Long-Term Stability of Defibrillation Thresholds with Intrapericardial Defibrillator Patches

From March 1982 to May 1, 1992, 105 consecutive patients underwent initial implant of cardioverter defibrillators (ICD) at our institution. Twenty-nine patients (23 male and 6 female, average ejection fraction 32.24%) with ICD systems implanted via thoracotomy and either intra- or extrapericardial patches, had one or more revisions including 56 generator changes or staged implant procedures, three patch revisions, one patch lead fracture without revision, and one sensing lead revision. The time between pulse generator revisions averaged 19.5 months. Initial defibrillation threshold mean was 12.8 joules (n = 25); at first revision, 14.46 joules (n = 29), (P = NS); by fifth revision, 15.0 joules (n = 2), (P = NS). One patch was noted to be crinkled at 70 months; one patch had migrated by 39 months, and two patch leads had fractured at the costal margin by 69 and 90 months. One patient with marginal defibrillation thresholds had an additional patch placed at revision to an upgraded ICD unit. Once acceptable defibrillation threshold (DFT) is obtained, the long-term intrapericardial DFT remains stable unless a specific problem occurs. As a small, nonstatistically significant increase in DFT may occur, caution must be exercised in patients with marginal DFTs.     

Transesophageal Echocardiographic Diagnosis of Aortic Graft Dehiscense at Coronary Anastomoses and Pseudonaneurysm Rupture into Right Atrium

We describe a case of aortic graft dehiscence at coronary anastomoses with rupture into the right atrium of the pseudoaneurysm complicating aortic graft replacement. These were diagnosed by intraoperative transesophageal echocardiography.     

Automatic Implantable Cardioverter/ Defibrillator: Inadvertent Discharges During Permanent Pacemaker Magnet Tests

A patient with an automatic implantable cardioverter defibrillator (AICD)® received two inadvertent shacks when a magnet was placed over the pacer during a routine permanent pacer check. Analysis of the rhythm strip suggested that both patients' QRS complexes (133 beats/minute) and asynchronous pacer artifacts (70 beats/minute) were counted by the AICD sensing system and exceeded the rate criteria of 153 beats/minute. This resulted in shocks from the AICD during sinus rhythm at 133 beats/minute. To avoid possible inadvertent shocks, an AICD should be deactivated while a magnet is placed over the pacemaker during a permanent pacer check.     

Regulatory Volume Increase of Human Non-pigmented Ciliary Epithelial Cells

Cells (ODM/SV40) derived from human non-pigmented ciliary epithelial cells were studied by electronic cell sizing. After transiently suspending the cells in hypotonic solution, isotonicity was restored by addition of sucrose. The cell volumes (v_c) initially fell below those of control isotonic suspensions, and subsequently increased towards the baseline level. This secondary increase inv_cis termed the regulatory volume increase (RVI). Results obtained with ionic substitutions and transport inhibitors indicate that four ionic mechanisms can support the RVI in these cells: coupled Na⁺/H⁺and Cl⁻/HCO₃⁻antiports, a Na⁺/Cl⁻symport, a Na⁺/K⁺/2Cl⁻symport, and a Na⁺⁻channel in parallel with a Cl⁻/HCO₃⁻antiport. Arachidonic acid metabolites regulate the RVI very differently from their effects on the regulatory volume response (RVD) of the same cells to cell swelling. Prostaglandin E₂(PGE₂), leukotriene (LTD₄) and the PKC-inhibitor staurosporine all inhibit the RVI. Blockade of the cyclooxygenase, lipoxygenase and epoxygenase pathways of arachidonic acid metabolism [with 5,8,11,14-eicosatetraynoic acid (ETYA)] produces a net acceleration of the RVI. In contrast, PGE₂and staurosporine stimulate, LTD₄has no effect, and ETYA inhibits the RVD. We suggest that knowledge of the ionic mechanisms and intracellular signalling underlying the RVI phenomenon may provide a basis for reducing the rate of net aqueous humor formation by increasing the rate of reabsorption of fluid from the aqueous humor into the non-pigmented ciliary epithelial cells.     

Transesophageal Echocardiography Identification and Validation of Individual Tricuspid Valve Leaflets

The present study demonstrates the usefulness of transesophageal echocardiography in the identification of individual leaflets of the tricuspid valve. Validation was obtained by selecting patients with specific lesions involving individual tricuspid leaflets and correlating the transesophageal echocardiographic findings with surgery.     

Lipoprotein (a) and apolipoprotein A-1 and B in schoolchildren whose grandparents had coronary and cerebrovascular events: A preliminary study of 12–13 year old Japanese children

The aim of this study was to evaluate the relationship between the serum levels of lipoprotein (a) [Lp (a)] and apolipoproteins (apo A-1 and apo B) in schoolchildren with a history of coronary and cerebrovascular events in their grandparents. We measured serum concentrations of Lp (a) and apoliproteins immunochemically in 289 schoolchildren aged 12–13 years and questioned parents about coronary and cerebrovascular events in the children's grandparents. In boys and girls, mean ± s.d. levels of apo A-1, apo B and Lp (a) were 134 ± 20.3 and 136 ± 17.4 mg/dL, 61 ± 16 and 66 ± 15 mg/dL and 12.5 ± 15.3 and 12.5 ± 15.1 mg/dL, respectively. There were no significant sex differences in the levels of apo A-1, apo B, and Lp (a). The Lp (a) levels (mean ± s.d., 12.5 ± 15.2 mg/dL; median 7.5 mg/dL, n = 289) were not affected by other variables. The Lp (a) distribution was strongly positively skewed and 75% of schoolchildren had very low levels. In the total 289 schoolchildren, thirty-two grandparents who had had coronary vascular events (21 myocardial infarction, 11 angina pectoris) and twenty-three grandparents who had had cerebrovascular events were recorded. By the boxplot statistical analysis, no difference was found in Lp (a) levels in children whose grandparents had myocardial infarction compared with those whose grandparents had no such history, or compared with those whose grandparents had suffered cerebrovascular events. Analysis also showed that the values of log Lp (a) in children whose grandparents had myocardial infarction tended to be higher than the values in children whose grandparents had no such history (P = 0.09). No significant differences in the levels of apo A-1 and apo B and in the apo B/A-1 ratio could be seen between children grouped according to the presence or absence of coronary and cerebrovascular events in their grandparents. These results suggest that high levels of Lp (a) in schoolchildren aged 12–13 years may partly reflect the existence of coronary vascular disease in older family members. Lp (a) may account for the strongest index of family history to disease risk in comparison with other apolipoproteins. Further study is needed to clarify the appropriate mass measurement method for Lp (a) in schoolchildren.     

Disposition of topically applied sodium cromoglycate in the albino rabbit eye

The influence of pH, tonicity, preservatives, polymers and instilled drop size on the disposition of sodium cromoglycate, an agent used in the prophylaxis of vernal keratoconjunctivitis, in the tear chamber of the albino rabbit eye has been examined. Radiotracer techniques were used throughout. The initial decline in concentration in the tear chamber was found to be unaffected by the presence of preservatives, pH, and tonicity over the ranges studied. However, significant increases in the residence time of sodium cromoglycate in the precorneal area were noted when a smaller instilled drop size was used and when 5% polyvinyl alcohol (PVA) was added to the aqueous vehicle. Tissue uptake was found to be greatest in the conjunctiva, followed by the cornea, the iris-ciliary body and the aqueous humor. In both the conjunctiva and the cornea, the addition of 5% PVA produced an elevation in the peak concentration of sodium cromoglycate and an increase in the time at which the peak concentration was achieved, indicating improved drug delivery to these sites.     

Neurodevelopmental outcome of infants with birth asphyxia treated with magnesium sulfate

BACKGROUND: A neuroprotective effect of MgSO(4) has been shown in some animal models of perinatal hypoxic-ischemic brain damage. The aim of the present paper was to determine whether postnatal MgSO(4) infusion (250 mg/kg per day i.v. for 3 days, in combination with dopamine) is safe in infants with severe birth asphyxia, and also observe effects on neurodevelopmental outcome at 18 months. METHODS: Inclusion criteria were clinical history consistent with perinatal asphyxia; gestational age at least 37 weeks; 5 min Apgar score < or =6; failure to initiate spontaneous respiration within 10 min after birth; and symptoms of encephalopathy. On each day MgSO(4) was infused over 1 h in combination with dopamine (5 microg/kg per min). Changes in vital signs, clinical course of encephalopathy, laboratory variables, and adverse events were monitored. Infants were followed for 18 months. RESULTS: Thirty infants were studied. Mean birthweight was 2878 g; mean gestational age, 39.6 weeks, and median 5 min Apgar score, 3. All required endotracheal intubation for resuscitation. Median age at MgSO(4) initiation was 5 h. All infants had moderate or severe hypoxic-ischemic encephalopathy. Mean serum Mg(2+) concentration remained at least 1.3 mmol/L. MgSO(4) caused no change in physiological variables including mean arterial pressure. Two infants died as neonates, while six of 28 survivors had severe neurodevelopmental disability at 18 months; the remaining 22 had no neurodevelopmental disability. CONCLUSION: Postnatal infusion of MgSO(4) with dopamine caused no change in physiological variables. Deaths and severe sequelae were less frequent than in reported cases with the same grade of hypoxic-ischemic encephalopathy severity, and this treatment may improve neurodevelopmental outcome in infants with severe birth asphyxia.     

3,5-二羟基联苄的合成方法改进

目的 改进3,5-二羟基联苄的合成方法。方法 以3,5-二甲氧基苯甲醛为起始原料，经过Wittig反应、还原反应、脱甲基反应共3步反应得到目标化合物。结果 成功地合成了3,5-二羟基联苄，总收率为88.2%。结论 改进后的合成方法反应时间明显缩短，操作方法大大简化，收率由40%提高到88.2%。