A clinicopathological study on combined hepatocellular and cholangiocarcinoma

We clinicopathologically studied 23 surgically resected cases of combined hepatocellular and cholangiocarcinoma (HCC-CC). The frequency of this cancer in our subjects, who had primary liver cancer and who underwent hepatectomy, was 6.3%. The mean age of patients was 64.0 years old and the male: female ratio was 1.9:1. Serum alpha-fetoprotein was positive in 70% of cases and its levels were relatively low (< or = 1000 ng/mL) in most cases. The positive rate of serum carcinoembryonic antigen was 18% and its levels were also low. In regard to hepatitis virus markers, 17% of the 20 combined HCC-CC cases were positive to HBs antigen and 70% were positive to the HCV antibody. Of the 23 combined HCC-CC cases, 9 cases (39%) were associated with liver cirrhosis. Tumours were classified macroscopically into a separated type (HCC and CC are clearly separated 17%), a HCC-predominant type (resembles HCC 49%), and a CC-predominant type (resembles CC 34%). The separated and HCC-predominant types were associated with liver cirrhosis in 50 and 55% of cases, respectively. These cases with liver cirrhosis presented the features of HCC more apparently, while those without liver cirrhosis presented the features of CC. Histologically, all cases were classified into either Type I (HCC and CC were clearly distinguished; 17%), Type II (HCC and CC were contiguous and shared transitional features; 66%), and Type III (cancer cells were able to be evaluated as either HCC or CC and were considered to be an intermediate type; 17%). Immunohistological stains for cytokeratin were useful to distinguish HCC and CC. Specifically, CC was positive to cytokeratin 7 and 19. The tumour, in which HCC and CC were almost indistinguishable, such as Type III), indicates the presence of intermediate tumour cells that can differentiate either to HCC or CC.

Sugammadex and rocuronium-induced anaphylaxis

Perioperative anaphylaxis is a life-threatening clinical condition that is typically the result of drugs or substances used for anesthesia or surgery. The most common cause of anaphylaxis during anesthesia is reportedly neuromuscular blocking agents. Of the many muscle relaxants that are clinically available, rocuronium is becoming popular in many countries. Recent studies have demonstrated that succinylcholine (but also rocuronium use) is associated with a relatively high rate of IgE-mediated anaphylaxis compared with other muscle relaxant agents. Sugammadex is widely used for reversal of the effects of steroidal neuromuscular blocking agents, such as rocuronium and vecuronium. Confirmed cases of allergic reactions to clinical doses of sugammadex have also been recently reported. Given these circumstances, the number of cases of hypersensitivity to either sugammadex or rocuronium is likely to increase. Thus, anesthesiologists should be familiar with the epidemiology, mechanisms, and clinical presentations of anaphylaxis induced by these drugs. In this review, we focus on the diagnosis and treatment of anaphylaxis to sugammadex and neuromuscular blocking agents. Moreover, we discuss recent studies in this field, including the diagnostic utility of flow cytometry and improvement of rocuronium-induced anaphylaxis with the use of sugammadex.

Glycinergic and GABAergic tonic inhibition fine tune inhibitory control in regionally distinct subpopulations of dorsal horn neurons

Inhibition mediated by glycine and GABA in the spinal cord dorsal horn is essential for controlling sensitivity to painful stimuli. Loss of inhibition results in hyperalgesia, a sensitized response to a painful stimulus, and allodynia, a pain-like response to an innocuous stimulus like touch. The latter is due, in part, to disinhibition of an excitatory polysynaptic pathway linking low threshold touch input to pain projection neurons. This critical impact of disinhibition raises the issue of what regulates the activity of inhibitory interneurons in the dorsal horn under non-pathological conditions. We have found that inhibitory neurons throughout lamina I-III, identified by the GAD67 promoter-driven EGFP, are tonically inhibited by glycine or GABA in a regionally distinct way that is mirrored by their inhibitory synaptic input. This tonic inhibition strongly modifies action potential firing properties. Surprisingly, we found that inhibitory neurons at the lamina II/III border are under tonic glycinergic control and receive synapses that are predominantly glycinergic. Futhermore, this tonic glycinergic inhibition remains strong as the mice mature postnatally. Interestingly, GlyT1, the glial glycine transporter, regulates the strength of tonic glycinergic inhibition of these glycine-dominant neurons. The more dorsal lamina I and IIo inhibitory neurons are mainly under control by tonic GABA action and receive synapses that are predominantly GABAergic. Our work supports the hypothesis that tonic glycine inhibition controls the inhibitory circuitry deep in lamina II that is likely to be responsible for separating low threshold input from high threshold output neurons of lamina I.

Pre- and postsynaptic inhibitory control in the spinal cord dorsal horn

Sensory information transmitted to the spinal cord dorsal horn is modulated by a complex network of excitatory and inhibitory interneurons. The two main inhibitory transmitters, GABA and glycine, control the flow of sensory information mainly by regulating the excitability of dorsal horn neurons. A presynaptic action of GABA has also been proposed as an important modulatory mechanism of transmitter release from sensory primary afferent terminals. By inhibiting the release of glutamate from primary afferent terminals, activation of presynaptic GABA receptors could play an important role in nociceptive and tactile sensory coding, while changes in their expression or function could be involved in pathological pain conditions, such as allodynia.

Synaptic pathways and inhibitory gates in the spinal cord dorsal horn

Disinhibition in the dorsal horn accompanies peripheral nerve injury and causes the development of hypersensitivity to mild stimuli. This demonstrates the critical importance of inhibition in the dorsal horn for maintaining normal sensory signaling. Here we show that disinhibition induces a novel polysynaptic low-threshold input onto lamina I output neurons, suggesting that inhibition normally suppresses a preexisting pathway that probably contributes to abnormal pain sensations such as allodynia. In addition, we show that a significant proportion of superficial dorsal horn inhibitory neurons are activated by low-threshold input. These neurons are well situated to contribute to suppressing low-threshold activation of pain output neurons in lamina I. We further discuss several aspects of inhibition in the dorsal horn that might contribute to suppressing pathological signaling.

Membrane and firing properties of glutamatergic and GABAergic neurons in the rat medial vestibular nucleus

In previous studies, neurons in the medial vestibular nucleus (MVN) were classified mainly into 2 types according to their intrinsic membrane properties in in vitro slice preparations. However, it has not been determined whether the classified neurons are excitatory or inhibitory ones. In the present study, to clarify the relationship between the chemical and electrophysiological properties of MVN neurons, we explored mRNAs of cellular markers for GABAergic (glutamic acid decarboxylase 65, 67, and neuronal GABA transporter), glutamatergic (vesicular glutamate transporter 1 and 2), glycinergic (glycine transporter 2), and cholinergic neurons (choline acetyltransferase and vesicular acetylcholine transporter) expressed in electrophysiologically characterized MVN neurons in rat brain stem slice preparations. For this purpose, we combined whole cell patch-clamp recording analysis with single-cell reverse transcription-polymerase chain reaction (RT-PCR) analysis. We examined the membrane properties such as afterhyperpolarization (AHP), firing pattern, and response to hyperpolarizing current pulse to classify MVN neurons. From the single-cell RT-PCR analysis, we found that GABAergic neurons consisted of heterogeneous populations with different membrane properties. Comparison of the membrane properties of GABAergic neurons with those of other neurons revealed that AHPs without slow components and a firing pattern with delayed spike generation (late spiking) were preferential properties of GABAergic neurons. On the other hand, most glutamatergic neurons formed a homogeneous subclass of neurons exhibiting AHPs with slow components, repetitive firings with constant interspike intervals (continuous spiking), and time-dependent inward rectification in response to hyperpolarizing current pulses. We also found a small number of cholinergic neurons with various membrane properties. These findings clarify the electrophysiological properties of excitatory and inhibitory neurons in the MVN, and the information about the preferential membrane properties may be useful for identifying GABAergic and glutamatergic MVN neurons electrophysiologically.

Identification and C-terminal characterization of proteins from two-dimensional polyacrylamide gels by a combination of isotopic labeling and nanoelectrospray Fourier transform ion cyclotron resonance mass spectrometry

We propose a novel method for the identification and C-terminal characterization of proteins separated by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). Proteins were digested in a gel in a buffer solution containing 50% 18O-labeled water, and mixtures of 18O/16O-labeled peptides were analyzed by nanoelectrospray Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). This method was evaluated using horse skeletal muscle myoglobin as the model protein in SDS gel. The high resolution of FT-ICR MS minimized the overlapping of peptide peaks and facilitated identification of the C-terminal peptide, which was done by observing the undisrupted isotope peak pattern. As well, with its low ppm-level high mass accuracy, it can rapidly and reliably identify the in-gel-separated protein and determine its C-terminal by peptide mass fingerprinting alone. Therefore, this method should be applicable to routine and high-throughput proteome studies. Here, the method was applied to the analysis of rat liver proteins separated by 2D-PAGE. The C-termini of eight proteins were successfully identified out of 10 randomly picked Coomassie brilliant blue-stained spots. The feasibility and limitations of this approach are reported in this paper.

Maturation of spinal motor neurons derived from human embryonic stem cells

Our understanding of motor neuron biology in humans is derived mainly from investigation of human postmortem tissue and more indirectly from live animal models such as rodents. Thus generation of motor neurons from human embryonic stem cells and human induced pluripotent stem cells is an important new approach to model motor neuron function. To be useful models of human motor neuron function, cells generated in vitro should develop mature properties that are the hallmarks of motor neurons in vivo such as elaborated neuronal processes and mature electrophysiological characteristics. Here we have investigated changes in morphological and electrophysiological properties associated with maturation of neurons differentiated from human embryonic stem cells expressing GFP driven by a motor neuron specific reporter (Hb9::GFP) in culture. We observed maturation in cellular morphology seen as more complex neurite outgrowth and increased soma area over time. Electrophysiological changes included decreasing input resistance and increasing action potential firing frequency over 13 days in vitro. Furthermore, these human embryonic stem cell derived motor neurons acquired two physiological characteristics that are thought to underpin motor neuron integrated function in motor circuits; spike frequency adaptation and rebound action potential firing. These findings show that human embryonic stem cell derived motor neurons develop functional characteristics typical of spinal motor neurons in vivo and suggest that they are a relevant and useful platform for studying motor neuron development and function and for modeling motor neuron diseases.

Three suspected cases of sugammadex-induced anaphylactic shock

Background

Sugammadex has a unique mechanism of action and is widely used because of its safety and efficacy. A few recent reports have described allergic reactions to clinical doses of sugammadex. We hereby describe another series of cases of possible anaphylaxis to sugammadex.

Case presentation

We present three suspected cases of sugammadex-induced anaphylactic shock, including a 13-year-old boy who underwent laparoscopic appendectomy, a 75-year-old woman who underwent left knee arthroplasty, and a 34-year-old man who underwent left pansinectomy for sinobronchitis. All three patients received general anesthesia with rocuronium and their tracheas were intubated. Shortly after injection of sugammadex for reversal of rocuronium, all of them experienced a decrease in blood pressure along with mucocutaneous erythema. In the most severe case, reintubation after extubation was required due to difficulty in manual ventilation. All patients recovered with anti-allergic therapy. On later investigation, all three patients had a positive skin reaction to sugammadex.

Conclusion

Our results suggest that physicians using sugammadex should be aware of the possibility of sugammadex-induced anaphylaxis.

Plasma proinflammatory cytokine response to surgical stress in elderly patients

We investigated the change of plasma cytokines concentrations in elderly patients during lower abdominal surgery. Plasma interleukin (IL-)6 concentrations (68.0+/-15.4 and 36.1+/-20.7 pg/ml) in elderly patients at 24 h and at 3 days after surgery were significantly higher than those (35.1+/-21.5 and 18.6+/-10.6 pg/ml) of young adults. Plasma IL-6 concentrations (92.3+/- 31.9 pg/ml) in elderly patients anesthetized with propofol and fentanyl were significantly higher at the end of the operation than that (57.9+/-36.7 pg/ml) of elderly patients anesthetized with sevoflurane and fentanyl. In conclusion, elderly patients have an increased and delayed IL-6 response to surgical trauma compared with young adults. Plasma IL-6 production after surgical trauma in elderly patients with total intravenous anesthesia with propofol was significantly higher than that in elderly patients with sevoflurane anesthesia.

Management of a surgical patient with a label of penicillin allergy: narrative review and consensus recommendations

Unsubstantiated penicillin-allergy labels are common in surgical patients, and can lead to significant harm through avoidance of best first-line prophylaxis of surgical site infections and increased infection with resistant bacterial strains. Up to 98% of penicillin-allergy labels are incorrect when tested. Because of the scarcity of trained allergists in all healthcare systems, only a minority of surgical patients have the opportunity to undergo testing and de-labelling before surgery. Testing pathways can be modified and shortened in selected patients. A variety of healthcare professionals can, with appropriate training and in collaboration with allergists, provide testing for selected patients. We review how patients might be assessed, the appropriate testing strategies that can be used, and the minimum standards of safe testing.

Practical guidelines for the response to perioperative anaphylaxis

Perioperative anaphylaxis is a severe adverse event during anesthesia that requires prompt diagnosis and treatment by physicians, including anesthesiologists. Muscle relaxants and antibiotics are the most common drugs that cause perioperative anaphylaxis in Japan, as in many countries. In addition, sugammadex appears to be a primary causative agent. Obtaining previous anesthesia records is necessary in a patient with a history of allergic reactions during anesthesia, whenever possible, to avoid recurrence of anaphylaxis. Although medical staff are likely to notice abnormal vital signs because of complete monitoring during anesthesia, surgical drapes make it difficult to notice the appearance of skin symptoms. Even if there are no skin symptoms, anaphylaxis should be suspected, especially when hypotension resistant to inotropes and vasopressors persists. For improving the diagnostic accuracy of anaphylaxis, it is helpful to collect blood samples to measure histamine/tryptase concentrations immediately after the events and at baseline. The first-line treatment for anaphylaxis is adrenaline. In the perioperative setting, adrenaline should be administered through the intravenous route, which has a faster effect onset and is secured in most cases. Adrenaline can cause serious complications including severe arrhythmias if the appropriate dose is not selected according to the severity of symptoms. The anesthesiologist should identify the causative agent after adverse events. The gold standard for identifying the causative agent is the skin test, but in vitro tests including specific IgE antibody measurements and basophil activation tests are also beneficial. The Working Group of the Japanese Society of Anesthesiologists has developed this practical guide to help appropriate prevention, early diagnosis and treatment, and postoperative diagnosis of anaphylaxis during anesthesia.Grade of recommendations and levels of evidence Anaphylaxis is a relatively rare condition with few controlled trials, and thus a so-called evidence-based scrutiny is difficult. Therefore, rather than showing evidence levels and indicating the level of recommendation, this practical guideline only describes the results of research available to date. The JSA will continue to investigate anaphylaxis during anesthesia, and the results may lead to an amendment of this practical guideline.

The Japanese Epidemiologic Study for Perioperative Anaphylaxis, a prospective nationwide study: allergen exposure, epidemiology, and diagnosis of anaphylaxis during general anaesthesia

BACKGROUND

Diagnosis of perioperative anaphylaxis is often challenging. This study describes the utility of a newly developed tool for identifying patients with a high possibility of anaphylaxis, and aimed to investigate the frequency of anaphylaxis with each drug during the perioperative period in Japan.

METHODS

This study included patients with anaphylaxis of Grade 2 or higher severity during general anaesthesia at 42 facilities across Japan in 2019 and 2020. We developed and adopted a unique objective evaluation tool yielding a composite score for diagnosing anaphylaxis, which includes the results of skin tests and basophil activation tests, and clinical scores for perioperative anaphylaxis. The number of cases using each drug and the total number of anaphylaxis cases were investigated to calculate the frequency of anaphylaxis.

RESULTS

General anaesthesia was performed in 218 936 cases, which included 55 patients with suspected perioperative anaphylaxis. The developed composite score diagnosed 43 of them with a high probability of anaphylaxis. The causative agent was identified in 32 cases. Plasma histamine levels showed high diagnostic accuracy for anaphylaxis. The top causative agents were rocuronium (10 cases in 210 852 patients, 0.005%), sugammadex (7 cases in 150 629 patients, 0.005%), and cefazolin (7 cases in 106 005 patients, 0.007%).

CONCLUSIONS

We developed a composite tool to diagnose anaphylaxis, and found that the combination of tryptase levels, skin testing, and basophil activation testing results and clinical score improved the certainty of anaphylaxis diagnosis. The incidence of perioperative anaphylaxis in our study was 1 in about 5000 general anaesthesia cases.

CLINICAL TRIAL REGISTRATION

UMIN000035350.

Relationship between afterhyperpolarization profiles and the regularity of spontaneous firings in rat medial vestibular nucleus neurons

Our previous in vivo and in vitro whole-cell patch-clamp recording studies demonstrated that neurons in the medial vestibular nucleus (MVN) could be characterized on the basis of three electrophysiological properties: afterhyperpolarization (AHP) profile; firing pattern; and response pattern to hyperpolarizing current pulses. In the present study, to clarify which types of the classified MVN neurons correspond to neurons with regular or irregular firing, we investigated their spike discharge patterns using whole-cell patch-clamp recording in both in vivo and in vitro preparations. The discharge regularity was related to AHP profiles, and we found that: (i) the coefficient of variation (CV) of interspike intervals during spike discharges was smaller in neurons exhibiting AHP with a slow component [AHP(s+)] than in those without a slow component [AHP(s-)], or with a slow AHP component preceded by afterdepolarization (ADP) [AHP(s+) with ADP]; (ii) the blockade of Ca(2+)-dependent K(+) channels by 100 nm apamin abolished the slow component and increased the CV in neurons exhibiting AHP(s+); and (iii) the modulation of firing (firing gain) in response to ramp current was larger in neurons exhibiting AHP(s-) than in the other two neuronal types. These results suggest that neurons exhibiting AHP(s+) are regularly discharging neurons with small firing gains to stimulus, neurons exhibiting AHP(s+) with ADP are irregularly discharging neurons with small firing gains, and neurons exhibiting AHP(s-) are irregularly discharging neurons with large firing gains. The regular firing of neurons exhibiting AHP(s+) is attributed to the activation of apamin-sensitive Ca(2+)-dependent K(+) channels.

Plasma inflammatory cytokine response to surgical trauma in chronic depressed patients

We investigated inflammatory cytokine response in chronic depressed patients during abdominal surgery. Twenty-five major depressed patients (Group D) and twenty-five patients (Group C) as the control were studied. Plasma interleukin 6 (IL-6), interleukin 8 (IL-8) and tumour necrosis factor-alpha (TNF-alpha) concentrations were measured before and at 15 min after induction of anesthesia, the end of surgery, 24 h and 3 days after the operation. Plasma IL-6 concentrations in Group D at the end of the operation and 24 h after surgery were significantly lower than those of Group C. The plasma IL-6 concentration (87.1+/-55.3 pg/ml) of patients scoring more than 18 points in the Hamilton depression-rating score at the end of the operation was significantly higher than 57.5+/-76.7 pg/ml of patients scoring less than 18 points. Plasma IL-8 concentration (6.1+/-3.2 pg/ml) in Group D at the end of the operation was significantly lower than 8.7+/-4.2 pg/ml of Group C. We conclude that plasma IL-6 and IL-8 response to surgical trauma is inhibited in chronic depressed patients. The IL-6 response to surgical trauma is depending on the clinical state of depression.

Remimazolam anaphylaxis during anesthesia induction

Anaphylactic shock is a potentially lethal complication during anesthesia and requires appropriate management to save the patient's life. We report a 32-year-old man who developed anaphylaxis during induction of general anesthesia with remimazolam for hand surgery. He received general anesthesia with midazolam 4 weeks before. This time facial flushing followed by a decrease of peripheral oxygen saturation (SpO₂) and blood pressure occurred 2 min after starting continuous remimazolam infusion at 6 mg/kg/h. Hypotension and SpO₂ were recovered by repeated administration of adrenaline. Despite no increase of serum tryptase levels, intradermal allergy tests 4 weeks postoperatively revealed that remimazolam and midazolam were positive, suggesting remimazolam as a causative agent for anaphylaxis. In the previous surgery, midazolam, which has a similar structure to remimazolam, may have caused sensitization. This is probably the first case report of anaphylaxis caused by remimazolam.

Exercise-induced cerebral deoxygenation among untrained trekkers at moderate altitudes

The pathophysiology of altitude-related disorders in untrained trekkers has not been clarified. In the present study, the effects of workload on cardiovascular parameters and regional cerebral oxygenation were studied in untrained trekkers at altitudes of 2700 m and 3700 m above sea level. We studied 6 males and 4 females at each altitude, and their average ages were 31.3+/-7.1 y at 2700 m and 31.2+/-6.8 y at 3700 m, respectively. The resting values of heart rate and mean blood pressure were not significantly different at 2700 m and 3700 m than at sea level. However, increases in these values after exercise were more prominent at high altitudes (heart rate increase = 51.6% at 2700 m and 70.4% at 3700 m; mean blood pressure increase: 19.0% at 2700 m and 17.2% at 3700 m). In addition, post-exercise blood lactate concentration was significantly higher at 3700 m than at sea level or at 2700 m (i.e., 7.6 mM at 3700 m, 3.8 mM at 2700 m, and 4.17 mM at 0 m, respectively). Exercise induced an acute reduction in the arterial oxygen saturation value (SpO2) at 2700 m and 3700 m (i.e., 11.2% reduction at 2700 m and 9.4% at 3700 m), whereas no changes were observed at sea level. The resting values of regional oxygen saturation (rSO2)--measured by a near infra-red spectrophotometer at sea level, 2700 m, and 3700 m-were nearly identical. Exercise at sea level did not reduce this value. In contrast, we observed a decrease in rSO2 after subjects exercised at 2700 m and 3700 m (i.e., 26.9% at 2700 m and 48.1% at 3700 m, respectively). The rSO2 measured 2 min and 3 min after exercise at 3700 m was significantly higher than the preexercise value. From these observations, we concluded that alterations in cardiovascular parameters were apparent only after an exercise load occurred at approximately 3000 m altitude. Acute reduction in cerebral regional oxygen saturation might be a primary cause of headache and acute mountain sickness among unacclimatized trekkers.