[Clinical results of left ventricular free wall rupture following acute myocardial infarction]

We studied 19 cases of Left Ventricular Free Wall Rupture (LVFWR) following acute myocardial infarction, admitted to our CCU between 1987 and 1996. We were able to treat 15 patients and diagnosed 4 cases as LVFWR at postmortem after sudden deaths. Of the treated 15 patients, 11 survived: 1 out of 2 repaired under cardiopulmonary bypass (CPB), 5 out of 7 repaired without CPB, and 5 out of 6 non-surgically treated. Although the survival rate for those able to be treated was 73%, overall rate was 58%. There were 7 cases of blow-out type: 4 of which were sudden deaths, and 3 were operated. Thoracotomy and direct closure of rupture without CPB was done at bed-side in 2 cases. Even though hemostasis was successful, they did not survive. The 3rd case survived with the patch closure under CPB. In this case, the circulation was maintained pre-operatively with the pericardial-central venous bypass drainage method. This method seems to be extremely effective in saving blow-out cases. There were 12 subacute patients. Although 2 cases were lost, total of 10 patients were saved, including 2 direct suture closures of rupture without CPB, 3 median sternotomy and fibrin-glue fixations, 1 where only pericardial drainage was done, and 4 in whom percutaneous intrapericardial fibrin-glue fixation therapy was utilized. Since the risk of secondary damage to the fragile infarcted are from direct suturing of ruptured myocardium exists in LVFWR, we changed to the Infarction Exclusion Technique under CPB during surgical repair, based on our experiences with ruptured intraventricular septum. In general, the only treatment believed to be available for LVFWR has been surgical. However, our experiences suggest that other treatments may also be effective. If the best suitable method could be chosen from various therapies, it may contribute to improving outcome statistics. The reduction of left ventricular pressure in the treatment is extremely important, being the key to improving survival rate.

Radial artery diameter decreases with increased femoral to radial arterial pressure gradient during cardiopulmonary bypass

A clinically significant femoral to radial artery pressure gradient sometimes develops during cardiopulmonary bypass (CPB), but the mechanism responsible is not clear. We investigated when the pressure gradient developed and what mechanism could be responsible by comparing mean femoral to mean radial artery pressure and radial artery diameter in 75 male patients undergoing coronary artery bypass grafting. A pressure gradient > or =5 mm Hg (High-P) occurred in 38 patients, and the remaining 37 patients had pressure gradients <5 mm Hg (Low-P) at sternal closure. In High-P group, the pressure gradient was significantly greater (4.8 +/- 3.1 vs 1.0 +/- 3.1 mm Hg; P < 0.001) than in Low-P group, and the ratio of radial artery diameter to the diameter after induction of anesthesia was significantly decreased (0.79 +/- 0.12 vs 0.87 +/- 0.14; P = 0.006) at 5 min after aortic clamping. The pressure gradient and the arterial diameter changes persisted until sternal closure. There was a negative linear correlation between the pressure gradient (deltaP) and the radial artery diameter ratio (D) at sternal closure (D = -15.0deltaP + 16.6, r = 0.39, P < 0.001). In a subgroup of 11 High-P patients, palm temperature was significantly lower (P < 0.05) than that of 11 Low-P patients during and after CPB. We conclude that the femoral to radial artery pressure gradient develops by 5 min after aortic clamping during CPB and persists until sternal closure, and that radial artery constriction could be responsible for the pressure gradient.

IMPLICATIONS

A femoral to radial pressure gradient has been observed after cardiopulmonary bypass. Arterial vasodilation and vasoconstriction have been considered as causes for this gradient. We measured radial artery diameter using pulsed Doppler ultrasound and examined radial artery vasodilation versus vasoconstriction as possible mechanisms for the pressure gradient.

Serum insulin and lipoprotein(a) concentrations. The Jichi Medical School Cohort Study

OBJECTIVE

To examine the relationship between serum insulin and lipoprotein (a) [Lp(a)] concentrations in both sexes in a large population.

RESEARCH DESIGN AND METHODS

The authors conducted a cross-sectional investigation of fasting serum concentrations of insulin and Lp(a), other blood tests, blood pressures, anthropological measurements, physical activity index, smoking habit, alcohol consumption, and menopause. The subjects were 1,121 men and 1,480 women, ranging between 30 and 90 years of age, who were voluntary participants in the Jichi Medical Cohort Study and who resided in one of five rural communities in Japan.

RESULTS

In men, insulin, age, BMI, LDL cholesterol, triglycerides, glucose, and fibrinogen were significantly correlated with Lp(a). In women, insulin, age, LDL cholesterol, fibrinogen, and activated coagulation factor VII were significantly correlated with Lp(a). However, all correlations were weak in either sex. Insulin was inversely correlated with Lp(a) in both sexes. However, the coefficients were weak (r = -0.16 in mean and r = -0.06 in women). In the partial correlation analyses, Lp(a) was not significantly associated with insulin in either sex. The result was not influenced by selecting the subjects on the basis of detectable values of insulin and Lp(a) and stratifying them by serum glucose level.

CONCLUSIONS

There was no significant relationship found between serum insulin and Lp(a) concentrations in either sex of the cohort, which indicates that Lp(a) does not play a role in the increased risk of cardiovascular disease in hyperinsulinemic subjects.

Unsuccessful CTL transfusion in a case of post-BMT Epstein-Barr virus-associated lymphoproliferative disorder (EBV-LPD)

A patient with AML (FAB M4Eo) developed EBV-LPD 1.5 months after allogeneic BMT from his one locus-mismatched mother, the diagnosis being confirmed on day +82. Attempts to eradicate the monoclonally proliferating LPD using chemotherapy (VP16/dexamethasone) followed by two doses of EBV-specific CTL and one dose of unstimulated donor leukocytes were not successful. We assume delay of infusions (day +100, +107) and insufficient CTL cell doses (total 9.2 x 10(6)) may have been responsible for the poor outcome in this case.

Immunoglobulin class switch from IgA1 to IgG2 and simultaneous association with Bence Jones proteinuria in the escape phase in a myeloma patient treated with interferon alpha

Immunoglobulin (Ig) class switch from alpha1 to gamma2 associated with kappa-type Bence Jones proteinuria was evident in the escape phase of an IgA1 myeloma patient treated with interferon alpha (IFN alpha). The additional M-protein, IgG2-kappa, level rapidly increased and was associated with Bence Jones proteinuria, whereas monoclonal IgA1-kappa progressively declined. The N-terminal 21 amino acid sequences of the kappa-chains of monoclonal IgA1, IgG2 and the Bence Jones protein were the same. The N-terminal 15 amino acid sequence of the gamma2-chain was identical to that of the alpha1-chain. Based on these findings, the IgA1 myeloma cells underwent a class switch in CH gene expression from alpha1 to gamma2 with cell differentiation in vivo. The mechanism of the Ig class switching is discussed from three points of view: (1) Increase in immature and plasmablastic myeloma cells in the escape phase is susceptible to Ig class switching by the T-cell-derived cytokines. (2) We presumed that administered IFN alpha increased the amounts of secreted IFN gamma from the Th1 cells. (3) Due to a large quantity of IFN gamma, an inducer of Cgamma2 germline transcript, Ig class switching occurred stepwise from the alpha1 constant region gene to the next 3'CH gamma2 gene.

[Usefulness of directional coronary atherectomy as a bail-out device for acute closure after coronary angioplasty]

The usefulness of directional coronary atherectomy (DCA) as a bail-out device for acute closure (reclosure) after percutaneous transluminal coronary angioplasty (PTCA) was evaluated. PTCA was performed in 1,023 patients (182 with acute myocardial infarction) between January 1993 and January 1994 in our hospital. Thirty-one patients (11 with acute myocardial infarction) suffered acute closure (reclosure) after PTCA. In six patients (five with acute myocardial infarction), DCA was performed as a rescue treatment for acute closure (reclosure). In three of these patients, angioscopy was performed before DCA, which demonstrated intimal tear and some thrombi although coronary angiography showed no evidence of thrombus. Bail-out DCA was successful in all six patients without complications. DCA is useful as a bail-out device for acute closure (reclosure) after PTCA when the thrombus is not massive.

Use of head-up tilt testing to determine a possible cause of unexpected cardiac asystole during epidural anesthesia

Head-up tilt testing is widely used in the diagnosis of syncope of unknown origin. In this report, head-up tilt testing elucidated the etiology of cardiac asystole of unexpected and sudden onset during orthopedic surgery under epidural anesthesia in a 30-year-old woman. Conventional diagnostic approaches were ineffective. Venous pooling in the lower legs as a result of vasodilation and subsequent vagotony due to epidural anesthesia, a condition mimicking orthostatic stress, is proposed as the mechanism of asystole. Follow-up examinations over 16 months revealed no further syncope and a good clinical course. Head-up tilt testing was useful in determining etiology in this case.

Xenon provides faster emergence from anesthesia than does nitrous oxide-sevoflurane or nitrous oxide-isoflurane

BACKGROUND

Xenon, an inert gas with anesthetic properties (minimum alveolar concentration [MAC] = 71%), has an extremely low blood:gas partition coefficient (0.14). Therefore, we predicted that xenon would provide more rapid emergence from anesthesia than does N2O+isoflurane or N2O+sevoflurane of equivalent MAC.

METHODS

Thirty American Society of Anesthsiologists class I or II patients undergoing total abdominal hysterectomy were randomly assigned to receive 60% xenon, 60% N2O + 0.5% isoflurane, or 60% N2O + 0.70% sevoflurane (all concentrations are end-tidal: n = 10 per group). After placement of an epidural catheter, anesthesia was induced with standardized doses of midazolam, thiopental, and fentanyl. Thirty minutes later, xenon, N2O+isoflurane, or N2O+sevoflurane was started as previously assigned. These regimens were supplemented with epidural anesthesia with mepivacaine so that the mean arterial pressure and heart rate were controlled within 20% of the preoperative values. At the end of operation lasting approximately 2 h, all inhalational anesthetics were discontinued, and the patients were allowed to awaken while breathing spontaneously on an 8 l/min inflow of oxygen. A blinded investigator recorded the time until the patient opened her eyes on command (T1), was judged ready for extubation (T2), could correctly state her name, her date of birth, and the name of the hospital (T3), and could count backward from 10 to 1 in less than 15 s (T4).

RESULTS

Emergence times from xenon anesthesia were: T1, 3.4 +/- 0.9 min; T2, 3.6 +/- 1 min; T3, 5.2 +/- 1.4 min; and T4, 6.0 +/- 1.6 min (mean +/- SD). These were one half to one third of those from N2O+sevoflurane (T1, 6.0 +/- 1.7 min; T4, 10.5 +/- 2.5 min) or N2O+isoflurane (T1, 7.0 +/- 1.9 min; T4, 14.3 +/- 2.8 min) anesthesia. The three groups did not differ in terms of patient demographics, the duration of anesthesia, the amount of epidural mepivacaine administered, or the postoperative pain rating. No patient could recalls intraoperative events.

CONCLUSIONS

Emergence from xenon anesthesia is two or three times faster than that from equal-MAC N2O+isoflurane or N2O+sevoflurane anesthesia.

Time-resolved fluoroimmunoassay for pituitary adenylate cyclase activating polypeptide 27 (PACAP27) using europium (III) ion chelate labeled streptavidin-biotin complex

Pituitary adenylate cyclase activating polypeptide (PACAP) is a novel peptide hormone and has a variety of biological action. In studies of the physiological behaviour of endogenous PACAP, the determination of PACAP levels in biological materials require a highly sensitive and specific method. Therefore, we developed a sensitive time-resolved fluoroimmunoassay (TR-FIA) for PACAP27 which is the biologically important fragment of PACAP. Accordingly, we developed TR-FIA using a biotinylated PACAP27 (b-PACAP27) as a tracer and europium (III) chelate labeled streptavidin-biotinylated bovine serum albumin complex as a detection of biotin on solid phase. A measurable range of PACAP27 was 7.8-1000 pg m1-1 by the proposed TR-FIA. For measurement of biological samples, the samples were purified to eliminate substances which interfered with the TR-FIA. The mean recovery of PACAP27 using commercially reversed phase column was 74.7% (n = 12). The various tissues, extracts and plasma concentrations of rat could be measured by the proposed TR-FIA.

Factor VII and fibrinogen levels examined by age, sex, and other atherosclerotic risk factors in a Japanese population. The Jichi Medical School Cohort Study

Factor VII coagulant activity (FVIIc) and fibrinogen (Fbg) levels have been investigated as cardiovascular risk factors. We studied these two factors with stratification for age, sex and blood pressure, and the relation with other atherosclerotic risk factors in a Japanese general population. The subjects were 3,139 Japanese (1,315 males and 1,824 females) aged 30 to 89 in 1992 and 1993. A linear increase with age was observed in the levels of Fbg in both men and women, but no differences were observed between men and women in each age group. A linear increase with age was also seen in the levels of FVIIc in women, but the levels of FVIIc in men were significantly higher for the age group 40-49 years than for any other age group. The levels of FVIIc in women were significantly higher than in men at age > or = 60 years. As concerning the effect of alcohol intake status, Fbg had a tendency to decrease with alcohol intake. Fbg and FVIIc levels were associated with an increase in smoking status in men, but no association was seen in women in either Fbg or FVIIc. FVIIc was positively correlated with age, body mass index, total cholesterol, triglycerides and fasting insulin level. Fbg was positively correlated with age, systolic blood pressure, diastolic blood pressure, total cholesterol, LDL-cholesterol and triglycerides in women, but Fbg had few positive correlations with risk factors in men. A comparison with previous Western studies showed that the Fbg levels of our Japanese population were lower than those of the Caucasians studied, but the present FVIIc levels were nearly the same level or slightly higher than theirs. The association of Fbg and FVIIc and with other cardiovascular risk factors in Japanese was similar to those observed in Caucasians.

Chronic extracellular acidosis induces plasmalemmal vacuolar type H+ ATPase activity in osteoclasts

Proton extrusion into an extracellular resorption compartment is an essential component of bone degradation by osteoclasts. Chronic metabolic acidosis is known to induce negative calcium balance and bone loss by stimulating osteoclastic bone resorption, but the underlying mechanism is not known. The present studies were undertaken to evaluate whether chronic acidosis affects proton extrusion mechanisms in osteoclasts cultured on glass coverslips. Acidosis, mimicked experimentally by maintaining the cells at extracellular pH 6.5, rapidly lowered intracellular pH to 6.8. However, after 2 hours, a proportion of cells demonstrated the capacity to restore intracellular pH to near normal levels. To define the mechanism responsible for this recovery, the activity of individual H+ transport pathways was analyzed. We found that chronic acid treatment for up to 6 h did not significantly affect the cellular buffering power or Na+/H+ antiport activity. In contrast, chronic acidosis activated vacuolar H+ pumps in the osteoclasts. Although only approximately 5% of the control cells displayed proton pump activity, about 40% of cells kept at extracellular pH 6. 5 for 4-6 h were able to recover from the acute acid load by means of bafilomycin A1-sensitive proton extrusion. Conversely, the H+-selective conductance recently described in the plasma membrane of osteoclasts was clearly inhibited in the cells exposed to chronic acidosis. Following acid treatment, the activation threshold of the H+ conductance was shifted to more positive potentials, and the current density was significantly reduced. Considered together, these results suggest that induction of plasmalemmal vacuolar type ATPase activity by chronic acidosis, generated either systemically due to metabolic disease or locally at sites of inflammation, is likely to stimulate osteoclastic bone resorption and thus to promote bone loss.

Ten-year follow-up study of conical crown-retained dentures

This study reports the results of a long-term evaluation of conical crown-retained dentures. One hundred fifty-two restorations that had been in place for over 10 years were analyzed. Restorations were divided according to the Kennedy classification. Abutment and periodontal health, occlusion, retention, and frequency of relining and repair were among the factors evaluated. Good prognoses of removable partial dentures were shown in Kennedy Classes I, II, and III arches. However, some of the restorations placed on only a few remaining abutments showed rather unfavorable situations with almost all of the factors evaluated.

Novel histamine H3 receptor antagonists: synthesis and evaluation of formamidine and S-methylisothiourea derivatives

In order to obtain a new, potent and selective histamine H3 receptor antagonists, chemical modifications of thioperamide, a well-known H3 receptor antagonist, were conducted. A new series of compounds has been synthesized by modifying the thiourea and cyclohexyl groups of thioperamide, and tested for H3 affinity by receptor binding assay using plasma membrane from rat cerebral cortex. The thiourea group of thioperamide was found to be replaceable with a basic moiety such as formamidine or S-methylisothiourea. Replacement of the cyclohexyl group in thioperamide by a 1-adamantyl or an exo-2-norbornyl group increased the affinity for H3 receptor. Among the compounds synthesized, N-(1-adamantyl)-N',N'-[3-(4(5)-1H-imidazolyl)pentamethylene] formamidine 3f (AQ0145) showed the highest H3 receptor affinity, having a potent antagonistic activity. This compound was at least 1,000-fold more active towards H3 than towards H1 and H2 receptors.

Priming of anesthesia circuit with xenon for closed circuit anesthesia

Xenon is an inert gas with a practical anesthetic potency (1 MAC = 71%). Because it is very expensive, the use of closed circuit anesthesia technique is ideal for the conduction of xenon anesthesia. Here we describe our methods of starting closed circuit anesthesia without excessive waste of xenon gas. We induce anesthesia with intravenous agents, and after endotracheal intubation, denitrogenate the patient for approximately 30 min with a high flow of oxygen. This is done to minimize accumulation of nitrogen in the anesthesia circuit during the subsequent closed-circuit anesthesia with xenon. Anesthesia is maintained with an inhalational anesthetic during this period. Then, we discontinue the inhalation agent and start xenon. For this transition, we feel it is unacceptable to simply administer xenon at a high flow until the desired end-tidal concentration is reached because it is too costly. Instead we set up another machine with its circuit filled in advance (i.e., primed) with at least 60% xenon in oxygen and switch the patient to this machine. To prime the circuit, we push xenon using a large syringe into a circuit, which was prefilled with oxygen. Oxygen inside the circuit is pushed out before it is mixed with xenon, and xenon waste will thus be minimized. In this way, we can achieve close to 1 MAC from the beginning of xenon anesthesia, and thereby minimize the risk of light anesthesia and awareness during transition from denitrogenation to closed-circuit xenon anesthesia.

Cerebral ischemic disorders and cerebral oxygen balance during cardiopulmonary bypass surgery: preoperative evaluation using magnetic resonance imaging and angiography

We compared the preoperative prevalence of small cerebral infarctions and carotid stenosis to jugular venous oxygen saturation (Sjvo2) during coronary artery bypass grafting (CABG). Sjvo2 served as an indicator of whether cerebral oxygen supply meets demand in patients on cardiopulmonary bypass (CPB). The study population consisted of 121 patients who were either older than 65 yr or had a history of cerebrovascular disease. The patients underwent preoperative cerebral magnetic resonance imaging (MRI) and cervical magnetic resonance angiography (MRA) to detect small cerebral infarctions and carotid artery stenosis. Patients with atherosclerosis of the ascending aorta were identified by intraoperative epiaortic ultrasonography. Liberation of emboli from the aorta in these patients was prevented by modification of the standard operation. From preoperative MRI and MRA, 65 patients (54%) had small cerebral infarctions in the white matter or basal ganglia and nine patients (7%) demonstrated moderate or severe stenosis in the carotid arteries. Thirteen patients (11%) had moderate or severe atheromatous disease of the ascending aorta. The severity of aortic atherosclerosis was significantly correlated with the grade of carotid stenosis (P < 0.05). In patients with small infarctions, Sjvo2 was significantly lower than in patients without infarctions (controls) at initiation of CPB, 30 min after aortic cross-clamping, and during the rewarming period of CPB (P < 0.05). Thus, small cerebral infarctions were not uncommon in elderly patients undergoing CABG. Patients with small cerebral infarctions may be at risk for an imbalance in cerebral oxygen supply and demand during the rewarming period because they are unable to deliver the necessary compensatory blood flow.

Paternal X-chromosome inactivation in human trophoblastic cells

Dosage compensation for X-chromosome-linked genes between male and female mammals occurs by inactivation of one of the two X chromosomes in the female. In somatic cells, either the paternal or the maternal X chromosome is randomly inactivated in a given cell. In contrast, in the extra-embryonic tissues of mice, the paternally-derived X chromosome is preferentially inactivated. The evidence for paternal X-chromosome inactivation in humans is controversial and remains to be clarified. In this study, we have developed a sensitive polymerase chain reaction (PCR) technique to investigate the methylation pattern of the X-linked androgen receptor (AR) gene. The 5' CpG island of this gene is methylated on the inactive X chromosome and hypomethylated on the active X chromosome in somatic cells. The paternal and the maternal alleles of the AR gene may be distinguished by a polymorphism in the number of CAG triplet repeats within the CpG island. As a source of human extra-embryonic tissue, we used chorionic villus (CV) samples from female conceptuses of 10-12 weeks gestation. From a tiny branch of a CV sample, two distinct cell lineages, the trophoblastic and mesodermal lineages, were dissected apart by trypsin digestion and micromanipulation and DNA was extracted separately from these purified tissues. Digestion of the DNA with the methylation-sensitive restriction enzyme, Hpall, followed by PCR amplification revealed that the paternal allele is preferentially methylated in trophoblastic cells, but not in mesodermal cells. These results strongly suggest that the paternal X chromosome is preferentially inactivated in the human extra-embryonic tissues early in development.

Nonconvulsive status epilepticus during antidepressant treatment

We report 3 patients who experienced nonconvulsive status epilepticus following generalized convulsions during antidepressant treatment. All showed prolonged confusion with some psychiatric symptoms, and their electroencephalograms (EEGs) showed either bilateral synchronous multiple spike wave discharges or continuous diffuse sharp and slow waves. When diazepam was administered intravenously to 1 patient, the clinical symptoms and EEG improved markedly.