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Biomedical subjects

Y Kosaka

Publications and source records attributed to Y Kosaka.

At least 145 records · Page 8Linked to original sources
PubMed1991

Fulminant hepatitis B: induction by hepatitis B virus mutants defective in the precore region and incapable of encoding e antigen.

Clones of hepatitis B virus were propagated from 10 cases of fulminant hepatitis B after amplification by polymerase chain reaction and their nucleotide sequences of the precore region were determined. All 113 clones from 9 cases had a point mutation from guanine to adenine at nucleotide 83 in the precore region, which converted codon 28 for tryptophan (TGG) to a stop codon (TAG) and prohibited the synthesis and secretion of hepatitis B e antigen. Precore-region defects were not detected in any of 23 clones from the remaining 1 case. By contrast, precore-region defects were not found in any of 180 clones from 8 cases of acute hepatitis B without hepatic failure serving as controls. The source of infection was traceable in 3 cases. The same precore-region defect, along with the sequence identity of 435 nucleotides, was observed in clones from the case of a baby and his grandmother, who carried the virus and was implicated in the transmission, and also in clones from two pediatricians and the carrier patients they attended. These findings support the hypothesis that precore-defective mutants have stronger activity to induce fulminant hepatitis than nondefective viruses.

Adolescent↗
PubMed1991

Epidural analgesia in Eaton-Lambert myasthenic syndrome. Effects on respiratory function.

The anaesthetic management of a patient with Eaton-Lambert myasthenic syndrome undergoing thoracotomy is described. Epidural anaesthesia, in combination with a light level of general anaesthesia, provided good operating conditions and postoperative analgesia. Pulmonary function and ventilatory responses to carbon dioxide and hypoxia were measured before operation. These tests were repeated after the epidural administration of 8 ml 2% lignocaine before surgery and after 2 mg morphine sulphate in 10 ml saline postoperatively. Minor reductions in some of the ventilatory parameters were observed. The epidural technique appears to be a useful and safe method by which to manage patients with Eaton-Lambert syndrome undergoing thoracotomy.

Analgesia, Epidural↗
PubMed1991

Pharmacokinetics of pirarubicin in pediatric patients.

The pharmacokinetics of pirarubicin and its active metabolite, doxorubicin, were studied after intravenous administration of pirarubicin (25-45 mg/m2) to ten pediatric patients. The concentration-time curves of pirarubicin in both blood and plasma showed representative biphasic patterns. Pirarubicin concentrations decreased rapidly from 0.5 to 2 h after administration and then decreased slowly until 24 h in all subjects. High concentrations of the metabolite, doxorubicin, were detected at 0.5 h after administration of pirarubicin which decreased gradually until 24 h. The area under the concentration-time curve from 0 to 24 h (AUC0-24) of pirarubicin and doxorubicin in blood were 3-4 times higher than those in plasma, suggesting that these drugs had a high affinity for blood cells. The AUC0-24 ratio of doxorubicin to pirarubicin in plasma was calculated to be 0.441. It might be indicated that not only pirarubicin but also doxorubicin are responsible for the therapeutic efficacy and the incidence of toxicity of pirarubicin. The pharmacokinetics of pirarubicin in pediatric patients was fundamentally similar to that of adults, but it was recognized that considerable interindividual variation in the disposition of pirarubicin and doxorubicin exists.

Adolescent↗
PubMed1991

[Effects of intravenous lidocaine administration on auditory brainstem response].

The effect of lidocaine on the auditory brainstem response (ABR) was investigated in 14 neurologically normal patients. Lidocaine 1.5 mg.kg-1.min-1 was injected intravenously over a 5 min period immediately followed by a continuous infusion of lidocaine 60 micrograms.kg-1.min-1. The seven peak latencies (waves I-VII) and amplitudes (waves I-VII) of the ABR were recorded before and 7-8 min after lidocaine infusion. Peak latencies of waves IV, V, VI, VII increased after epidural anesthesia compared with control values. Amplitudes of all waves were unchanged following intravenous lidocaine injection compared with control values. Interpeak latencies (I-II, II-III, III-IV, IV-V, V-VI, VI-VII), of every second peak (I-III, II-IV, III-V, IV-VI, V-VII), of every third peak except (III-VI, IV-VII) were unchanged compared with control values. Interpeak latencies of every fourth peak, of fifth peak increased after lidocaine injection compared with control values. The data obtained in this study with lidocaine injection were similar to the data after epidural anesthesia with lidocaine. One of the reason of the latency changes of ABR after epidural anesthesia was the systemic effect of lidocaine absorbed intravenously from the epidural space.

Adult↗
PubMed1991

[Effects of lumbar epidural anesthesia on brainstem auditory response].

Auditory brainstem responses (ABR) are used increasingly to monitor the integrity of neural pathways in anesthetized patients. To evaluate the effect of epidural anesthesia on the central nervous system, we studied the effects of lumbar epidural anesthesia with lidocaine on the ABR in 10 patients. The seven peak latencies (waves I-VII) and amplitudes (waves I-VII) of the ABR were recorded before and 15 min after epidural anesthesia. Peak latencies of waves III, IV, V, VI, VII increased after epidural anesthesia compared with control values. Amplitude of waves II only decreased significantly following epidural anesthesia compared with control values. We further compared the interpeak latencies to investigate the brainstem transmission. Interpeak latencies (I-II, II-III, III-IV, IV-V, V-VI, VI-VII) were unchanged from the control values except waves VI-VII interval. Interpeak latencies of every second peak (II-IV, IV-VI, V-VII), of every third peak (II-V, III-VI, IV-VII), of every forth peak (I-VI, II-VII), of every fifth peak (I-VII) increased after epidural anesthesia compared with control values. The data obtained in the study demonstrated that lumbar epidural anesthesia with lidocaine prolonged the interpeak latencies of ABR. Considering that the waves of ABR are related to anatomically distinct sites in the auditory pathway (I; Acoustic nerve, II; Cochlear nucleus, III; Superior olivary complex, IV; Lateral lemniscus, V; Inferior colliculus, VI: Medial geniculate body, VII; Auditory radiation), the delay in the latencies of ABR seems to be present in the time intervals which involve more than two or three synaptic transmissions.

Anesthesia, Epidural↗
PubMed1991

[Effects of rectal premedication and the mother's presence on induction of pediatric anesthesia].

The effects of the rectal premedication and the mother's presence on induction of anesthesia were studied with 67 children between the ages of 1 and 6 years. All children were induced with mask using nitrous oxide-oxygen-halothane. Children's emotional states during induction were categorized as excellent, good or fair. Rating of excellent or good was considered to indicate satisfactory induction. Forty-seven children were accompanied by their mother. Twenty-two of them were premedicated with rectal bromazepam (3 mg), while another twenty-five children were not premedicated. Satisfactory induction after premedication was performed on 78% of the 1-3 year olds and 100% of the 4-6 year olds, whereas without rectal premedication, satisfactory induction was achieved in 42% of the 1-3 year olds and 69% of the 4-6 year olds. Rectal premedication was important for satisfactory induction. Another twenty of all children were premedicated with rectal bromazepam (3 mg) and induced without mother presence. Satisfactory induction was performed on 38% of the 1-3 year olds and 100% of the 4-6 year olds. Mother's presence tended to lead to satisfactory induction. Furthermore, we sought feedback from the mothers about their presence during induction of anesthesia. Almost all of the mothers said they appreciated the opportunity to be present, with the exception of four mothers (8.5%) who reported feeling of some anxiety to be in an operating room.

Administration, Rectal↗
PubMed1991

[A case report of anesthetic management of orthotopic liver transplantation from a living donor to his son].

In November 1989, transplantation of a liver graft from a living related donor was performed at Shimane Medical University Hospital. The donor was a 26-year-old man and the recipient his 1-year-old son. The child had been in end stage of liver cirrhosis. Before the surgery, he required intensive care because of massive bleeding from varices. Anesthesia of the recipient was rapidly induced with ketamine and the trachea was intubated with succinylcholine using cricoid pressure. Anesthesia was maintained with enflurane, fentanyl and pancuronium. Nitrous oxide was used only in the preanhepatic period. Total surgical time and anesthetic time were 945 min and 1065 min, respectively. Total estimated blood loss was 3650 ml and 2780 ml of fresh whole blood was transfused. Careful attention was paid to body temperature, serum potassium, ionized calcium and blood coagulation function, as well as to general cardiovascular and respiratory functions. During anhepatic period, the inferior caval vein was not clamped. Hemodynamic function was relatively stable throughout the operation. At the time of reperfusion of the transplanted graft, there was little change in serum potassium levels or other parameters. Postoperative mechanical ventilation was required for 8 days.

Adult↗
PubMed1991

[Cardiac arrest during anesthesia--a case of effective open chest massage].

A 58-year-old man suffering from esophageal cancer was scheduled for radical resection and reconstruction of the esophagus. Immediately after the start of the operation, with the patient under general anesthesia, cardiac arrest occurred. The operation was immediately discontinued and closed chest heart massage was started. As the patient did not respond, open chest massage was initiated. Cardiac arrest can be caused by any one of a number of factors. This case was suspected to have had a coronary artery spasm. It took a total of 100 minutes to resuscitate the patient. But resuscitation was successful without any resulting neurological damage. This was attributed to appropriate open chest massage. If a case of cardiac arrest due to any coronary artery disease does not respond to the usual cardiopulmonary resuscitation, we should consider open chest massage.

Anesthesia, General↗
PubMed1991

[Effects of intravenous lidocaine administration on median nerve somatosensory evoked potentials].

The effect of lidocaine on the median nerve somatosensory evoked potential (SSEP) was investigated in 14 neurologically normal patients. Lidocaine 1.5 mg.kg-1.min-1 was injected intravenously over a 5 min period immediately followed by a continuous infusion of lidocaine 60 micrograms.kg-1.min-1. The peak latencies (N1, P2, N2) and amplitudes (N1-P2, P2-N2) of the SSEP response over the sensory cortex were recorded before and after lidocaine infusion. The peak latencies in the control group and in the experimental group after lidocaine infusion of N1, P1, N2 were 19.4 +/- 1.0 msec, 19.7 +/- 1.0 msec (N1), 24.6 +/- 1.4 msec, 25.0 +/- 1.5 msec (P2), 32.5 +/- 2.5 msec, and 33.3 +/- 2.8 msec (N2), respectively. The amplitudes in the control group and in the experimental group after lidocaine infusion of N1-P2, P2-N2 were 9.0 +/- 4.3 microV, 10.3 +/- 4.7 microV (N1-P2), 7.2 +/- 3.6 microV, 8.6 +/- 3.9 microV (P2-N2), respectively. Peak latencies of all components (N1, P2, N2) increased after lidocaine infusion compared with control values. Amplitude of N1-P2 and P2-N2 increased significantly following lidocaine infusion compared with control values. The data obtained in this study suggested that the changes in peak latencies and amplitude after epidural anesthesia with lidocaine were due to the systemic effect of lidocaine absorbed intravenously from the epidural space.

Aged↗
PubMed1990

Continuous epidural infusion for postoperative pain relief: a comparison of three regimens.

We evaluated the postoperative pain relief and side-effects of continuous epidural infusion of three analgesic regimens following major thoracic and/or abdominal surgery. One hundred and twenty patients were randomly divided into three treatment groups: (1) 0.25% or 0.5% bupivacaine at a rate of 3-7 ml.hr(-1), (2) 0.01% morphine at a rate of 1-2 ml.hr(-1), (3) a combination of 0.125% or 0.25% bupivacaine and 0.0025% or 0.005% morphine at a rate of 2-4 ml.hr(-1). The study continued for the first 48 postoperative hours. The effect of pain relief was evaluated by assessment of the further requirement for parenteral analgesics. Sixty-four percent of the patients given bupivacaine, 56% of the patients given morphine and 80% of the patients given the combination required no supplemental analgesics. Continuous epidural infusion of bupivacaine was associated with hypotension (21%) and with numbness and weakness of hands or legs (18%). Continuous epidural infusion of morphine was associated with pruritus (18%) and with peristaltic depression (12%). The combination regimen was associated with pruritus (17%) and with drowsiness (14%). We conclude that the combination of bupivacaine and morphine significantly provides superior analgesia with less deleterious complications compared with either bupivacaine or morphine alone.

Clinical Trial↗
PubMed1990

Continuous epidural infusion for postoperative mechanical ventilation.

We evaluated in analgesic and sedative effects of continuous epidural infusion of two analgesic regimens in ventilated patients following esophagectomy. Forty-six patients, divided into two treatment groups, received postoperative continuous epidural infusion of morphine, or that of a combination of bupivacaine and morphine. Assessments were made with the following indices: pain relief score, somnolence score, patient ventilator coordination score, and the number of supplemental administrations of analgesics and sedatives. No significant differences occurred in somnolence scores or patient ventilator coordination scores between the two groups, which revealed satisfactory sedation for mechanical ventilation. Patients receiving the combination of bupivacaine and morphine had significantly less pain postoperatively, requiring a smaller number of supplemental administrations of analgesics and sedatives ( P < 0.05). It is concluded that: 1) continuous epidural infusion of analgesics gives potent analgesia and sedation of ventilated patients following esophagectomy; 2) the combination of bupivacaine and morphine gives pain relief superior to morphine alone.

Journal Article↗
PubMed1990

Changes in pulmonary function during continuous epidural bupivacaine with or without morphine following upper abdominal surgery.

To assess the effect of postoperative continuous thoracic epidural infusion of bupivacaine on pulmonary function, a prospective randomized study was conducted in patients undergoing upper abdominal surgery (UAS). Sixteen patients, divided into two treatment groups, received continuous epidural infusion of 0.25% bupivacaine at a rate of 2-5 ml.hr(-1), or that of a combination of 0.125% or 0.25% bupivacaine and 0.0025% or 0.005% morphine at a rate of 2-4 ml.hr(-1). One, 4, 10, 16, 24 and 40 hr postoperatively, the following indices were measured: visual analogue scale score, modified Prince Henry pain scale score, arterial Pa(O)(2) and Pa(CO)(2), functional residual capacity (FRC), and tidal volume (TV). There was no difference in pain scores between the two groups except for significantly less pain at 40 hr in the combination group. Postoperative measurements of pulmonary function revealed a significant fall in Pa(O)(2), FRC and TV, indicating a reduction of 15-25% as compared with the preoperative values, and no significant differences between the two groups. The authors conclude that postoperative continuous epidural infusion of bupivacaine combined with morphine is highly effective in alleviating pain and improving pulmonary function in patients following USA.

Clinical Trial↗
PubMed1990

Determination of 2,5-hexanedione and N-methylformamide in urine by gas chromatography.

Methods for the clinical testing of 2,5-hexanedione and N-methylformamide, urinary metabolites of n-hexane and N,N-dimethylformamide, respectively, were established by capillary column GLC. Recovery rates of 2,5-hexanedione and N-methylformamide from urine were 80.2-108.9% and 99.6-104.2%, respectively. Coefficients of variation (C.V.) for the amount of each product added were 3.1%, 1.8% (intra-assay) and 5.7%, 3.3% (inter-assay), respectively. The concentration ranges of metabolites from urine of healthy subjects without exposure to these organic solvents were less than or equal to 0.5 mg/l (2,5-hexanedione), less than or equal to 1.5 mg/l (N-methylformamide), respectively.

Air Pollutants, Occupational↗
PubMed1990

[Prevention of hepatitis B virus infection].

The incidence of the carrier of hepatitis B virus (HBV) in Japan is about ten times higher than that in U.S.A. and Western Europe. Countermeasures against HBV infection have been proposed on a national basis. The main route of HBV infection is due to contamination of blood and secretion from the carrier of HBV. The contamination would occur in many circumstances such as in the case of blood transfusion, needle accidents in hospital, vertical infection from mother to baby at the time of delivery and infection within family members. To prevent the posttransfusion hepatitis due to HBV, rapid and high sensitive measurement of HBs antigen should be introduced. Countermeasures have begun against the vertical infection from mother to baby at the time of delivery by the National Treasury. Already, a good result has been obtained. Recently the vaccination against HBV is generally performed. However, a low incidence of people have a high anti-HBs titer for a long period. The new countermeasure against this problem should be worked up as soon as possible.

Hepatitis B↗
PubMed1990

[The effects of thiamylal, ketamine and nicardipine on the hippocampal theta waves produced by cerebral ischemia in cats].

Spontaneous hippocampal electroencephalogram (EEG) was recorded in the pyramidal cell layer (PCL) and dentate gyrus (DG) during and after ischemia produced by bilateral clamping of the common carotid arteries in cats. Hippocampal theta waves, approximately 180 degree out of phase in PCL and DG, appeared within 4.3 +/- 2.3 seconds after the onset of bilateral carotid artery occlusion and continued for more than 60 minute. These hippocampal theta waves disappeared 34.2 +/- 10.2 seconds after 4 vessel occlusion. We could not find the clear difference between the two areas in the appearance and disappearance of the hippocampal theta waves. We further investigated the effects of thiamylal, ketamine and nicardipine on the hippocampal theta waves during bilateral carotid artery occlusion. Thiamylal changed the two hippocampal theta waves to a similar pattern of EEG, which has irregular slow and fast waves, in both PCL and DG. Ketamine changed the two theta waves to irregular complex pattern of fast and slow waves and spike activity, which is independent at two areas. Nicardipine, a Ca antagonist, changed the theta waves to irregular slow waves which were similar to the pattern of EEG observed before carotid artery occlusion. These results indicate that thiamylal, ketamine and nicardipine have different effects on the ischemia of hippocampus.

Animals↗
PubMed1990

[Effects of lumbar or thoracic epidural anesthesia on median nerve somatosensory evoked potentials].

Somatosensory evoked potentials (SSEP) are used increasingly to monitor the integrity of neural pathways in anesthetized patients. To evaluate the influence of epidural anesthesia on the central nervous system, we studied the effects of lumbar or thoracic epidural anesthesia with lidocaine on the median nerve SSEP in 9 patients. The peak latencies (N1, P2, N2) and amplitudes (N1-P2, P2-N2) of the SSEP response over the sensory cortex were recorded before and 15 min after epidural anesthesia. The peak latencies of control and post epidural anesthesia of N1, P1, N2 were 19.2 +/- 1.7 msec, 19.6 +/- 1.6 msec (N1), 24.7 +/- 2.3 msec, 25.7 +/- 2.0 msec (P2), 32.8 +/- 2.8 msec and 34.6 +/- 2.5 msec (N2), respectively. The amplitude of control and post epidural anesthesia of N1-P2, P2-N2 were 4.5 +/- 2.9 microV, 5.9 +/- 6.6 microV (N1-P2), 4.4 +/- 3.2 microV and 5.6 +/- 5.2 microV (P2-N2), respectively. Peak latencies of all components (L1, P2, N2) increased after epidural anesthesia compared with control values. Amplitude of N1-P2 increased significantly following epidural anesthesia compared with control values. The data obtained in this study were contrary to the previous concept that anesthetic agents generally increase the latency of SSEP and decrease their amplitude.

Adult↗
PubMed1990

[Continuous epidural infusion of bupivacaine and morphine for postoperative pain relief].

Forty-five patients admitted to the intensive care unit following thoracic or abdominal surgery received continuous epidural infusion of bupivacaine and morphine for 48 hours. During the first 10 hours, the patients received 0.25% bupivacaine solution with 0.005% morphine at the rate of 4 ml.h-1, and bupivacaine concentration was decreased to 0.125% with the same morphine concentration. The mean infusion rate of bupivacaine during 48 hours was 0.12 +/- 0.03 (SD) mg.kg-1.h-1 and that of morphine was 4.0 +/- 1.0 micrograms.kg-1.h-1. Thirty-one patients (69%) complained no pain on deep breathing at 24 hours and 33 patients (74%) required no other type of analgesics during this study. The mean plasma bupivacaine concentration was 0.6 +/- 0.3 microgram.ml-1 at 48 hours. Hypotension defined as systolic arterial pressure below 90 mmHg and itching were observed in 15 patients (33%), but no other severe side effects were noted. Continuous epidural infusion of bupivacaine and morphine mixture for 48 hours postoperatively provided effective pain relief with a low incidence of side effects.

Abdomen↗