attack of typical chest pain. On electrocardiograms (ECGs) taken during pain, 15 patients (group I) had new signs of ischemia; the other 15 patients (group II) did not. In none of the patients were cardiac enzymes elevated. As soon as possible, but within 2 hours after admission, combined 24-hour recording of esophageal pressure and pH was performed. During chest pain, 12-lead ECG recording was carried out. RESULTS: In group I, all 15 patients experienced one or more pain episodes during admission, 25 of which were associated with ischemic electrocardiographic changes. The other two episodes were reflux-related. Only one of the 25 ischemia-associated pain episodes was also reflux-related, ie, it was preceded by a reflux episode. In group II, 19 chest pain episodes occurred in 11 patients. None of these was associated with electrocardiographic changes, but 8 were associated with reflux (42%) and 8 with abnormal esophageal motility (42%). CONCLUSION: Linked angina is a rare phenomenon.

Aged↗
PubMed1992

Acute noncardiac chest pain in a coronary care unit. Evaluation by 24-hour pressure and pH recording of the esophagus.

Twenty-four-hour recording of esophageal pressure and pH was performed successfully in 41 patients admitted to the coronary care unit of a general hospital who had an episode of acute, prolonged retrosternal chest pain and who were initially suspected of suffering from coronary artery disease (severe angina pectoris, myocardial infarction), but in whom the pain was subsequently shown not to be of cardiac origin. The recordings were analyzed with fully automated techniques. A pain episode was considered to be related to abnormal esophageal motility when contraction amplitudes or durations in the pain episode exceeded the patient's upper limit of normal (97.5th percentile) or when the proportion of abnormal propagated contractions (simultaneous, nontransmitted) in the pain episode was significantly increased (chi 2 test). Thirty patients (73%) had one or more pain episodes (in total 63 pain episodes) during the 24-hour recording. Forty-three percent of the pain episodes was related to abnormal motility and 30% to reflux, and 27% was not related to esophageal function disturbance. Using the criterium that the symptom index had to be greater than or equal to 75%, it was found that the pain was related to reflux in 13 patients (43%) and to motor abnormalities in 10 patients (33%). It is concluded that in the majority of patients acutely admitted with noncardiac chest pain, esophageal motor abnormalities and reflux can be shown to be the likely cause of the symptoms.

Acute Disease↗
PubMed1986

Incidence, timing and prognostic value of left ventricular aneurysm formation after myocardial infarction: a prospective, serial echocardiographic study of 158 patients.

Serial 2-dimensional echocardiography was performed prospectively in 158 consecutive patients with first acute myocardial infarction (AMI) to determine the incidence of left ventricular (LV) aneurysm formation and the time course required for, and the clinical significance of, onset of LV aneurysm formation. Studies were performed throughout the first 5 days and after 3 months and 1 year. LV aneurysm was defined as an abnormal bulge in the LV contour during both systole and diastole. Eighty-four patients had anterior, 68 posterior and 6 anteroposterior AMI defined echocardiographically. During the study period, LV aneurysm was found in 35 of 158 patients (22%): in anterior AMI in 27, in posterior AMI in 6 and in anteroposterior AMI in 2. No new aneurysm developed after 3 months. Early aneurysm formation, during the first 5 days after AMI, was seen in 15 patients with anterior infarction. Twelve of these 15 (80%) died within 1 year (10 within 3 months), in contrast to 5 (25%) of the remaining 20 patients with LV aneurysm (p less than 0.05). Dyskinesia of the anterior wall in the acute stage usually resulted in aneurysm formation. Thus, LV aneurysm formation is seen in 22% of mostly anterior AMI and occurs within 3 months after AMI. Early aneurysm formation is associated with a high 3-month (67%) and 1-year (80%) mortality rate.

Echocardiography↗
PubMed1986

Two-dimensional echocardiography during percutaneous transluminal coronary angioplasty.

In order to study myocardial and clinical events during transient coronary occlusion in humans, two-dimensional echocardiography was continuously performed in 15 patients undergoing 49 balloon inflations during percutaneous transluminal coronary angioplasty (PTCA). Transient segmental asynergy developed in all patients 8 +/- 3 seconds after balloon inflation and returned to baseline 19 +/- 8 seconds after balloon deflation. Segmental dyskinesis was seen in only 8 of 11 patients undergoing PTCA of the left anterior descending artery (LAD). A wall motion score, based on degree of asynergy of 13 segments of the left ventricle, was significantly higher during LAD than during right coronary artery inflation (7.9 +/- 1.3 vs 4.0 +/- 1.4, p less than 0.01). Left ventricular size index increased significantly during balloon inflation, from 179 +/- 9 to 196 +/- 10 mm (p less than 0.01). Four patients developed transient ST segment changes in the extremity leads of the ECG and five patients had angina pectoris. The very first sign of ischemia in three patients, who developed all of these symptoms together, was consistently asynergy, followed by ECG changes, and last, angina pectoris. Thus during PTCA, transient asynergy and left ventricular dilatation develop, which are often clinically silent.

Angina Pectoris↗
PubMed1986

Short and long term predictive value of admission wall motion score in acute myocardial infarction. A cross sectional echocardiographic study of 345 patients.

A score of left ventricular segmental wall motion was used as a convenient rapid way to assess overall left ventricular function in acute myocardial infarction. Its success in risk stratification at admission was assessed by a blind review of cross sectional echocardiographic tape recordings from multiple acoustic windows. Sixty nine (20%) of the 345 patients died during hospital stay or within a one year follow up. The mean (SD) wall motion score in those who died was significantly higher than in those who survived (16.2 (5.9) vs 5.7 (3.9)). There were no differences between the group that died in hospital within three months of discharge and the group that died between three months and one year after discharge. Among the 31 patients who died in hospital, however, wall motion score was highest in 15 patients dying of cardiogenic shock (19.2 (4.2)). In 16 patients with lethal ruptures it was 13.5 (6.1). The nine patients with free wall ruptures had higher wall motion scores than those with ventricular septal rupture or papillary muscle rupture (15.7 (6.9) vs 8.5 (5.3)). Eight (3.3%) of 245 patients with a score less than 10 died, compared with 61 (61%) of 100 scoring greater than or equal to 10. The sensitivity of a score of greater than or equal to 10 in predicting death within one year was 88%, the specificity was 86%, the positive predictive value was 61%, and the negative predictive value was 97%.

Aged↗
PubMed1985

Assessment of left ventricular aneurysm resectability by two-dimensional echocardiography.

Mortality of surgical resection of a left ventricular (LV) aneurysm is largely determined by size and function of nonaneurysmal or residual myocardium. A residual myocardial index was determined using 2-dimensional echocardiography (2-D echo) in 56 consecutive patients scheduled for LV aneurysmectomy, and these results were correlated with surgical outcome. The index was calculated using 3 apical cross sections: the 2- and 4-chamber views and the long-axis view. These views were recorded at mutual angles of 60 degrees. In each view the end-diastolic length of normally moving endocardium of the 2 opposite walls was expressed as a fraction of the end-diastolic LV long axis. The index was assessed by averaging the 6 ratios obtained. In 41 survivors the index ranged from 40 to 71% (mean +/- standard deviation 53 +/- 7.8) and in 15 nonsurvivors from 29 to 67% (mean 38 +/- 8.5, p less than 0.01). With 1 exception, this echocardiographic index sharply separated survivors from nonsurvivors. The lower limit to survive aneurysmectomy was 40%.

Adult↗
PubMed1985

Quantification of myocardium at risk in unstable angina: comparison of patients with and without previous infarction.

We studied two subgroups of patients with unstable angina pectoris: 35 without (Group A) and 73 with (Group B) previous myocardial infarction. The severity of coronary artery disease was assessed by means of a previously described scoring system. This scoring system was used to calculate the proportion of left ventricular myocardium fed by significantly (greater than 75% luminal area reduction) stenosed coronary arteries (called percent myocardium threatened). To estimate the amount of myocardium lost by previous infarction we used a four-point wall motion score for each of seven left ventricular wall segments: a value of 2 was given to normokinetic segments, 1 for hypokinetic segments, 0 for akinetic and -1 for dyskinetic segments. The deficit in wall motion score was used to estimate the amount of myocardium infarcted. This was then subtracted from the proportion of myocardium threatened to yield the proportion of myocardium still in jeopardy. We found a different extent and severity of coronary artery disease between the two subgroups. In the group without previous infarction, the numbers of patients with one-, two- and three-vessel disease were 15, 9, and 11, respectively (or 43, 26, and 31%). In those with a previous infarction, the respective numbers were 11, 23, and 39 (or 15, 31.5, and 53.5%). This difference is statistically significant (P less than 0.01). The mean number of stenotic arteries was 1.9 +/- 0.9 in the patients without previous infarction and 2.4 +/- 0.7 in those with an infarction (P less than 0.05). Using the above-mentioned scoring system the score was 3.2 +/- 1.4 in patients without previous infarction and 4.0 +/- 1.6 in those with previous infarction (P less than 0.05). The percent myocardium threatened was 53.6 +/- 24.1 vs. 68.7 +/- 24.7 (P less than 0.01). Wall motion score was 13.8 +/- 0.6 in Group A and 10.6 +/- 3.1 in Group B (P less than 0.01), which gives values for the proportion of myocardium infarcted of 1.6 +/- 4.2 and 24.2 +/- 22.0%, respectively. The percentage still in jeopardy (after subtracting that infarcted from that threatened) was 51.8 +/- 22.7 in those without and 44.2 +/- 31.1 in those with a previous infarction: this difference is not statistically significant. We conclude that patients with unstable angina pectoris who have sustained a previous myocardial infarction have more severe coronary artery disease than similar patients without previous infarction. The amount of left ventricular myocardium still in jeopardy of becoming infarcted is, however, the same.

Aged↗
PubMed1985

Embolic potential of left ventricular thrombus after myocardial infarction: a two-dimensional echocardiographic study of 119 patients.

Left ventricular thrombus complicating myocardial infarction was diagnosed by two-dimensional echocardiography in 119 patients. The infarct site was anterior in 98 patients and inferior in 11. Systemic embolism occurred in 26 patients (stroke in 18, lower limb embolism in 7 and mesenteric embolism in 1). A protruding configuration of the thrombus was more common in the patients with embolism than in those without (23 [88%] of 26 versus 17 [18%] of 93) (p less than 0.01). Free mobility of the thrombus was found in 15 (58%) of 26 and 3 (3%) of 93 cases, respectively (p less than 0.01). In predicting embolism, protruding thrombus configuration had a sensitivity of 88% and a specificity of 82%, and positive and negative predictive accuracy was 57 and 96%, respectively. For free mobility of the thrombus, sensitivity was 58%, specificity 97%, positive predictive accuracy 85% and negative predictive accuracy 89%. In the 46 patients whose echocardiogram was obtained during the hospital admission for the index infarct, repeat echocardiograms were obtained during oral anticoagulant therapy. Twelve of these 46 patients had embolism and 2 of the 12 died. In seven of these patients, full dose oral anticoagulant therapy had been given before embolism occurred and in five it was started after an embolic event. The thrombus decreased in size or disappeared in six patients; in four the thrombus showed no change, and in two of these four emboli recurred despite anticoagulation. It is concluded that two-dimensional echocardiography may help delineate the embolic potential of left ventricular thrombus complicating myocardial infarction and may be of value in weighing the benefits and disadvantages of oral anticoagulant therapy.

Anticoagulants↗
PubMed1985

Immediate and long-term effects of nicardipine, at rest and during exercise, in patients with coronary artery disease.

Haemodynamic effects of nicardipine were studied in 12 patients with documented coronary artery disease. Following nicardipine 10 mg, given intravenously to patients at rest, the heart rate increased, mean arterial pressure decreased, cardiac index increased, and systemic vascular resistance decreased significantly. Compared with the control exercise values, significant increases in heart rate and cardiac index and significant decreases in mean arterial pressure, systemic vascular resistance, and left ventricular end diastolic pressure occurred when nicardipine, 10 mg i.v., was given to the patients during exercise. All 12 patients complained of angina during the exercise phase, but following treatment with nicardipine, 10 mg i.v., only four patients reported angina when exercising to the same level. Exercise capacity on oral nicardipine treatment tended to increase whilst the ejection fraction response to exercise did not change. Thus, nicardipine was a potent vasodilator, which produced a marked reduction of systemic vascular resistance and left ventricular end diastolic pressure during exercise.

Aged↗
PubMed1984

Two-dimensional echocardiographic appearance of left ventricular thrombi with systemic emboli after myocardial infarction.

To test the hypothesis that left ventricular (LV) thrombi that project into the lumen and are mobile are more likely to embolize than those that do not have these characteristics, the 2-dimensional echocardiograms of 16 patients with LV thrombi after myocardial infarction were retrospectively reviewed. Ten had evidence of peripheral embolization and 6 did not. The studies were reviewed in random order by an observer blinded to the clinical data. Each echocardiogram was graded as showing a protruding or nonprotruding thrombus and the presence or absence of increased mobility. The thrombus projected into the lumen on the echocardiograms of 8 of 10 patients who had had emboli and in 0 of 6 who had not. The thrombus had increased mobility in 4 of 10 patients with emboli and 0 of 6 without. Thus, LV thrombi that project into the lumen and have increased mobility are more likely to embolize than those without these characteristics.

Adult↗
PubMed1984

Early two-dimensional echocardiographic measurement of left ventricular ejection fraction in acute myocardial infarction.

Left ventricular volume and ejection fraction were measured by 2-dimensional echocardiography from 2 orthogonal apical long axis views in 90 patients admitted with acute transmural myocardial infarction. Results were correlated with worst Killip class during hospital stay, enzymatic infarct size (peak CK-MB) and mortality. We used two algorithms, a biplane area-length algorithm and a modification of Simpson's rule. Both algorithms yielded essentially the same results: there were statistically significant trends towards higher end-diastolic and end-systolic volumes and lower ejection fraction with higher Killip -class. Ejection fraction was lower (P less than 0.01) in the 6 patients dying from cardiogenic shock (28.0 +/- 7.8% v. 46.6 +/- 10.1% in survivors with the area--length algorithm; 28.1 +/- 6.2% v. 48.1 +/- 10.2% with modified Simpson's rule). In 5 patients dying from other causes ejection fraction was 46.0 +/- 14.9% with the area-length method or 46.2 +/- 14.5% with Simpson's rule (not different from survivors). Correlation with peak CK-MB was only modest, though statistically significant: the regression equation was: y = -0. 39x + 54 (r = -0.35; P less than 0.01) with the area-length method; and y = -0. 41x + 55 (r = -0.37; P less than 0.01) with Simpson's rule. Left ventricular ejection fraction measured at the bedside in patients with acute myocardial infarction, can provide useful clinical information. Patients likely to develop shock can be identified shortly after admission.

Aged↗