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Biomedical subjects

K Y Lee

Publications and source records attributed to K Y Lee.

At least 19 recordsLinked to original sources
PubMed1992

Efficacy of flecainide for the reversion of acute onset atrial fibrillation.

The efficacy and safety of intravenous flecainide to convert recent-onset atrial fibrillation (AF) (present for greater than or equal to 30 minutes and less than or equal to 72 hours and a ventricular response greater than or equal to 120 beats/min) was investigated. A total of 102 patients without severe heart or circulatory failure were randomized to receive either intravenous flecainide (2 mg/kg, maximum dose 150 mg; 51 patients) or placebo (51 patients) in a double-blind trial. Digoxin (500 micrograms intravenously) was administered to all patients who had not previously been receiving digoxin. The electrocardiogram was monitored continuously during the study. In 29 (57%) patients stable sinus rhythm was restored within 1 hour after flecainide and in only 7 (14%) given placebo (chi square 18.9; p = 0.000013; odds ratio 8.3; 95% confidence interval 2.9-24.8). Reversion to sinus rhythm within 1 hour after starting the trial medication was considered a pretrial end point and likely to be due to a drug effect. At the end of the 6-hour monitoring period, 34 patients (67%) in the flecainide group were in sinus rhythm whereas only 18 (35%) in the placebo group had reverted (chi square 8.83, p = 0.003; odds ratio 3.67; 95% confidence interval 1.5-9.1). Significant hypotension, although short lived, was more common in the flecainide group. One patient given flecainide developed torsades de pointes and was successfully electrically cardioverted. Flecainide is useful for the management of recent-onset AF both for control of the ventricular response and conversion to sinus rhythm.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1992

On detecting the presence of fetal R-wave using the moving averaged magnitude difference algorithm.

An efficient algorithm detecting the presence of a fetal QRS complex is presented. The proposed fetal QRS detection method computes the averaged magnitude of the difference between the fetal ECG signal and the reference signal to detect the fetal QRS event. The detected fetal QRS complexes are exponentially averaged to generate the template signal which can track the slowly varying shape of the fetal ECG signal. As an effort to obtain improved detection performances, two approaches of normalizing the fetal ECG signal and the template are considered.

Algorithms↗
PubMed1992

Release of cholecystokinin and secretin by sodium oleate in dogs: molecular form and bioactivity.

The release of cholecystokinin (CCK) and secretin into both circulation and duodenal lumen, after intraduodenal perfusion with sodium oleate or oral ingestion of fat, was studied in anesthetized and conscious dogs, respectively. Intraduodenal infusion with sodium oleate (4 mmol.kg.-1.h-1, pH 9.5) in anesthetized dogs with diversion of bile and pancreatic juice stimulated the release of both CCK and secretin not only into the circulation but also into the duodenal lumen. The concentration of CCK and secretin in the luminal perfusate increased from 0.2 +/- 0.1 to 2.1 +/- 0.4 nM and 0.34 +/- 0.16 to 2.59 +/- 0.63 nM, respectively. Intraduodenal infusion of NaHCO3 solution at pH 9.5 did not result in release of either hormone. Luminal release of both hormones was also observed by intraduodenal infusion of sodium oleate in the dogs without diversion of bile and pancreatic juice, albeit at lower concentrations than those released in the dogs with diversion. Analysis of the molecular form of luminal secretin by gel filtration, ion-exchange chromatography, and high-performance liquid chromatography showed only a single form of secretin with molecular size, hydrophobicity, and charge similar to those of natural porcine secretin. In contrast, multiple forms of CCK were released into both circulation and duodenal lumen with CCK-58 as the predominant form. In conscious dogs, CCK-58 was also found to be the predominant form of CCK released into the circulation after oral ingestion of fat.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Neurohormonal mechanism of pancreatic exocrine secretion stimulated by sodium oleate and L-tryptophan in dogs.

In the present investigation, we have studied the effect of atropine on the pancreatic secretion stimulated by intraduodenal administration of either sodium oleate or exogenous cholecystokinin (CCK). In four dogs prepared with gastric and Thomas duodenal cannulas, pancreatic juice was collected for measurement of volume, bicarbonate, and protein output, and peripheral venous blood samples were obtained for radioimmunoassay of both secretin and CCK. Volume, bicarbonate, and protein output of the pancreatic juice increased significantly in response to sodium oleate (1-4 mmol/h) in a dose-dependent manner. The increase in pancreatic secretion paralleled the increments in both plasma CCK and secretin. Atropine given intravenously suppressed completely both pancreatic secretion and release of CCK stimulated by sodium oleate, whereas the release of secretin was not affected. Pancreatic secretion was significantly increased in a dose-dependent manner by exogenous CCK octapeptide (CCK-8) at 16, 32, and 64 micrograms (14, 28, and 56 pmol).kg-1.h-1. Atropine inhibited protein output only partially, but it did not influence bicarbonate output. In five additional dogs, the effect of atropine on L-tryptophan-stimulated pancreatic secretion was studied. Interestingly, atropine failed to influence the CCK release and pancreatic secretion of volume and bicarbonate, except for protein secretion, which was significantly inhibited. It was shown previously that atropine inhibited significantly the pancreatic secretion of bicarbonate stimulated by secretin in physiological doses. Thus we conclude that the inhibition by atropine of the pancreatic exocrine secretion stimulated by sodium oleate is mediated by both suppression of CCK release and inhibition of action of secretin on the exocrine pancreas.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Changes in extrahepatic bile duct caliber in liver transplant recipients without evidence of biliary obstruction.

To better understand changes in the size of the extrahepatic bile duct after liver transplantation, we retrospectively studied the luminal diameter of the extrahepatic bile duct on serial cholangiograms in 40 liver transplant recipients with choledochocholedochostomy biliary anastomoses and without biliary complications. Forty operative and 105 postoperative cholangiograms were reviewed. The average interval between operative and last postoperative cholangiogram was 5 weeks (range, 1-17 weeks). The mean diameter of the donor common hepatic duct increased from 5.5 +/- 2.1 mm to 6.3 +/- 2.4 mm (p = .015). The mean diameter of the native common bile duct increased from 5.1 +/- 1.4 mm to 6.8 +/- 2.4 mm (p less than .001). The diameter of the donor common hepatic duct increased by 3 mm or more in six patients (15%); the diameter of the native common bile duct increased by 3 mm or more in nine (23%). Increased diameter of the native common bile duct was associated with T-tube migration into the duct in four cases. The size of the extrahepatic bile duct on cholangiograms is stable or increases slightly in most liver transplant recipients. Mild increases unassociated with a specific cause of obstruction or hepatic dysfunction do not portend biliary obstruction and are clinically benign.

Bile Ducts↗
PubMed1992

Small airway disease in rheumatoid arthritis.

Variety of pulmonary lesions are thought to be associated with rheumatoid arthritis (RA). These lesions traditionally have included pleurisy with or without effusion, Caplan's syndrome, pulmonary rheumatoid nodules, diffuse interstitial fibrosis, and pulmonary arteritis and hypertension. But little attention has been paid to the airways in RA. Recently, several reports have suggested an association between airflow limitation and RA, but its incidence is not known. Also whether there exists a parameter of disease activity of RA, suggesting the presence of small airway disease (SAD) is not clear. To answer these questions, the serologic parameters which reflect the disease activity of RA and pulmonary function tests which reflect small airway dysfunction were performed on 36 lifetime nonsmokers with RA who had normal chest x-ray findings. The prevalence of SAD and the relationships between the disease activity parameters of RA and pulmonary function were observed. The results were as follows. The percentages of patients with abnormal values for diffusing capacity, frequency dependence of compliance (C1.0/C0.0), forced expiratory flow 25-75%, Vmax50% and Vmax 75% were 45.5%, 62.5%, 40%, 22.8% and 11.4%, respectively. There was statistically significant negative correlation between C1.0/C0.0 and ESR. But consistent correlation between other pulmonary function tests and clinical and serologic parameters of RA, and differences in pulmonary function between patients who were serologically positive and negative for CRP and FANA, were not found. In conclusion, SAD, without the influence of smoking, is frequently associated with RA, but the presence of SAD cannot be predicted from any clinical and serologic parameters of RA currently in use.

Adult↗
PubMed1991

Household electric shocks: who should be monitored?

OBJECTIVE: To decide who should be monitored after exposure to household 240 volt 50 Hz alternating current electric shocks. DESIGN AND SETTING: Records of patients admitted to the Intensive Care Unit of Royal Perth Hospital for the period 1978-1987 were retrospectively reviewed. A literature review was also performed to compare previous findings with our own (Medline search; keywords--electrical injury, arrhythmia). RESULTS: There were 20 patients in the series, and all patients survived the electric shock. Of the 18 who presented with no cardiovascular symptoms or electrocardiographic abnormalities, none developed arrhythmias while being monitored in the Intensive Care Unit. CONCLUSION: Routine cardiac monitoring is not required after electric shock with household alternating current if the patient is asymptomatic and has a normal electrocardiogram on presentation.

Accidents, Home↗
PubMed1991

Reversion of recent-onset atrial fibrillation to sinus rhythm by intravenous flecainide.

Spontaneous reversion to sinus rhythm is a frequent occurrence in recent-onset atrial fibrillation (AF). In a randomized, double-blind, controlled study, intravenous flecainide (2 mg/kg, maximum dose 150 mg) was compared with placebo in the treatment of recent-onset AF (present for greater than or equal to 30 minutes and less than or equal to 72 hours' duration and a ventricular response greater than or equal to 120 beats/min). Intravenous digoxin (500 micrograms) was administered concurrently to all patients in both groups who had not previously taken digoxin. The trial medication was administered over 30 minutes. Exclusion criteria included hemodynamic instability, severe heart failure, recent antiarrhythmic therapy, hypokalemia and pacemaker dependence. One hundred two consecutive patients with recent-onset AF were enrolled in the study. All patients underwent continuous electrocardiographic monitoring in the intensive care or coronary care unit. Twenty-nine (57%) patients given flecainide and digoxin, but only 7 (14%) given placebo and digoxin, reverted to sinus rhythm in less than or equal to 1 hour after starting the trial medication infusion and remained in stable sinus rhythm (chi-square 18.9, p = 0.000013; odds ratio 8.3, 95% confidence interval 2.9 to 24.8). At the end of the 6-hour monitoring period, 34 patients (67%) in the flecainide-digoxin group were in stable sinus rhythm, whereas only 18 patients (35%) in the placebo-digoxin group had reverted (chi-square 8.83, p = 0.003; odds ratio 3.67, 95% confidence interval 1.5 to 9.1).(ABSTRACT TRUNCATED AT 250 WORDS)

Atrial Fibrillation↗
PubMed1991

Gly-238-Ser substitution changes the substrate specificity of the SHV class A beta-lactamases.

The SHV-type beta-lactamase SHV-2A is related to SHV-1 by a Gly-238-Ser replacement. Strains carrying SHV-2A are resistant to the third generation cephems cefotaxime and ceftizoxime, whereas those that carry SHV-1 are sensitive to these drugs. We present a kinetic analysis of a SHV-1 and SHV-2A enzymes, with the goal of gaining insight into the role of residue 238 in hydrolyzing cefotaxime and ceftizoxime. SHV-2A shows altered kinetic properties for a number of other cephems that also have heterocyclic side chains at the amino position of the 7-aminocephalosporanic acid nucleus (R1 side chain), including a significantly higher kcat/Km than does SHV-1 for cephaloridine, cephalothin, and cefotiam. Two cephems with straight chain R1 substitutions, cephalosporin C and cephacetrile, are not hydrolyzed more efficiently by SHV-2A. These results indicate that the Ser-238-Gly substitution increases the affinity toward cephems with a heterocyclic ring in the R1 side chain. In addition, the data for ampicillin and benzylpenicillin show that addition of a nitrogen to the second carbon of the R1 side chain of a penem results in a lower kcat/Km for SHV-2A relative to SHV-1. These data strongly suggest that the previously proposed hydrogen bond formation between Ser-238 and the second carbon nitrogen of cefotaxime is not an important factor in hydrolysis by SHV-2A. We propose that the Gly-238 to Ser-238 replacement in SHV-2A has altered the hydrophobic pocket so that it can better accommodate cephems with bulky R1 side chains.

Amino Acid Sequence↗
PubMed1991

Congenital hydrocephalus associated with anomalies of midline telencephalic structures. A case report.

Hydrocephalus is classified into communicating, if cerebrospinal fluid (CSF) can flow freely from the ventricle to the subarachnoid space, and into non-communicating, if it cannot. The cause of hydrocephalus is diverse, either congenital or acquired conditions causing obstruction to the flow of CSF. The location of the lesion is more important than the size or nature of the lesion. We describe an unusual case of congenital communicating hydrocephalus associated with multiple malformations of midline telencephalic structures. This was a premature male baby of 30 weeks gestational age. The pregnancy was terminated after revealing a hydrocephalus by ultrasonography. The cerebral hemispheres showed marked thinning of parenchyme with dilated lateral ventricles, communication of lateral and third ventricles with dilated foramina of Monro, absence of the septum pellucidum, and hypoplasia or focal agenesis of posterior portion of corpus callosum with dorsal dilation of the third ventricle. The right fornix appeared as a single thick midline cord in its approximately normal position and the hippocampi were poorly developed, especially in the left side. The left fornix was rudimentary.

Humans↗
PubMed1991

Contaminant reduction by ventilation in a confined space model--toxic concentrations versus oxygen deficiency.

Airborne contaminants can create hazardous conditions in confined spaces (CS) across a broad range of concentrations, e.g., from relatively low, potentially toxic levels (ppm) to much higher levels (%) causing oxygen deficiency. This study investigated ventilation characteristics for isobutylene (IBE) at relatively low concentrations, simulating toxic levels. Experimental data were compared to results from previous studies of oxygen deficiency. Data were obtained at several locations in a cubical CS model, with several variable test parameters: ventilation mode (exhaust and supply), volume flow rate ("air changes" per hour), and ventilation inlet/outlet elevation (% of model height). Findings indicated similar ventilation characteristics, in general, for simulated toxic (IBE) levels compared to oxygen deficiency. Both IBE and O2 deficiency data have shown that supply ventilation is typically more effective than exhaust and that CS locations aligned with supply outlets experience much more rapid contaminant reduction than do other locations. The data suggest that highly accurate predictions of ventilation characteristics cannot be expected for all cases with widely different contaminants and concentrations. Findings from this study indicate that ventilation guidelines for one range of contaminant concentration (e.g., causing oxygen deficiency) can be extended reasonably to encompass a broader range of concentration (e.g., to include toxic or flammable atmospheres).

Air Pollutants, Occupational↗
PubMed1991

Hemodynamic benefit of maintaining atrioventricular synchrony during cardiac pacing in critically ill patients.

OBJECTIVE: To determine the hemodynamic effects of maintaining atrioventricular synchrony during emergency cardiac pacing in critically ill patients. DESIGN: Prospective, within patient double-blind study. SETTING: ICU or coronary care unit patients in a university hospital. PATIENTS: Forty (23 cardiac surgery, ten acute myocardial infarction, and seven general intensive care) seriously ill patients with severe symptomatic bradycardia. INTERVENTION: Initial randomization of patients to receive either a pacing mode where atrioventricular synchronization was maintained (atrioventricular pacing: atrial demand, atrioventricular sequential, atrioventricular universal) or a mode of pacing where atrioventricular synchrony was not preserved (ventricular demand pacing). MEASUREMENTS AND MAIN RESULTS: The cardiac output increased from a mean of 4.5 +/- 1.7 L/min (95% confidence intervals: 4.0 to 5.0 L/min) during ventricular demand pacing to 5.3 +/- 1.7 L/min (95% confidence intervals: 4.9 to 5.9 L/min) during atrioventricular pacing (p less than .0001) despite trivial decreases in CVP from 14 +/- 4 mm Hg (95% confidence intervals: 13 to 15 mm Hg) to 13 +/- 5 mm Hg (95% confidence intervals: 12 to 15 mm Hg) and pulmonary artery occlusion pressure from 18 +/- 5 mm Hg (95% confidence intervals: 16 to 20 mm Hg) to 17 +/- 5 mm Hg (95% confidence intervals: 15 to 18 mm Hg). At the same time, mean arterial pressure (MAP) increased from 74 +/- 15 mm Hg (95% confidence intervals: 64 to 79 mm Hg) to 83 +/- 15 mm Hg (95% confidence intervals: 80 to 88 mm Hg) and left ventricular stroke work index from 22 +/- 10 g.m/m2 (95% confidence intervals: 19 to 25 g.m/m2) to 30 +/- 11 g.m/m2 (95% confidence intervals: 26 to 33 g.m/m2). There was no significant change in mean pulmonary artery pressure, pulmonary vascular resistance index, or systemic vascular resistance index. CONCLUSION: When cardiac pacing is required in critically ill patients, maintaining atrioventricular synchrony increases stroke volume, cardiac output, and MAP apparently with minimal effects on preload and afterload.

Adult↗
PubMed1991

Role of cholecystokinin in pancreatic bicarbonate secretion in dogs.

We investigated the effects of endogenous and exogenous cholecystokinin (CCK) on pancreatic exocrine secretion, in particular that of bicarbonate. In six dogs prepared with gastric cannulas and Thomas duodenal cannulas, intraduodenal administration of corn oil (Lipomul) incubated with hog pancreatic enzymes significantly increased pancreatic secretion of both bicarbonate and protein. Increase in pancreatic secretion of both bicarbonate and protein was accompanied by the increase in plasma CCK concentration. However, the increase in bicarbonate as well as protein secretion was blocked by proglumide, a CCK antagonist, given intravenously. In contrast, intraduodenal infusion of undigested Lipomul failed to stimulate the pancreatic exocrine secretion or release of endogenous CCK. These observations indicate that endogenous CCK plays an important role in secretion of both bicarbonate and protein stimulated by digested corn oil. In a group of four dogs with pancreatic fistulas, intravenous infusion of CCK potentiated the stimulatory effect of secretin on pancreatic bicarbonate secretion. The stimulatory effect as well as potentiating effect of CCK on pancreatic bicarbonate secretion was blocked by infusion of proglumide. We conclude that endogenous CCK plays a significant role in fat-stimulated pancreatic secretion, and it is apparent that both endogenous CCK and secretin are equally important for stimulation of pancreatic bicarbonate secretion, which results from potentiation of the action of the two hormones.

Animals↗
PubMed1991

Evolved neomycin phosphotransferase from an isolate of Klebsiella pneumoniae.

A new aminoglycoside resistance gene (aphA1-IAB) confers high-level resistance to neomycin. The sequence of aphA1-IAB is closely related to aphA1 found in the transposons Tn4352, Tn903 and Tn602. For example, aphA1-IAB differs from aphA1-903 at five nucleotides that result in four amino acid replacements. The enzyme encoded by aphA1-IAB has a significantly higher turnover number with neomycin, kanamycin and G418 as substrates than does the aphA1-903 enzyme. A parsimonious phylogenetic tree suggests that aphA1-IAB evolved from an ancestral form that is closely related or identical to the aphA1 found in Tn903. The excess of replacement substitutions over silent substitutions in aphA1-IAB, as well as its convergence toward aphA3 from Staphylococcus aureus, is indicative of selective evolution. Our hypothesis to explain these results is that aphA1-IAB evolved under the selective pressure of neomycin use in relatively recent times.

Amino Acid Sequence↗
PubMed1991

Mechanism of oleic acid-induced inhibition on gastric acid secretion in rats.

We investigated the existence of an enterogastrone in rats induced by duodenal administration of oleic acid. Acid secretion by the luminally perfused stomach was stimulated in anesthetized rats by intravenous infusion of 0.3 micrograms.kg-1.h-1 pentagastrin. Intraduodenal administration of 3 mmol of oleic acid produced a profound inhibition (94%) of pentagastrin-stimulated acid output in 10 rats (P less than 0.01). Of several peptides in plasma including secretin, neurotensin, somatostatin, and peptide YY, only secretin was found to increase significantly (P less than 0.001). A similar degree of inhibition of acid output (93%) was caused by porcine secretin, 5.6 pmol.kg-1.h-1, given intravenously to mimic the plasma level of secretin produced by oleic acid infusion. The inhibitory effect of oleic acid on the acid secretion was completely reversed by intravenous injection of a rabbit antisecretin serum but not by a normal rabbit serum. These observations strongly suggest that the inhibition was mediated via circulating secretin. The inhibition produced by either oleic acid or secretin was completely blocked by indomethacin. The blocking action was completely reversed by intravenous administration of 48 micrograms.kg-1.h-1 prostaglandin E2. We conclude that endogenous secretin is a major enterogastrone released by oleic acid in anesthetized rats and that the inhibitory action of secretin requires endogenous prostaglandins.

Animals↗
PubMed1991

Obstructive dilatation of extrahepatic recipient and donor bile ducts complicating orthotopic liver transplantation: imaging and laboratory findings.

Biliary obstruction in liver transplants is most commonly due to stricture at the biliary anastomosis. The native common bile duct typically is normal. We retrospectively studied 28 patients with choledochocholedochostomy anastomoses who had marked native and donor extrahepatic bile duct dilatation associated with clinical evidence of biliary obstruction. Operative cholangiograms were compared with postoperative cholangiograms obtained a mean of 50 weeks (range, 2-246 weeks) later. Mean caliber of the native common bile duct increased from 7.5 +/- 2.0 mm on operative cholangiograms to 14.8 +/- 3.9 mm on postoperative cholangiograms (p less than .001). Mean caliber of the donor common hepatic duct increased from 5.9 +/- 1.3 mm on operative cholangiograms to 12.8 +/- 3.8 mm on postoperative cholangiograms (p less than .001). Dilatation of the cystic duct remnant was seen in 15 patients. All patients had surgical revision to choledochojejunostomy with improved results of liver function studies in most cases. Diffuse dilatation of native and donor extrahepatic bile ducts may develop in liver transplant recipients. Typical features include native and donor extrahepatic ducts greater than 12 mm in diameter and a dilated cystic duct remnant on postoperative cholangiography in a patient with otherwise unexplained hepatic dysfunction.

Adult↗
PubMed1990

Effect of pancreatic proteases on plasma cholecystokinin, secretin, and pancreatic exocrine secretion in response to sodium oleate.

The effect of pancreatic proteases or juice on the sodium oleate-stimulated pancreatic secretion and plasma concentrations of secretin and cholecystokinin in anesthetized rats was investigated. Each rat received sodium oleate in a dose of 0.12 mmol.h-1 via a duodenal tube. Sodium oleate infusion significantly increased pancreatic secretion (volume and protein output) compared with the saline given the control group. The increase in pancreatic secretion paralleled significant elevations of plasma concentrations of secretin and cholecystokinin. To determine a possible role of pancreatic proteases on the responses induced by sodium oleate, saline, chymotrypsin, and trypsin, a combination of chymotrypsin and trypsin or pancreatic juice was infused into the duodenum. The pancreatic secretion was significantly reduced by pancreatic proteases or pancreatic juice, and the reduction paralleled the decreases in plasma concentrations of the two hormones. These agents suppressed both pancreatic secretion and plasma hormone levels in the following order of magnitude: (pancreatic juice or chymotrypsin + trypsin) greater than (trypsin) greater than (chymotrypsin). The reduction of pancreatic secretion by pancreatic proteases was reversed by intravenous administration of secretin and cholecystokinin in physiological doses. It is concluded that negative-feedback regulation of pancreatic secretion is operative in the intestinal phase in rats and that both secretin and cholecystokinin are involved in the regulation.

Animals↗