Anti-PD-1 antibody monotherapy versus anti-PD-1 plus anti-CTLA-4 combination therapy as first-line immunotherapy in unresectable or metastatic mucosal melanoma: a retrospective, multicenter study of 329 Japanese cases (JMAC study)

Background

Anti-programmed cell death protein 1 (PD-1) antibody monotherapy (PD1) has led to favorable responses in advanced non-acral cutaneous melanoma among Caucasian populations; however, recent studies suggest that this therapy has limited efficacy in mucosal melanoma (MCM). Thus, advanced MCM patients are candidates for PD1 plus anti-cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) combination therapy (PD1 + CTLA4). Data on the efficacy of immunotherapy in MCM, however, are limited. We aimed to compare the efficacies of PD1 and PD1 + CTLA4 in Japanese advanced MCM patients.

Patients and methods

We retrospectively assessed advanced MCM patients treated with PD1 or PD1 + CTLA4 at 24 Japanese institutions. Patient baseline characteristics, clinical responses (RECIST), progression-free survival (PFS), and overall survival (OS) were estimated using Kaplan–Meier analysis, and toxicity was assessed to estimate the efficacy and safety of PD1 and PD1 + CTLA4.

Results

Altogether, 329 patients with advanced MCM were included in this study. PD1 and PD1 + CTLA4 were used in 263 and 66 patients, respectively. Baseline characteristics were similar between both treatment groups, except for age (median age 71 versus 65 years; P < 0.001). No significant differences were observed between the PD1 and PD1 + CTLA4 groups with respect to objective response rate (26% versus 29%; P = 0.26) or PFS and OS (median PFS 5.9 months versus 6.8 months; P = 0.55, median OS 20.4 months versus 20.1 months; P = 0.55). Cox multivariate survival analysis revealed that PD1 + CTLA4 did not prolong PFS and OS (PFS: hazard ratio 0.83, 95% confidence interval 0.58-1.19, P = 0.30; OS: HR 0.89, 95% confidence interval 0.57-1.38, P = 0.59). The rate of ≥grade 3 immune-related adverse events was higher in the PD1 + CTLA4 group than in the PD1 group (53% versus 17%; P < 0.001).

Conclusions

First-line PD1 + CTLA4 demonstrated comparable clinical efficacy to PD1 in Japanese MCM patients, but with a higher rate of immune-related adverse events.

•

Anti-PD-1 plus anti-CTLA-4 antibody therapy (PD1 + CTLA4) is an option for patients with advanced mucosal melanoma (MCM).

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Data on the efficacy of PD1 + CTLA4 compared with PD-1 monotherapy (PD1) for MCM, however, are limited.

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We retrospectively analyzed data from 329 Japanese patients with advanced MCM treated with PD1 or PD1 + CTLA4.

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No significant differences in objective response rate, progression-free survival, or overall survival were observed.

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Immune-related adverse events resulting in treatment cessation were higher in the PD1 + CTLA4 group.

Propofol But Not Desflurane Maintains Rat Cerebral Arteriolar Responses to Acetylcholine During Acute Hyperglycemia

BACKGROUND

Acute hyperglycemia causes vascular endothelial dysfunction in various organs including the cerebral vessels. It is associated with increased mortality and morbidity in the perioperative period. The impact of anesthetic agents on cerebral vasodilatory responses during hyperglycemia remains unclear. We investigated endothelial function in rat cerebral arterioles during acute hyperglycemia, under propofol or desflurane anesthesia.

MATERIALS AND METHODS

A closed cranial window preparation was used to measure changes in pial arteriole diameter induced by topical application of acetylcholine (ACh), an endothelium-dependent vasodilator, in rats anesthetized with propofol or desflurane. Pial arteriole responses to ACh were measured during normoglycemia and hyperglycemia. We then investigated whether the response of cerebral arterioles to acute hyperglycemia under propofol anesthesia were related to propofol or its vehicle, intralipid.

RESULTS

ACh resulted in a dose-dependent dilation of cerebral arterioles during propofol and desflurane anesthesia under normoglycemic conditions. The vasodilatory effects of ACh were also maintained under hyperglycemic conditions during propofol anesthesia, but the vasodilator response to ACh was significantly impaired during hyperglycemia compared with normoglycemia with desflurane anesthesia. The vasodilatory effects of ACh were maintained during normoglycemia and hyperglycemia in rats receiving propofol or intralipid.

CONCLUSIONS

Rat pial arteriole responses to ACh are maintained during conditions of acute hyperglycemia with propofol anesthesia but suppressed compared with normoglycemia with desflurane anesthesia.

A Comparison of the Required Bronchial Cuff Volume Obtained by 2 Cuff Inflation Methods, Capnogram Waveform-Guided Versus Pressure-Guided: A Prospective Randomized Controlled Study

BACKGROUND

Double-lumen endobronchial tubes (DLTs) are used for one-lung ventilation (OLV) during thoracic surgery. Overinflation into the bronchial cuff causes damage to the tracheobronchial mucosa, whereas underinflation leads to an incomplete collapse of the nonventilated lung or incomplete ventilation of the ventilated lung. However, how to determine the appropriate bronchial cuff volume and pressure during OLV is unclear. The objective of this study is to compare the required bronchial cuff volume for lung separation obtained by 2 different cuff inflation methods under closed- and open-chest conditions.

METHODS

A total of 64 patients scheduled to undergo elective thoracic surgery requiring OLV were recruited. Left DLTs were used for both right- and left-sided surgery. The patients were randomly assigned to 1 of 2 inflation-type groups to estimate the bronchial cuff volume. In the capnogram waveform-guided bronchial cuff inflation group (capno group, n = 27), the bronchial cuff was inflated until a capnometer sampling gas containing CO2 from the nonventilated lung displayed a flat line. The corresponding bronchial cuff volume and pressure were then recorded. In the pressure-guided bronchial cuff inflation group (pressure group, n = 29), the bronchial cuff was inflated by a cuff inflator to a pressure of 20 cm H2O. Lung separation was confirmed when a flat line of a capnometer was observed after gas sampling from the nonventilated lung.

RESULTS

Under closed-chest conditions, the bronchial cuff sealing volume for the capno group was significantly lower than that for the pressure group (mean [standard deviation {SD}], 1.00 [0.65] mL vs 1.44 [0.59] mL, mean difference, -0.44; 97.5% confidence interval [CI], -0.78 to -0.11; P = .010). Under open-chest conditions, the bronchial cuff sealing volume for the capno group was also significantly lower than that for the pressure group (mean [SD], 0.65 [0.66] mL vs 1.22 [0.45] mL, mean difference, -0.58; 97.5% CI, -0.88 to -0.27; P < .001).

CONCLUSIONS

The lowest cuff volume providing an air-tight bronchial seal was obtained by the capnogram waveform-guided bronchial cuff inflation method. Since the cuff volume required to achieve an air-tight seal decreases after opening the chest, readjustment of the bronchial cuff volume to prevent bronchial cuff damage to the tracheobronchial mucosa after opening the chest may be advisable.

Cigarette Smoking Cessation Temporarily Enhances the Release of Phosphorylated-HSP27 from Human Platelets

Objective Cigarette smoking is a risk factor for arteriopathy, including acute coronary syndrome, stroke and peripheral vascular disease. Thus, cessation is strongly recommended in order to reduce these risks. We recently demonstrated that smoking cessation causes temporary hyper-aggregability of human platelets. We previously showed that heat shock protein 27 (HSP27) is released from human platelets stimulated by collagen, accompanied by its phosphorylation. Accumulating evidence indicates potent roles of extracellular HSP27 as a modulator of inflammation. In the present study, using the stored samples obtained in the previous study, we investigated the effect of cigarette smoking cessation on the release of phosphorylated-HSP27 from collagen-activated human platelets (n=15 patients). Methods We enrolled patients who visited smoking cessation outpatient services between January 2012 and November 2014. Platelet-rich plasma, chronologically obtained before and after the cessation, was stimulated by collagen using a PA-200 aggregometer in the previous study. The levels of phosphorylated-HSP27 released from platelets were determined by an enzyme-linked immunosorbent assay. The phosphorylation of HSP27 in platelets was evaluated by a Western blot analysis. Results Cessation of cigarette smoking significantly upregulated the levels of collagen-stimulated release of phosphorylated-HSP27 at four and eight weeks after quitting smoking compared to before cessation. However, there was no significant difference between the levels before cessation and those at 12 weeks after cessation. The levels of phosphorylated-HSP27 stimulated by collagen in the platelets at four weeks after smoking cessation were remarkably enhanced compared to before cessation. Conclusion Cigarette smoking cessation temporarily enhances the collagen-stimulated release of phosphorylated-HSP27 from human platelets in the short term.

Smoking cessation affects human platelet activation induced by collagen

It is firmly established that smoking is a risk factor of cardiovascular disease, stroke and peripheral vascular disease. Although smoking alters the hemostatic process, the influence of smoking on human platelet activation remains controversial. For patients undergoing surgery, cessation of smoking prior to the procedure is recommended as it increases the risk of postoperative morbidity or mortality. The presented study investigated the effects of smoking cessation on human platelet activation induced via collagen (n=19 patients). Blood samples were taken on four occasions: Before smoking cessation, and at 4, 8 and 12 weeks after smoking cessation. Platelet aggregation using citrated platelet-rich plasma (PRP) was monitored using a PA-200 aggregometer, which determined the size of platelet aggregates using laser scattering methods. A low dose of collagen (1 µg/ml) accelerated platelet aggregation at 4 or 8 weeks after smoking cessation when compared with results before cessation. After 12 weeks, levels of platelet aggregation induced by collagen were almost equal to those recorded prior to smoking cessation. The secretion levels of collagen-induced platelet-derived growth factor (PDGF)-AB at 4 or 8 weeks after smoking cessation were significantly higher than those before smoking was stopped. Furthermore, smoking cessation markedly strengthened the collagen-induced phosphorylation of p38 mitogen-activated protein (MAP) kinase after 4 weeks. The results of the current study indicated that smoking cessation causes temporary short-term human platelet hyper-activation. The further suggest that the incidence of complications due to human platelet hyper-reactivity may be lowered by considering the period of smoking abstinence.

Cerebrovascular reactivity to hypercapnia during sevoflurane or desflurane anesthesia in rats

Background

Hypercapnia causes dilation of cerebral vessels and increases cerebral blood flow, resulting in increased intracranial pressure. Sevoflurane is reported to preserve cerebrovascular carbon dioxide reactivity. However, the contribution of inhaled anesthetics to vasodilatory responses to hypercapnia has not been clarified. Moreover, the cerebrovascular response to desflurane under hypercapnia has not been reported. We examined the effects of sevoflurane and desflurane on vasodilatory responses to hypercapnia in rats.

Methods

A closed cranial window preparation was used to measure the changes in pial vessel diameters. To evaluate the cerebrovascular response to hypercapnia and/or inhaled anesthetics, the pial vessel diameters were measured in the following states: without inhaled anesthetics at normocapnia (control values) and hypercapnia, with inhaled end-tidal minimal alveolar concentration (MAC) of 0.5 or 1.0 of either sevoflurane or desflurane at normocapnia, and an MAC of 1.0 of sevoflurane or desflurane at hypercapnia.

Results

Under normocapnia, 1.0 MAC, but not 0.5 MAC, of sevoflurane or desflurane dilated the pial arterioles and venules. In addition, under both 1.0 MAC of sevoflurane and 1.0 MAC of desflurane, hypercapnia significantly dilated the pial arterioles and venules in comparison to their diameters without inhaled anesthetics. The degrees of vasodilation were similar for desflurane and sevoflurane under both normocapnia and hypercapnia.

Conclusions

Desflurane induces cerebrovascular responses similar to those of sevoflurane. Desflurane can be used as safely as sevoflurane in neurosurgical anesthesia.

Sphingosine 1-phosphate (S1P) suppresses the collagen-induced activation of human platelets via S1P4 receptor

Sphingosine 1-phosphate (S1P) is as an extracellular factor that acts as a potent lipid mediator by binding to specific receptors, S1P receptors (S1PRs). However, the precise role of S1P in human platelets that express S1PRs has not yet been fully clarified. We previously reported that heat shock protein 27 (HSP27) is released from human platelets accompanied by its phosphorylation stimulated by collagen. In the present study, we investigated the effect of S1P on the collagen-induced platelet activation. S1P pretreatment markedly attenuated the collagen-induced aggregation. Co-stimulation with S1P and collagen suppressed collagen-induced platelet activation, but the effect was weaker than that of S1P-pretreatment. The collagen-stimulated secretion of platelet-derived growth factor (PDGF)-AB and the soluble CD40 ligand (sCD40L) release were significantly reduced by S1P. In addition, S1P suppressed the collagen-induced release of HSP27 as well as the phosphorylation of HSP27. S1P significantly suppressed the collagen-induced phosphorylation of p38 mitogen-activated protein kinase. S1P increased the levels of GTP-bound Gαi and GTP-bound Gα13 coupled to S1PPR1 and/or S1PR4. CYM50260, a selective S1PR4 agonist, but not SEW2871, a selective S1PR1 agonist, suppressed the collagen-stimulated platelet aggregation, PDGF-AB secretion and sCD40L release. In addition, CYM50260 reduced the release of phosphorylated-HSP27 by collagen as well as the phosphorylation of HSP27. The selective S1PR4 antagonist CYM50358, which failed to affect collagen-induced HSP27 phosphorylation, reversed the S1P-induced attenuation of HSP27 phosphorylation by collagen. These results strongly suggest that S1P inhibits the collagen-induced human platelet activation through S1PR4 but not S1PR1.

Effect of blood pressure elevation on cerebral oxygen desaturation in the beach chair position

OBJECTIVE

The beach chair position (BCP) during shoulder arthroscopy is a known risk factor for cerebral ischemia. We retrospectively investigated whether maintaining the arterial blood pressure (ABP) prevented the decrease in the regional cerebral tissue oxygen saturation (rSO₂).

METHODS

We analyzed 20 consecutive patients who underwent elective shoulder surgery in the BCP under general anesthesia. The bilateral rSO₂ was monitored continuously throughout the procedure with the help of near-infrared spectroscopy (INVOS 5100 Cerebral Oximeter, Somanetics Corporation, Troy, MI, USA). Anesthesiologists maintained patient blood pressure while they were in the BCP, which was measured using an ABP transducer placed at the level of the external auditory meatus. We compared rSO₂ measured in the supine position and in the BCP.

RESULTS

Measurement of cortex level mean ABP (mABP) values in the BCP were >50 mmHg and over 60% higher than those noted for the supine position in most patients. Although all bilateral rSO₂ values in the BCP were significantly lower than those in the supine position, the reductions was <20%. Further, 35% (7 of 20) patients that were part of the study experienced cerebral desaturation events at any given point during the procedure. None of the patients experienced clinical postoperative neurological complications.

CONCLUSIONS

Although cortex level mABP in the BCP was >50 mmHg, a decrease was recorded in the rSO₂ values. This rSO₂ decrease was proportional to the reduction in the cortex level mABP induced by a postural change to the BCP. Therefore, despite appropriate blood pressure management, shoulder surgery in the BCP might involve certain risks for patients with cerebrovascular diseases.

Localized NMR Mediated by Electrical-Field-Induced Domain Wall Oscillation in Quantum-Hall-Ferromagnet Nanowire

We present fractional quantum Hall domain walls confined in a gate-defined wire structure. Our experiments utilize spatial oscillation of domain walls driven by radio frequency electric fields to cause nuclear magnetic resonance. The resulting spectra are discussed in terms of both large quadrupole fields created around the wire and hyperfine fields associated with the oscillating domain walls. This provides the experimental fact that the domain walls survive near the confined geometry despite of potential deformation, by which a localized magnetic resonance is allowed in electrical means.

Performance of a new carbon dioxide absorbent, Yabashi lime® as compared to conventional carbon dioxide absorbent during sevoflurane anesthesia in dogs

In the present study, we compare a new carbon dioxide (CO2) absorbent, Yabashi lime(®) with a conventional CO2 absorbent, Sodasorb(®) as a control CO2 absorbent for Compound A (CA) and Carbon monoxide (CO) productions. Four dogs were anesthetized with sevoflurane. Each dog was anesthetized with four preparations, Yabashi lime(®) with high or low-flow rate of oxygen and control CO2 absorbent with high or low-flow rate. CA and CO concentrations in the anesthetic circuit, canister temperature and carbooxyhemoglobin (COHb) concentration in the blood were measured. Yabashi lime(®) did not produce CA. Control CO2 absorbent generated CA, and its concentration was significantly higher in low-flow rate than a high-flow rate. CO was generated only in low-flow rate groups, but there was no significance between Yabashi lime(®) groups and control CO2 absorbent groups. However, the CO concentration in the circuit could not be detected (≤5ppm), and no change was found in COHb level. Canister temperature was significantly higher in low-flow rate groups than high-flow rate groups. Furthermore, in low-flow rate groups, the lower layer of canister temperature in control CO2 absorbent group was significantly higher than Yabashi lime(®) group. CA and CO productions are thought to be related to the composition of CO2 absorbent, flow rate and canister temperature. Though CO concentration is equal, it might be safer to use Yabashi lime(®) with sevoflurane anesthesia in dogs than conventional CO2 absorbent at the point of CA production.

[Comparison of vecuronium doses in general anesthesia administered with remifentanil or fentanyl]

BACKGROUND

It is recommended to minimize neuromuscular blocker administration during general anesthesia for the efficacy of operating room utilization and potential hazards of unintended awareness during anesthesia.

METHODS

We retrospectively compared the dose of vecuronium in consecutive 8,007 patients under general anesthesia receiving remifentanil or fentanyl. In analyzing electronic anesthesia records over 4 years in a single university institute, we also examined the type of general anesthesia and the required time of each pro- cedure in the operating room.

RESULTS

Less vecuronium was necessary in patients administered remifentanil than those given fentanyl both maintained with inhalational and intravenous anesthesia. Supplementation with epidural anesthesia did not influence the dose of vecuronium in patients under general anesthesia receiving remifentanil or fentanyl. We also measured the time necessary before extubating trachea after finishing surgery, while no difference was found between the patients recieving remifentanil and fentanyl.

CONCLUSIONS

Anesthesia with remifentanil reduces requirement of vecuronium dose greater than with fentanyl, while it does not affect the emergence time from anesthesia.

[Report of a tour of the surgical centers in the United States organized by the Japanese Association for Operative Medicine]

We, 4 authors, visited 4 surgical centers in the United States last year on a tour sponsored by the Japanese Association for Operative Medicine. The surgical center of each hospital we visited aimed to contribute to the hospital not only in terms of financial strength but also in the creation of a unique hospital brand value by increasing the number of surgeries compared with previous years as much as possible. The role of surgical centers in the United States was comparable with what we consider an ideal center in Japan. We also found that management of the surgical centers by directors who are specialized anesthesiologists is well organized to promote efficiency with respect to organization, utilities and human resources, and realized that these anesthesiologists must know how to manage the team members and the organization of the surgical centers to improve the quality of operative medicine.

Schwann cell autophagy induced by SAHA, 17-AAG, or clonazepam can reduce bortezomib-induced peripheral neuropathy

BACKGROUND

The proteasome inhibitor bortezomib has improved the survival of patients with multiple myeloma but bortezomib-induced peripheral neuropathy (BiPN) has emerged as a serious potential complication of this therapy. Animal studies suggest that bortezomib predominantly causes pathological changes in Schwann cells. A tractable system to evaluate combination drugs for use with bortezomib is essential to enable continuing clinical benefit from this drug.

METHODS

Rat schwannoma cells were pretreated with vincristine (VCR), histone deacetylase inhibitors, anticonvulsants, or a heat-shock protein 90 (HSP90) inhibitor. To then monitor aggresome formation as a result of proteasome inhibition and the activation of chaperone-mediated autophagy (CMA), we performed double-labelling immunofluorescent analyses of a cellular aggregation-prone protein marker.

RESULTS

Aggresome formation was interrupted by VCR, whereas combination treatments with bortezomib involving suberoylanilide hydroxamic acid, 17-allylamino-17-demethoxy-geldanamycin, or clonazepam appear to facilitate the disposal of unfolded proteins via CMA, inducing HSP70 and lysosome-associated membrane protein type 2A (LAMP-2A).

CONCLUSIONS

This schwannoma model can be used to test BiPN-reducing drugs. The present data suggest that aggresome formation in Schwann cells is a possible mechanism of BiPN, and drugs that induce HSP70 or LAMP-2A have the potential to alleviate this complication. Combination clinical trials are warranted to confirm the relevance of these observations.

An organotypic culture system of Merkel cells using isolated epidermal sheets

BACKGROUND

Merkel cells (MCs) exist in the epidermal basal layer, in contact with keratinocytes. This direct contact seems critical for maintaining MCs in vitro.

OBJECTIVES

To estimate the effects of nerve cells on the maintenance of MCs within epidermal sheets in a new organotypic culture system of MCs.

METHODS

We developed a new organotypic culture system of MCs, using MC-containing epidermal sheets embedded in collagen gel. To estimate the effects of nerve cells on the maintenance of MCs within the epidermal sheets, we cocultured nerve cells and MC-containing epidermal sheets. In these culture assemblies, cellular behaviour was analysed by histochemistry, immunohistochemistry, electron microscopy and enzyme-linked immunosorbent assay.

RESULTS

This culture, even in the absence of neurotrophin (NT)-3 and nerve growth factor (NGF) (which are crucial for MC biology), retained cytokeratin (CK)-20-positive and neuroendocrine granule-containing MCs within the sheets for over 2 weeks. Coculture of MCs with PC-12 nerve cells significantly increased the number of MCs within the epidermal sheets, and the keratinocytes had almost identical expression levels of CK1, CK10, CK14 and the progenitor marker p63 to those produced by keratinocytes in vivo. Uptake of the growth marker bromodeoxyuridine by MCs and levels of NT-3 and NGF in the culture supernatants were undetectable in this system, regardless of the presence or absence of PC-12.

CONCLUSIONS

The data suggest, first, that direct contact between MCs and keratinocytes may be critical for retaining MCs in vitro; second, that nerve cell-affected maintenance of keratinocyte differentiation, but not NT-3 and NGF, may contribute to MC maintenance; and third, that MCs are not able to grow, at least in our system. Our method would be useful for studying MC biology.

The expression profile of functional regulatory T cells, CD4+CD25high+/forkhead box protein P3+, in patients with ulcerative colitis during active and quiescent disease

Regulatory T cells (T(reg)) have an essential role in maintaining immune tolerance in the gut. The functional CD4(+) T(reg) express the transcription factor forkhead box protein 3 (FoxP3) or a CD25(high) in humans. Further, depletion of elevated granulocytes/monocytes by extracorporeal adsorption (GMA) induces immunomodulation in patients with ulcerative colitis (UC). We investigated the impact of GMA on T(reg). Thirty-one UC patients, clinical activity index (CAI) 12.1 +/- 2.97, refractory to conventional medications including intravenous corticosteroid and 13 healthy controls (HC), were included. Patients received five GMA sessions over 5 weeks. Biopsies from the rectal mucosa and blood samples at baseline and post-GMA were immunostained with anti-CD4/FoxP3 and anti-CD4/CD25 antibodies for immunohistochemistry and flow cytometry. Following GMA, 22 of 31 patients achieved remission (CAI <or= 4, P < 0.01) and their endoscopic activity index decreased from 10.6 +/- 2.32 to 4.75 +/- 1.48 (P = 0.003). The circulating CD4(+)CD25(high+) T(reg) level was low and increased markedly in responders (P < 0.02). In the nine non-responders, the baseline CD4(+)CD25(high+) T(reg) level was about 50% of the level in the responders (P < 0.03) or in the HC (P < 0.01), and all nine had to undergo colectomy. Conversely, the number of CD4(+)/FoxP3(+) mucosal T(reg) in GMA responders decreased significantly after the fifth GMA session compared with the baseline level (P < 0.05). It is believed that the CD4(+) T(reg) has an essential role in the control of immune pathology in UC patients and a net influx of these cells from the circulation into the mucosa may proceed to suppress inflammation. GMA can impact the circulating as well as the mucosal levels of T(reg).

Basic study on a lower-energy defibrillation method using computer simulation and cultured myocardial cell models

Computer simulation and myocardial cell models were used to evaluate a low-energy defibrillation technique. A generated spiral wave, considered to be a mechanism of fibrillation, and fibrillation were investigated using two myocardial sheet models: a two-dimensional computer simulation model and a two-dimensional experimental model. A new defibrillation technique that has few side effects, which are induced by the current passing into the patient's body, on cardiac muscle is desired. The purpose of the present study is to conduct a basic investigation into an efficient defibrillation method. In order to evaluate the defibrillation method, the propagation of excitation in the myocardial sheet is measured during the normal state and during fibrillation, respectively. The advantages of the low-energy defibrillation technique are then discussed based on the stimulation timing.

Hypothermia Attenuates the Vasodilator Effects of Dexmedetomidine on Pial Vessels in Rabbits In Vivo

Studies have indicated that mild to moderate hypothermia or dexmedetomidine may have neuroprotective properties in animal models. In this study, we investigated the effects of hypothermia on dexmedetomidine-induced responses in cerebral vessels in anesthetized rabbits by using the cranial-window preparation. After instrumentation under pentobarbital anesthesia, 12 rabbits were assigned to 1 of 2 equal groups: normothermic (nasopharyngeal and intrawindow temperature, 38.5 degrees C-39.5 degrees C) or hypothermic (33.0 degrees C-34.0 degrees C). Each rabbit received three different concentrations (10(-7), 10(-5), and 10(-3) M) of dexmedetomidine under the window, and cerebral pial vessel diameters were measured in a sequential manner. In the normothermic group, dexmedetomidine induced a significant concentration-dependent dilation in both large and small arterioles. In the hypothermia group, dexmedetomidine produced a U-shaped dose-response in both large and small cerebral arterioles (concentration-related vasoconstriction at 10(-7) and 10(-5) M, but vasodilation at 10(-3) M). In cerebral venules, a similar pattern of results was obtained, but changes were generally smaller than in arterioles. In conclusion, topically applied dexmedetomidine induces concentration-dependent dilation in cerebral arterioles in normothermic rabbits anesthetized with pentobarbital, but mild to moderate hypothermia attenuates these responses, with smaller dexmedetomidine concentrations causing vasoconstriction.

IMPLICATIONS

In normothermic rabbits anesthetized with pentobarbital, topically applied dexmedetomidine induces a concentration-dependent dilation in both large and small cerebral arterioles, but mild to moderate hypothermia attenuates these responses.

Effects of ketamine on isoflurane- and sevoflurane-induced cerebral vasodilation in rabbits

Although ketamine has been reported to have little effect on the cerebral circulation when used with other anesthetics, its effect on the cerebral vascular response to volatile anesthetics, which increase cerebral blood flow in a concentration-dependent manner, remains obscure. A closed cranial window was prepared in 15 pentobarbital-anesthetized adult rabbits. The cerebral pial arteriolar alteration induced by either isoflurane (n = 8) or sevoflurane (n = 7) at 0 (before volatile anesthetic), 0.33, 0.67, and 1.0 minimum alveolar concentration (MAC) was measured under three consecutive conditions: intravenous infusion with saline, with ketamine, and with ketamine plus l-arginine. Ketamine reduced the vasodilation induced by 0.67 (120 +/- 9% versus 113 +/- 9%; P <.05) and 1.0 MAC isoflurane (136 +/- 11% versus 118 +/- 10%; P <.05), but l-arginine did not restore the isoflurane-induced cerebral vasodilation. In rabbits inhaling sevoflurane, the degree of cerebral vasodilator response was smaller than that by isoflurane, and the cerebral vasodilation was comparable whether in the presence or absence of ketamine (with or without l-arginine). In conclusion, ketamine reduces isoflurane-induced cerebral vasodilation, apparently independently of nitric oxide formation, while sevoflurane-induced cerebral vasodilation is not significantly affected by ketamine.

L-arginine and nitroglycerin restore hypercapnia-induced cerebral vasodilation in rabbits after its attenuation by ketamine

Although it has been reported that ketamine attenuates hypercapnia-induced cerebral vasodilation, the mechanism remains unknown. Because nitric oxide is involved in cerebral CO2 reactivity, we studied the effects of L-arginine and nitroglycerin on ketamine-mediated attenuation of vascular responses to hypercapnia. Under pentobarbital anesthesia, 16 rabbits underwent closed cranial window preparation. Hypercapnic challenges were repeated after IV saline, ketamine (10 mg/kg, followed by 20 mg x kg(-1) x h(-1)), or ketamine plus either L-arginine (150 mg/kg, followed by 100 mg x kg(-1) x h(-1); n = 8) or nitroglycerin (5 microg x kg(-1) x min(-1) infusion; n = 8). Ketamine reduced hypercapnia-induced cerebral vasodilation (1.27%/mm Hg +/- 0.45%/mm Hg [saline] versus 0.82%/mm Hg +/- 0.53%/mm Hg [ketamine]: P < 0.05), but L-arginine restored reactivity (1.28%/mm Hg +/- 0.73%/mm Hg: P < 0.05 versus ketamine), as did nitroglycerin (1.14%/mm Hg +/- 0.73%/mm Hg [saline] versus 0.56%/mm Hg +/- 0.63%/mm Hg [ketamine]: P < 0.05, and 1.15%/mm Hg +/- 0.74%/mm Hg [ketamine plus nitroglycerin]: P < 0.05 versus ketamine). This indicates that ketamine attenuates cerebral CO2 reactivity, at least in part, via suppression of nitric oxide-cyclic guanosine monophosphate mechanisms in the cerebral vasculature.

IMPLICATIONS

The attenuation of cerebral vasodilation to hypercapnia seen under ketamine anesthesia is reversed by L-arginine or nitroglycerin infusion.

Spontaneous normalization of negative T waves in infarct-related leads reflects improvement in left ventricular wall motion even in patients with persistent abnormal Q waves after anterior wall acute myocardial infarction

This study aimed to clarify whether spontaneous T-wave normalization (TWN) in infarct-related leads reflects improvement in left ventricular (LV) wall motion even in patients with persistent abnormal Q waves after acute myocardial infarction (AMI). Eighty-five patients were classified into the following 3 groups: patients with Q-wave regression (group A, n = 21), those with persistent abnormal Q waves and TWN (group B, n = 36), and those with persistent abnormal Q waves and absence of TWN (group C, n = 28). Groups A and B had greater improvement in LV ejection fraction and regional wall motion between 1 and 6 months after AMI than group C. In conclusion, spontaneous TWN in the healing stage of anterior AMI reflects functional recovery of viable myocardium in the infarct region even in patients with persistent abnormal Q waves.

Ketamine, not propofol, attenuates cerebrovascular response to carbon dioxide in humans with isoflurane anesthesia

STUDY OBJECTIVES

To investigate the effects of ketamine and propofol on the cerebrovascular response to carbon dioxide (CO(2)) in humans during isoflurane anesthesia.

DESIGN

Randomized clinical investigation.

SETTINGS

University hospital of a medical school.

PATIENTS

30 ASA physical status I and II adult, elective surgical patients.

INTERVENTIONS AND MEASUREMENTS

With each patient given air/oxygen/isoflurane anesthesia, the flow velocity in the middle cerebral artery (Vmca) and pulsatility index were measured using the transcranial Doppler method under hypocapnic [arterial CO(2)tension (PaCO(2)) 28-32 mmHg], normocapnic (PaCO(2) 38-42 mmHg), and hypercapnic conditions (PaCO(2) 48-52 mmHg). PaCO(2) was altered by supplementing the inspired gas with CO(2) without changing the respiratory conditions. Patients were then randomly assigned to receive either ketamine 1 mg. kg(-1) or propofol (2 mg. kg(-1)followed by an infusion of 6-10 mg. kg(-1). hr(-1)) (n = 15 for each drug), and the measurements were repeated.

MAIN RESULTS

Ketamine reduced both absolute and relative cerebrovascular reactivity to CO(2) significantly [2.9 +/- 0.8 (control) vs. 2.6 +/- 1.0 (ketamine) cm. sec(-1). mmHg(-1): p < 0.05; and 3.5 +/- 0.7 (control) vs. 2.8 +/- 0.9 (ketamine) %. mmHg(-1): p < 0.01, respectively]. However, ketamine did not reduce Vmca during hypercapnic conditions (117 +/- 29 cm. sec(-1)) compared with controls (120 +/- 28 cm. sec(-1)). Although propofol decreased Vmca during all conditions, it did not cause any change in either absolute or relative CO(2) reactivity [2.5 +/- 0.8 (control) vs. 2.5 +/- 1.0 (propofol) cm. sec(-1). mmHg(-1), and 3.3 +/- 1.3 (control) vs. 4.1 +/- 1.0 (propofol) %. mmHg(-1), respectively].

CONCLUSIONS

In humans given isoflurane anesthesia, a) ketamine reduced cerebrovascular response to CO(2), but cerebral blood flow (CBF) during hypercapnic conditions was comparable with controls, and b) although propofol decreases CBF, it maintains the cerebrovascular response to CO(2).

The differential effects of stereoisomers of ropivacaine and bupivacaine on cerebral pial arterioles in dogs

We investigated whether the stereoisomers of ropivacaine and bupivacaine exert differential effects on the cerebral microcirculation. Pentobarbital-anesthetized dogs (n = 16) were prepared for measurement of cerebral pial vessel diameters by using a closed cranial window preparation. We administered three different concentrations (10(-7), 10(-5), and 10(-3) M) of each of three drug solutions [R(+), racemic, and S(-) forms of ropivacaine (n = 8) or bupivacaine (n = 8)] under the window in a randomized manner and measured cerebral pial arteriolar diameters. Various physiologic data were obtained before and after topical application of each test solution. All three forms of ropivacaine constricted cerebral pial arterioles, each in a concentration-dependent manner. The rank order for degree of vasoconstriction was S(-) ropivacaine > racemic ropivacaine > R(+) ropivacaine. In contrast, R(+) and racemic bupivacaine dilated, but S(-) bupivacaine constricted, cerebral pial arterioles, each in a concentration-dependent manner. We could find no difference in vascular reactivity to these drugs between large (> or = microm) and small (<100 microm) arterioles. Topical application of these drugs induced no changes in mean blood pressure or heart rate. The observed differences in the microvascular alterations induced by the stereoisomers of ropivacaine and bupivacaine suggest that the vasoactive effects of these drugs on cerebral arterioles could, at least in part, depend on their chirality.

IMPLICATIONS

The differential effects of the stereoisomers of ropivacaine and bupivacaine on cerebral pial vessels could, at least in part, depend on their chirality.

The anxiolytic effects of the 5-hydroxytryptamine-1A agonist tandospirone before otolaryngologic surgery

We studied 160 ASA I or II patients undergoing elective otolaryngologic surgery in order to compare the anxiolytic effects of a novel 5-hydroxytryptamine-1A agonist, tandospirone, with diazepam. To monitor preoperative anxiety, the following variables were used: systolic and diastolic arterial pressure, heart rate, and the state anxiety score yielded by the Spielberger State-Trait Anxiety Inventory. We performed pretreatment evaluation on the day before surgery and posttreatment examination immediately after entry into the operating room. In a double-blinded, randomized design, four groups of 40 patients each received one of the following oral medications 90 min before entry into the operating room: 1) tandospirone 10 mg (T10 group); 2) tandospirone 30 mg (T30 group); 3) diazepam 10 mg (D group); or 4) placebo (P group). After premedication, the State-Trait Anxiety Inventory state anxiety decreased in the T10 (P < 0.02), T30 (P < 0.02), and D groups (P < 0.001), but it increased in the P group (P < 0.001). Tandospirone, 10 and 30 mg, safely reduced preoperative anxiety to a similar extent as oral diazepam 10 mg in patients undergoing elective otolaryngologic surgery.

IMPLICATIONS

Oral tandospirone reduces preoperative anxiety to a similar extent as oral diazepam in patients undergoing elective otolaryngologic surgery. This finding implies that tandospirone can be used as an oral premedicant drug for relieving anxiety before surgery.

The effects of topical and intravenous ketamine on cerebral arterioles in dogs receiving pentobarbital or isoflurane anesthesia

To evaluate the effects of ketamine on cerebral arterioles, we used a closed cranial window technique in mechanically ventilated, anesthetized dogs. Fourteen dogs were assigned to one of the following two basal-anesthesia groups: pentobarbital 2 mg. kg(-1). h(-1) or isoflurane 0.5 MAC (n = 7 each). We administered three different concentrations of ketamine (10(-7), 10(-5), and 10(-3) M) under the window and measured arteriolar diameters. For comparison, in another 14 dogs we examined the effect of systemic (IV) ketamine (1 mg/kg and 5 mg/kg) using the same two basal anesthetics. We measured diameters before and after ketamine administration, and we evaluated the effect of ketamine on CO(2) reactivity of the cerebral arterioles. Neither topical nor systemic ketamine dilated pial arterioles in either basal-anesthesia group. CO(2) reactivity of pial arterioles was reduced under systemic ketamine in both basal-anesthesia groups. The results indicate that although ketamine does not dilate pial arteriolar diameters when topically or IV administered, IV ketamine does attenuate hypercapnic vasodilation in dogs under basal pentobarbital or isoflurane anesthesia. These results provide some insight that ketamine is suitable for supplementary neurosurgical anesthesia.

Relationship between terminal QRS distortion on the admission electrocardiogram and the time course of left ventricular wall motion in anterior wall acute myocardial infarction

In order to clarify the time course of left ventricular (LV) wall motion in patients with anterior acute myocardial infarction (AMI) showing terminal QRS distortion on the admission electrocardiogram (ECG), the present study examined 106 patients with their first anterior AMI (< or =6 h) who underwent emergency coronary arteriography and cardiac cathetherization at 1 and 6 months after the infarction. The patients were classified into 2 groups according to the presence (group A, n=23) or absence (group B, n=83) of terminal QRS distortion (emergence of the J point at > or =50% of the R-wave amplitude in leads with QR configuration and/or absence of S waves in leads with RS configuration) on the admission ECG. Group A had a lower LV ejection fraction and more reduced regional wall motion (RWM) in the infarct region at both 1 and 6 months after AMI than group B. The degree of improvement in RWM between 1 and 6 months after AMI was less in group A than in group B (-0.1+/-0.5 vs 0.4+/-0.6 SD/chord, p<0.01). This study indicates that patients with anterior AMI showing terminal QRS distortion on the admission ECG have more severely depressed LV wall motion and less improvement in RWM in the infarct region in the healing stage, suggesting that this sign is an indicator of severe myocardial damage.

Isolation of antigen from the circulating immune complex in mice infected with Plasmodium berghei

Circulating immune complex (CIC) is known to play a role in pathological glomerular alterations in malaria. However, the nature of the antigens comprising the CIC is still not fully understood. We report here the isolation of the antigen in CIC and its localisation in mice infected with Plasmodium berghei NK65. The antigen was successfully isolated from CIC extracted from the blood of mice infected with P. berghei, by using C1q-coated microplates. The molecular mass of the antigen separated from CIC bound to C1q was found to be 78 kDa. Furthermore, localisation of the antigen was examined by the fluorescent antibody technique and immunoelectron microscopy. The antigen was detected in the parasitised erythrocyte and the mesangial matrix by both methods. These results suggest that the 78 kDa protein might be associated with the glomerular alterations in malaria infection.

[The efficacy of SEMS for malignant upper gastrointestinal stenosis, evaluated by a "home index"]

We used a self expandable metalic stent (SEMS) on 24 patients (average age 68.6 years, 20 males, 4 females) with malignant upper gastrointestinal stenosis from August, 1997 to March, 1999. The primary diseases of the 24 patients were gastric cancer (13 cases: 54%), esophageal cancer (10 cases: 42%) and paraesophageal lymph node metastasis of breast cancer (one case: 4%). In this study, we present a "Home Index" as an indicator to evaluate a patient's quality of life, and investigated the efficacy and problem of SEMS.

Attenuated additional hypocapnic constriction, but not hypercapnic dilation, of spinal pial arterioles during spinal ropivacaine

Ropivacaine constricts spinal vessels. Because the CO2 response of spinal vessels is similar to that of cerebral vessels, we tested to see if hypocapnia would cause further spinal vasoconstriction during ropivacaine administration. In 12 pentobarbital-anesthetized dogs, spinal pial arteriolar diameter was measured using a closed spinal window preparation. Either ropivacaine solution (0.1%; n = 6) or artificial cerebrospinal fluid (n = 6) was infused continuously into the spinal window. After a period of hypocapnia (Paco2, 20-25 mm Hg) had been induced, inspired CO2 levels were adjusted to produce normocapnia (35-40 mm Hg) followed by hypercapnia (55-60 mm Hg). When the desired Paco2 was reached, measurements were made of the arteriolar diameter and physiological variables. During normocapnia, ropivacaine infusion produced a significant constriction of pial arterioles, whereas artificial cerebrospinal fluid caused no change. Hypocapnia induced a much smaller (almost nonexistent) additional vasoconstriction in the ropivacaine group than in the control group (P < 0.01). The final hypercapnic vasodilation was somewhat greater during ropivacaine (P < 0.05 versus control group). Topical ropivacaine induced no change in hemodynamic variables. We conclude that hypocapnia of the magnitude tested did not cause further constriction in spinal vessels during spinal ropivacaine.

IMPLICATIONS

During topical application of the local anesthetic ropivacaine in dogs, hypocapnia (Paco2, 20-25 mm Hg) induced almost no additional constriction of spinal arterioles, and the hypercapnic vasodilation was maintained. These data suggest that an additional constriction in spinal vessels is unlikely when hypocapnia occurs during spinal ropivacaine.

Significance of spontaneous normalization of negative T waves in infarct-related leads during healing of anterior wall acute myocardial infarction

This study was conducted to elucidate the significance of spontaneous normalization of negative T waves in infarct-related leads during the chronic phase of anterior wall acute myocardial infarction. Results of this study indicate that patients with spontaneous normalization of negative T waves in infarct-related leads between 1 and 6 months after anterior wall acute myocardial infarction have smaller infarct size, decreased left ventricular dysfunction, and greater improvement in left ventricular wall motion in the infarct area, suggesting that T-wave normalization represents functional recovery of viable myocardium in the infarct area.