Biomedical subjects
Publications and source records attributed to M Fu.
Our preliminary observations show that intraaortic intravascular ultrasound using 10 MHz transducer catheters is safe and feasible in the assessment of coronary ostial lesions. This imaging modality is potentially useful in decision making regarding the choice of coronary intervention.
Percutaneous transvenous mitral commissurotomy (PTMC) was performed successfully without complications in 3 patients with severe mitral stenosis and hyperthyroidism. All 3 patients had pliable, noncalcified mitral valves. One patient who had been treated with methimazole for 6 months was still in a hyperthyroid state when she presented with intractable congestive heart failure and was found to have severe mitral stenosis. The heart failure improved immediately after PTMC, but the patient remained in New York Heart Association functional class 2 until a euthyroid state was achieved with I131 therapy. In the other 2 patients, hyperthyroidism was unsuspected at the time of PTMC. Unexpectedly suboptimal symptom improvement led to the diagnosis of hyperthyroidism 1 month after the intervention. In all 3 patients, PTMC resulted in an immediate hemodynamic and clinical improvement. However, complete clinical improvement occurred only when euthyroid state was achieved after antithyroid treatment. The present study suggests that PTMC is a safe and effective intervention modality in patients with coexisting hyperthyroidism and severe mitral stenosis. The procedure may be considered a therapeutic option in patients with hyperthyroidism and severe mitral stenosis.
OBJECTIVE: To examine the utility of intracardiac echocardiography in guiding complex transseptal catheterization of patients undergoing percutaneous transvenous mitral commissurotomy. DESIGN: We assessed this procedure in high-risk patients in whom transseptal catheterization is technically complex and more demanding. MATERIAL AND METHODS: Fifteen patients with mitral stenosis were studied. Twelve patients had giant left atria (70 mm or more), two had atrial septal aneurysms, and one had severe kyphoscoliosis. A newly developed 8-F 10-MHz intracardiac transducer catheter was placed in the right atrium through an 8-F Mullins sheath inserted from the left femoral vein. Echocardiographic images were used to confirm the septal position of the Brockenbrough needle tip before septal punctures. RESULTS: Transseptal puncture was successful and uncomplicated in all 15 patients. Use of intracardiac echocardiography eliminated the need for atrial angiography. Before transseptal puncture, the needle tip was identified to be in contact with the atrial septum, as an echogenic point with its acoustic shadow and septal indentation. In addition, in the two patients with aneurysms, puncture of the thin-walled aneurysms was avoided. CONCLUSION: Intracardiac echocardiography facilitates safe complex transseptal catheterization in patients with mitral stenosis and giant left atria, atrial septal aneurysms, or severe kyphoscoliosis.
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The arterial smooth muscle cells (SMC) are the predominant type of cells in atherosclerotic lesions, and their proliferation plays an important role in the process of AS genesis. We established the primary culture and sub-culture method for human arterial SMC and observed the effects of LDL, VLDL, HDL, OX-LDL, OX-VLDL and OX-HDL on the morphological appearance and phenotype of cultured human arterial SMC. The results revealed that the cells cultured in the medium containing OX-LDL, OX-VLDL and OX-HDL (25 micrograms/ml) became more irregular with long finger-like projects and lacked a bipolar shape, and the characteristic "hills" and "valleys" disappeared. LDL and VLDL also had the influence but in smaller degrees. HDL did not have any effect. The SMC cultured in the presence of OX-LDL (25 micrograms/ml) had less myofilaments and more endoplasmic reticulua, Golgi and mitochondria in cytoplasm compared with the cells in control group under electronmicroscope. These results suggest that the atherogenic role of LDL, VLDL, OX-LDL, OX-HDL, and OX-VLDL are closely related to their stimulating effects on the modulation of phenotype of arterial SMCs from "contractile" towards "synthetic".
In this research, we used the Gunne's spectrophotometry method to measure the masticatory efficiency in 30 skeletal Class III patients and in 55 normal people. After groups comparing and step wise-regression analysis, we found that masticatory efficiency in Class III malocclusion group was much lower than that in normal occlusion group, and the masticatory efficiency in Class III malocclusion was about 60% of that in normal peoples. Masticatory efficiency in male was higher than that in female.
The primary culture of human arterial smooth cells (SMC) was performed successfully using the primary-explant method. The cells formed "hills and valleys" characteristic of SMC; the myofilament bundles were observed in the cytoplasm of the cells under an electron microscope and the cells were stained red with Ma's method. The growing character of 35th passage SMC kept unchanged. In addition, some problems concerning the culture of human arterial smooth muscle cells are discussed.
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In the present study, hypertriglyceridemia was induced by feeding S. D. rats with high carbohydrate diet (carbohydrate accounting for 80% of total calorie) for 5 days. Rat liver parenchymal cells (PC) and non-parenchymal cells (NPC) were prepared by collagenase method. Human plasma LDL, VLDL and HDL were isolated by density gradient ultracentrifugation method. 125I-LDL was labelled by ICI method. 125I-LDL binding to rat liver PC and NPC were measured by Goldstein and Brown's method. The results showed that both rat liver PC and NPC had LDL receptors to bind, uptake and degradate 125I labelled human plasma LDL. The Bmax of 125I-LDL binding to NPC was 7-fold higher than that of PC (P < 0.01), but the Kd values remained unchanged. The Bmax of 125I-LDL binding to liver NPC from hypertriglyceridemic rats was significantly higher than that of NPC from the normal diet (carbohydrate accounting for 60% of total calorie) rats (435.4 + 100.0 vs 307.1 +/- 76.8 ng/mg cell protein, n = 6, P > 0.05), but there was no difference in Kd between the HTG rats and normal rats (18.1 +/- 4.1 vs 17.2 +/- 4.0 micrograms/ml n = 6, P > 0.05). These results suggest that the increase in fractional catabolic rate of LDL in patients with hypertriglyceridemia reported by Vega and Grundy might be induced by the increase in number of LDL receptor on liver non-parenchymal cells.
The water extract of Radix Cynanchi Atrati used as intraperitoneal injection has been proved to have an obvious antifebrile++ effect on rat fever caused by 15% yeast suspension hypodermic injection as well as a significant anti-inflammatory effect. But the antiferbrile effect of its ethanol extract is not clear.
Properties of the receptor--G protein--adenylyl cyclase system were studied in spontaneously hypertensive rats (SHR) and age-matched normotensive Wistar-Kyoto rats (WKY) treated with adriamycin (ADR, 1 mg/kg per week) for 12 weeks. An identical dosing schedule caused a significantly greater decline in body weight gain and a marked elevation of plasma norepinephrine level in SHR than in WKY. A significant increase in the messenger RNA encoding Gi-alpha 2 was found in SHR+ADR group. The activity of the adenylyl cyclase stimulated by guanyliminodiphosphate [Gpp(NH)p] was decreased by 49% in SHR and 73% in SHR+ADR. However, stimulated activities of adenylyl cyclase by both sodium fluoride and forskolin remained unchanged. Functional level of stimulatory G-protein (Gs) as measured by reconstitution assay in sarcolemmal membrane was unaltered among different groups. Furthermore, the density of beta-adrenoceptor was significantly decreased without change of its affinity. Muscarinic receptors exhibited a three-site affinity distribution in SHR+ADR whereas other groups displayed only two-site affinity distribution. These results suggest that SHR exhibited a depressed myocardial adenylyl cyclase signaling system which may not be due to the functional uncoupling of beta-adrenoceptors from Gs but to the increased inhibitory G-protein (Gi) activity as demonstrated by the increased mRNA of Gi-alpha 2, increased inhibition of Gpp(NH)p-mediated adenylyl cyclase and the super high affinity for carbachol of the muscarinic receptors. Decreased beta-adrenoceptor density and functional alteration of Gi might be regarded as the predisposing factors for the increased susceptibility of myocardium of SHR to ADR.
Urgent/emergent percutaneous transvenous mitral commissurotomy (PTMC) was performed in 10 patients (two men and eight women, aged 21 to 60 yr). All patients had arterial hypoxemia and four required mechanical respirators. PTMC was performed in the semi-recumbent position in four patients. The seven patients with pliable valves (group 1) achieved good hemodynamic and echocardiographic results after PTMC, but one died 2 wk later because of sepsis complicating preexisting pneumonitis. The two pregnant patients uneventfully delivered normal babies at term. There was continued clinical improvement in the six surviving patients at last follow-up at 11 to 39 mon (median 26). Of the three patients with calcified valves and severe subvalvular lesions (group 2), the premoribund patient in whom last-resort PTMC created severe mitral regurgitation died 3 days later of multiple organ failure. The other two patients underwent mitral valve replacement 1-6 days later because of lack of clinical improvement due to creation of severe mitral regurgitation and ineffective mitral valve dilation, respectively. In conclusion, urgent/emergent PTMC is feasible and safe. However, its outcomes are dictated by the status of diseased mitral valve and coexisting illness.
We produced antibodies against a synthetic peptide corresponding to amino acids 168-192 of the second extracellular loop of the M2 human muscarinic receptor in rabbits. In immunoblot, affinity-purified antibodies specifically recognized a major band of rat ventricular muscarinic receptor protein with a molecular weight of about 80 KD. This recognition could be blocked by pre-incubation with peptide. Moreover, with both light (LM) and electron microscopic (EM) immunocytochemistry techniques, muscarinic receptors were detected on sarcolemma and T-tubules of rat cardiomyocytes. In addition, immunoreactions were localized in membranes of capillaries. Likewise, these reactivities were abolished by pre-incubation with peptide. These results suggest that the antibodies against the second extracellular loop of human M2 muscarinic receptor could specifically recognize rat ventricular muscarinic receptor protein and could be a powerful tool to study the fate of this receptor under different pathological or physiological conditions.
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Further studies regarding the potentiometric response to heparin of polymeric membranes doped with lipophilic quaternary ammonium salts are reported. Among a wide range of membrane formulations examined, optimum response toward macromolecular heparin is achieved using tridodecylmethylammonium chloride as the active membrane component within poly(vinyl chloride) or poly(vinyl chloride)/(vinyl acetate) films plasticized with dioctyl sebacate. Although such membranes are shown to exhibit a typical Hofmeister potentiometric selectivity pattern toward small inorganic and organic anions, a very large and reproducible response to heparin at submicromolar levels is observed in the presence of physiological saline (0.12-0.15 M NaCl), as well as in citrated whole blood. Equal response on a mass basis occurs with fragments of heparin's as small as 2500 Da. Complexation of heparin's anionic sites by macromolecules that bind heparin with high affinity (e.g., protamine and poly(L-lysine)) reduces the membrane electrode's heparin response, indicating that the electrode detects biologically available (unbound) heparin levels in solution. Quantitative potentiometric titrations of protamine with porcine mucosa heparin followed by the sensor yield stoichiometric values in good agreement with the literature. The biomedical utility of the sensor is demonstrated by measuring its response in whole blood from patients undergoing open heart surgery before and after heparin therapy and correlating such response to conventional blood clotting time measurements.
This report describes a new balloon pulmonary valvuloplasty technique using the Inoue balloon catheter performed in 14 consecutive adult patients, aged 17-47 years (mean 27). The mean right ventricular systolic pressure and the pulmonary valvular peak-to-peak systolic gradient decreased from 102 +/- 41 to 52 +/- 19 mm Hg (p = 0.001) and 81 +/- 40 to 7 +/- 7 mm Hg (p = 0.0002), respectively. An infundibular peak-to-peak systolic gradient either developed (n = 13) or increased (n = 1). None of the patients were treated with beta-adrenergic blockers before or after the valvuloplasty. Eight patients underwent repeat hemodynamic study 12-30 months (mean 17) after treatment, and had no evidence of valvular restenosis. The mean right ventricular systolic pressure and the mean infundibular peak-to-peak systolic gradient decreased, compared to the values immediately after valvuloplasty (54 to 40 mm Hg, p = 0.03, and 28 to 10 mm Hg, p = 0.03, respectively). The study suggests that pulmonary valvuloplasty in adults using the Inoue balloon catheter technique is feasible, safe, and effective.
Because transseptal catheterization is felt to be contraindicated in patients with severe kyphoscoliosis, there have been no reports of percutaneous transvenous mitral commissurotomy performed in such patients. This report describes percutaneous transvenous mitral commissurotomy in three patients with severe thoracic kyphoscoliosis, with special emphasis on the transseptal puncture technique. Biplane right atrial angiography and the contrast septal flush method are very useful in landmark selection for a safe transseptal puncture.