Biomedical subjects

T Kumazawa

Publications and source records attributed to T Kumazawa.

At least 73 records · Page 4Linked to original sources

PubMed1999

[Cesarean section in a patient with severe diabetic ketoacidosis associated with intracranial hemorrhage of the fetus].

A patient at 33 weeks of pregnancy with diabetic ketoacidosis was transferred to our hospital. Despite intensive medical treatment, fetal state deteriorated and fetal distress was documented. A decision was made to deliver the fetus immediately. An asphyxial neonate was delivered by cesarean section under spinal anesthesia. The neonate was resuscitated in the operating room and intensively managed at the pediatric ward. CT scan revealed the multiple intracranial hemorrhage in the neonate on the fifth day of the birth. Stringent glucose control during pregnancy is crucial for the health of both the mother and fetus.

Adult↗

PubMed1999

[Hyperkalemia after irradiated blood transfusion].

A 70-yr-old woman was scheduled for hepatectomy and colectomy. We gave general anesthesia with N2O-O2-Isoflurane and continuous epidural block. About 4.5 hours after the start of the operation, 8 units of irradiated RBC-MAP were transfused. Then elevated T waves were noted and serum potassium was increased to 5.4 mmol.l-1. The transfusion of RBC-MAP was stopped and calcium gluconate was administered immediately. Then serum potassium decreased to 4.3 mmol.l-1 and ECG returned to normal. During the operation, 10 units of irradiated RBC-MAP were transfused and 8 units of them had been stored more than 1 week after the irradiation. We suspect that hyperkalemia was induced by high concentration of potassium in RBC-MAP. Irradiation of blood products is an effective way to prevent post-transfusion graft versus host disease. However, the increase in potassium is greater in the irradiated than nonirradiated RBC-MAP. We must pay attention to the high concentration of potassium in th eplasma of RBC-MAP stored after irradiation.

Aged↗

PubMed1999

[Anesthetic management of cesarean section for conjoined twins].

A 31-year-old female patient underwent cesarean section for conjoined twins under general anesthesia. In the 33rd week of pregnancy, MRI showed the twins to be a thoracopagus, whose hearts and livers are combined. The patient was not informed that her fetus combined. General anesthesia was induced with thiamylal 200 mg and vecuronium 8 mg in the presence of two pediatricians. Anesthesia was maintained with 66% nitrous oxide in oxygen until the delivery. Just after the delivery, methylergometrine maleate 0.2 mg, midazolam 5 mg, and fentanyl 100 micrograms were administered intravenously. PGF2 alpha was administered in the uterus because of inadequate contraction of the uterus. Apgar score was 0 point at both 1 minute and 5 minutes. Autopsy showed their hearts and livers combined. Conjoined twins tend to die early after birth because of abnormality in their hearts. We selected general anesthesia for this case considering mother's feeling, and we successfully held intraoperative bleeding down with methylergometrine maleate and extra PGF2 alpha.

Adult↗

PubMed1999

[Bilateral pneumothorax following lower neck and upper mediastinal surgery].

A 46-year-old male underwent resection of parathyroid tumor under general anesthesia. The preoperative chest radiography was normal. Arterial blood pressure, heart rate, and arterial oxygen saturation (SpO2) were stable during the operation. Because the tumor was in the mediastinum, incision was made behind the sternum and a drainage catheter was placed. At the completion of the surgery, spontaneous breathing began immediately. The neuromuscular blockade was reversed, and severe bucking was noted. Although the patient was not fully recovered from anesthesia, he was extubated because of his stable respiration and SpO2. Soon after the extubation, the patient developed cyanosis and the SpO2 declined to less than 50%. Chest radiography revealed bilateral pneumothorax, which was successfully treated by inserting bilateral chest tubes. Injury of parietal pleura, which might have been associated with the surgery and/or postoperative bucking, may be the main cause of the pneumothorax. Anesthetists should be aware of the occurrence of pneumothorax during neck surgery and have to avoid bucking postoperatively.

Anesthesia, General↗

PubMed1999

[Premixing of 5% dextrose in Ringer's acetate solution with propofol reduces incidence and severity of pain on propofol injection].

The purpose of this study was to compare the effect of premixed 5% dextrose in Ringer's acetate solution and premixed lidocaine with propofpl on the reduction of pain during injection of propofol in adult patients. We conducted a prospective, randomized, double-blinded trial. Ninety-six patients were randomly allocated to one of three groups according to the agents added to 1% propofol 20 ml; Group C, normal saline 2 ml, Group L, 2% lidocaine 2 ml, and Group A, 5% dextrose in Ringer's acetate solution 2 ml. The pain on injection was rated as none, mild, moderate, or severe. Seventy percent of patients in the C group experienced pain, while 33% and 25% of patients experienced pain in the A group and the L group, respectively. Forty-two percent of patients in the C group complained moderate to severe pain but only one patient in both A group and L group. In conclusion, 5% dextrose in Ringer's acetate solution premixed with 200 mg propofol significantly reduces incidence and severity of pain associated with propofol injection and is easier to use than premixed lidocaine.

Adult↗

PubMed1998

Determination of cyanide in whole blood by capillary gas chromatography with cryogenic oven trapping.

Cyanide, one of the most important toxic substances, has been found measurable with high sensitivity by capillary gas chromatography (GC) with cryogenic oven trapping upon injection of headspace (HS) vapor samples. The entire amount of cyanide in the HS sample could be cryogenically trapped prior to on-line GC analysis. A 0.5-mL volume of blood in the presence or absence of cyanide and propionitrile (internal standard, IS) was added to a vial containing 0.25 mL of distilled water, 0.3 g of Na2-SO4, 0.2 mL of 50% H3PO4, and 0.1 g of ascorbic acid (when needed), and the mixture was heated at 70 degrees C for 15 min. A 5-mL volume of the HS vapor was introduced into a GC capillary column in the splitless mode at -30 degrees C oven temperature that was programmed up to 160 degrees C for GC analysis with nitrogen-phosphorus detection. A sharp peak was obtained for cyanide under the present conditions, and backgrounds were very clean. The extraction efficiencies of cyanide and IS were 2.89-3.22 (100 or 500 ng/mL) and 2.42%, respectively. The calibration curve showed good linearity in the range of 25-1000 ng/mL and the detection limit was approximately 2 ng/mL. The coefficients of intraday and interday variations were 2.9 and 11.8%, respectively. The mean blood cyanide level measured for actual fire victims was 687 +/- 597 ng/mL (mean +/- SD, n = 9). Endogenous blood cyanide concentration for healthy subjects was 8.41 +/- 3.09 ng/mL (mean +/- SD, n = 6).

Chromatography, Gas↗

PubMed1998

Examination of colocalization of calcitonin gene-related peptide- and substance P-like immunoreactivity in the knee joint of the dog.

It is generally assumed that the majority of substance P (SP)-containing afferents are also immunoreactive for calcitonin gene-related peptide (CGRP). In order to determine whether this is also the case in articular afferents where the contents of these peptides are low, we carried out a double labeling study using Fast Blue (FB) as a retrograde tracer injected into the center of the knee joint cavity of the dog together with immunohistochemistry for SP and CGRP. After 7-36 days of survival, dorsal root ganglia (DRGs, L4-S1) were removed. Labeled cells were found mainly (94%) in L5 - 6 DRGs, and SP- and CGRP-like immunoreactivity was found in about 17 and 29% of FB-labeled cells, respectively. The coexistence of SP and CGRP was observed in 10.4% of articular afferents and only 62.7% of SP-positive articular neurons contained CGRP, a much lower ratio than in other afferents of the dog such as testicular afferents. Our data suggest that these peptides are not always released together and that they do not always work together in the joint under normal conditions.

Animals↗

PubMed1998

Headspace solid-phase microextraction and gas chromatographic determination of dinitroaniline herbicides in human blood, urine and environmental water.

Solid-phase microextraction (SPME) is a unique extraction and sampling technique, and it has been used for separation of volatile organics from water or other simple matrices. In this study, we have used SPME to separate dinitroaniline herbicides from complicated matrices of human urine and blood in order to broaden its application to biomedical analysis. The SPME conditions were optimized for water, urine and blood samples, in terms of pH, salt additives, extraction temperature, and fiber exposure time. Urine or water (1.0 ml) spiked with herbicides and 0.28 g of anhydrous sodium sulfate was preheated at 70 degrees C for 10 min, and a polydimethylsiloxane-coated fiber for SPME was exposed to the headspace at 70 degrees C for another 30 min; while spiked blood (0.5 ml) diluted with water (0.5 ml) was treated at 90 degrees C in the same way. The herbicides were extractable under these conditions, and could be determined by gas chromatography-electron capture detector (GC-ECD). The recoveries of the herbicides, measured at the concentrations of 0.50 and 1.0 ng/ml urine or water, or 6.0 and 20 ng/0.5 ml blood, ranged from 35 to 64% for different herbicides from water or urine, and from 3.2 to 7.2% from blood. The headspace SPME yielded clean extracts of dinitroaniline herbicides from urine, blood or water, which could be directly analyzed by GC-ECD without further purification. The peak areas of the extracted herbicides were proportional to their concentrations in the range 0.1-10 ng/ml in water or urine, or 1-60 ng/0.5 ml in blood. The lowest detectable concentration of the herbicides lay in 0.1 ng/ml water or urine, or in 0.5 ng/0.5 ml blood. The intra- and inter-day coefficients of variation were within 14% for most of the analytes. Although the recoveries of the herbicides were rather low, the linearity of calibration curve and the precision were good. The developed method is more sensitive and much simpler in sample preparation than previously reported ones. With the established SPME method, a dosed herbicide was successfully separated and determined in rats' blood.

Aniline Compounds↗

PubMed1998

Difference in sensitivity of inner cell mass and trophectoderm to X-irradiation in mouse blastocysts.

Pregnant B6C3F1 mice were exposed to a single whole body X-irradiation on day 4 (73-74 hr postconception) of gestation. In experiment 1, they were sacrificed at 2, 4, 6, or 9 hr after a dose of 2 Gy, and their embryos were removed and examined with light and electron microscopy. In experiment 2, dose-response effects of irradiation on the embryos were examined 4 hr after doses of 0-4 Gy. In experiment 3, DNA fragmentation (a marker of apoptosis) was observed by 3'-OH nick-end labeling technique. In inner cell mass (ICM) and trophectoderm (TE) of blastocysts exposed to 2 Gy, cells with cytoplasmic degeneration, or dead cells phagocytosed by their neighboring cells, were found. Although morphological features of these dying cells did not reveal typical characteristics of apoptosis such as nuclear condensation and membrane blebbing, DNA fragmentation was detected by nick-end labeling technique. The degenerated cytoplasm consisted of aggregating ribosomes. Degenerated cells began to increase from 2 hr after irradiation and reached maximal at 4 hr in both ICM and TE. The incidences of degenerated cells in ICM were higher than those in TE at any time point. These findings provide evidence that cell death observed in blastocysts after X-irradiation is apoptotic and sensitivity of the two groups of cells (ICM and TE) to X-rays is different.

Animals↗

PubMed1998

Amino acid-activated channels in the catfish taste system.

Membrane vesicles derived from external taste epithelia of channel catfish (Ictalurus punctatus) were incorporated into lipid bilayers on the tips of patch pipettes. Consistent with previous experiments (Teeter, J. H., J. G. Brand, and T. Kumazawa. 1990. Biophys. J. 58:253-259), micromolar (0.5-200 microM) concentrations of L-arginine (L-Arg), a potent taste stimulus for catfish, activated a nonselective cation conductance in some bilayers, which was antagonized by D-Arg. Two classes of L-Arg-gated receptor/channels were observed in reconstituted taste epithelial membranes: one with a unitary conductance of 40-60 pS, and the other with a conductance of 75-100 pS. A separate class of nonselective cation channels, with a conductance of 50-65 pS, was activated by high concentrations of L-proline (L-Pro) (0.1-3 mM), which is the range necessary to elicit neural responses in catfish taste fibers. The L-Pro-activated channels were not affected by either L- or D-Arg, but were blocked by millimolar concentrations of D-Pro. Conversely, neither L- nor D-Pro altered the activity of either class of L-Arg-activated channels, which were blocked by micromolar concentrations of D-Arg. These results are consistent with biochemical, neurophysiological, and behavioral studies indicating that taste responses of channel catfish to L-Arg are mediated by high-affinity receptors that are part of or closely coupled to nonselective cation channels directly gated by low concentrations of L-Arg, while responses to L-Pro are mediated by distinct, low-affinity receptors also associated with nonselective cation channels.

Amino Acids↗

PubMed1998

Tissue-specific effects of estrogen on monoamine oxidase A and B in the rat.

Estrogen replacement therapy is widely used in postmenopausal women. The current study examines the effect of varying concentrations of estrogen on the levels of activity of monoamine oxidase A and -B in brain and in other tissues. Adult female rats were ovariectomized and randomized to receive a subcutaneous, slow-release preparation of either placebo or one of three doses of 17-beta-estradiol (0.05, 0.5, or 5.0 mg/pellet, estimated serum levels of 20-25 pg/ml, 100-600 pg/ml, and 1-2 ng/ml, respectively). Animals were sacrificed at 3 weeks and MAO-A and -B activity was assessed in homogenates of heart, liver, lung, uterus, kidney, adrenal and small intestine using 5-hydroxytryptamine and phenylethylamine as substrates. Cortex, amygdala and hypothalamus were microdissected from frozen sections of the brain and were also assayed for MAO-A and -B activity. High dose estrogen (5 mg/pellet) significantly decreased MAO-B activity and resulted in lesser or insignificant changes in MAO-A activity, respectively in liver (-30%, +1%), kidney (-22%, -11%), and uterus (-57%, -35%) (p < 0.05). No significant changes in enzyme activity were observed in heart, adrenal, lung and small intestine. In brain, estrogen (5 mg/pellet) decreased MAO-A activity in the hypothalamus (-28%) and amygdala (-21%), with no significant change seen in MAO-B. Our results suggest that estrogen exerts a tissue-specific, differential regulation of MAO-A and -B activity.

Animals↗

PubMed1998

Primitivism and plasticity of pain--implication of polymodal receptors.

Bio-warning and defense mechanisms play the most fundamental roles in living organisms. From an evolutionary point of view, nociceptive systems are very primitive and are richly provided with humoral signaling mechanisms of aboriginal humoral defense systems, as reflected in the primitive nature of the polymodal receptor, a poorly differentiated sensory receptor signaling nociceptive information. Recent advances in studies on pain have made it possible to explain neural mechanisms of pain systems under physiological conditions and reveal that there is a large gap between physiological and pathological pains. Protracted nociceptive inputs under pathological conditions induce plastic, either functional or structural, alterations in the nociceptive pathways. These plastic changes lead to crosstalk among the neural networks, including circuits related to motor, autonomic, or psychological functions. These plastic changes, once established, persist even after the original pain sources disappear in a memory-like fashion. Thus, it is revealed that chronic pain cannot be treated by blocking pain pathways, which is effective against acute pain, but require treatment from a multidisciplinary perspective.

Animals↗

PubMed1998

Nerve growth factor increases sensitivity to bradykinin, mediated through B2 receptors, in capsaicin-sensitive small neurons cultured from rat dorsal root ganglia.

To examine the effects of nerve growth factor (NGF) on the response to bradykinin (BK) of primary afferent neurons, intracellular recordings were obtained from small (< 30 microm) and large (> or = 35 microm) neurons in rat dorsal root ganglia (DRG). The response to BK in the small neurons was tested in 23 freshly dissociated neurons (dissociated group), 37 neurons cultured in the absence of NGF (no-NGF group) and 117 neurons in the presence of NGF (NGF group). Application of BK (10(-7) or 10(-5) M) induced a depolarization in a small number of neurons in the freshly dissociated (13%) and the no-NGF (11%) groups. After cultivation with NGF, the percentage of neurons that were depolarized by BK significantly increased to 46% after 2 days of cultivation. In the NGF group, the percentage of neurons sensitive to BK was significantly greater among capsaicin (CAP)-sensitive than among CAP-insensitive neurons (48 vs 20%). This BK-induced depolarization was completely blocked by a B2 receptor antagonist, but not a B1 receptor antagonist. With large neurons, in contrast, NGF did not increase the percentage that were BK-sensitive (9% in the dissociated group vs 0% after being cultured 2 days with NGF). These results demonstrate that NGF increases sensitivity to BK, mediated through B2 receptors only, in capsaicin-sensitive small neurons cultured from rat DRGs.

Afferent Pathways↗

PubMed1998

Comparative effects of Ringer's acetate and lactate solutions on intraoperative central and peripheral temperatures.

STUDY OBJECTIVES: To compare the effects of Ringer's lactate (LR) and Ringer's acetate (AR) solutions on core body and peripheral temperatures during isoflurane or sevoflurane anesthesia. DESIGN: Prospective, randomized study. SETTING: Operating rooms of a university hospital. PATIENTS: 60 ASA physical status I and II patients undergoing general surgery. INTERVENTIONS: Following induction with 5 mg/kg of thiamylal and 0.1 mg/kg of vecuronium, patients were randomly assigned to one of four groups (15 patients per group). They received inhalation anesthetics (66% nitrous oxide [N2O] and 1.0% to 2.0% isoflurane or 1.3% to 2.6% sevoflurane) and LR or AR. MEASUREMENTS AND MAIN RESULTS: Tympanic membrane (central) temperatures, forearm temperatures, and fingertip temperatures were recorded during surgery every 30 minutes. Tympanic membrane temperatures in the patients given AR were significantly higher than those given LR during isoflurane anesthesia 5 and 30 minutes after induction of anesthesia. However, this was not the case for sevoflurane anesthesia. There were no significant differences in forearm and fingertip temperatures or fingertip bloodflow among the four groups. CONCLUSION: There was no significant difference between AR and LR in the preservation of heat during either sevoflurane or isoflurane anesthesia. However, AR may be superior to LR for maintaining central temperature during the early period of isoflurane anesthesia.

Acetates↗

PubMed1998

Propofol anesthesia for cesarean section successfully managed in a patient with moyamoya disease.

We report a case of general anesthesia in a 25 year-old female patient with moyamoya disease who presented for cesarean section. General anesthesia was induced with propofol 100 mg, succinylcholine 50 mg, and nicardipine 1 mg intravenously (i.v.), and maintained with 60% nitrous oxide in oxygen. Just after the clamp of the umbilical cord, propofol 10 mg/kg/hr following propofol 50 mg pentazocine 15 mg vecuronium 8 mg, and methylergometrine maleate 0.2 mg were given i.v. The rate of infusion of propofol was reduced to 8 mg/kg/hr 10 minutes after the clamp and reduced to 6 mg/kg/hr 20 minutes after the clamp. Additional pentazocine 15 mg was given i.v. Blood pressure was maintained between 110 and 145 systolic, and 50 and 85 diastolic mmHg, and end-tidal carbon dioxide was between 34 and 36 mmHg. No postoperative deterioration of the patient's neurologic findings occurred. For the anesthetic management of moyamoya disease patients, especially in delivery, it is important to avoid hemodynamic changes and to maintain cerebral blood flow (CBF). We used propofol for hemodynamic stability and avoided hyperventilation so as to maintain CBF. We successfully managed the patient perioperatively.

Adult↗

PubMed1998

Interpleural misplacement of an epidural catheter.

We report a case of interpleural misplacement of an epidural catheter possibly caused by inappropriate angle of the Tuohy needle. A 71-year-old man was scheduled for left lower lobectomy of the lung with general and epidural anesthesia. A 18-gauge Tuohy needle was introduced into the Th5-Th6 interspace with a right paramedian approach. The direction of the epidural needle was at an angle of about 30 degrees from the skin directed cephalad. The needle was advanced 8 cm from the skin, where loss-of-resistance feeling was evident, and an epidural catheter was easily inserted 5 cm beyond the needle tip. Administration of 7 ml of 1.5% lidocaine given 20 minutes before skin incision did not alter arterial blood pressure or heart rate. Thoracotomy was performed via the fifth intercostal space. The surgeon then found the epidural catheter to be in the left pleural cavity. The catheter was immediately withdrawn. It is, therefore, necessary to employ the appropriate angle of the Tuohy needle on attempting epidural anesthesia to avoid the complication that we experienced.

Aged↗

PubMed1998

Stellate ganglion block does not change the tympanic membrane temperatures of either block or unblock sides in male volunteers.

STUDY OBJECTIVES: To test the effect of stellate ganglion block on tympanic membrane temperatures. DESIGN: Prospective, observational study. SETTING: Department of Anesthesia, Yamanashi Medical University, Yamanashi, Japan. SUBJECTS: 7 healthy male volunteers. INTERVENTIONS: Stellate ganglion block, 6 ml of 1% mepivacaine hydrochloride, was administered. MEASUREMENTS AND MAIN RESULTS: Application of temperature probes (right and left tympanic membranes, eight adhesive right skin-surface temperatures at the chest, upper arm, digital fingertip, lateral calf, thigh, and great toe) was followed by a 30-minute control period. Temperatures were recorded every 15 minutes for 30 minutes before stellate ganglion block and every 5 minutes for 40 minutes after the block. The right tympanic membrane temperature increased slightly but not significantly compared with the left tympanic membrane temperature 10 minutes after stellate ganglion block and subsequently. Right skin-surface temperature gradients at the upper limb decreased slightly but not significantly after stellate ganglion block. Similarly, right skin-surface temperature gradients at the lower limb decreased slightly but not significantly after stellate ganglion block. CONCLUSIONS: Stellate ganglion block does not change the tympanic membrane temperatures of either block or unblock sides.

Adult↗

PubMed1998

Indole and benzimidazole derivatives as steroid 5alpha-reductase inhibitors in the rat prostate.

A novel series of indole and benzimidazole derivatives were synthesized and evaluated for their inhibitory activity of rat prostatic 5alpha-reductase. Among these compounds, 4-¿2-[1-(4,4'-dipropylbenzhydryl)indole-5-carboxamido]phenoxy¿buty ric acid (15) and its benzimidazole analogue 25 showed potent inhibitory activities for rat prostatic 5alpha-reductase (IC50 values of 9.6+/-1.0 and 13+/-1.5 nM, respectively), with the potency very close to that of finasteride. Compound 30, in which the moiety between the benzene ring and amide bond was replaced by quinolin-4-one ring, showed almost equipotent activity (IC50= 19+/-6.2nM) with the correspondent amide derivative 13. This result was consistent with the previous observation that the coplanarity of this moiety might contribute to the potent inhibitory activity.

5-alpha Reductase Inhibitors↗