Fourteen year experience with the omnicarbon prosthetic heart valve

The Omnicarbon prosthetic valve was implanted in 168 patients (mean age, 53 years); 84 had aortic valve replacement (AVR), 57 had mitral valve replacement (MVR), and 27 had both aortic and mitral valve replacement (DVR). The mean follow-up period was 6.8 years, with a maximum of 13.7 years. Three patients (1.8%) were lost to follow-up. There were 4 (2.4%) early deaths and 26 late deaths. Survival at 10 years was 76% in the AVR and MVR groups, and 85% in the DVR group. Freedom from thromboembolism at 10 years was 94% in the AVR group, 80% in the MVR group, and 92% in the DVR group. Freedom from hemorrhagic complications at 10 years was 86% in the AVR group and 92% in the MVR group. At 10 years, 97% in the AVR group and 96% in the MVR group were free from endocarditis. One patient in the DVR group suffered a paravalvular leak. At 10 years, 97% in the AVR group and 95% in the MVR group had not needed reoperation. Elevation of the postoperative serum lactate dehydrogenase levels were acceptable in the three groups. In conclusion, the Omnicarbon prosthetic valve has shown excellent long-term clinical results.

Reversibility of n-3 fatty acid deficiency-induced alterations of learning behavior in the rat: level of n-6 fatty acids as another critical factor

Rats fed a semipurified diet supplemented with 3% (w/w) safflower oil [Saf, n-3 fatty acid deficient, high linoleic acid (18:2n-6)] through two generations exhibit decreased correct response ratios in a brightness-discrimination learning test compared with rats fed 3% perilla oil [Per, high alpha-linolenic acid (18:3n-3)]. This is associated with a decreased DHA (22:6n-3)-to-arachidonic acid (20:4n-6) ratio in brain lipids. In the first set of experiments, dietary oil was shifted from Saf to a mixture of 2.4% safflower oil plus 0.6% DHA after weaning (Saf-DHA), but all parameters measured in the learning test were essentially unchanged. Brain 22:6n-3 content of the Saf-DHA group reached that of the Per group but the levels of 20:4n-6 and docosatetraenoic acid (22:4n-6) did not decrease to those of the Per group at the start of the test. In the second set of experiments, dietary oil was shifted to a mixture of 0.6% safflower oil plus 1.2% oleic acid (OA) plus 1.2% DHA (Saf-OA-DHA group) with 18:2n-6 content comparable to that of the Per group. The Saf-OA-DHA group exhibited a learning performance similar to that of the Per group; brain 22:6n-3, 20:4n-6, and 22:4n-6 contents were also comparable to those of the Per group. These results indicate that the altered learning behavior associated with a long-term n-3 fatty acid deficiency is reversed by supplementing 22:6n-3 after weaning, when the levels of competing n-6 fatty acids in the diet and brain lipids are limited.

An unusual complication associated with the Carpentier-Edwards porcine bioprosthesis

Primary tissue failure of bioprosthetic heart valves refers primarily to calcification of the leaflets of the bioprosthesis. A 75 year old patient underwent reoperation 15 years after mitral valve replacement with a Carpentier-Edwards porcine bioprosthesis. The extracted bioprosthetic valve was found to have one prolapsed leaflet and a small amount of calcification on all three leaflets without tear or perforation. The two commissures suspending the prolapsed leaflet were detached, causing mitral valve regurgitation.

Systematic status of Hynobius tokyoensis (Amphibia: Urodela) from Aichi Prefecture, Japan: a biochemical survey

Taxonomic status of a salamander now identified as Hynobius tokyoensis from Aichi Prefecture, Japan, was assessed by allozymic comparisons with its relatives. All three populations of H. tokyoensis from Aichi formed a monophyletic group with populations of H. nebulosus; this group is substantially diverged from a conspecific population from Kanagawa that formed another group with H. lichenatus. In the former group, the population of H. nebulosus from near the type locality was more divergent from the other conspecific populations than were three populations of H. tokyoensis from Aichi. It is quite clear that the salamander from Aichi now identified as H. tokyoensis is genetically much closer to H. nebulosus than to H. tokyoensis from Kanagawa, which is closest geographically to its type locality. This result conforms well to reported results of morphological and genetic studies, and the salamander from Aichi, now called H. tokyoensis, should be identified as H. nebulosus, which is sufficiently diverged from H. tokyoensis to be considered a distinct species.

A comparative study of characteristics of current-type and conventional-type cationic bactericides

We have synthesized new polycationic bactericides, polyloxyethylene(dimethyliminio)trimethylene(dimethyliminio)ethylene dichloridel (OXD) and poly(hexamethyleneguanidine phosphate) (HEP), in order to develop more active but less skin-irritative bactericides. The effects of these bactericides on Pseudomonas aeruginosa, Escherichia coli, Serratia marcescens, Klebsiella pneumoniae, methicillin resistant Staphylococcus aureus (MRSA) and the degree of their irritations on skin were compared with those of a widely used low molecular-weight cationic bactericide, benzalkonium chloride (BAC), and a polycationic bactericide, poly[2-hydroxyethylene(dimethyliminio)methylene chloride] (2HYC). The minimum bactericidal concentration (MBC) of OXD for 10 min contact incubation was 16 microg/ml against P. aeruginosa, E. coli, S. marcescens and K. pneumoniae, and >1000 microg/ml against MRSA. The MBC of HEP for 10 min contact incubation was 16 microg/ml against P. aeruginosa, 32 microg/ml against E. coli and K. pneumoniae, and 64 microg/ml against S. marcescens and MRSA. Itch, edema, erythema, heat, injury, desquamation and keratinization caused by skin irritation were examined in 21 subjects by patch tests. Only one subject treated with OXD experienced edema, and one subject with HEP experienced keratinization. However, BAC caused itch in 3 subjects, edema in 1, erythema in 10 and desquamation in 2, indicating that the incidence of skin irritation of BAC was higher than that of OXD or HEP. OXD and HEP had sterilization ability similar to BAC, however, they were less skin-irritative than BAC. This indicates that OXD and HEP can be used as safe bactericides.

Synthesis and antibacterial activity of the tricyclic ketolides TE-802 and its analogs

The novel 6-O-methyl tricyclic ketolides TE-802 and its analogs were synthesized by two successive cyclization reactions, 11,12-cyclic carbamate formation by intramolecular Michael addition and 9,11-diazaheptene ring construction by intramolecular dehydration reaction. These new tricyclic ketolides exhibited good in vitro antibacterial activity against not only erythromycin-susceptible strains but also erythromycin-resistant Staphylococcus aureus and Streptococcus pneumoniae, which are problematic pathogens of nosocomial and community-acquired respiratory tract infections, respectively.

Pitfalls in the development of a rotary blood pump controller

The controller presents a major obstacle in the development of the rotary blood pump as a left ventricular assist device (LVAD). Clinically, LVAD flow is a good indicator in the regulation of circulatory conditions and pump flow changes, depending on pump preload and afterload. Many investigators have tried estimating pump flow by referencing the motor current. There have been pitfalls in in vitro experimental settings, however. Using a test loop with a pneumatically driven LV chamber and a centrifugal pump as an LVAD, we monitored pump flow and pressure head to evaluate the pump performance curve (H-Q curve). Under pulsatile LV conditions, the H-Q curve was a loop that changed, depending on LV contractility. The pneumatically driven LV chamber cannot mimic the Starling phenomenon, so the developed LV pressure does not change according to the LV preload. Rotary pump flow estimation is the most effective control method. In pulsatile conditions, however, the H-Q curve is a loop that changes under various LV contractility conditions, complicating determination of linear equation for calculating flow. In addition, the LV chamber in the test loop cannot mimic native heart contractility as described by Starling's law. This finding can lead to a misanalysis of the H-Q curve under pulsatile conditions.

Organized thrombus of the tricuspid valve mimicking valvular tumor

We report on a case of organized thrombus of the tricuspid valve mimicking a valve tumor. Preoperative transesophageal echocardiography showed the mass to have originated from the septal leaflet of the tricuspid valve. A pouch of the tricuspid valve and a ventricular septal defect were observed perioperatively, with the mass attached to the septal leaflet. Histologic examination revealed the mass to be an organized thrombus without tumor components.

Collaborative work to evaluate toxicity on male reproductive organs by repeated dose studies in rats 11). Testicular toxicity of 2- or 4-week repeated or single-dose administration of a novel platinum complex

A novel platinum complex, compound C, developed as an antitumor agent, was intravenously administered at 10 mg/kg/day to 6-week-old and 8-week-old rats. After 4 weeks of administration to the former, testicular enlargement was observed at a similar incidence as testicular atrophy and dilatation or atrophy of the seminiferous tubules was observed. Degeneration/necrosis of the seminiferous epithelium, decrease of seminiferous epithelium, formation of multinucleated giant cells, and vacuolar degeneration of Sertoli cells were also seen. These lesions were more marked in seminiferous tubules with atrophy than in those without atrophy. After 2-week administration to 8-week-old rats, slight initial-phase findings such as dilatation of seminiferous tubules and degeneration/necrosis of the seminiferous epithelium were noted in all rats. In rats administered 20 mg/kg/day, for which the administration period was shortened to 1 week due to marked weight loss, very slight initial lesions were similarly observed. However, these lesions were not easy to detect in these rats. Following single administration of a sublethal dose (80 mg/kg), testicular lesions were clearly observed 14 days after administration, but the incidence and grade of lesions were very low at 7 days. In conclusion, testicular toxicity of compound C can be clearly detected after 2-week administration, although the progression of lesions differed from the case with 4-week administration.

Platelet activation and aggregation during normothermic cardiopulmonary bypass

OBJECTIVE

The usefulness of heparin-bonded circuits under normothermic cardiopulmonary bypass has not been elucidated. We studied platelet activation and aggregation differences between heparin-bonded and nonheparin-bonded circuits in patients undergoing surgery involving normothermic cardiopulmonary bypass.

METHODS

Eight patients underwent coronary artery bypass grafting with non heparin-bonded circuits (controls) and 7 the same with heparin-bonded circuits (heparin group). Heparin bonding was applied to the blood contact surface of our system, including the oxygenator and connecting tubes. Patient body temperature was kept between 36 and 37 degrees C. Beta-thromboglobulin and platelet factor 4 were measured before, during, and after cardiopulmonary bypass, and platelet aggregation was evaluated by laser-light scattering.

RESULTS

Changes in beta-thromboglobulin and platelet factor 4 during and after cardiopulmonary bypass were similar in both groups. Small particle formation was the primary aggregate induced during and after cardiopulmonary bypass in both groups, and serial changes in particle formation up to 24 hours after cardiopulmonary bypass were similar in both groups.

CONCLUSIONS

Our results indicate that in 2-3 hours of normothermic cardiopulmonary bypass, heparin-bonded circuits are similar to nonheparin-bonded ones in platelet compatibility.

[Effect of low dose aprotinin on reduction of blood loss after extracorpreal circulation]

Aprotinin administration during open heart surgery has been reported to reduce blood loss after extracorporeal circulation (ECC). We administered aprotinin to 12 patients undergoing CABG or prosthetic valve replacement. We examined the blood loss, the coagulation, and the fibrinolytic system in comparison with that in non-aprotinin group of 12 patients. In the aprotinin group, 1,000,000 units of aprotinin was infused intravenously before initiation of ECC and mixed with priming volume of ECC. After ECC, 250,000 units/hr was continuously infused until 1 hour after operation. The aprotinin group showed a significantly enhanced level of alpha 2 plasmin inhibitor and a significantly reduced level of plasmin-alpha 2 plasmin inhibitor complex and D-dimer. Post operative blood loss was not different between two groups. Operation time and closure time after heparinneutralization was shorter and postoperative blood use was lower in the aprotinin group. In conclusion, The administration of low dosed of aprotinin suppresses the fibrinolytic system resulting in the reduction of operation and closure time.

Cytokine mediated endothelial activation during and after normothermic cardiopulmonary bypass: heparin-bonded versus non heparin-bonded circuits

Studies evaluating cytokine production under normothermic cardiopulmonary bypass (CPB) are limited. We evaluated cytokine production, levels of thrombomodulin (TM), and soluble endothelium-derived adhesion molecules (ICAM-1) under normothermic CPB with and without heparin-bonded circuits. Nine patients treated with non heparin-bonded circuits (control group), and seven patients treated with heparin-bonded circuits (heparin group) were the subjects. Granulocyte elastase (G-E), and interleukin (IL) -6 and IL-8 were chosen as proinflammatory mediators, and TM and ICAM-1 served as indicators for endothelial damage. Blood samples were obtained before CPB, 30 minutes after initiation of CPB, at the termination of CPB, and 2 and 24 hours after CPB. G-E values in the heparin group were lower than those in the control group after 30 minutes of CPB. A G-E surge occurred at the end of CPB, and IL-6 and IL-8 surges were observed 2 hours after CPB in both groups. TM and ICAM-1 values, which were reduced at the initiation of CPB, returned to initial levels 2 hours after CPB, and exceeded them 24 hours after CPB compared with preCPB levels. Both groups showed similar changes. We conclude that there are no significant differences in serial G-E, IL-6, IL-8, TM, or ICAM-1 levels between the heparin and control groups during or after normothermic CPB for 2 to 3 hours.

Mechanical circulatory assist for pulmonary embolism

Optimal management of acute pulmonary embolism remains controversial, despite advances in thrombolytic therapy. Haemodynamic instability and, in particular, right ventricular dysfunction is associated with poor outcomes. Urgent surgical embolectomy has been the treatment of choice in this category of patients. We present two cases in which percutaneous cardiopulmonary support (PCPS) was used as an adjunct to thrombolytic therapy for progressive circulatory collapse secondary to massive acute pulmonary embolism. This experience suggests that PCPS may offer an attractive option for a condition which continues to carry significant morbidity and mortality.

Effect of n-3 fatty acid deficiency on fatty acid composition and metabolism of aminophospholipids in rat brain synaptosomes

Docosahexaenoic acid (DHA, 22:6n-3) is one of the major polyunsaturated fatty acids esterified predominantly in aminophospholipids such as ethanolamine glycerophospholipid (EtnGpl) and serine glycerophospholipid (SerGpl) in the brain. Synaptosomes prepared from rats fed an n-3 fatty acid-deficient safflower oil (Saf) diet had significantly decreased 22:6n-3 content with a compensatory increased 22:5n-6 content when compared with rats fed an n-3 fatty acid-sufficient perilla oil (Per) diet. When the Saf group was shifted to a diet supplemented with safflower oil plus 22:6n-3 (Saf + DHA) after weaning, 22:6n-3 content was found to be restored to the level of the Per group. The uptake of [3H]ethanolamine and its conversion to [3H]EtnGpl did not differ significantly among the three dietary groups, whereas the formation of [3H]lysoEtnGpl from [3H]ethanolamine was significantly lower in the Saf group than in the other groups. The uptake of [3H]serine, its incorporation into [3H]SerGpl, and the conversion into [3H]EtnGpl by decarboxylation of [3H]SerGpl did not differ among the three dietary groups. The observed decrease in lysoEtnGpl formation associated with a reduction of 22:6n-3 content in rat brain synaptosomes by n-3 fatty acid deprivation may provide a clue to reveal biochemical bases for the dietary fatty acids-behavior link.

Transient rise in serum soluble Fas (APO-1/CD95) in patients undergoing cardiac surgery

The Fas molecule, also designated APO-1/CD95, belongs to the tumor necrosis factor (TNF) receptor family. It is a widely expressed membrane-anchored protein that induces apoptosis by Fas/Fas ligand (Fas-L) mediation. It was reported that Fas-mediated apoptosis plays an important role in regulation of the immune system, systemic inflammatory response, and ischemia/reperfusion injury. A soluble form of Fas (sFas) is produced either through the proteolytic cleavage of membrane-bound receptors or by alternative splicing, and sFas is thought to be implicated in apoptosis. In addition, sFas released damaged cells, and elevated serum levels of sFas reflect systemic tissue damage. To examine the specificity of sFas production during cardiac surgery with cardiopulmonary bypass, we serially measured the serum sFas levels in 13 patients during and after surgery. Blood samples were obtained before surgery, at the end of cardiopulmonary bypass, at the end of surgery, and at 12 h after surgery. Levels of serum sFas were determined by sandwich ELISA. Seven patients undergoing other types of surgeries served as controls. Although increased sFas was not observed in the control group, a significantly higher sFas level was detected in cardiac surgical patients at the end of surgery than before surgery (p = 0. 028), and the level decreased at 12 h after surgery. A significant correlation was observed between the maximum sFas values and the length of surgery (r = 0.659, p = 0.012) and cardioplegic arrest (r = 0.559, p = 0.046). Elevated serum sFas levels were observed in patients undergoing cardiac surgery, and these serum sFas levels reflect the severity of a surgery. sFas may play an important role in the pathophysiology of surgical damage caused by cardiac surgery with cardiopulmonary bypass.

Dietary docosahexaenoic acid can alter the surface expression of CD4 and CD8 on T cells in peripheral blood

The effect of dietary docosahexaenoic acid (DHA) on T cell states in peripheral blood was investigated. Weanling male C57Bl/6N mice were kept on one of three 10% fat diets containing various amounts of DHA and linoleic acid for 4 weeks. Changing the concentration of dietary DHA did not alter the proportion of T cells expressing CD4 or CD8. However, increasing the concentration of dietary DHA lowered the expression of CD4 and CD8 on the cell surface. The decreased expression of these surface molecules involved in T cell proliferation has serious implications in the role of DHA as an immunosuppressant.

Dietary docosahexaenoic acid but not eicosapentaenoic acid suppresses lipopolysaccharide-induced interleukin-1 beta mRNA induction in mouse spleen leukocytes

Mice were fed a diet supplemented either with beef tallow (BT), BT plus ethyl eicosapentaenoate (EPA) or BT plus ethyl docosahexaenoate (DHA) for 9 weeks. EPA and DHA supplementation increased the content of the respective fatty acid in spleen leukocyte lipids, which was associated with the reduction in the arachidonate content. IL-1beta mRNA induction upon lipopolysaccharide (LPS) stimulation in spleen leukocytes in the DHA diet group was significantly lower than in the BT diet group, but the EPA diet was without any significant effect. The amount of prostaglandin E2 (PGE2) released from LPS-stimulated spleen leukocytes was significantly lower in both the EPA and DHA groups than in the BT group. Thus, dietary EPA and DHA inhibited arachidonate metabolism similarly but had different effects on IL-1beta mRNA induction in mouse spleen leukocytes.

Dietary docosahexaenoic acid ameliorates, but rapeseed oil and safflower oil accelerate renal injury in stroke-prone spontaneously hypertensive rats as compared with soybean oil, which is associated with expression for renal transforming growth factor-beta, fibronectin and renin

We have noted that n-3 fatty acid-rich oils, such as fish oil, perilla oil and flaxseed oil as well as ethyl docosahexaenoate (DHA) prolonged the survival time of stroke-prone spontaneously hypertensive rats (SHRSP) rats by approximately 10% as compared with linoleate (n-6)-rich safflower oil. Rapeseed oil with a relatively low n-6/n-3 ratio unusually shortened the survival time by approximately 40%, suggesting the presence of minor components unfavorable to SHRSP rats. This study examined the effects of dietary oils and DHA on renal injury and gene expression related to renal injury in SHRSP rats. Rats fed rapeseed oil- and safflower oil-supplemented diets developed more severe proteinuria than those fed soybean oil-supplemented diet used as a control, but there were no significant differences in blood pressure. In contrast, the DHA-supplemented diet inhibited the development of proteinuria and suppressed hypertension. The mRNA levels for renal TGF-beta, fibronectin and renin were higher in the rapeseed oil and safflower oil groups after 9 weeks of feeding of the experimental diet than in the soybean oil and DHA groups. The fatty acid composition of kidney phospholipids was markedly affected by these diets. These results indicate that the renal injury observed in the groups fed safflower oil with a high n-6/n-3 ratio and rapeseed oil with presumed minor components is accompanied by increased expression of the TGF-beta, renin and fibronectin genes, and that dietary DHA suppresses renal injury and gene expression as compared with soybean oil.

Allozymic variation of Hynobius kimurae Dunn (Amphibia, Caudata)

An electrophoretic survey was conducted to examine genetic divergence among 21 populations of a lotic-breeding salamander Hynobius kimurae from Honshu, Japan. Genetically H. kimurae proved to be specifically distinct from H. naevius. Hynobius kimurae is divided genetically into two groups of local populations, and the five populations from the eastern area are genetically distinct from the remaining populations of the central and western areas. Less prominent genetic differentiation was revealed between the western and central populations. Separation of the eastern and central-western groups are discussed in relation to the formation of the Japanese mainland.

Role of P-glycoprotein in human natural killer-like cell line-mediated cytotoxicity

Natural killer (NK) cells express the highest amount of P-glycoprotein (Pgp), a product of the multidrug resistance (MDR) 1 gene, among lymphoid cells, and our previous studies demonstrated that Pgp is required for NK cell-mediated cytotoxicity. In this study we examined the role of Pgp in NK cell-mediated cytotoxicity using a human NK-like cell line, i.e., YTN cells and two MDR reversing agents, nicardipine and its structural analog, AHC-93. These two agents inhibited the Pgp function (rhodamine-123 excretion) as well as cell-mediated cytotoxicity, confirming that Pgp is critical for NK cell-mediated cytotoxicity. As revealed by video-rate ultraviolet laser-scanning confocal microscopy, AHC-93 did not inhibit the increase in the intracellular calcium concentration upon binding to target cells, whereas nicardipine did, as reported previously. These two reagents relocated acridine orange dye from lysosomes to the cytoplasm at concentrations similar to those required for the inhibition of cell-mediated cytotoxicity. These results suggest that Pgp is directly or indirectly involved in pH regulation in lysosomes, but not in calcium homeostasis.

Conduction disturbances after superior septal approach for mitral valve repair

BACKGROUND

The superior septal approach sacrifices the sinus node artery, and it requires more invasive incisions into the right and left atria. Therefore, postoperative rhythm disturbances could be troublesome in patients with SSA. In this study, we evaluated perioperative and midterm conduction disturbances in the cardiac rhythms of patients who had a SSA for mitral valve repair.

METHODS

Fifty-two patients had mitral valve operations by the superior septal approach, and cardiac rhythm status was assessed. The mean follow-up period was 15 +/- 8 months. In patients with normal sinus rhythms preoperatively, serial changes in PR intervals were also assessed. Holter electrocardiograms were used 6 to 12 months postoperatively. Twelve patients who had mitral valve operations by conventional left atriotomy from the right side of the left atrium served as the control group.

RESULTS

There were no operative deaths, but one patient in the experimental group died of cerebral hemorrhage 4 months postoperatively. No intractable arrhythmias occurred. Of the 25 patients who maintained sinus rhythms, preoperative PR interval on electrocardiogram was 155 +/- 20 milliseconds. Postoperative PR intervals increased for 1 week, had decreased within 2 weeks postoperatively, and returned to the normal range by 6 months postoperatively. Holter electrocardiograms of 17 patients did not show supraventricular arrhythmias exceeding 3% of the total beats. None of the patients needed pacemaker implantation. The PR intervals of 5 patients with normal sinus rhythms in the control group did not show significant changes perioperatively.

CONCLUSIONS

The superior septal approach is excellent for mitral valve operations because it overcomes postoperative dysrhythmias.

Chronic administration of docosahexaenoic acid improves reference memory-related learning ability in young rats

Wistar rats were fed a fish oil-deficient diet through three generations. The young (five-week-old) male rats of the third generation were randomly divided into two groups. Over 10 weeks, one group was perorally administered docosahexaenoic acid dissolved in 5% gum Arabic solution at 300 mg/kg/day; the other group received a similar volume of vehicle alone. Five weeks after starting the administration, the rats were tested for learning ability related to two types of memory, reference memory and working memory, with the partially (four of eight) baited eight-arm radial maze. Reference memory is information that should be retained until the next trial. Working memory is information that disappears in a short time. Entries into unbaited arms and repeated entries into visited arms were defined as reference memory errors and working memory errors, respectively. Docosahexaenoic acid administration over 10 weeks significantly reduced the number of reference memory errors, without affecting the number of working memory errors, and significantly increased the docosahexaenoic acid content and the docosahexaenoic acid/arachidonic acid ratio in both the hippocampus and the cerebral cortex. In addition, the ratio demonstrated a significantly negative correlation with the number of reference memory errors. These results suggest that chronic administration of docosahexaenoic acid is conducive to the improvement of reference memory-related learning ability, and that the docosahexaenoic acid/arachidonic acid ratio in the hippocampus or the cerebral cortex, or both, may be an indicator of learning ability.