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Biomedical subjects

M N Kan

Publications and source records attributed to M N Kan.

At least 19 recordsLinked to original sources
PubMed2000

Nutritional status of mechanically ventilated critically ill patients: comparison of different types of nutritional support.

Malnutrition is a common problem in hospitalized patients. Early assessment of nutritional status may help in identifying patients for whom nutritional interventions are needed. The purpose of this study was to assess and compare the nutritional status of mechanically ventilated critically ill patients who were receiving nutritional support. Forty-nine patients were divided into either enteral nutrition, total parenteral nutrition or combined (enteral plus total parenteral nutrition) groups. Anthropometric and biochemical measurements, and medical status (APACHE II score) were assessed at the 1st day and 14th day of admission in the intensive care unit (ICU) of Taichung Veteran General Hospital. The length of ventilator dependency was significantly positively correlated with calorie and carbohydrate intake in the pooled group. Patients receiving enteral and combined nutrition showed significantly lower anthropometric measurements at the 14th day after admission. Patients in all groups had abnormal mean biochemical values at the 1st day of admission. Subjects in the combined group showed a significant increase in prealbumin and the Maastricht Index levels after 14 days. Patients in all three groups were malnourished when admitted to the ICU. Patients showed a slightly improvement of nutritional status after receiving nutritional support for 14 days.

APACHE↗
PubMed1992

Transesophageal echocardiography in adults with a continuous precordial murmur.

In order to assess the ability of echocardiography in the detection of intracardiac and extracardiac shunts, we studied 11 patients (aged 22-64 yr) with a continuous precordial murmur using transthoracic and transesophageal echocardiography, and correlated the results with the subsequent angiographic and surgical findings. We found that only in 5 of 6 patients with a patent arterial duct could the continuous flow pattern be detected in pulmonary artery using transthoracic echocardiography, whereas it could be readily and accurately identified by transesophageal echocardiography in all patients. The diameters of the patent arterial duct were also measured and found to be in good correlation with subsequent surgical findings (r = 0.98, p less than 0.05). In 2 patients with a ruptured aneurysm of sinus of Valsalva which originated from the right coronary sinus and perforated into the right ventricle, transesophageal echocardiography gave a better image than transthoracic echocardiography. In 2 patients with coronary artery fistula, the origin and site of drainage of the coronary artery could be imaged using transesophageal echocardiography, but the course of coronary artery fistula was more easily detected by transthoracic echocardiography. In one patient with aortopulmonary window, the defect between ascending aorta and main pulmonary artery could readily be imaged by transesophageal echocardiography. We therefore recommend transesophageal echocardiography when evaluating patients with precordial continuous murmur in whom intracardiac and extracardiac shunts or defects are suspected.

Adult↗
PubMed1992

Consequences of opiate agonist and antagonist in myocardial ischaemia suggest a role of endogenous opioid peptides in ischaemic heart disease.

OBJECTIVE: The aim was to evaluate the effects of an opiate agonist (U50,488H) and an opiate antagonist (naloxone) in myocardial ischaemia. METHODS: A left thoracotomy was performed and the left coronary artery was ligated in adult Sprague-Dawley rats of either sex (350-400 g). Blood pressure, heart rate and electrocardiogram were measured before and after injections of U50,488H or naloxone and throughout the 30 min postligation period. RESULTS: Following coronary artery occlusion, all rats in the control group developed arrhythmias, bradycardia, and hypotension. U50,488H potentiated and naloxone attenuated the ischaemia induced arrhythmias, bradycardia, and hypotension. CONCLUSIONS: The potentiating and blocking effects of U50,488H and naloxone, respectively, suggest that endogenous opioid peptides are involved in the pathophysiology of myocardial ischaemia and play an important role in ischaemic heart disease.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1992

Naloxone reversal of ischemic arrhythmia is stereospecific and suggests role of endogenous opioid peptides in ischemic heart disease.

The effects of the stereoisomers of naloxone during myocardial ischemia were studied. (-)-Naloxone (but not the (+)-isomer naloxone) attenuated the ischemia-induced cardiac arrhythmias, hypotension, and bradycardia that result from coronary artery occlusion in anesthetized rats. From these findings, it may be inferred that endogenous opioid peptides may play a role in the pathophysiology of myocardial ischemia. It is also suggested that naloxone may have therapeutic value in the prevention and treatment of ischemic heart disease.

Animals↗
PubMed1992

Pericardiocentesis: a 20 patients study.

Emergency pericardiocentesis, guided by a two-dimensional echocardiography, was performed on twenty patients with symptomatic pericardial effusion of various types and causes. There were fourteen men and six women. The underlying causes were: primary lung cancer (6 cases), metastatic cardiac tumors (3 cases), tuberculosis (4 cases), complicated interventional procedures with cardiac chamber or vessel perforations (2 cases), dissecting aortic aneurysm (1 case), systemic lupus erythematous (1 case), idiopathic pericarditis (1 case), bacterial pericarditis (1 case), and myxedema heart disease (1 case). Seventeen cases were performed through the left xipho-sternal approach and 3 cases through the apical approach. None of the patients died as a result of these procedures. A two-dimensional echocardiogram is useful in diagnosing cardiac tamponade as well as in guiding pericardiocentesis, and obtaines highly positive results (20/20). The positive rate of pericardial fluid cytology for malignant cells was 89% (8/9), however, pericardial fluid cultures or direct smear for tuberculosis were negative (0/4). In cancer patients, the mean survival time following pericardiocentesis was 4.2 months (range, 1-7.8 months). We concluded that neoplastic involvement of the pericardium is the most frequent cause of symptomatic pericardial effusion. Pericardiocentesis assisted by a two-dimensional echocardiogram is safe and easy. In addition, pericarditis caused by TB is still significant and must be considered in every case in our nation.

Adult↗
PubMed1991

Comparison of transesophageal to transthoracic color Doppler echocardiography in the identification of intracardiac mycotic aneurysms in infective endocarditis.

We report on cases of mycotic aneurysms in a group of 14 patients with infective endocarditis, all of whom were evaluated with transthoracic (TTE) and transesophageal (TEE) color Doppler echocardiography. Four mycotic aneurysms were found, one each in the left ventricular outflow tract, the right coronary sinus of Valsalva, the anterior mitral leaflet, and the atrial septum. With TTE, only three of four cases of mycotic aneurysms could be detected. Utilizing TEE, however, all were detected and their connections with the heart chambers or great vessels could be readily and clearly depicted, especially those in the atrial septum and mitral leaflet. We are of the opinion that TEE is superior to TTE in the identification and detailed analysis of mycotic aneurysms complicating infective endocarditis. In addition, we feel that echocardiography may help evaluate the progress of the disease, the location and direction of infection, and the extent of involvement of the mycotic aneurysms, providing useful information for guiding surgical intervention.

Adult↗
PubMed1990

Detection of prosthetic mitral valve leak: a comparative study using transesophageal echocardiography, transthoracic echocardiography, and auscultation.

Paravalvular leakage is a major complication of prosthetic valve dysfunction. Sixty-one subjects with valvular heart disease who had received prosthetic mitral valve replacement 5 months to 5 years before (43 received a porcine prosthesis and 18 received Bjork-Shiley valve prostheses) were evaluated for this complication. Careful auscultation was performed by two experienced cardiologists followed by transthoracic and transesophageal echocardiography. Physiologic leaks were detected in all Bjork-Shiley valves, but in only 30% of porcine valves using transesophageal echocardiography. These regurgitant jets were flame-like, with mean low velocities of 50 +/- 12.3 cm/sec and 48 +/- 18.2 cm/sec in the two types of valves. Neither transthoracic echocardiography nor auscultation could detect physiological regurgitant jets. Ten cases with paravalvular leak were detected by transesophageal echocardiography and subsequently demonstrated by left ventriculography (7 porcine, 3 Bjork-Shiley valves). Pathologic regurgitant jets were seen as high-velocity, systolic-retrograde turbulent flow across the prosthesis. However, only 6 cases of prosthetic valve dysfunction were detected by transthoracic echocardiography, 4 cases of mild paravalvular leakage went undetected. Thirteen of the 61 subjects had an apical systolic murmur and suspected prosthetic valve leakage; in 10 of the 13 cases the findings corresponded to those obtained by transesophageal echocardiography. In 3 cases of double valve replacement with Bjork-Shiley valves the magnitude of the leakage was overestimated by auscultation.

Adult↗
PubMed1990

Contributing factors to formation of left atrial spontaneous echo contrast in mitral valvular disease.

The formation of left atrial spontaneous echo contrast may relate to blood stasis. This study analyzed the factors contributing to the formation of that contrast. Transesophageal echocardiography, transthoracic echocardiography, cardiac catheterization, and left ventricular angiography were performed in 139 patients, divided into five groups. Predominant mitral stenosis with atrial fibrillation was found in 36 patients (group I); normal porcine valve in the mitral valvular area with atrial fibrillation in 31 (group II); predominant mitral stenosis with normal sinus rhythm in 26 (group III); moderate to severe mitral regurgitation with atrial fibrillation in 25 (group IV); atrial fibrillation with normal mitral valve in 21 (group V). The results showed left atrial spontaneous contrast echo was found in only 1 of 139 patients by transthoracic echocardiography and 62 of 139 cases were detected by transesophageal echocardiography. There was a high incidence of left atrial spontaneous echo contrast in cases of mitral obstruction with atrial fibrillation and enlarged left atrium (group I, 88%; group II, 74%), but a lower incidence in cases with normal sinus rhythm (group III, 4%), atrial fibrillation alone (group V, 16%), and increased left atrial flow velocity (group IV, 9.5%). The diameter of the left atrium was significantly different between presence and absence of left atrial spontaneous contrast echo (54.3 +/- 9.2 mm vs. 48.3 +/- 8.6 mm, p less than 0.01). The mean pressure gradient was similar in groups I and III (14.6 +/- 0.6 mHg and 14.4 +/- 2.8 mHg, respectively) but different in group II (10.9 +/- 3.2 mHg, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

The effect of intravenous captopril on the left ventricular function-an acute study by hemodynamics and radionuclide angiography.

Acute hemodynamic effects of intravenous captopril were measured, and left ventricular function was analyzed by radionuclide angiography in 11 patients with moderate to severe hypertension. All subjects received 1 mg captopril bolus injection initially, and followed in 10 minutes intervals by 2 mg or 5 mg injections according to their blood pressure response. Eight patients experienced an acute reduction of blood pressure; three patients remained unresponsive. The onset of action occurred within 5 minutes with peak effect at 5 to 10 minutes and a duration of action of 20 to 30 minutes. The hemodynamic effects were characterized by arteriolar dilation (reduced systemic vascular resistance P less than 0.01), and apparent venous dilatation (reduced right atrial, pulmonary wedge pressure P less than 0.05 & 0.01 respectively). Pulmonary vascular resistance was not altered. Ejection fraction remained unchanged. Isovolumic relaxation period lengthened (109 +/- 20.1 vs 137.39 +/- 21.15 msec, P less than 0.05) and coronary perfusion pressure gradients dropped (113.8 +/- 5.6 vs 101.1 +/- 11.3 mmHg P less than 0.001) following intravenously administered captopril. Intravenous captopril may reduce arterial pressure by inducing arterial dilatation with minimal adverse effect. The prolongation of isovolumic relaxation period should mainly attribute to the decrease of coronary filling load.

Captopril↗
PubMed1987

Color Doppler assessment of mitral regurgitation induced by supine exercise in patients with coronary artery disease.

Development of mitral regurgitation (MR) during acute myocardial ischemia is a well known occurrence. To assess the feasibility and clinical utility of detecting MR during exercise testing, color Doppler examinations were performed in 22 patients with angiographically proved coronary artery disease (CAD) and in 17 normal subjects before, during and after graded supine bicycle exercise. Not only was MR visualized using color Doppler during dynamic testing, but it was also slightly more sensitive (59% vs 54%) and specific (100% vs 88%) than the electrocardiographic response in identifying patients with CAD. When the appearance of MR or diagnostic electrocardiographic changes or both were used to identify patients with CAD, the sensitivity of exercise tolerance testing increased to 82%, although the specificity was 88%. In addition, exercise-induced MR was observed to be as sensitive and specific as exercise-induced wall motion abnormalities. Combining exercise-induced MR with wall motion abnormalities also increased the sensitivity to 82%, with the specificity remaining at 100%. With use of exercise-induced MR, wall motion abnormalities or electrocardiographic changes, the sensitivity and specificity of the exercise test in diagnosing CAD was 91% and 88%, respectively. The degree of MR as estimated by maximal area of regurgitation signals, as well as by its ratio to left atrial area, did not correlate with extent of CAD. However, the presence of exercise-induced MR suggested an increased likelihood of 3-vessel CAD because it was found in 9 of 11 patients with 3-vessel CAD, compared with 2 of 5 patients with 2-vessel and 2 of 6 patients with 1-vessel CAD.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Diagnosis of double aortic arch by cross sectional echocardiography with Doppler colour flow mapping.

A case of double aortic arch in a 15 month old boy was diagnosed by cross sectional echocardiography supplemented by Doppler colour flow mapping. These examinations showed two very large vessels communicating with the aorta; the demonstration of anterograde flow in one vessel and retrograde flow in the other enabled a definite diagnosis of Edwards type IA double aortic arch to be made.

Aorta, Thoracic↗
PubMed1978

Quantitation by gas chromatography-chemical ionization mass spectrometry of cyclophosphamide, phosphoramide mustard, and nornitrogen mustard in the plasma and urine of patients receiving cyclophosphamide therapy.

Unambiguous and sensitive methods based on gas chromatography-chemical ionization mass spectrometry have been developed to quantitate cyclophosphamide and two alkylating and cytotoxic metabolites, phosphoramide mustard and nornitrogen mustard. The levels of these materials have been determined in the plasma and urine of five patients receiving cyclophosphamide, 60 or 75 mg/kg i.v. Peak plasma levels of phosphoramide mustard of 50 to 100 nmoles/ml were found at 3 hr after cyclophosphamide administration. Variable levels of nornitrogen mustard were found in the plasma. This product may be arising in part from the decomposition of other metabolites during sample storage and preparation.

Adolescent↗
PubMed1977

Identification of aldophosphamide as a metabolite of cyclophosphamide in vitro and in vivo in humans.

Aldophosphamide (NSC 254), a putative key metabolite of cyclophosphamide, has now been isolated as a cyanohydrin derivative from an incubation mixture of cyclophosphamide with mouse liver microsomes in vitro and from the plasma of a cyclophosphamide-treated patient. The cyanohydrin has been shown to be identical with an authenic synthetic sample by mass spectrometry and combined gas chromatography-mass spectrometry.

Aldehydes↗
PubMed1976

Alkylating properties of phosphoramide mustard.

The relative alkylating activities of two of the cytotoxic metabolites of cyclophosphamide, phosphoramide mustard and nornitrogen mustard, have been studied at pH 4.6 and 7.4. The products formed on alkylation of ethanethiol by these metabolites have been identified, confirming that phosphoramide mustard undergoes alkylation reactions as an intact molecule. Deuterated analogs of the two metabolites have been synthesized, namely N,N-bis(2,2-dideutero-2-chloroethyl)-phosphorodiamidic acid and N,N-bis(2,2-dideutero-2-chloroethyl)amine and used to determine that alkylation proceeds directly via an aziridinium intermediate rather than a direct SN2 displacement of the chlorine atom.

Alkylation↗