Surgical correction of giant patent ductus arteriosus

In reviewing the literature, there was only one report having the ductus over 30 mm in width. Recently, we utilized cardiopulmonary bypass, hypothermia, and low flow through a transpulmonary approach to close 2 cases of giant patent ductus arteriosus. Both cases complicated with systemic pulmonary hypertension. Its outside diameters were 31 mm and 36 mm respectively based on the measurement from magnetic resonance imaging. To our knowledge, its seem the biggest ductus in comparison to previous reports. Both cases survived the operation and doing well for a follow-up time of 5 years and 4 years 10 months respectively.

Mitochondrial myopathy-encephalopathy-lactic acidosis-and strokelike episodes (MELAS) syndrome: CT and MR findings in seven children

OBJECTIVE

The purpose of this study was to describe the imaging characteristics of mitochondrial myopathy-encephalopathy-lactic acidosis-and strokelike episodes (MELAS) syndrome.

MATERIALS AND METHODS

Twelve CT scans and 15 MR images were retrospectively reviewed in seven patients with proven MELAS syndrome. Follow-up studies were performed in all patients, and the total follow-up period ranged from 3 months to 3 years. Images were analyzed in terms of lesion distribution, enhancement pattern, presence of mass effect or atrophy, calcification, and changes on follow-up studies.

RESULTS

CT and MR imaging showed multiple cortical and subcortical infarctlike lesions, which crossed vascular boundaries, and various degrees of generalized cerebral and cerebellar atrophy. Lesions were distributed in the posterior, parietal, and occipital areas in six patients, the putamen in five, the caudate nucleus in two, the thalamus in two, the frontal lobe in two, the globus pallidus in one, and the brainstem in one. Contrast enhancement was noted in two of seven cases on MR images and in three of five cases on CT scans. In the early stage, infarctlike lesions showed swelling and mass effect. Lesions resolved with or without local tissue loss in five patients, and new lesions appeared in another part of the brain in five patients. Generalized atrophy progressed in six cases and was most severe in the posterior part of the cerebral hemispheres.

CONCLUSION

Our results indicate that imaging findings of multiple migrating infarctlike lesions that are not limited to a specific vascular territory, especially in the basal ganglia and posterior part of the cerebral hemisphere in children, are diagnostic of MELAS syndrome.

Electrophysiological manifestations of the excitable gap of slow-fast AV nodal reentrant tachycardia demonstrated by single extrastimulation

BACKGROUND

Although AV nodal reentrant tachycardia (AVNRT) is a well-known rhythm disorder, its anatomic substrate and electrophysiological mechanism remain to be defined. Previously, the description of the excitable gap (EG) of AVNRT was based on electrical stimulation performed from sites remote from the reentrant circuit. In the present study, we characterized the EG of AVNRT by atrial extrastimulation close to the putative reentrant circuit in the AV junction.

METHODS AND RESULTS

In 16 patients (3 men, 13 women; mean age, 45 +/- 13 years) with inducible slow-fast AVNRT (mean cycle length, 353 +/- 52 ms), single extrastimuli with a 10-ms decrement in the premature coupling interval were delivered from the anterosuperior interatrial septum (fast pathway area) and the posteroinferior interatrial septum (slow pathway area) from late diastole until atrial refractoriness. An EG was considered present when resetting or termination of AVNRT was induced by single atrial extrastimulation. The study showed that the duration of the EG of AVNRT was wide, measuring 121 +/- 56 and 123 +/- 47 ms and occupying 33 +/- 11% and 34 +/- 9% of the tachycardia cycle length during single extrastimulation from the slow pathway area and the fast pathway area, respectively. The resetting pattern most commonly manifested as the sum of the coupling interval and the return cycle being less than a fully compensatory pause (two times the basic tachycardia cycle length). However, patterns equal to and greater than a fully compensatory pause were also observed. Of note, in 2 of the 16 patients, atrial extrastimulation from either the fast or slow pathway area also affected the preceding tachycardia cycle length (HH interval), indicating alteration of the anterograde input. In all patients, the curve derived from plotting the coupling interval of extrastimuli against the return cycle during resetting exhibited an "increasing" pattern. The mode of tachycardia termination usually occurred when the premature atrial impulse was orthodromically blocked in the anterograde slow pathway.

CONCLUSIONS

The EG of slow-fast AVNRT is relatively wide, as demonstrated by single atrial extrastimulation from the interatrial septum near the AV junction. Overall, the electrophysiological manifestations of the EG of AVNRT are very similar to those described in AV reciprocating tachycardia incorporating an accessory connection. These findings lend further support to the notion that, in humans, AVNRT involves a reentrant mechanism with a wide excitable gap.

Experience of anesthesia for transthoracic endoscopic sympathectomy in palmar hyperhidrosis--110 cases

Transthoracic endoscopic sympathectomy (TES) is an effective treatment for palmar hyperhidrosis. We review our experience and discuss the anesthetic technique and perioperative complications encountered in 110 patients undergoing TES for palmar hyperhidrosis. All patients were monitored with EKG, NIBP and pulse oximetry (SPO2) during the operation. The trachea was intubated with a single lumen endotracheal tube and ventilation was controlled manually. 100% inspired oxygen was necessary during TES to avoid hypoxia. One patient developed sudden cardiac arrest during electrocauterization of the left sympathetic chain and two patients required underwater drainage for hemothorax. Minimal pneumothorax was diagnosed in 4 patients and all cases resolved spontaneously without active treatment.

Hemolytic uremic syndrome: MR findings of CNS complications

MR findings of a patient with hemolytic uremic syndrome involving the CNS are described. Abnormal high signal intensity on T2-weighted images combined with swelling in the lentiform nucleus, posterior limb of internal capsule, external capsule bilaterally, and left extreme capsule was shown on initial MR; a small low signal intensity in the left putamen on T1- and T2-weighted images and generalized atrophy in the area of high signal intensity on previous T2-weighted images was shown on follow-up MR. These findings indicate infarct with focal hemorrhage, which is one of the histopathological features of CNS complication in hemolytic uremic syndrome.

Hallervorden-Spatz syndrome in two siblings diagnosed by the clinical features and magnetic resonance imaging (MRI)

Hallervorden-Spatz syndrome (HSS) is a heredodegenerative disorder characterized by both progressive pyramidal and extrapyramidal signs, dysarthric speech, and mental deterioration. No diagnostic biochemical test is yet available, and diagnosis of HSS can be confirmed only at autopsy by the characteristic neuropathology including abnormal iron storage, disordered myelination, and loss of brain substance. We present two siblings with clinical features consistent with HSS, in whom magnetic resonance imaging (MRI) demonstrated the deposition of iron in the globus pallidus and the substantia nigra thus allowing an antemortem diagnosis of HSS.

[The study of anatomic factors in difficult intubations]

Endotracheal intubation is a common procedure in anesthesia which can usually be accomplished easily. However if the attempt is unexpectedly difficult the patient may be seriously at risk. If all difficult airways can be predicted confidently in the pre-operative period, anesthesiologists can plan the safest and most effective way of managing tracheal intubation. The purpose of this study was to analyze not only the incidence, anatomic factors, immediate complications and management of difficult intubation cases but also the view obtained at laryngoscope which was graded according to the Cormack's and Lehane's description. Patients who received general anesthesia with endotracheal tube within 1 year's period from November 1, 1991 to October 31, 1992 in Show Chwan Memorial Hospital were collected. All difficult intubations were performed by senior anesthesiologists. 3925 patients were intubated, 92 cases were noted to have difficult intubations and their overall incidence were 2.3%. Among the 92 patients, those with 2 anatomic factors (41 patients, 44.6%) represented the majority for patients with difficult intubations. On the other hand, the four most common anatomic factors and their incidences in order of frequency included short neck (48.9%), protruding teeth (38.0%), receding mandible (27.2%) and limited opening mouth (26.1%). According to Cormack's and Lehane's laryngoscopic grading, the results were shown respectively as follow: 4 cases (4.4%) for grade 1;2 cases (2.2%) for grade 2;82 case (89%) for grade 3 and 4 cases (4.4%) for grade 4. We also found that tachycardia/hypertension (70.7%), bleeding (37.0%) and esophageal intubation (33.7%) were the three most frequent immediate complications during difficult intubations.(ABSTRACT TRUNCATED AT 250 WORDS)

Central core disease--a case report

Central core disease is a rare congenital myopathy characterized by the formation of "cores" that consist of abnormal arrangement of myofibrils inside the myofibers. We report a 5-year-old Korean girl who showed a fairly typical clinical course of non-progressive muscle weakness. Electrodiagnostic studies showed low-amplitude polyphasic electromyograph and normal nerve conduction velocity. Gastrocnemius muscle biopsy showed central cores in over 80% of the fibers on H&E section. Histochemistry revealed deficient or absent mitochondrial enzyme in the cores and type I predominance. Ultrastructurally both structured and non-structured cores were found separately or simultaneously in one fiber. This case is the first report in the Korean literature.

Comparison of the electrophysiologic effects of oral sustained-release and intravenous verapamil in patients with paroxysmal supraventricular tachycardia

The electrophysiologic effects of intravenous verapamil (0.15 mg/kg) and oral sustained-release verapamil (verapamil-SR) (240 mg once daily for 7 days) were studied in 17 patients with paroxysmal supraventricular tachycardia (SVT). Ten patients had atrioventricular (AV) nodal reentrant tachycardia and 7 had AV reciprocating tachycardia involving an accessory AV pathway. Both preparations significantly prolonged anterograde effective refractory period of the AV node and depressed the retrograde AV nodal conduction system. The sinus cycle length, and atrial and ventricular effective refractory periods were prolonged after oral verapamil-SR. Furthermore, oral verapamil-SR depressed retrograde accessory pathway conduction which was not interfered with by intravenous verapamil. Intravenous verapamil and oral verapamil-SR prevented induction of sustained SVT in 12 of 17 (71%) and 10 of 17 (59%) patients, respectively. Follow-up study with oral verapamil-SR 240 mg once daily in 15 patients for 19 +/- 6 months revealed that among the 8 patients without induction of sustained SVT, 7 have been free of symptomatic arrhythmia; only 1 patient had occasional SVT attacks. For the 7 patients with induction of sustained SVT, 3 patients failed to respond to oral verapamil-SR, 1 patient became symptom free, and the remaining 3 patients had less frequent SVT attacks. Thus, immediate intravenous verapamil testing predicts the electrophysiologic results of oral verapamil-SR therapy, and oral verapamil-SR once daily may be used for long-term prophylaxis of SVT with better patient compliance.

Efficacy of once-daily lisinopril monotherapy in systemic hypertension

Lisinopril is a new, long-acting angiotensin-converting enzyme inhibitor formulated for once-daily treatment of hypertension. This study assessed the 24-h efficacy and tolerability of lisinopril in Chinese patients with mild to moderate hypertension of World Health Organization Stages I to II. A total of 30 patients aged 30 to 60 years (mean 47 +/- 9) entered a 2-week washout period. All patients had ambulatory diastolic blood pressure (BP) > 90 mmHg and were given active treatment with lisinopril for 4 to 7 weeks. The dose of lisinopril was titrated from 10 to 40 mg daily (at 8-9 A.M.). In each patient, 24-h ambulatory blood pressure (BP) monitoring (SpaceLabs 90202) was performed twice, once before and once following treatment. Mean 24-hour systolic/diastolic BPs after lisinopril were significantly decreased compared with baseline values (132 +/- 12/86 +/- 7 vs. 150 +/- 11/98 +/- 7 mmHg; p < 0.0005/0.0005). The average dose of lisinopril was 14.5 +/- 5 mg daily after a titration period of 5 weeks of treatment. Mean daytime (6 A.M. to 6 P.M.) BP decreased from 152 +/- 11/100 +/- 8 to 134 +/- 12/87 +/- 8 mmHg (p < 0.0005/0.0005) and nighttime (6 P.M. to 6 A.M.) BP from 147 +/- 14/95 +/- 9 to 128 +/- 14/83 +/- 8 mmHg (p < 0.0005/0.0005). BP reduction was more pronounced during the night. Before treatment, the circadian variation showed a peak BP at 11 A.M. and nadir at 3 P.M. After treatment, significant BP reduction (p < 0.0005/0.0005) was seen throughout the 24-h period.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of thromboxane synthase and cyclooxygenase inhibition on PAF-induced changes in lung function and arachidonic acid metabolism

PAF was administered as an intravenous bolus (0.1 micrograms/kg) to eight chronically instrumented awake sheep. The effects of pretreatment with an inhibitor of cyclooxygenase (meclofenamate) on PAF-induced changes in lung function were compared to those observed with a specific inhibitor of thromboxane synthase (DP1904). Each animal was studied four times in varied order: PAF alone, PAF + DP1904, PAF + meclofenamate, and DP1904 alone. Saline alone (control), DP1904 alone, and meclofenamate alone did not cause changes in any of the measured variables. DP1904 and meclofenamate significantly attenuated the PAF-induced fall in lung compliance, elevation in peak pulmonary artery pressure, and increased lung lymph flow. Both drugs abolished the PAF-induced increases in lung lymph thromboxane B2 concentrations. Meclofenamate, but not DP1904, blocked the rise in lymph 6-keto-PGF1 alpha. Although meclofenamate blocked the rise in lymph PGE2, DP1904 resulted in levels 2.7 times higher than PAF alone. We conclude that: (1) inhibition of thromboxane synthase is as effective as inhibition of cyclooxygenase in attenuating PAF-induced changes in lung function, and (2) thromboxane synthase inhibition results in augmented production of PGE2 following PAF administration in vivo.

Sparganosis in the spinal canal with partial block: an uncommon infection

A case of rare intraspinal sparganosis treated by surgical excision is described. In this 59-year-old male with paraparesis and voiding problem, an intradural mass was noted on myelogram. Magnetic resonance (MR) and computed tomographic appearance of spinal and associated cerebral lesion are illustrated and possible route of migration discussed. This represents, to our knowledge, the first MRI demonstration of intraspinal sparganosis reported in the literature.

Is sick sinus syndrome an adenosine-mediated disease? Effects of intravenous aminophylline on sick sinus node function after pharmacologic autonomic blockade

To assess the effects of intravenous aminophylline on the sinus node, 12 patients with clinical and Holter monitor-documented sick sinus syndrome were studied (1) during the control state, (2) after pharmacologic autonomic blockade and (3) 5 min after intravenous administration of aminophylline. The effects of aminophylline on sinus node function were compared with those after pharmacologic autonomic blockade. No significant improvement of sinus node function was found after intravenous aminophylline administration with a mean sinus cycle length and a mean maximum CSRT of 968 +/- 218 and 1832 +/- 1036 ms, respectively. The mean serum theophylline level was 10.9 +/- 1.7 micrograms/ml. Since aminophylline is an adenosine receptor antagonist, these findings suggest that intrinsic adenosine may not play an important role in pathogenesis in patients with chronic and advanced sick sinus syndrome.

Phase II Radiation Therapy Oncology Group study of hormonal cytoreduction with flutamide and Zoladex in locally advanced carcinoma of the prostate treated with definitive radiotherapy

In patients with locally advanced (bulky) carcinoma of the prostate, definitive radiotherapy is associated with a high rate of local recurrence. The Radiation Therapy Oncology Group (RTOG) has conducted several studies evaluating hormonal cytoreduction (used as an induction regimen) as a means of improving the local control rate. RTOG 85-19 tested an induction regimen consisting of a depot LH-RH agonist (Zoladex) and an antiandrogen (flutamide). Eligible patients were those with bulky primary lesions (stage B2 and C) with disease confined to the pelvis. Zoladex was administered every 29 days via a subcutaneous injection. Flutamide was given by mouth in a dose of 250 mg t.i.d. Administration of the drugs was initiated 2 months prior to start of radiotherapy and was terminated at completion of the radiotherapy course. Radiotherapy consisted of 180-200 rad/day, 4,400-4,500 rad to the regional lymphatics, and 6,500-7,000 rad to the prostate. The primary aim of the study was to evaluate the effectiveness and toxicity of the combined (hormonal cytoreduction plus definitive radiotherapy) regimen. Thirty-one patients were accessioned; 30 are analyzable. The drug-related toxicity appears acceptable. It included appearance of diarrhea before initiation of radiotherapy in two patients, nausea during the 2nd week of drug administration in two patients, and skin rash in three patients. These phenomena appear to be related to flutamide. Hot flashes were recorded in 17 patients. With a minimum follow-up of 2 years, clearance of the primary lesions (by clinical examination) was documented in 28 of 30 patients. During the 1st year, two of 30 patients died (of unrelated causes) with residual palpable tumors. The observed toxicity appears acceptable and the response rate encouraging. A phase III study comparing the tested regimen against radiotherapy alone appears warranted.

Nifedipine retard in the treatment of hypertension. A study using ambulatory blood pressure recordings

The subjects were 24 patients, aged 37 to 66 years, with mild to moderate hypertension, treated with nifedipine retard (mean dose, 47 mg daily) for 7 to 16 weeks. The mean 24-hour ambulatory blood pressure (BP) declined significantly from 158/101 before treatment to 136/87 mmHg after treatment. Daytime BP declined from 160/101 to 133/86 mmHg and nighttime BP from 152/98 to 132/85 mmHg; the diurnal variation in diastolic BP was lost during treatment with nifedipine. The consecutive hourly BPs were all significantly lower after treatment. BPs in response to physiologic tests were significantly reduced after treatment. Heart rate increased significantly during treatment. Side effects (palpitations, pedal edema, and flushing of the face) were reported by four patients. It is concluded that nifedipine retard is safe and effective in the treatment of mild to moderate hypertension.

Polarization characteristics of wire mesh at 119 microm

Polarization characteristics of the transmitted beam through the various sizes of metal wire grid meshes are examined experimentally at 118.8 microm. When these results were compared to Chen's waveguide theory, we obtained excellent agreement. In particular, when the incident beam polarization is neither parallel (TM) nor perpendicular (TE) to the wire grid axis, a linearly polarized incident beam can be made elliptic due to the phase difference between the TE and TM modes.

Structure and expression of the rice glutelin multigene family

A near full-length cDNA and three genomic clones for rice (Oryza sativa L.) glutelin were isolated and studied. Based on nucleic acid sequence and Southern blot analyses, the three isolated glutelin genomic clones were representative members of three gene subfamilies each containing five to eight copies. A comparison of DNA sequences displayed by relevant regions of these genomic clones showed that two subfamilies, represented by clones Gt1 and Gt2, were closely related and evolved by more recent gene duplication events. The 5'-flanking and coding sequences of Gt1 and Gt2 displayed at least 87% homology. In contrast, Gt3 showed little or no homology in the 5'-flanking sequences upstream of the putative CAAT boxes and exhibited significant divergence in all other portions of the gene. Conserved sequences in the 5'-flanking regions of these genes were identified and discussed in light of their potential regulatory role. The derived primary sequences of all three glutelin genomic clones showed significant homology to the legume 11 S storage proteins indicating a common gene origin. A comparison of the derived glutelin primary sequences showed that mutations were clustered in three peptide regions. One peptide region corresponded to the highly mutable hypervariable region of legume 11 S storage proteins, a potential target area for protein modification. Expression studies indicated that glutelin mRNA transcripts are differentially accumulated during endosperm development. Promoters of Gt2 and Gt3 were functional as they direct transient expression of chloramphenicol acetyltransferase in cultured plant cells.

Efficacy of mexiletine in ventricular arrhythmias among patients in Taiwan: assessment by 24-hour Holter electrocardiography

The effects of mexiletine in 30 patients with symptomatic recurrent ventricular arrhythmias were assessed by 24-hour Holter electrocardiography and M-mode echocardiography. The mean daily dose of mexiletine was 534 mg (range, 300 to 900 mg) and the interval of Holter follow-up was 16.9 days (range, 10 to 25 days). Total ventricular premature beats were reduced by 85% or more in 21 patients; in 19 of these patients there was a reduction of one or more modified Lown grades of ventricular arrhythmias. The overall reduction in Lown grades in the 30 patients was from 3.3 +/- 0.8 to 1.5 +/- 1.4 (P less than 0.0001). No significant changes in heart rate before or after mexiletine therapy were noted. Left ventricular echocardiography showed no significant changes in percentage fractional shortening after treatment. Adverse effects included gastrointestinal intolerance in seven patients and neurogenic symptoms in three. During the follow-up period of 1 to 11 (mean, 3.2) months, ventricular arrhythmias recurred in three patients. It is concluded that oral mexiletine is moderately effective and safe in controlling symptomatic recurrent ventricular arrhythmias.

Monoclonal antibodies that recognize specific antigens of Mycoplasma gallisepticum and M. synoviae

The polypeptide profiles of the type strains of Mycoplasma gallisepticum (PG 31) and M. synoviae (WVU 1853) resolved by sodium dodecyl sulfate-polyacrylamide gel electrophoresis were compared. Except for a few discrete peptides that were similar, the species varied considerably in peptide profiles. Congruence was observed between the type strains of each species and homologous cloned serotypes. Protein blots of each species were probed with 2 mouse monoclonal antibodies. Monoclonal antibody G 46 was specific for the antigen p 110 (G) in M. gallisepticum, and S 221 was specific for an antigen complex p 45-50 (S) in M. synoviae. The 2 monoclonal antibodies clearly distinguished between all serotypes of M. gallisepticum and M. synoviae that were examined by Western blot transfer. Autoradiographs of 125I-labeled M. gallisepticum and M. synoviae indicated that p 110 (G) and p 45-50 (S) were surface membrane peptides. Indirect immunofluorescence of M. gallisepticum and M. synoviae in Vero cell cultures supported the autoradiographic findings. The p 110 (G) antigen of M. gallisepticum was heat-stable, pronase-sensitive, and resistant to periodate oxidation, suggesting that its chemical composition is protein. In contrast, the p 45-50 antigen complex of M. synoviae appeared as a broad band in protein blots treated with monoclonal antibody S 221, was sensitive to pronase, and responded to Schiff's reagent but was not completely inhibited by periodate oxidation, suggesting that it is a complex of repeating sequences probably composed of glycosylated peptides.