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Biomedical subjects

F Y Lin

Publications and source records attributed to F Y Lin.

At least 73 records · Page 4Linked to original sources
PubMed1998

Capsular polysaccharide types of group B streptococcal isolates from neonates with early-onset systemic infection.

The distribution of serotypes of group B streptococci (GBS) isolated from 67 infants with early-onset sepsis are described. Case-infants were assembled from 13 hospitals across the United States from 15 July 1995 to 5 February 1997 through prospective active surveillance. The distribution of GBS serotypes was Ia, 40%; Ib, 9%; II, 6%; III, 27%; V, 15%; and nontypeable, 3%. Type V occurred more frequently in the northeast region (New York and New Jersey) than in other regions (29% vs. 9%, P = .06). Conversely, type III occurred significantly less frequently in the northeast region than other regions (10% vs. 35%, P = .04). GBS types Ia, III, and V accounted for 82% of the isolates. This report supports previous observations about the emergence of GBS type V, but our data caution that conclusions about serotype distributions based on one geographic location or on a small number of patients may not be generally applicable. Continued monitoring seems necessary for the design of a GBS vaccine.

Bacterial Capsules↗
PubMed1998

Viral etiology of intussusception in Taiwanese childhood.

BACKGROUND: Adenovirus infection and lymphoid hyperplasia have been associated with childhood intussusception. However, the extent of other viruses involved in this condition remains unclear. This prospective study investigates the relationship between some lymphotropic viruses and current childhood intussusception. METHODS: Patients with intussusception encountered in a pediatric emergency department in a recent 3-year period were studied. Healthy infants and toddlers of comparable age served as controls. Throat and rectal viral cultures were performed in patients and controls. Viral antibodies against adenovirus, cytomegalovirus, human herpesvirus (HHV)-6, HHV-7 and Epstein-Barr virus (EBV) were tested in paired sera from the patients. Acute stage serum from each patient and mesenteric lymph nodes from patients requiring surgery were studied for the presence of adenovirus genome by PCR. RESULTS: Twenty-seven of 61 (44.3%) intussusception patients, but only 2 of 52 (3.8%) healthy controls shed nonenteric adenovirus in throat and rectal specimens (P < 0.001). Of the 27 (74.1%) patients who shed adenovirus, 20 were older than 1 year old, whereas only 1 of 15 (6.7%) similarly aged patients in a previous study from the same area three decades ago did so (P = 0.001). Among 43 patients with available paired sera, acute primary viral infection was found in 17 (39.5%) by adenovirus, 4 (9.3%) by HHV-6, 5 (11.6%) by HHV-7, 2 (4.7%) by EBV and none by cytomegalovirus. Multiple viral infections occurred in 6 patients. Adenovirus genome was detected in 4 of 9 mesenteric lymph nodes and in only 3 of 60 (5%) acute phase sera. CONCLUSIONS: Primary nonenteric adenovirus infection contributes to current childhood intussusception. Acute primary HHV-6, HHV-7 and EBV infections also play etiologic roles.

Acute-Phase Reaction↗
PubMed1998

Atrial dissociation after atrial compartment operation for chronic atrial fibrillation in mitral valve disease.

Atrial dissociation with segmental atrial arrhythmia is an interesting electrophysiological phenomenon. It was rarely reported before to be caused by anatomical exit block after cardiac surgery. We report the case of a 28-year-old patient who developed atrial disassociation after a surgical method for correcting atrial fibrillation--atrial compartment operation. The segmental atrial flutter was first found by Doppler echocardiography and proved later by detailed intracardiac mapping.

Adult↗
PubMed1998

Extracorporeal membrane oxygenation in treatment of cardiogenic shock caused by acute myocarditis.

We report a 31-year-old woman with acute myocarditis who was transferred to our hospital because of rapidly progressive cardiogenic shock unresponsive to infusion of high doses of inotropic agents and intraaortic balloon pump support. Upon arrival at our hospital, extracorporeal membrane oxygenation (ECMO) was immediately established through a right femoral venoarterial route by percutaneous cannulation; the blood flow of ECMO was maintained at around 2,100 mL/min. Shock-induced rhabdomyolysis complicated with acute renal failure occurred. During treatment with ECMO and hemodialysis, the patient gradually recovered cardiac and renal function. The patient was maintained on ECMO for 90 hours then successfully weaned from the machine without major complications. Our experience suggests that ECMO can be used for temporary mechanical circulatory support in patients with cardiogenic shock due to acute myocarditis.

Acute Disease↗
PubMed1998

Traumatic tricuspid regurgitation complicating endocarditis and right-to-left intracardiac shunt. A case report of successful operation.

Tricuspid regurgitation caused by blunt chest trauma is generally quite tolerable for a long time in a clinical setting. This article reports on a 68-year-old patient suffering from progressive dyspnea after a blunt chest trauma having occurred 5 months previously. Flu-like symptoms occurred for several days before severe respiratory distress began upon the day of admission. Transesophageal echocardiographic evidence of endocarditis and right-to-left shunt across a patent foramen ovale (PFO) was demonstrated. Traumatic tricuspid insufficiency in this case was complicated with infective endocarditis and right-to-left intracardiac shunt. Cyanotic congestive heart failure occurred suddenly. He underwent emergency surgical repair with success. Based on the results presented herein, we recommend that early diagnosis be made for traumatic regurgitation and endocarditis by echocardiography so as to ensure therapeutic intervention.

Acute Disease↗
PubMed1998

Standardization may suffice for licensure of conjugate vaccines.

Standardization schemes devised by Control Agencies have followed clinical trials of experimental vaccines. The wealth of information about the pathogenesis of and immunity to bacteria, whose surface polysaccharides are protective antigens, now permits standardization to predict the efficacy of polysaccharide-based vaccines. There has been tacit acceptance of this notion with the licensure of groups Y and W135 meningococcal vaccines and of many of the pneumococcal types whose frequency in patients was too low for statistical significance to be assigned for their clinical efficacy. In fact, this was also the case for licensure of polio virus type 2 vaccine. We can reliably measure the level of anti-polysaccharide antibodies for meningococci, pneumococci, GBS and the Vi of S. typhi. Haemophilus type b conjugates have been reliably standardized by physico-chemical assays. New conjugates, therefore, may be licensed by data provided by standardization without awaiting the results of costly and time-consuming efficacy trials. Adoption of this scientifically-based approach to licensure will hasten the implementation of new and more effective vaccines.

Bacterial Vaccines↗
PubMed1998

Video-assisted endoscopic saphenous vein harvesting for coronary artery bypass grafting.

Saphenous vein grafts for coronary artery bypass can be harvested by means of the traditional long incision method, the skin bridge method, or a newly developed endoscopic technique. We applied the endoscopic technique to reduce the length of leg incision and to decrease the frequency of complications. Between September and December 1996, 47 patients underwent coronary artery bypass grafts, 17 of whom volunteered to undergo saphenous vein harvest with the Endopath video-assisted endoscopic saphenous vein harvest (ESVH) system; the other 30 patients underwent the traditional long incision harvest procedure. A total of 22 saphenous veins were harvested from the 17 patients who underwent ESVH. The mean length of the leg wound was 5.8 +/- 1.3 cm and the mean length of the vein harvested was 32.9 +/- 3.4 cm (wound/vein length ratio 17.6%). The wound/vein length ratio of the 30 patients who underwent the traditional open harvest method was 91.5% (30.8 +/- 2.2 cm/34.1 +/- 3.0 cm). ESVH failed and was converted to the conventional method in two cases. The mean time required to harvest the saphenous vein was 72.7 +/- 20.8 minutes in the ESVH group and 45.8 +/- 12.5 minutes in the open surgery group. No wound complications were noted in the ESVH group, except for ecchymosis in three cases. Five patients in the open surgery group had wound discharge (17%). The length of hospital stay was shorter (10.5 +/- 2.6 days vs 15.8 +/- 4.2 days) and fewer analgesics were used in the ESVH group. The rate of cardiac complications was not different between the two groups. Examination of the vein graft under light microscopy also did not reveal any differences. We conclude that the endoscopic technique can provide adequate vein grafts for use in coronary artery bypass grafting and reduce the leg wound complication rate, hospital stay, and use of analgesics.

Aged↗
PubMed1997

Congenital mitral stenosis: challenge of percutaneous transvenous mitral commissurotomy.

A 26-year-old woman with congenital mitral stenosis and embolic stroke was referred to our hospital. The echocardiogram showed a hypoplastic posterior mitral valve leaflet with short, unbalanced chordal attachments to the posteromedial papillary muscle. The mitral valve area was 0.9 cm2 by the pressure half-time method. There was no left atrial thrombus and spontaneous echo contrast. Percutaneous transvenous mitral commissurotomy was performed since the suggestion of surgical management was refused by her family members. A rupture at the chordae tendinae of the hypoplastic posterior papillary muscle developed during the procedure and needed mitral replacement. We advise that percutaneous transvenous mitral commissurotomy be avoided in adult patients with congenital mitral stenosis having an asymmetric and hypoplastic mitral valve.

Adult↗
PubMed1997

Electrophysiological properties in patients undergoing atrial compartment operation for chronic atrial fibrillation with mitral valve disease.

AIMS: Surgical treatment for atrial fibrillation is now feasible in selective cases. The aim of this study was to assess the electrophysiological properties of patients undergoing atrial compartment operation for chronic atrial fibrillation. METHODS AND RESULTS: Electrophysiological studies were performed in 20 mitral valve patients with atrial fibrillation who had been maintained in sinus rhythm for more than 1 year after atrial compartment operation. Intra-cardiac recording and programmed electrical stimulation were performed in various atrial compartments. The parameters studied included sinus node function, atrial conduction and refractoriness, atrioventricular conduction function and inducible arrhythmias if any. Intra-cardiac recordings showed that the rhythm was of sinus origin in all cases, with the earliest atrial activity located in the high right atrium. The mean sinus cycle length was 750 +/- 110 ms, AH time 106 +/- 29 ms, and HV time 53 +/- 7 ms. The sinus node function was normal in 18 patients (90%), and only two patients had prolonged sinus node recovery and sino-atrial conduction. The right atrial appendage compartment was driven by the sinus node in all patients. However, the conduction time from the high right atrium to the right atrial appendage compartment was markedly prolonged in 12 of 15 patients (80%) undergoing the three-compartment operation in which an incision was placed between the high right atrium and right atrial appendage compartments. On the other hand, the electrical activities in the left atrial compartment were much more varied. In 13 of 20 patients (65%), the left atrial compartment was driven by the sinus node; 11 of the 13 patients had a normal or mildly prolonged conduction time (ranged 75 to 146 ms), whereas two patients had a marked delay in conduction (200 ms and 266 ms, respectively). In the remaining seven patients, the left atrial compartments were dissociated from the rest of the heart; five of them had a quiescent left atrium, one a fluttering left atrial rhythm, and one a slow left atrial rhythm. The effective refractory period was longer in the left atrial compartment (242 +/- 47 ms) as compared to that of the high right atrium (224 +/- 26 ms, P < 0.01) and right atrial appendage compartments (219 +/- 25 ms, P < 0.01). Programmed electrical stimulation could not induce atrial fibrillation in any patient, whereas two patients had inducible atrial flutter and three repetitive atrial responses. CONCLUSIONS: (1) Atrial compartment operation does not impair sinus node function in most cases. (2) Elimination of atrial fibrillation while maintaining the electrical connection between different atrial compartments is feasible.

Adolescent↗
PubMed1997

Penetration of the interatrial septum: a rare complication of percutaneous transluminal mitral commissurotomy.

Interatrial septal dissection and penetration into the aorta by a balloon catheter occurred in a 38-year-old man with mitral stenosis as a complication of percutaneous transluminal mitral commissurotomy during trans-septal puncture. It was speculated that the thickened septum was partially punctured into the potential space between the septa primum and secundum. Then, the balloon catheter went through the interatrial septum dissection into the aortic root. Emergency surgery was performed with the catheter left in situ. The surgical findings confirmed the speculated mechanism of this rare complication. In order to avoid this complication, the location of the tip of the Brockenbrough catheter after transeptal puncture must be confirmed. Checking the left atrial pressure tracing, arterial oxygenation and contrast injection are all important and indispensable procedures.

Adult↗
PubMed1996

Atrial compartment surgery for chronic atrial fibrillation associated with congenital heart defects.

In three adult patients, two with atrial septal defect and one with Ebstein's anomaly, chronic atrial fibrillation was documented for 13, 21, and 3 years, respectively. Atrial compartment surgery was performed for ablation of the atrial fibrillation concomitant with repair of the cardiac defects. The operation was performed with traditional cardiopulmonary bypass and crystalloid cardioplegia myocardial protection. A U-shaped incision was made in the right atrium: a longitudinal incision 1 cm lateral and parallel to the sulcus terminalis, extending along the borders of the atrial septum to 3 cm (upper margin) and 1 cm (lower margin) distant to the tricuspid anulus. Cryolesions of the atrial isthmus between the upper incision margin and the tricuspid valve anulus were created at -60 degrees C for 180 seconds at a time. After the operation, all three patients had restored and maintained normal sinus rhythm during follow-up periods of 32, 16, and 3 months. Doppler echocardiography detected the recovery of atrial contractility in all three patients. Atrial compartment surgery is a simple and effective method for elimination of chronic atrial fibrillation associated with congenital heart defects.

Adult↗
PubMed1996

Clinical use of CarboMedics and St. Jude Medical valves.

Three hundred and twenty-six patients underwent CarboMedics valve implantation (CM) in the aortic (119 patients), mitral (148 patients) or aortic and mitral (59 patients) positions while 371 patients underwent St. Jude Medical valve implantation (SJ) in the aortic (113 patients), mitral (184 patient), or aortic and mitral (74 patients) positions at National Taiwan University Hospital from August 1991 through 1995. All patients received warfarin (Coumadin) anticoagulation with the target international normalized ratio around 1.5. The hospital mortality was 3.7% in the CM group and 4.3% in the SJ group. In the CM group at 5 years, the actuarial freedom from thromboembolism, valve thrombosis, and anticoagulant-related hemorrhage was 89.91 +/- 2.66%, 95. 23 +/- 1.50%, and 99.62 +/- 0.37%, respectively, and the actuarial survival rate was 90.4 +/- 1.6%. In the SJ group at 5 years, the actuarial freedom from thromboembolism, valve thrombosis, and anticoagulant-related hemorrhage was 94.79% +/- 1.70%, 98.80 +/- 0.72%, and 99.68 +/- 0.31%, respectively, and the actuarial survival rate was 91.3 +/- 1.7%. We therefore concluded that a similar survival rate was noted in the CM and SJ groups. With low dose anticoagulation, the complications of thromboembolism, valve thrombosis, and anticoagulant-related hemorrhage were low in the SJ group.

Adolescent↗
PubMed1995

Anatomic substrate of the experimentally-created atrioventricular node re-entrant tachycardia in the dog.

Despite major success in the treatment of atrioventricular (AV) node reentrant tachycardia using either catheter ablation or surgery, the morphologic basis underlying AV node reentry is not yet clear. A canine model of AV node reentrant tachycardia was used to examine the histologic features of the reentry circuit. AV node reentrant tachycardia was created in 4 of 8 dogs by a right atrial division which divided the right atrial free wall and the atrial septum into upper and lower portions on a plane between the mid-right atrial free wall and the fossa ovalis. The AV junctional area of all dogs were serially sectioned on a plane that was perpendicular to the AV annulus and the septum. The slices were stained with Masson's trichrome technique. The connections between atrial fibers and the compact AV node and the common AV bundle were examined, and comparison of the histologic features between dogs with and without AV nodal re-entry was made. The histologic examinations showed that, in all dogs, the operation scar was remote from the AV junctional area leaving the Koch's triangle intact. The compact node received its atrial inputs mainly from the anterosuperior and posterior aspects of the Koch's triangle. However, both atrial inputs gave off superficial (subendocardial) fibers that by-passed the compact node to terminate at the base of tricuspid valve. These superficial fibers might function as the proximal link between the dual AV nodal inputs by means of lateral connections. There was no bypass connection between atrial fibers and the common AV bundle. The histologic features of the AV junctional area was not different between dogs with and without AV nodal reentry. In conclusion, AV nodal reentry involves the anterior and posterior atrio-nodal inputs which function as dual AV nodal pathways, and the superficial bypass fibers form the proximal linkage between the two inputs. These structures, together with the compact node, complete the reentry circuit.

Animals↗
PubMed1995

Perinodal slow potential as a local guide for transcatheter radiofrequency ablation of atrioventricular nodal reentrant tachycardia: therapeutic efficacy and electrophysiological mechanisms of success.

BACKGROUND: A specific local indicator in the Koch's triangle could be critical to the complication-free treatment of atrioventricular nodal reentrant tachycardia by transcatheter radiofrequency ablation. Recording of perinodal slow potential reflects a slow conduction area, and probably indicates the location of the slow pathway component of the circuit. Specific ablation of the slow pathway would carry the least risk of atrioventricular block. METHOD AND RESULTS: Guided by the mapped perinodal slow potential, atrioventricular nodal reentrant tachycardia was successfully eliminated in all of 55 consecutive patients in one session. Fifty two patients (94.5%) had confirmed slow potential at the final success sites. Despite the good result, the underlying electrophysiological mechanisms of early success from slow-potential-guiding catheter ablation were heterogeneous: selective slow pathway eradication in 31 patients (56.4%, group A), selective slow pathway modification in 18 patients (32.7%, group B), inadvertent fast pathway damage in six patients (10.9%, group C). Group B patients had the preservation of dual atrioventricular nodal pathways, adequate atrio-Hisian delay, fast pathway facilitation, and a higher frequency of inducible, single non-conducted nodal echo (15/18, 83.3% v 6/31, 19.4% in group A, P << 0.001). The upper communicating path of the circuit was implicated as another site of radiofrequency destruction. Three recurrences were documented in follow up study. However, reablation by the same approach caused complete atrioventricular block in one patient (1.7%, 1/58 procedures). None of the local characteristics of ablation sites was an independent predictor of procedure outcome. CONCLUSIONS: Perinodal slow potential is not a specific slow pathway indicator in transcatheter radiofrequency ablation of atrioventricular nodal reentrant tachycardia. Multiple strategic sites of the reentry circuit may be damaged through similar local signals.

Adolescent↗
PubMed1995

Effects of dicentrine on the mechanical properties of systemic arterial trees in dogs.

We evaluated the effects of dicentrine on the physical properties of systemic arterial trees. Dicentrine, isolated from Lindera megaphylla, was identified as a potent, selective alpha 1-adrenoceptor antagonist. We used high-fidelity multisensor catheter to measure the ascending aortic pressure and flow signals in 9 mongrel dogs. A succinct T-tube model with vascular nonuniformity was adopted to relate the pulsatile pressure and flow waves. The model-estimated parameters were capable of representing the mechanical properties of the blood vessel walls. Dicentrine had a beneficial effect on the rigidity of head and body circulation, respectively. There were great improvements not only in the tube distensibility and wave transmission time, but also in the peripheral load compliance and resistance. In global circulation that was defined as the parallel combination of head and body circulation, dicentrine significantly reduced values in characteristic impedance of the ascending aorta from 164 +/- 67 to 105 +/- 43 dynes/s/cm5, and in wave reflection factor from 0.46 +/- 0.14 to 0.36 +/- 0.13, and in total peripheral vascular resistance from 4,751 +/- 1,226 to 3,581 +/- 1,277 dynes/s/cm5. On the other hand, total peripheral load compliance was increased from 0.2950 +/- 0.1794 to 0.4457 +/- 0.2199 ml/mm Hg. Cardiac output (CO) and heart rate (HR) remained unchanged, however. Dicentrine had an impact on the mechanical properties of Windkessel vessels and resistance vessels in the systemic circulation.

Adrenergic alpha-Antagonists↗