Isoflurane exerts a short-term but not a long-term preconditioning effect in neonatal rats exposed to a hypoxic-ischaemic neuronal injury.

BACKGROUND: Isoflurane has been shown to induce tolerance against ischaemic injury in adult rodents. Although the delayed preconditioning effect of isoflurane has been demonstrated in neonatal rat pups, the acute preconditioning effects of isoflurane remained undetermined. The present study was therefore conducted to evaluate the acute preconditioning efficacy of isoflurane in neonatal rats subjected to a hypoxic-ischaemic (HI) injury. METHODS: Post-natal day 7 pups were exposed to 1 or 2% isoflurane in oxygen for either 30, 60 or 90 min. Fifteen minutes after isoflurane exposure, the pups were subjected to an HI injury induced by left common carotid artery ligation and exposure to 8% oxygen for 2 h. Pups not exposed to isoflurane or not subjected to HI served as controls. Histopathologic injury to the cortex and hippocampus was evaluated 7 and 49 days after HI. RESULTS: Isoflurane 2% exposure for 60 or 90 min before HI induced tolerance in the hippocampus and the number of normal neurons in the CA1 sector 7 days after HI was significantly greater than in non-preconditioned animals. This protective efficacy of isoflurane preconditioning was not observed 49 days after HI. CONCLUSIONS: Exposure of 2% isoflurane for at least 60 min is required to induce tolerance against HI injury in rat pups. However, this neuroprotective efficacy results in only transient neuroprotection.

Effect of continuous morphine infusion on hypoxic-ischaemic brain damage of neonatal rats.

BACKGROUND: Opioids are commonly administered to critically ill neonates and infants for general anaesthesia and sedation. However, the clinical safety of these drugs, especially the effects on hypoxic-ischaemic damage of the developing brain, has not been well investigated. The present study was therefore conducted to investigate the effects of continuous morphine infusion on brain damage after hypoxic-ischaemic insults in neonatal rats. METHODS: Seven-day-old Sprague-Dawley rats were subjected to left common carotid artery ligation followed by a 90-min exposure of 8% oxygen. The rats were administered morphine (0.1, 0.3 or 1 mg/kg/h) or saline continuously for 72 h using osmotic minipumps. Seven days later, the rats were weighed and their brains were morphologically categorized into groups based on the following grades: 0=normal, 1=mild atrophy, 2=moderate atrophy, 3=atrophy with cystic cavitation <3 mm and 4=cystic cavitation >3 mm. For histological assessment, the ratio of the surviving neurons (ipsilateral/contralateral) was calculated in the cornu ammonis fields, CA1 and CA3, and the dentate gyrus (DG). RESULTS: One week after recovery (P14), the rats in the 1 mg/kg/h group showed significantly poorer weight gain compared with the other groups. However, the morphological score of the brains and the ratio of the surviving neurons in the CA1, CA3 and DG were similar among the groups. CONCLUSION: Our results indicate that continuous administration of morphine does not worsen brain damage 7 days after hypoxic-ischaemic insults in neonatal rats.

Population research of genetic polymorphism at amino acid position 631 in chicken Mx protein with differential antiviral activity.

A single amino acid substitution between Asn and Ser at position 631 in the chicken Mx protein has been reported to determine resistant and sensitive antiviral activity. In this study, we investigate whether various kinds of chicken breeds and jungle fowls carry the resistant or sensitive Mx allelic gene by using the mismatched PCR-restriction fragment length polymorphism (RFLP) technique. In total, 271 samples from 36 strains of 17 chicken breeds and from 3 kinds of jungle fowls were examined. The rates of the resistant Mx gene and sensitive gene were 59.2% and 40.8%, respectively. Only a Red jungle fowl captured in Laos carried the resistant Mx gene, and the other three Red jungle fowls from Indonesia and Gray and Green jungle fowls all had the sensitive Mx gene. These results were confirmed by the determination of amino acid sequences in the GTPase effector domain of jungle fowls.

Comparison of changes in jugular venous bulb oxygen saturation and cerebral oxygen saturation during variations of haemoglobin concentration under propofol and sevoflurane anaesthesia.

BACKGROUND: A severe reduction in haemoglobin concentration can lead to a decrease in jugular venous bulb oxygen saturation (Sj(O(2))). However, recent evidences suggests that cerebral oxygen saturation (Sc(O(2))) measured by near infrared spectroscopy decreased during even mild haemodilution. We therefore tested the hypothesis that the changes in Sc(O(2)) may not be parallel to those in Sj(O(2)) during haemodilution. In addition, as cerebral oxygen balance during the operation can vary depending on the anaesthetics used, the changes in Sj(O(2)) and Sc(O(2)) during haemodilution were compared between patients under propofol and isoflurane/nitrous oxide anaesthesia. METHODS: Forty-two patients with pre-donated autologous blood were randomly assigned to receive propofol (Group P) or sevoflurane/nitrous oxide (Group S) anaesthesia. A fibreoptic catheter was placed in the jugular bulb to measure Sj(O(2)). A cerebral oximeter, INVOS 4100S was used to monitor Sc(O(2)). Arterial and jugular bulb blood samples were drawn simultaneously at: (i) 10 min after the start of operation, (ii) after 400 ml of blood loss, (iii) after 800 ml of blood loss, (iv) just before the transfusion of pre-donated autologous blood, and (v) after 400 ml transfusion. RESULTS: Mean (sd) control values of Sj(O(2)) in Group P were significantly lower than those in Group S (55 (8)% vs 71 (10)%, respectively; P<0.05), whereas there was no significant difference in control values of Sc(O(2)) between the two groups. During the operation, haemoglobin (Hb) concentrations significantly deceased in the both groups compared with control values (from 9.8 to 7.6 g dl(-1) in Group P and from 9.9 to 8.0 g dl(-1) in Group S). During a reduction in Hb concentration, Sj(O(2)) values remained unchanged in both groups, whereas Sc(O(2)) values significantly decreased in both groups (from 57 to 51% in Group P and from 59 to 52% in Group S). CONCLUSION: The results indicated that, although the changes in Sj(O(2)) and Sc(O(2)) during a reduction in haemoglobin concentration were similar under propofol and sevoflurane/nitrous oxide anaesthesia, the changes in Sc(O(2)) were not parallel to those in Sj(O(2)). The discrepancy of the results in Sj(O(2)) and Sc(O(2)) may make the interpretation of their values difficult during haemodilution.

Evaluation of genitofemoral nerve block, in addition to ilioinguinal and iliohypogastric nerve block, during inguinal hernia repair in children.

BACKGROUND: Ilioinguinal and iliohypogastric (IG-IH) nerve block has been widely used in children undergoing inguinal hernia repair. This technique may provide insufficient analgesia for intraoperative management as the inguinal region may receive sensory innervation from genitofemoral nerve. We proposed that addition of a genitofemoral nerve block might improve the quality of analgesia. METHODS: Ninety-eight children undergoing inguinal hernia repair were assigned randomly to receive either IG-IH nerve block (Group I) or IG-IH and genitofemoral nerve blocks (Group II). Systolic arterial pressure (SAP) and heart rate (HR) were recorded before surgery (control), after skin incision, at sac traction and at the end of surgery. Postoperative analgesic requirements and incidence of complications were recorded until discharge. RESULTS: At sac traction, SAP and HR were significantly higher in Group I (P<0.05), and the incidence of episodes of increased HR was also significantly higher in Group II (29 vs 12%, respectively, P<0.05). There were no significant differences in SAP and HR at other time points, postoperative analgesic requirements or incidence of complications between the groups. CONCLUSIONS: The benefit of the additional genitofemoral nerve block to IG-IH nerve block was limited only to the time of sac traction without any postoperative effect. This suggests there is little clinical benefit in the addition of a genitofemoral nerve block.

[Perioperative management of twins with prenatally diagnosed congenital diaphragmatic hernia].

Congenital Diaphragmatic Hernia (CDH) occurs in one of every 2000-3000 births, and most of them are sporadic, and therefore recognized as a circumstantial event. But its occurrence in 85 children among the 40 families is also reported, and some reports suggest that an autosomal recessive gene may be responsible for this disease. We experienced identical twins (babies A and B) both with prenatally diagnosed CDH. They were delivered by emergent cesarean section at 33 weeks of gestation with birth weight of 1857 g and 1561 g, respectively. They were intubated immediately after birth, and ventilated with high frequency oscillation. Baby A presented persistent pulmonary hypertension of newborn, and received nitric oxide inhalation. At the age of 2 days, both of them were stabilized and underwent repair of CDH. After the repair, baby A developed perforation of ileum, airway bleeding and retinopathy of prematurity (ROP), and needed 28 days before extubation. Baby B also developed ROP, but had no other problem, and the trachea was extubated at the age of 12 days. They are the seventh pair reported in the world literature.

[Cesarean section in a pregnant patient with placenta percreta involving the urinary bladder].

Placenta percreta involving adjacent structures is serious complication of pregnancy with a high mortality rate. A 32-year-old woman, gravida 4, para 3, who had previously undergone a cesarean section, was admitted to our hospital at 31 weeks' gestation for placenta previa. At 33 weeks' gestation, the diagnosis of placenta percreta with involvement of the urinary bladder was made by ultrasonography and magnetic resonance imaging. At 34 weeks' gestation, an elective cesarean section was scheduled. Anesthesia was maintained with sevoflurane in oxygen before delivery, and with nitrous oxide in oxygen, fentanyl and midazolam after delivery. During the operation, attempts to remove the placenta resulted in massive hemorrhage. Blood loss for the procedure was 13,800 g. Because of the extreme hemorrhage, we encountered hemorrhagic shock and postoperative complications despite the preoperative preparation. In case of placenta percreta, it is essential to prepare adequate volume of blood for transfusion at the start of surgery and secure large bore intravenous lines. A rapid transfusion device may be recommended. Regarding the anesthetic management, general anesthesia is preferable in consideration of the risk of hemorrhagic shock and the length of operation time. Furthermore, we need team approach and preoperative management to prevent the uncontrolled hemorrhage in such a severe case.

[Perioperative management of two neonates with severe Ebstein's anomaly with pulmonary atresia].

Ebstein's anomaly appearing during the neonatal period carries a high mortality rate. We report the perioperative management of two neonates with severe Ebstein's anomaly associated with pulmonary atresia. Their chest radiography revealed massive cardiomegaly, with cardiothoracic ratio of 90% and 100%, respectively. Their tracheas were intubated immediately after birth because of severe respiratory distress. The babies were laid in the prone position and one of them was managed with high frequency oscillatory ventilation (HFO) for prevention of pulmonary barotrauma and extensive atelectasis in the preoperative period. On the 4th and 3rd day after birth, respectively, they underwent Starnes procedure which consists of closure of tricuspid valve, enlargement of atrial septal defect, reduction of right atrium and creation of aortopulmonary shunt reported to be a useful palliative treatment for critically ill neonates with Ebstein's anomaly. Case 1 baby could not be weaned from cardiopulmonary bypass because of low cardiac output. Case 2 could not be weaned from extracorporeal membrane oxygenation due to hypoxia. We consider, however, treatment of respiratory failure and lung protection after birth are important for the prognosis. Perioperative use of HFO may be advantageous for the neonate with severe Ebstein's anomaly with pulmonary atresia.

[Perinatal and perianesthetic management of the sacrococcygeal teratoma in a neonate].

We report perinatal and perianesthetic management of a female infant with sacrococcygeal teratoma who underwent fetal bladder puncture and postnatal tumor resection. At 33 weeks' gestation, fetal ultrasonography revealed an intrapelvic mass, oligohydramnios and the dilatation of the bladder. At 34 weeks' gestation, bladder puncture was performed in utero to relieve urinary obstruction by the mass. And it served to reserve the renal function but caused remarkable ascites at birth due to urine leakage to the peritoneum through the puncture site. After the delivery by cesarean section, the patient underwent the tumor extirpation at 2 days of life. The operation and anesthesia proceeded uneventfully. In previous reports, several mortalities due to exsanguinating hemorrhage during surgery have been reported. In addition, sacrococcygeal teratoma is occasionally accompanied by coagulopathy and high output cardiac failure caused by arteriovenous fistulae. Therefore it is important for good patient outcomes to evaluate preoperatively the risks mentioned above.

Growth, hemorrhage, and regression of multiple intracerebral vasoformative tumors: report of an unusual case.

A rare case of multiple hemorrhagic vascular tumors of the cerebrum and cerebellum is reported. Computed tomographic scans in a 16-year-old girl revealed multifocal brain lesions with "jewel ring"-like areas of contrast enhancement. An old hematoma cavity was found inside the surgical specimen. Histologically, it was a vascular tumor composed of anastomosing vascular channels with proliferating endothelial cells and hemorrhages at different stages. Upon further histopathological study, this lesion could not be classified as any known vascular tumor entity, although it resembled some vascular tumors, such as cavernous hemangioma and hemangioendothelioma. The patient received steroid and alpha interferon treatment. The lesions initially increased in number once, then resolved 10 months after onset. The neuroradiological and histopathological features in the present case were characteristic, and the clinical course was unusual.

[Quantitative analysis of DNA topoisomerase I activity in human and rat glioma: characterization and mechanism of resistance to antitopoisomerase chemical, camptothecin-11].

Camptothecin-11 (CPT-11) is a new derivation of camptothecin, a plant alkaloid antitumor agent. Previous studies indicated that antitumor activity of CPT-11 was mediated through interaction of the drugs with its target enzyme, DNA topoisomerase I (topo I). In this study, we studied the relation between sensitivity to CPT-11 and topo I activity of glioma cells. Furthermore, we established CPT-11 resistant cell lines in order to elucidate potential mechanisms of drug resistance. A clear correlation between the sensitivities to CPT-11 and topo I activities in surgical glioma specimens was demonstrated. Activities of topo I in CPT-11 sensitive group (IC50 values for CPT-11; < 50 micrograms/ml) tended to be higher than those in CPT-11 resistant group (IC50 values; > or = 50). Topo I activity may serve as a novel marker to predict the sensitivity of gliomas to topo inhibitors. CPT-11 resistance cell lines (T98G/CPT-11 and C6) respectively exhibit a 5.4- and 7.3-fold increase in resistance to CPT-11. No differences in topo I activity and intracellular accumulation of CPT-11 were observed between parent and CPT-11 resistant lines. On the other hand, topo I from T98G/CPT-11 and C6/CPT-11 cells were at least 4- and 2-fold resistant to the inhibitory effect of the CPT-11 on the relaxation activity of topo I in comparison with their parent lines. This enzymological difference may be responsible for the resistance to CPT-11.

Quantitative analysis of DNA topoisomerase I activity in human and rat glioma: characterization and mechanism of resistance to antitopoisomerase chemical, camptothecin-11.

Camptothecin-11 (CPT-11) is a new derivative of camptothecin, a plant alkaloid antitumor agent. Previous studies indicated that antitumor activity of CPT-11 was mediated through interaction of the drugs with its target enzyme, DNA topoisomerase I (topo I). In this study, we studied the relation between sensitivity to CPT-11 and topo I activity of glioma cells. Furthermore, we established CPT-11 resistant cell lines in order to elucidate the potential mechanisms of drug resistance. A clear correlation between the sensitivities to CPT-11 and topo I activities in surgical glioma specimens was demonstrated. Activities of topo I in the CPT-11-sensitive group (IC50 values for CPT-11; < 50 micrograms/ml) tended to be higher than those in the CPT-11-resistant group (IC50 values, > or = 50). Topo I activity may serve as a novel marker to predict the sensitivity of gliomas to topo inhibitors. CPT-11-resistant cell lines (T98G/CPT-11 and C6), respectively, exhibit a 5.4- and 7.3-fold increase in resistance to CPT-11. No differences in topo I activity and intracellular accumulation of CPT-11 were observed between the parent and CPT-11-resistant lines. On the other hand, topo I from T98G/CPT-11 and C6-CPT-11 cells was at least 4- and 2-fold resistant to the inhibitory effect of the CPT-11 on the relaxation activity of topo I, in comparison with their parent lines. This enzymological difference may be responsible for the resistance to CPT-11.

[Quantitative analysis of glutathione and glutathione S-transferase in human brain tumors, C6 rat glioma cells and drug resistant C6 cells].

Glutathione (GSH) and Glutathione S-transferase (GST) plays an important role in the protection of cells against damage from free radicals and also influences cytotoxicity to some kinds of chemotherapeutic agents. GST comprises a group of abundant and widely distributed catalytic and binding proteins that facilitate the conjugation of GSH with the electrophilic center of a large spectrum of hydrophilic molecules. Multiple GST isozymes in mammalian tissues arise from dimeric combination of a number of distinct subunits grouped into three major classes: alpha (alpha), mu (mu), and pi (p). We report the total GST, GST-p activity and GSH content of human brain tumors, C6 rat glioma cells and drug resistant C6 cells. The values of total GST activity in 42 normal brain and brain tumors were quantitatively analyzed. Total GST activity was 92.6 +/- 25.1 units (mean +/- standard deviation) in 8 samples of normal brain tissues, 126 +/- 58.8 units in five grade II or III astrocytomas (154 +/- 63.3 units in grade II astrocytomas, 84.4 +/- 2.7 units in 2 grade III astrocytoma), 66.2 +/- 29.3 in 5 glioblastoma cases, 94.7 +/- 47.7 units in 3 metastatic tumors, 302 +/- 114 unit in 8 meningiomas and 213 +/- 90.4 units in 3 neurinomas. Differences of GST activity between glioblastomas and meningiomas, grade II or III astrocytomas and meningioma, in normal brain tissues and meningioma were statistically significant (p < 0.01). The difference between normal brain tissues and benign tumors (meningiomas and neurinomas), gliomas and benign tumors were also statistically significant (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Fluorescent dye rhodamine 6G as a molecular probe to study drug resistance of C6 rat glioma cells.

A study was made of the membrane transport of cytoplasm and mitochondria stained fluorescence dye Rhodamine 6G (R6G). In rat glioma C6 cells and 1-(4-amino-2-methyl-5-pyrymidinyl)-methyl-3-(2-chloroethyl) -3-nitrosourea hydrochloride (ACNU) and vincristine (VCR) resistant cell lines (C6/ACNU, C6/VCR), the rate of uptake of R6G decreased in C6/VCR cells, but verapamil increased the intracellular accumulation of R6G in C6/VCR. The intracellular accumulation of R6G of C6/ACNU cells was essentially the same as that of wild-type cells. C6/ACNU cells did not show cross resistance and were sensitive to VCR and cisplatin. C6/VCR cells showed cross resistance to ACNU and CDDP, but C6/VCR cells in the presence of verapamil were more sensitive to drugs than C6/VCR cells in the absence of verapamil. We conclude that the reduction of R6G fluorescence staining intensity in C6/VCR cells compared to wild-type cells may be associated with the mechanism of multidrug resistance (MDR) but does not reflect the mechanism of resistance to ACNU. Verapamil increased the accumulation of R6G in C6/VCR cells and overcame MDR, suggesting that there is a correlation between the MDR overcoming effect and enhancement of R6G accumulation, and that this correlation validates the use of the R6G staining test for clinical and laboratory investigation of MDR.

[Chemosensitivity assays for malignant gliomas].

Chemosensitivity assays including colony forming assay (CFA), MTT dye reduction assay (MTT assay) and thymidine incorporation assay (TIA) for cultured rat and human glioma cells were conducted to determine the correlation among them and the in vivo antitumor efficacy of anticancer drugs using rats implanted glioma cells. Cytotoxicity of various agents such as ACNU, ACR, CDDP, VCR or BLM, was estimated from the concentrations which caused 50% inhibition of the cell growth at the peak plasma concentration. The survival time of tumor bearing rats was assessed after ip treatment with these agents at their estimated clinical doses. This parameter was greater in the drugs that were shown to be highly sensitive in CFA and was consistent with the data for CFA. In the chemosensitivity assays, CFA closely correlated to MTT assay for all agents except VCR, but poorly so to TIA. The results in this study indicate that MTT assay seemed to be useful for determining the chemosensitivity of anticancer drugs and that chemosensitivity assay should be conducted depending on the nature of anticancer drug.