Michiko Sugita

Rhythmic Cl− current and physiological roles of the intestinal c-kit-positive cells

Chronic injection of an anti-c-KIT receptor tyrosine kinase monoclonal antibody (ACK2) results in the disruption of the normal motility patterns of young BALB/c mice intestine. This effect is accompanied by a drastic decrease in the number of intestinal c-kit-expressing (c-kit+) cells when studied immuno-histochemically with the fluorescence-labelled antibody. In order to clarify the mechanism underlying the ACK2 action and the physiological roles of intestinal c -kit+ cells, we studied the excitability of intestinal c -kit+ cells in primary culture by use of the nystatin perforated-patch-clamp technique. Under voltageclamp at −40 mV, the majority of c -kif+cells tested (59/70) elicited rhythmic current waves with an amplitude and frequency of 263±24 pA and 2.30±0.25 cycles/min (mean±SEM), respectively. Intracellular perfusion of the c -kit+ cells with ethylenebis (okonitrilo) tetraacetate (EGTA) as well as a nominally Ca2+-free external solution or low holding voltage (<-60 mV) prevented the rhythmic current. The reversal potential of the rhythmic current was close to the equilibrium potential for Cl−(ECl) Moreover the rhythmic current was depressed by a Cl− channel blocker, 4-acetoamido-4-isothiocyanat-ostilbene-2,2′-disulphonic acid (SITS). The smooth muscle cells freshly dissociated from the same intestinal specimen revealed a Ca2+-activated K+current, as has been described in a variety of smooth muscle cells. Cultured smooth muscle cells from the ileum preparation lacked neither the Ca2+-activated K+nor rhythmic Cl− currents. Smooth muscle cells freshly dissociated from the same ileum preparation and those in culture showed no immunoreactivity with the labelled ACK2, which was consistent with our previous in situ study. Results provided direct evidence that the intestinal c -kit+ cells, but not the smooth muscle cells, possess a rhythmic Cl− current oscillation, suggesting their participation in pacemaker activity for the peristaltic gut movement.

Differential expression of CCAAT enhancer binding protein family in rat alveolar epithelial cell proliferation and in acute lung injury.

Abstract Although alveolar reorganization after acute lung injury depends on regeneration of alveolar epithelial cells, there is little knowledge of regulation of pulmonary healing process. Transcription factors may play key roles in this regulation. To investigate whether the CCAAT enhancer binding protein (C/EBP) family, α, β, and δ, were involved in alveolar reorganization after injury, we examined expression of C/EBP proteins and mRNAs in lung injuries induced by lipopolysaccharide (LPS) or bleomycin (Bleo) and in cell proliferation by keratinocyte growth factor (KGF). By immunohistochemistry, we demonstrated that C/EBPα and C/EBPβ were expressed in alveolar type II cells and alveolar macrophages, but C/EBPδ was expressed restrictedly in some of alveolar type II cells in a spatial pattern in the control lungs. Further, these three C/EBP family members were differentially expressed in alveolar cell proliferation and in acute lung injury, in which, interestingly, C/EBPα and C/EBPδ were reciprocally expressed in alveolar type II cell proliferation and in pulmonary fibrosis. However, expressions of their mRNAs by in situ hybridization were dramatically increased in the affected lesions of the lungs by LPS and Bleo, and Northern blot analysis showed an increased abundance of the mRNA for C/EBPβ in LPS-treated lungs and for C/EBPδ in Bleo-treated lungs, compared with those in the control lungs. Thus, differential expression of the C/EBP family may be required to maintain and reorganize the basic integrity of alveolar structure during pathological states, which suggests an important role for the C/EBP family in maintaining normal alveolar architecture and function and in repairing the damaged epithelium after injury.

The properties of caffeine- and carbachol-induced intracellular Ca2+ release in mouse bladder smooth muscle cells.

Freshly dissociated bladder smooth muscle cells of mice developed spontaneous, caffeine- (ICAF) and carbachol-induced (ICCh) currents under voltage-clamped conditions. Spontaneous currents, ICAF and ICCh were blocked with tetraethylammonium at 3 x 10(-4)-10(-2) M but were resistant to both charybdotoxin (10(-7)-10(-6) M) and iberiotoxin (10(-7)-10(-6) M). The reversal potential for each current indicated that K+ channels play a major role in the generation of each current. Both spontaneous currents and ICAF but not ICCh were abolished in nominally Ca2+-free and nicardipine (10(-6) M)-containing media. These results suggest that the activity of L-type voltage-sensitive Ca2+ channels is important in the generation and maintenance of spontaneous currents and ICAF but not ICCh. Ryanodine (10(-6) M) prevented spontaneous currents, ICAF and caffeine-induced [Ca2+]i elevation but not ICCh and carbachol-induced [Ca2+]i elevation, suggesting that the response of bladder smooth muscle cells to carbachol may involve a Ca2+ store distinct from that for caffeine. Pretreatment with carbachol suppressed ICAF to 22 +/- 7% (n = 7) and the caffeine-induced [Ca2+]i elevation to 25 + 3% (n = 6). Similarly, caffeine suppressed ICCh to 23 +/- 4% (n = 9) and the carbachol-induced [Ca2+]i elevation to 24 +/- 6% (n = 6).

Perioperative management of a patient with thyroid hormone resistance who underwent total thyroidectomy for thyroid cancer

Resistance to thyroid hormone (RTH) is a rare, predominantly inherited syndrome that involves impaired tissue responsiveness to thyroid hormones. We describe the perioperative management of a patient with RTH who underwent total thyroidectomy. Although surgery performed under general anesthesia was uneventful, after the surgery the patient developed difficult-to-treat hypocalcemia that lasted until postoperative day 4. Moreover, thyroid function even after discharge remained unstable despite replacement therapy. We suggest that the parathyroid and thyroid function of patients with RTH be followed very closely and that nociceptive stimulus of the surgery and postoperative pain be reduced as much as possible.

Visual hallucinations on eye closure after orthopedic surgery under general anesthesia

A 61-year-old woman suffering from rheumatoid arthritis without a contributory neurological, mental, or psychological history experienced visual hallucinations solely on eye closure after total hip arthroplasty under general anesthesia combined with epidural anesthesia. The visual hallucinations first appeared when she arose from sleep early on postoperative day 1, approximately 12 h after the end of surgery. Only on closing her eyes, she had a clear view of colored clothes, lace curtains, handbags, hats, and sofas, all of which were vivid, realistic, complex, of natural size, and in normal perspective without distortion and appeared independently and randomly in succession. The hallucinations disappeared when she opened her eyes even in the dark. The visual hallucinations gradually decreased as the days elapsed and they had entirely subsided on postoperative day 4. The level and content of her consciousness seemed entirely normal throughout her hospital course. Although postoperative visual hallucinations are not uncommon, they do not always show the closed-eye variation. The causes and underlying mechanisms of this type of visual hallucination remain to be elucidated.

Effect of the season on the neurological outcome in children with cardiac arrest

Abstract Twenty children who were successfully resuscitated after cardiac arrest (CA) were retrospectively studied to examine the hypothesis that children with CA may have a worse neurological outcome in hot weather than in cold weather. Of 7 children with CA in the cold season (atmospheric temperature < 14oC), 4 in the warm season (14‐24oC) and 9 in the hot season (> 24oC). 5 (71%), 2 (50%), and 1 (11%), respectively, recovered consciousness (/3<0.05). Postresuscitative hyperthermia tended to be frequently observed in the group of children who suffered CA in the hot season, and it appeared to be associated with neurological damage. This preliminary study suggests that the neurological outcome of children with CA changes with the seasons, with a worse neurological outcome for CA in hot weather than in cold weather. A prospective study is required to determine whether, in a hot season or area, cooling of pediatric cardiac arrest victims during cardiopulmonary resuscitation on the scene improves the neurological outcome.

Even low doses of dexmedetomidine produced obstructive apnea during spinal anesthesia

To the Editor, Dexmedetomidine (DEX) is a sedative that produces less respiratory depression than midazolam or opioids. We examined whether DEX at \ 0.7 ng mL (an appropriate plasma concentration for sedation in the intensive care unit) provided a plasma concentration that would sedate surgical patients sufficiently under spinal anesthesia. The protocol of this study was approved by the Ethics Committee of Kumamoto University Hospital, Kumamoto, Japan and is registered in the UMIN Clinical Trial Registry (UMIN 000013558). The study included 23 patients who were scheduled for surgery with spinal anesthesia using 0.5% isobaric bupivacaine (puncture site at L3/4 or L4/5; upper effective level at Th5). In a pilot study, in which DEX was administered at a dose recommended in the package insert (1 lg kg for ten minutes and then 0.2 lg kg hr), we found that the mean (SD) plasma DEX concentration (DEXC) was 0.78 (0.21) ng mL at the end of surgery. In the present study, DEX was administered intravenously at a dose of 0.5 lg kg for ten minutes and then 0.2 lg kg hr after sensory blockade was achieved up to the appropriate level. Oxygen at 2 L min was administered using a nasal cannula. The respiratory pattern was evaluated during the entire surgical period by measuring chest and abdominal excursions, airflow at the nose and mouth, snoring sounds at the neck using SAS-3200 (Nihon Kohden, Tokyo, Japan), and measuring the CO2 concentration at the nose and mouth using Capnostream 20 (Nihon Kohden). Apnea was defined as airflow cessation for more than 15 sec. Obstructive apnea was defined as airflow cessation while chest and/or abdominal excursions were observed. The sedative effect was estimated using the Observer’s Assessment of Alertness/Sedation (OAA/S) score. Patient satisfaction level was evaluated using a five-point scale (5: very satisfied, 1: very unsatisfied) at the time of discharge. Dexmedetomidine concentration and PaCO2 were measured at the end of surgery. Dexmedetomidine concentrations were measured by its manufacturer (Maruishi Pharmaceutical, Osaka, Japan), with the precise measurement method not yet published. The mean (standard deviation [SD]) patient characteristics for the 21 men and two women were as follows: age 71 (10) yr; height 162 (7) cm; weight 60 (11) kg; body mass index 23.0 (3.6) kg m. The mean (SD) duration of DEX infusions was 49 (31) min. The mean (SD) cumulative dose of DEX was 42.6 (9.5) lg, with the DEXC at the end of surgery at 0.47 (0.09) ng mL. The minimum OAA/S score was 3.3 (range 1-5). The satisfaction level on the five-point scale was 4.2 (range 2-5). Overall, 17/23 (73.9%) patients had apnea, with each event being of an obstructive type. At the end of the surgery, the PaCO2 level was 43 (5) mmHg. There was no correlation between the DEXC and PaCO2 (see Figure, r = 0.39, P = 0.07). There was no difference between the DEXC of apnea(?) patients [(0.47 (0.10) ng mL] and that of apnea(-) patients [0.47 (0.09) ng mL] (see Figure, P = 0.9 by Student’s t test). Although the SpO2 Trial registration: www.umin.ac.jp/ctr/. Registered 30 March 2014.

Preoperative acute hypervolemic hemodilution with hydroxyethylstarch in a Jehovah's Witness: effects on hemodynamics and coagulation systems

The increased attention to the risks associated with homologous blood transfusion has provided the impetus for the development of techniques to minimize transfusion. Transfusion with donor blood may be diminished by the use of predeposited autologous blood, intraoperative autotransfusion with a cell-saving device, and hemodilution techniques. Preoperative hemodilution can be achieved either by withdrawal of blood and simultaneous infusion of fluid, i.e., normovolemic hemodilution (ANH), or by rapid infusion of fluid without blood withdrawal, i.e., acute hypervolemic hemodilution (AHH). A H H is induced by hemodilution with hydroxyethylstarch preoperatively without removing autologous blood, and in order to prevent the hemodynamic effect of a large intravascular volume, we must use vasodilators [1-3]. Hypervolemic hemodilution is not time-consuming and requires no special procedure, such as collection and storage of the patients blood [2]. Patients who refuse ANH, such as Jehovahs Witnesses, are particularly good candidates for AHH. However, in patients who suffer from cardiovascular disease, coagulation disorder, renal dysfunction, particular attention should be paid to AHH. We treated a patient who was a Jehovahs Witness and underwent major surgery under general anesthesia. The patient refused blood transfusion on religious