PubMed Health⌕ Search

Biomedical subjects

L Fei

Publications and source records attributed to L Fei.

At least 55 records · Page 3Linked to original sources
PubMed1994

[Endoscopic ultrasonography in preoperative staging of esophageal cancer].

Thirty-two consecutive patients with esophageal carcinoma (squamous cell carcinoma: 23, adenocarcinoma: 9) were pre-operatively examined by endoscopic ultrasonography (EUS) in order to evaluate the accuracy of this diagnostic procedure in loco-regional staging. Six patients were not operated on, due to a poor general conditions or widespread tumor disease and were not included in this study. Results of EUS staging from the remaining patients were compared with intra-operative exploration and histopathological evaluation of resection specimens. Seven stenosing tumors were not traversable by echoendoscope. In such cases the lesion was visualized only in part by scanning the top of the stenosis. The overall EUS accuracy in T staging was 80.7% (75% in T2 stage, 90.9% in T3, 71.4% in T4). Three tumors were overstaged; two not traversable stenosing tumors were understaged. The overall accuracy in N staging was 73% (sensitivity 77.7%, specificity 62.5%). For celiac nodes EUS sensitivity was only 57.1%. Authors conclude that the presence of a not traversable stenosis is still a limit for EUS in diagnosing infiltration of adjacent structures as well as in detecting lymph node metastases.

Adenocarcinoma↗
PubMed1993

Effects of propafenone on calcium currents in single ventricular myocytes of guinea-pig.

1. The effects of propafenone on the inward calcium current (ICa) were investigated in isolated single ventricular myocytes of the guinea-pig by the whole-cell clamp method. Propafenone inhibited ICa in a dose-dependent manner at concentrations of propafenone ranging from 1 x 10(-8) to 1 x 10(-3) M and half maximal block of ICa occurred at a propafenone concentration of 1.5 x 10(-6) M. Propafenone did not change the current-voltage relation of ICa other than a reduction in amplitude and showed no clear use- or frequency-dependent effects upon ICa (stimulation frequencies from 0.03 to 2 Hz). Propafenone did not alter the steady-state inactivation process: the half maximal activation potentials were 18.5 +/- 2.2 mV in the control state and 20.9 +/- 5.0 mV in the presence of 1 x 10(-6) M propafenone (n = 12, NS). Propafenone (1 x 10(-6) M) increased the half-time of reactivation by 73.9% (n = 6, 212.3 +/- 1.2 ms vs 369.2 +/- 1.5 ms, P < 0.05). 2. We conclude that propafenone blocks ICa in a concentration-dependent and a channel state-, use- or frequency-independent manner. The ICa blockade elicited by propafenone at clinically therapeutic plasma concentration is significant and may be involved in its anti-arrhythmic effects.

Animals↗
PubMed1993

Abnormal autonomic modulation of QT interval in patients with idiopathic ventricular tachycardia associated with clinically normal hearts.

BACKGROUND: Idiopathic ventricular tachycardia (VT) occurs in a small but important subset of patients without clinically overt heart disease. The mechanism of the arrhythmogenesis remains unclear in these patients. This study examines modulation of the QT interval by the autonomic nervous system in a group of patients with idiopathic ventricular tachycardia. METHODS: Cardiac autonomic activity and ventricular repolarisation were studied in 27 patients with VT associated with a clinically normal heart (NHVT) and in 20 normal subjects. All the patients were in sinus rhythm, had normal atrioventricular conduction, and were in a drug free state. Cardiac efferent autonomic activity was measured by spectral analysis of heart rate variability from 24 hour ambulatory electrocardiograms on a Holter analysis system (Marquette). Ventricular repolarisation was evaluated by measuring the QT intervals from the same 24 hour Holter tapes at one hour intervals. RESULTS: There was no difference in any of the QT interval variables including the maximum, minimum, and mean of both the QT interval and its corrected value (Bazett's formula) between patients with NHVT and normal subjects. The high frequency component (0.04-0.15 Hz) of heart rate variability was significantly decreased in patients with NHVT compared with normal subjects (16 (8) v 21 (12) ms, p < 0.05). There was a significant correlation between the spectral variables of heart rate variability and the mean, maximal, and minimal QT intervals in normal subjects, whereas the relation was lost in patients with NHVT. No difference was found in mean heart rate between normal subjects and patients with NHVT (70 (9) v 72 (13) beats/min, NS). CONCLUSIONS: The high frequency component of heart rate variability is significantly decreased and the relation of QT interval to heart rate variability is significantly altered in patients with NHVT as compared with normal subjects. These findings suggest that abnormal modulation of the QT interval by the autonomic nervous system may play an important part in the arrhythmogenesis of NHVT. This might result from impaired vagal efferent cardiac activity in these patients.

Adolescent↗
PubMed1993

Assessment of heart rate variability in hypertrophic cardiomyopathy. Association with clinical and prognostic features.

BACKGROUND: Altered vascular responses during exercise and disturbed responses to autonomic function testing have been documented in hypertrophic cardiomyopathy (HCM) and are associated with markers of an adverse prognosis. Reduced heart rate variability (HRV) and baroreflex sensitivity are predictors of increased risk of sudden death after myocardial infarction, but the value of these parameters in HCM is unknown. METHODS AND RESULTS: To determine the clinical significance of HRV and its relation to markers of electrical and hemodynamic instability in HCM, the 24-hour Holter recordings of 104 patients in sinus rhythm and off medication were analyzed. Five nonspectral measures of HRV were computed. The frequency components of HRV were calculated by fast Fourier transformation of the RR time intervals; the areas under the low (0.04 to 0.15 Hz) and high (0.15 to 0.4 Hz) frequency portions of the spectrum were measured as indices of autonomic and specific vagal influences on HRV, respectively. Spectral and nonspectral measures were compared with clinical, echo/Doppler, and Holter variables. ANCOVA was performed to allow for the effect of age on differences between variables. Spectral and nonspectral measures of HRV were correlated (r > .65; P < or = .001), indicating that the different time-domain and frequency parameters reflected similar measures of HRV. Global measures of HRV including the standard deviation of the mean of RR intervals (SDRR) and the standard deviation of 5-minute mean RR intervals (SDANN) were increased in patients with an adverse family history of HCM (173 +/- 67 vs 131 +/- 38 milliseconds, P = .001, and 158 +/- 66 vs 116 +/- 36 milliseconds, P = .004, respectively). In patients with exertional chest pain, global nonspectral measures were reduced compared with asymptomatic patients (118 +/- 31 vs 152 +/- 53 milliseconds, P = .006, and 105 +/- 30 vs 136 +/- 52 milliseconds, P = .014, respectively). Specific vagal influences on HRV including the proportion of RR intervals more than 50 milliseconds different (PNN50) and the high frequency peak on spectral analysis were less in patients with supraventricular arrhythmias on Holter monitoring (7.2 +/- 8 vs 16 +/- 13%, P = .012, and 21 +/- 10 vs 28 +/- 13 milliseconds, P = .048, respectively). Similarly, both global and specific vagal measures of HRV were less in the 27 patients with nonsustained ventricular tachycardia on Holter (PNN50, 7.7 +/- 9 vs 15 +/- 13 milliseconds, P = .048, and high frequency component, 19 +/- 9 vs 28 +/- 13 milliseconds, P = .05. During follow-up, 10 patients, 9 of whom were aged less than 33 years, experienced catastrophic events; 6 were resuscitated from ventricular fibrillation and 4 died suddenly. Indices of HRV were similar in these 10 patients to indices in the 94 survivors. CONCLUSIONS: Time-domain and spectral measures of HRV yield similar information about the specific autonomic influences on the heart. Global and specific vagal influences on HRV were reduced in patients with symptoms and arrhythmias and global HRV is increased in patients with an adverse family history of HCM, but these indices do not add to the predictive accuracy of established risk factors.

Adult↗
PubMed1992

Effect of heparin on the anionic sites of glomerular basement membrane in adriamycin nephrosis in rats.

The effect of heparin on the anionic sites of glomerular basement membrane (GBM) in adriamycin-induced nephrotic rats was studied by means of calculating the polyethyleneimine (PEI) stained particles under electron microscope. The results showed that treatment with heparin under the anticoagulant effect markedly reduced the loss of anionic sites within lamina rara externa (LRE) of GBM and also the urinary protein excretion in nephrotic rats. The results demonstrated that one of the mechanisms of heparin in preventing the structural damage of glomeruli in kidney diseases was the reduction of the loss of anionic sites within LRE, indicating that changes in biomembrane charge played an important role in the pathogenesis of nephrotic syndrome. The results provided a scientific basis for the use of heparin to treat glomerular diseases.

Animals↗
PubMed1991

[Evaluation of esophageal function in surgically-treated patients].

The authors report on their experience acquired in the surgical treatment of functional esophageal disease (achalasia, diffuse esophageal spasm, diverticula and gastroesophageal reflux). The authors affirm that a correct and meticulous functional study of the esophagus is fundamental for the adoption of precise surgical plotting, in order to circumvent all of the complications and failures described in Literature. Such an objective can be achieved intraoperatively thanks to myotomy and fundoplication with the aid of intraoperative manometry (IEM) that, when performed in the course of myotomy, circumvents the execution of incomplete procedures (incomplete myotomies). The same holds true in the case of anti-reflux plasty (Nissen's in particular) where IEM enables a plication that is neither too wide nor too narrow, too long, too short, but "calibrated". Then, instrumental probes are even more capable of assessing the effects of functional surgery, by enabling the documentation of perfect postoperative results. More precisely they make it possible to study patients presenting with motor disorders pre-operatively, as in the case of achalasia or diverticula, and to sanction their resolution postoperatively. In addition they enable documentation of the effectiveness of Nissen's fundoplication, performed either to prevent gastroesophageal reflux after myectomy or to treat primary reflux. This is made possible by studying not only the tone at a distance, but especially relaxation in the course of deglutition. Finally, pH-metry permits the documentation of the complete clearing of gastroesophageal reflux, even when physiologic and post-prandial (hypercompetent Nissen).

Diverticulum, Esophageal↗
PubMed1991

[Current views and controversies about reconstruction after esophagectomy].

The Authors examine the reconstructive procedures following total or partial esophagectomy, reporting advantages and disadvantages related to stomach, colon or jejunum transposition. The stomach is certainly the organ most widely employed for its adaptability and excellent vascularization; furthermore, only one anastomosis is needed. After a short note on pathophysiology of the most common complications, the Authors point out the advantages of using stapling devices, with special attention to the low incidence of anastomotic dehiscence.

Colon↗
PubMed1987

[Classical Kaposi's sarcoma. Study of the lymphatic system of lower limbs].

Eight patients with classical Kaposi's sarcoma histologically confirmed underwent lymphoscopic and/or lymphographic exploration of the lower limbs where the lesions were located. In all patients lymphoscopy showed abnormal images ranging from irregular distribution of the colouring agent to "starlike images" and dermal reflux. Lymphography was performed in 3 patients and demonstrated, in 2 of them, "lymphatic pools", obvious hyperplasia of the superficial lymphatic vessels and areas of lymphangectasia. The finding in all 8 patients of dynamic abnormalities of the lymphatic system should encourage further investigations in this field, notably to detect a possible correlation between lymph stasis, disorders in regional immunity and the development of classical Kaposi's sarcoma.

Female↗
PubMed1985

[Behavior of the pressure of the lower esophageal sphincter after intravenous administration of domperidone in normal subjects].

Manometric studies on the action of domperidone 10 mg and 20 mg i.v. on the lower esophageal sphincter pressure (LESP) have been carried on ten healthy volunteers. Domperidone inhibits dopamine receptors and results in an increase of LESP. A dose of 10 mg produces a significant increase in LESP which is rapid and prolonged for thirty minutes; a dose of 20 mg is less efficient. The stimulatory effect of domperidone on LESP suggests an important role for endogenous dopamine as an inhibitory neuromodulator of LES pressure. The use of domperidone in therapy for reflux esophagitis is suggested.

Adult↗
PubMed1985

Radionuclide techniques in the study of delayed gastric emptying in patients with gastroesophageal reflux.

Gastric emptying was studied in 15 patients with hiatal hernia and gastroesophageal reflux by a radionuclide technique with solid meal. Thirteen healthy subjects were used as control group. The obtained results have shown that, even in the time when the radionuclide activity decreases of 50% in the region of gastric activity (T1/2) in the 15 patients was not statistically different with respect to the control group, ten patients showed delayed emptying (116.4 +/- 16.88 min) with a mean delay of 30% in the time of half-emptying with respect to the control group (p less than 0.01). This finding is important for its surgical implications since this delayed emptying should be kept in mind when planning Nissen fundoplication or other antireflux procedures: in such case surgery can be complicated with a "gas bloat syndrome".

Adult↗
PubMed1984

Acute aperistaltic megaesophagus as a complication of Nissen fundoplication: a case report.

A case of acute aperistaltic megaesophagus which arose after Nissen fundoplication for sliding hiatal hernia, is reported. The resolution of the clinical and instrumental picture with cholinergic drugs leads to the conclusion that the phenomenon observed is of vagal origin. This may be an extreme picture of the mild esophageal dilatation and transitory dysphagia that sometimes occur after Nissen fundoplication.

Esophageal Achalasia↗