P3098Association with coronary high-intensity plaque on T1-weighted magnetic resonance imaging and circulating levels of malondialdehyde-modified low-density lipoprotein

Objectives

This study aimed to evaluate the association with coronary high-intensity plaque (HIP) on non-contrast T1-weighted magnetic resonance imaging (T1WI) and circulating levels of malondialdehyde-modified low-density lipoprotein (MDA-LDL).

Methods

A total of 139 patients with coronary artery stenosis (>70%) were imaged with non-contrast T1WI by using a 1.5-T magnetic resonance system (HIP: n=60, non-HIP: n=79). HIP was defined as a signal intensity of coronary plaque to cardiac muscle ratio (PMR) of ≥1.4. At admission, circulating levels of MDA-LDL and other lipid-related markers (triglyceride, HDL, LDL, Lp(a), RLP-C, and EPA/AA) were measured.

Results

Circulating levels of MDA-LDL (p=0.001) and LDL (p=0.041) were significantly higher in patients with HIP than those without, whereas the other lipid-related markers were not significantly different between both groups. In multivariable logistic regression analysis, MDA-LDL levels were independently associated with the presence of HIP (OR 1.03; 95% CI, 1.00–1.06, p=0.015) after adjusting for cofounding factors (age, sex, triglyceride, LDL, Lp(a), RLP-C, and EPA/AA). The optimal MDA-LDL threshold for predicting coronary HIP was 90.4 U/L, identified by the receiver operating characteristic curve.

Conclusion

MDA-LDL levels might be associated with the presence of HIP in patients with coronary artery disease.

Clinical characteristics and outcome of human herpesvirus-6 encephalitis after allogeneic hematopoietic stem cell transplantation

In this retrospective analysis using the Transplant Registry Unified Management Program, we identified 145 patients with human herpesvirus (HHV)-6 encephalitis among 6593 recipients. The cumulative incidences of HHV-6 encephalitis at 100 days after transplantation in all patients, recipients of bone marrow or PBSCs and recipients of cord blood were 2.3%, 1.6% and 5.0%, respectively. Risk factors identified in multivariate analysis were male sex, type of transplanted cells (relative risk in cord blood transplantation, 11.09, P<0.001; relative risk in transplantation from HLA-mismatched unrelated donor, 9.48, P<0.001; vs transplantation from HLA-matched related donor) and GvHD prophylaxis by calcineurin inhibitor alone. At 100 days after transplantation, the overall survival rate was 58.3% and 80.5% among patients with and without HHV-6 encephalitis, respectively (P<0.001). Neuropsychological sequelae remained in 57% of 121 evaluated patients. With both foscarnet and ganciclovir, full-dose therapy (foscarnet ⩾180 mg/kg, ganciclovir ⩾10 mg/kg) was associated with better response rate (foscarnet, 93% vs 74%, P=0.044; ganciclovir, 84% vs 58%, P=0.047). HHV-6 encephalitis is not rare not only in cord blood transplant recipients but also in recipients of HLA-mismatched unrelated donors. In this study, development of HHV-6 encephalitis was associated with a poor survival rate, and neurological sequelae remained in many patients.

Impact of the presence of HLA 1-locus mismatch and the use of low-dose antithymocyte globulin in unrelated bone marrow transplantation

HLA 1-locus-mismatched unrelated donors (1MMUD) have been used in allogeneic hematopoietic stem cell transplantation (allo-HCT) for patients who lack an HLA-matched donor. We retrospectively analyzed 3313 patients with acute leukemia or myelodysplastic syndrome who underwent bone marrow transplantation from an HLA allele-matched unrelated donor (MUD) or 1MMUD between 2009 and 2014. We compared the outcomes of MUD (n=2089) and 1MMUD with antithymocyte globulin (ATG) (1MM-ATG(+); n=109) with those of 1MMUD without ATG (1MM-ATG(-); n=1115). The median total dose of ATG (thymoglobulin) was 2.5 mg/kg (range 1.0-11.0 mg/kg) in the 1MM-ATG(+) group. The rates of grade III-IV acute GvHD, non-relapse mortality (NRM) and overall mortality were significantly lower in the MUD group than in the 1MM-ATG(-) group (hazard ratio (HR) 0.77, P=0.016; HR 0.74; P<0.001; and HR 0.87, P=0.020, respectively). Likewise, the rates of grade III-IV acute GVHD, NRM and overall mortality were significantly lower in the 1MM-ATG(+) group than in the 1MM-ATG(-) group (HR 0.42, P=0.035; HR 0.35, P<0.001; and HR 0.71, P=0.042, respectively). The outcome of allo-HCT from 1MM-ATG(-) was inferior to that of allo-HCT from MUD even in the recent cohort. However, the negative impact of 1MMUD disappeared with the use of low-dose ATG without increasing the risk of relapse.

Low-dose thymoglobulin as second-line treatment for steroid-resistant acute GvHD: an analysis of the JSHCT

A nationwide retrospective study for the clinical outcomes of 99 patients who had received thymoglobulin at a median total dose of 2.5 mg/kg (range, 0.5-18.5 mg/kg) as a second-line treatment for steroid-resistant acute GvHD was conducted. Of the 92 evaluable patients, improvement (complete or partial response) was observed in 55 patients (60%). Multivariate analysis demonstrated that male sex and grade III and IV acute GvHD were associated with a lower improvement rate, whereas thymoglobulin dose (<2.0, 2.0-3.9 and ⩾4.0 mg/kg) was NS. Factors associated with significantly higher nonrelapse mortality included higher patient age (⩾50 years), grade IV acute GvHD, no improvement of GvHD and higher dose of thymoglobulin (hazard ratio, 2.55; 95% confidence interval, 1.34-4.85; P=0.004 for 2.0-3.9 mg/kg group and 1.79; 0.91-3.55; P=0.093 for ⩾4.0 mg/kg group). Higher dose of thymoglobulin was associated with a higher incidence of bacterial infections, CMV antigenemia and any additional infection. Taken together, low-dose thymoglobulin at a median total dose of 2.5 mg/kg provides a comparable response rate to standard-dose thymoglobulin reported previously, and <2.0 mg/kg thymoglobulin is recommended in terms of the balance between efficacy and adverse effects.

Continuous postoperative pain control using a multiple-hole catheter after iliac bone grafting: comparison between ropivacaine and levobupivacaine

The aim of this study was to compare the analgesic effects of ropivacaine and levobupivacaine in continuous infiltration anaesthesia delivered via a multiple-hole catheter for the purpose of postoperative analgesia after iliac bone grafting. Thirty-four patients scheduled for iliac bone grafting in the maxillofacial region participated in this study. The patients were randomized to a ropivacaine group (Ropi group) and a levobupivacaine group (Levo group). After harvesting the iliac bone for grafting, a multiple-hole catheter was placed on the periosteum of the iliac bone. When surgery was completed, continuous administration was started at 4 ml/h of 0.2% ropivacaine (Ropi group) or 0.25% levobupivacaine (Levo group). Pain was evaluated in the recovery room and at 4h after surgery, as well as at 9:00 and 18:00 on postoperative days 1, 2, and 3, using a visual analogue scale. Side effects were also recorded. No significant difference in the visual analogue scale scores at rest or in motion was observed between the two groups. In addition, there were no side effects in the two groups. Both 0.2% ropivacaine and 0.25% levobupivacaine provided comparable analgesic effects in continuous infiltration anaesthesia delivered via a multiple-hole catheter after iliac bone grafting.

Early application of related SCT might improve clinical outcome in adult T-cell leukemia/lymphoma

Allogeneic hematopoietic SCT (allo-HSCT) is a curative treatment for aggressive adult T-cell leukemia/lymphoma (ATLL). Considering the dismal prognosis associated with conventional chemotherapies, early application of allo-HSCT might be beneficial for patients with ATLL. However, no previous study has addressed the optimal timing of allo-HSCT from related donors. Hence, to evaluate the impact of timing of allo-HSCT for patients with ATLL, we retrospectively analyzed data from patients with ATLL who received an allo-HSCT from a related donor. The median age was 52 years. Patients were grouped according to the interval from diagnosis to allo-HSCT: early transplant group, <100 days, n=72; late transplant group, ⩾100 days, n=428. The corresponding constituents of disease status were not statistically different between the two groups (P=0.11). The probability of OS in the early transplant group was significantly higher than that in the late transplant group (4-year OS, 49.3% vs 31.2%). Multivariate analysis revealed that late allo-HSCT was an unfavorable prognostic factor for OS (hazard ratio, 1.46; 95% confidence interval (CI), 1.01-2.11; P=0.04). Despite the limitations of a retrospective study, it might be acceptable to consider early application of allo-HSCT for ATLL.

Impact of HLA allele mismatch on the clinical outcome in serologically matched related hematopoietic SCT

In unrelated hematopoietic SCT (HSCT), HLA allele mismatch has been shown to have a significant role. To clarify the importance of HLA allele mismatch in the GVH direction in related HSCT, we retrospectively evaluated 2377 patients who received stem cells from an HLA serologically matched related donor in the GVH direction using the database of the Japan Society for Hematopoietic Cell Transplantation. The cumulative incidences of grade II-IV and grade III-IV acute GVHD in patients with an HLA allele-mismatched donor (n=133, 5.6%) were significantly higher than those in patients with an HLA allele-matched donor. Multivariate analyses showed that the presence of HLA allele mismatch was associated with increased risks of grade II-IV and grade III-IV acute GVHD. In particular, HLA-B mismatch and multiple allele mismatches were associated with an increased risk of acute GVHD. The presence of HLA allele mismatch was associated with an inferior OS owing to an increased risk of non-relapse mortality (NRM). In conclusion, the presence of HLA allele mismatch in the GVH direction in related HSCT was associated with increased risks of GVHD and NRM, which led to an inferior OS. HLA allele typing is recommended in related HSCT.

The combined effects of midazolam and propofol sedation on muscle power

We performed a randomised, crossover study to investigate the effects of intravenous sedation on grip strength and bite force. Twenty male volunteers received a bolus intravenous injection of midazolam (0.02 mg.kg(-1)) together with a 30-min propofol infusion designed to achieve an effect-site concentration of 1.0 μg.ml(-1). Observed variables included bispectral index, observer's assessment of alertness/sedation, correct answer rate of Stroop colour-word test, grip strength and bite force. Grip strength decreased from a median (IQR [range]) of 483 (443-517 [380-586]) N to 358 (280-405 [108-580]) N (p < 0.001) during sedation and recovered following flumazenil administration, while bite force increased from 818 (593-1026 [405-1406]) N to 1377 (1243-1585 [836-2357]) N (p < 0.001) during sedation. Although bite force gradually returned to baseline following flumazenil administration, it remained increased throughout the experimental period. We conclude that bite force increased during intravenous sedation and that this may have clinical implications.

Pretransplant serum ferritin and C-reactive protein as predictive factors for early bacterial infection after allogeneic hematopoietic cell transplantation

Although fluoroquinolones or other antibiotics are commonly used to prevent bacterial infections after hematopoietic cell transplantation (HCT), because of the growing presence of multidrug-resistant microorganisms, it is important to identify patients who are more likely to benefit from antibacterial prophylaxis. To evaluate risk factors for early bacterial infection after allogeneic HCT, we retrospectively analyzed clinical data for 112 consecutive adult patients with hematological malignancies who received transplants without any antibacterial prophylaxis. The cumulative incidence of bacterial infection at 30 days after transplantation was 16%. Among various pre-transplant factors, only high serum ferritin (>700 ng/mL, 47 patients) and high C-reactive protein (CRP) (>0.3 mg/dL, 28 patients) levels were significantly associated with the development of bacterial infection in a multivariate analysis (hazard ratio (95% confidence interval): ferritin, 4.00 (1.32-12.17); CRP, 3.64 (1.44-9.20)). In addition, septic shock and sepsis with organ failure were exclusively observed in patients who had high ferritin and/or high CRP levels. These results suggest that pretransplant serum ferritin and CRP levels can be useful markers for predicting the risk of early bacterial infection after allogeneic HCT. It may be prudent to limit antibacterial prophylaxis to patients with predefined risk factors to ensure the safety of HCT with the use of fewer antibiotics.

Effects on spectrum and susceptibility patterns of isolates causing bloodstream infection by restriction of fluoroquinolone prophylaxis in a hematology-oncology unit

The emergence of fluoroquinolone-resistant gram-negative organisms has been demonstrated in patients given fluoroquinolone prophylaxis. To prevent increases in resistant bacteria, we restricted prophylactic use of fluoroquinolones. The spectrum and susceptibility patterns of isolates causing bloodstream infection (BSI) were assessed in patients receiving chemotherapy during periods of routine prophylaxis (period A: October 2001 to May 2003) and restricted prophylaxis (period B: June 2003 to January 2005). The total number of patients receiving chemotherapy was 442 during period A and 365 during period B. No significant differences were seen between periods with respect to patient characteristics. BSI was identified in 42 patients (44 episodes) during period A and 69 patients (74 episodes) during period B. Incidence of BSI increased significantly from 10.0% (44/442) during period A to 20.3% (74/365) during period B (P < 0.0001). Rate of Enterobacteriaceae BSI increased significantly, from 2.0% (9/442) during period A to 8.2% (30/365) during period B (P < 0.0001). For all BSI episodes, the proportion of BSI with gram-positive cocci decreased from 63.6% (28/44) during period A to 44.6% (33/74) during period B (P = 0.045), while the proportion of BSI with Enterobacteriaceae increased from 20.5% (9/44) to 40.5% (30/74) (P < 0.0001). The proportion of fluoroquinolone-resistant Enterobacteriaceae BSI for all Enterobacteriaceae BSI decreased from 75% (9/12) during period A to 17% (5/30) during period B (P = 0.0078). Restriction of fluoroquinolone prophylaxis affects the etiology of BSI and reduces the proportion of drug-resistant organisms.

Cortical representation area of human dental pulp

To elucidate the dental pulp-representing area in the human primary somatosensory cortex and the presence of A-beta fibers in dental pulp, we recorded somatosensory-evoked magnetic fields from the cortex in seven healthy persons using magnetoencephalography. Following non-painful electrical stimulation of the right maxillary first premolar dental pulp, short latency (27 ms) cortical responses on the magnetic waveforms were observed. However, no response was seen when stimulation was applied to pulpless teeth, such as devitalized teeth. The current source generating the early component of the magnetic fields was located anterior-inferiorly compared with the locations for the hand area in the primary somatosensory cortex. These results demonstrate the dental pulp representation area in the primary somatosensory cortex, and that it receives input from intradental A-beta neurons, providing a detailed organizational map of the orofacial area, by adding dental pulp to the classic "sensory homunculus".

Mechanism of NKT cell activation by intranasal coadministration of alpha-galactosylceramide, which can induce cross-protection against influenza viruses

In a nasal vaccine against influenza, the activation of natural killer T (NKT) cells by intranasal coadministration of alpha-galactosylceramide (alpha-GalCer) can potently enhance protective immune responses. The results of this study show that the NKT cell-activated nasal vaccine can induce an effective cross-protection against different strains of influenza virus, including H5 type. To analyze the mechanism of NKT cell activation by this nasal vaccine, we prepared fluorescence-labeled alpha-GalCer by which we detect a direct interaction between NKT cells and alpha-GalCer-stored dendritic cells in nasal mucosa-associated tissues. Accordingly, although very few NKT cells exist at mucosa, the nasal vaccination induced a localized increase in NKT cell population, which is partly dependent on CXCL16/CXCR6. Furthermore, we found that NKT cell activation stimulates mucosal IgA production by a mechanism that is dependent on interleukin (IL)-4 production. These results strengthen the basis of nasal vaccination via NKT cell activation, which can induce immune cross-protection.

Amnesia for electric dental pulp stimulation and picture recall test under different levels of propofol or midazolam sedation

AIM

To compare the amnesic effect of propofol and midazolam to electric dental pulp stimulation (invasive) and picture recall test (non-invasive) at two sedation levels with the aid of bispectral index (BIS) monitoring.

METHODS

The subjects were 10 male volunteers (24-34 years) classified as ASA physical status I. Propofol was administered to achieve a sedation score of three with a target-controlled infusion technique; it was then regulated to give a sedation score of two (P group). Midazolam was administered by a titration dosage to achieve a sedation score of three (M group). It then gradually decreased to give a sedation score of two. The BIS score, sedation score, plasma/serum concentration of propofol and midazolam, blood pressure, pulse rate, respiratory rate, end-tidal CO(2) tension and arterial oxygen saturation were observed at each sedation level in both groups. Amnesic effects were evaluated using a picture recall test and electric dental pulp stimulation.

RESULT

No difference was observed in the amnesic effect evaluated by picture recall test at the two sedation levels. Likewise, there was no difference at a sedation score of three when the amnesic effect was evaluated by electric dental pulp stimulation. In contrast, a significant difference was observed at a sedation score of two; midazolam produced amnesia in more subjects than did propofol.

CONCLUSION

Propofol and midazolam did not show any significant difference in amnesic effects to non-invasive stimuli. For invasive stimuli, midazolam showed a stronger amnesic effect at the moderate sedation level, but not at the deeper sedation level.

Comparison between reduced intensity and conventional myeloablative allogeneic stem-cell transplantation in patients with hematologic malignancies aged between 50 and 59 years

To evaluate the efficacy of reduced-intensity stem-cell transplantation (RIST), we retrospectively compared outcomes of 207 consecutive Japanese patients aged between 50 and 59 years with hematologic malignancies who received RIST (n=70) and conventional stem-cell transplantation (CST) (n=137). CST recipients received total body irradiation (TBI)-based or busulfan/cyclophosphamide-based regimens. RIST regimens were purine analog-based (n=67), 2 Gy TBI-based (n=2), and others (n=1). Most CST recipients (129/137) received calcineurin inhibitors and methotrexate as graft-versus-host (GVHD) prophylaxis, while 32 RIST recipients received cyclosporin. In all, 23 CST and five RIST recipients died without disease progression within 100 days of transplant. Grade II to IV acute GVHD occurred in 56 CST and 38 RIST recipients. There was no significant difference in overall survival (OS) and progression-free survival between CST and RIST. On multivariate analysis on OS, five variables were significant: preparative regimens (CST vs RIST) (hazard ratio=1.92, 95% confidence interval, 1.25-2.97; P=0.003), performance status (2-4 vs 0-1) (2.50, 1.51-4.16; P<0.001), risk of underlying diseases (1.85, 1.21-2.83; P=0.004), acute GVHD (2.57, 1.72-3.84; P<0.001), and CML (0.38, 0.21-0.69; P=0.002). We should be careful in interpreting results of this small-sized retrospective study; however, reduced regimen-related toxicity might contribute to better survival in RIST. The low relapse rates following RIST suggest a strong antitumor activity through allogeneic immunity.

Compromised recovery of natural interferon-alpha/beta-producing cells after allogeneic hematopoietic stem cell transplantation complicated by acute graft-versus-host disease and glucocorticoid administration

Delayed recovery of the immune system is a major cause of post-transplant infection. Natural interferon (IFN)-alpha/beta-producing cells (IPC) appear to play a critical role in inducing effective immune responses to a variety of microbial pathogens by producing an enormous amount of IFN-alpha/beta and thereafter by differentiating into dendritic cells. Here, we examined the recovery of IPC as well as other immune cells in 28 patients after allogeneic hematopoietic stem cell transplantation (HSCT) in order to investigate the role of IPC in post-transplant immune reconstitution. In uncomplicated cases, IPC frequency recovered to the lower range of normal values within 30 days after transplantation, resembling the prompt recovery of other cell types in innate immunity. In contrast, the recovery of IPC was profoundly suppressed in the cases with acute graft-versus-host disease (GVHD) and glucocorticoid administration. The patients with lower numbers of IPC were significantly more susceptible to viral infection. The prompt recovery of IPC in uncomplicated cases may contribute to establishing a first line of host defense at the early stage after allogeneic HSCT, whereas the marked suppression of IPC recovery accompanying acute GVHD and glucocorticoid administration may increase the risk of opportunistic infections.

Successful T-cell-replete peripheral blood stem cell transplantation from HLA-haploidentical microchimeric mother to daughter with refractory acute lymphoblastic leukemia using reduced-intensity conditioning

A 16-year-old girl with refractory acute lymphoblastic leukemia underwent reduced-intensity hematopoietic stem cell transplantation from her two-locus-mismatched haploidentical mother, who was microchimeric for the patient's hematopoietic cells. The conditioning regimen comprised melphalan, fludarabine, and low-dose total body irradiation. Non-T-cell-depleted peripheral blood stem cells were infused with graft-versus-host disease (GVHD) prophylaxis consisting of tacrolimus, prednisolone, and short-course methotrexate. Complete donor-type engraftment without evidence of residual leukemia was confirmed on day 22. Severe GVHD was not observed despite rapid cessation of immunosuppression. The patient remains well in continuous remission 15 months after transplant. This successful experience suggests that maternal hematopoietic stem cell transplants for children, in the presence of microchimerism, may be associated with hyporesponsiveness to the inherited paternal HLA antigens (IPA); preventing severe GVHD.

Correlation of peripheral blood OX40+(CD134+) T cells with chronic graft-versus-host disease in patients who underwent allogeneic hematopoietic stem cell transplantation

There is no reliable laboratory indicator of the onset of chronic graft-versus-host disease (cGVHD). This study looks at whether the expression of OX40, a member of the tumor necrosis factor receptor family, is related to the development of cGVHD in patients who underwent allogeneic hematopoietic stem cell transplantation. Peripheral blood mononuclear cells from 22 patients after day 100 were subjected to multicolor flow cytometry. The percentages of both OX40+CD4+ and OX40+CD8+ T cells were significantly higher in patients with cGVHD than those without (P <.0001 and P =.001, respectively). Serial analyses showed that OX40+CD4+ T cells elevated before the onset of cGVHD and closely correlated with the therapeutic response. The expression of CD25, CD69, and HLA-DR was partially detectable on OX40+ T cells. These results indicate that serial measurement of OX40+ T cells is useful for predicting the onset as well as the therapeutic response of cGVHD and raise a possibility that the OX40/gp34 system is involved in the pathogenesis of cGVHD.

Analysis of gene expression of lymphocytes in microgravity

It has been reported that lymphocyte function decreases under microgravity. Though molecular mechanism of the immunosuppression in microgravity still remains enigmatic, it is suggested that gene expression of lymphocytes may be altered in microgravity. In this study we developed automatic flash-freezing equipment which can be utilized for exposing lymphocytes to microgravity by drop shaft experiments in Japan Microgravity Center (JAMIC). Gene expression profiles were analyzed by using DNA array in ground control lymphocytes and microgravity-exposed lymphocytes.

Superior survival of blood and marrow stem cell recipients given maternal grafts over recipients given paternal grafts

During the reproductive period, mothers and offspring exchange hematopoietic cells and develop a form of immunological tolerance bidirectionally. To examine whether previous experience of such communication has any remote effect when maternal hematopoietic cells are later transplanted to the children, we retrospectively compared the outcomes of blood and marrow stem cell transplantation from maternal donors (n = 46) to those from paternal donors (n = 50) by using the database of the Japanese nationwide surveys for adult hematopoietic cell transplants between 1990 and 1998. At 5 years, recipients of maternal hematopoietic cells had a significantly higher overall survival than patients receiving paternal grafts (60% vs 32%, P = 0.006). Although no significant difference was observed in the occurrence of severe acute GVHD (grade > or =III) and the relapse of malignant diseases between two groups, the probability of non-relapse treatment-related mortality was significantly lower after maternal donor transplants. Furthermore, multivariate analysis revealed that parental donor type was the only factor significantly associated with overall survival. In conclusion, our analysis indicates superior survival of maternally donated recipients in hematopoietic stem-cell transplantations from biological parents. This finding has important implications in the selection of alternative familial donors, and warrants further prospective analysis of parental donor transplantations.

The cell surface-expressed HSC70-like molecule preferentially reacts with the rat T-cell receptor Vdelta6 family

We previously showed that the cell surface-expressed Mr 70,000 heat shock cognate (hsc70, a constitutively expressed member of the hsp70 family) protein-like molecule (#067 molecule) interacts with rat CD3+, CD4-, CD8-, T-cell receptor (TCR)alphabeta-, natural killer recetor-P1- T cells. This 70hsc-like molecule was also suggested to present cellular peptide antigens to these T cells. In the present study, we identified the genetic structure of the TCR by establishing T-cell hybridomas between these T cells and mouse BW5147 cells. Our data indicated that these T cells preferentially used TCRs with the Vdelta6 family. Analysis of the nucleotide sequence of the CDR3 junctional portion showed that there are substantial diversities, with insertion of seven to nine amino acid residues. These data provide indirect evidences for our hypothesis that an hsc70-like molecule could be presented together with cellular peptide antigens to particular T cells with TCR gammadelta chains. Since the expression of this hsc70-like #067 antigen on the cell surface is usually induced along with cell transformation by activated oncogenes, T cells with the TCR Vdelta6 family are likely to contribute to host resistance to tumor cells.

Comparative study on anesthetic potency depending on concentrations of lidocaine and epinephrine: assessment of dental local anesthetics using the jaw-opening reflex

Anesthetic potency of a local anesthetic on the dental pulp was investigated by increasing or decreasing the concentration of lidocaine and that of epinephrine. An electromyogram of the digastric muscle in Japan White male rabbits was recorded during the jaw-opening reflex induced by electrical stimulation of the dental pulp. Probit analysis was used for the determination of the 50% effective volume (ED50) values of the anesthetic. The anesthetics used were plain 2% lidocaine solution (2Lid-0 group), 2% lidocaine solution with 12.5 microgram/mL of epinephrine (2Lid-1/8 group), 2% lidocaine solution with 6.25 microgram/mL of epinephrine (2Lid-1/16 group), and 4% lidocaine solution with 5 microgram/mL of epinephrine (4Lid-1/20 group). No anesthetic effect was shown in the 2Lid-0 group. The 2Lid-1/8 group indicated adequate anesthetic potency with the smallest dosage at all observation periods. The potency in the 2Lid-1/16 group was 0.3-0.5 times, and that in the 4Lid-1/20 group was 0.3-0.4 times as much as the 2Lid-1/8 group. The decrease in epinephrine concentration produced the decrease in the anesthetic potency on the dental pulp independent of lidocaine concentration. These results suggest that the increase in lidocaine concentration may not compensate the decrease in epinephrine concentration.

Adenosine and amrinone reverse felypressin-induced depression of myocardial tissue oxygen tension in dogs

PURPOSE

To determine whether continuous infusion of adenosine triphosphate (ATP), nitroglycerin (NTG) or amrinone (AM) would ameliorate the reductions in coronary blood flow (CBF) and myocardial oxygen tension (PmO2) induced by felypressin.

METHODS

Seven open-chest dogs were studied under urethane and alpha-chloralose anesthesia. Hemodynamic variables including heart rate (HR), systolic blood pressure, diastolic blood pressure (DBP), mean pulmonary artery pressure, pulmonary capillary wedge pressure, CBF (ultrasound flowmetry), PmO2(polarography) and cardiac output (thermodilution method) were recorded. Felypressin was infused in a loading dose of 6 mIU x kg(-1) for five minutes and then continued at 0.2 mIU x kg(-1) x min(-1). After 30 min felypressin infusion, each agent was administered for 15 min to evaluate hemodynamic changes. Infusions were 100 and 200 microg x kg(-1) x min(-1) for ATP, 2.5 and 5 microg x kg(-1) x min(-1) for NTG, and 10 and 20 microg x kg(-1) x min(-1) for AM.

RESULTS

After felypressin DBP increased by 17 +/- 5 (mean +/- SD) %; CBF decreased by 49 +/- 9%; CI decreased by 40 +/- 13%; HR decreased by 29 +/- 11%; PmO2 in the inner layer decreased by 21 +/- 7%. The Cl and CBF returned to baseline afterATP 100 and 200 microg x kg(-1) x min(-1), AM 10 and 20 microg x kg(-1) x min(-1), but not after NTG. The PmO2 in the inner layer returned to the baseline value by any infusion except for NTG 5 microg x kg(-1) min(-1)

CONCLUSION

Adenosine and amrinone, but not nitroglycerin reverses the adverse cardiovascular effects of felypressin.

Interaction of nitrous oxide and propofol to reduce hypertensive response to stimulation

PURPOSE

To evaluate the interaction between nitrous oxide and propofol for the suppression of hypertension following electrical stimulation of the mental nerve in the rabbit.

METHODS

Male Japan White rabbits were tracheostomized, cannulated and mechanically ventilated under isoflurane anesthesia. Square wave pulses (5 V, 0.5 msec, 50 Hz for 5 sec) were delivered to the left mental nerve. Animals received nitrous oxide 20, 40, 60 and 80% (Group 1); propofol 200, 400, 600 and 800 microg x kg(-1) min(-1) (Group 2); or combinations of nitrous oxide and propofol at 10 + 100, 20 + 200, 30 + 300 and 40 % + 400 microg x kg(-1) x min(-1) (Group 3). Systolic blood pressure was recorded from immediately before to maximal increase following nerve stimulation. Probit analysis was used to obtain ED(50) values for 50% suppression of blood pressure elevation. Isobolographic analysis was used to evaluate the interaction between nitrous oxide and propofol.

RESULTS

ED(50) values are 52.9% for nitrous oxide (Group 1), 464.1 microg x kg(-1) min(-1) for propofol (Group 2), 21.7 % + 217.1 microg x kg(-1) min(-1) for nitrous oxide and propofol combination (Group 3) and 24. 7 % + 247.1 microg x kg(-1) x min(-1) for the theoretically additive combination of nitrous oxide and propofol, respectively.

CONCLUSION

The interaction between nitrous oxide and propofol for the suppression of blood pressure elevation following electrical stimulation of the mental nerve is additive.