Tetanic Stimulation of the Peripheral Nerve before Transcranial Electrical Stimulation Can Enlarge Amplitudes of Myogenic Motor Evoked Potentials during General Anesthesia with Meeting Abstracts

Background

Neuromuscular blockade can suppress myogenic motor evoked potentials (MEPs). The authors hypothesized that tetanic stimulation (TS) of the peripheral nerve before transcranial stimulation may enhance myogenic MEPs during neuromuscular blockade. In the current study, the authors evaluated MEP augmentations by TS at different levels of duration, posttetanic interval, neuromuscular blockade, and stimulus intensity.

Methods

Thirty-two patients undergoing propofol-fentanyl-nitrous oxide anesthesia were examined. Train-of-five stimulation was delivered to C3-C4, and MEPs were recorded from the abductor hallucis muscle. In study 1, TS with a duration of 1, 3, or 5 s was delivered at 50 Hz to the tibial nerve 1, 3, or 5 s (interval) before transcranial stimulation, and the effects of TS on MEP amplitude were evaluated. In study 2, TS-induced MEP augmentations were evaluated at the neuromuscular blockade level (%T1) of 50% or 5%. In study 3, MEP augmentations by TS at stimulus intensities of 0, 5, 25, and 50 mA were evaluated.

Results

The application of TS significantly enlarged the amplitudes of MEPs at the combinations of duration (3, 5 s) and interval (1, 3, 5 s) compared with those without TS. TS-induced MEP augmentations were similarly observed at %T1 of both 50% and 5%. TS-induced MEP augmentations were observed at stimulus intensities of 25 and 50 mA.

Conclusions

The results indicate that TS of the peripheral nerve before transcranial stimulation can enlarge the amplitude of MEPs during general anesthesia with neuromuscular blockade. TS of the peripheral nerve can be intraoperatively applied as a method to augment myogenic MEP responses.

An Evaluation of White Matter Injury After Spinal Cord Ischemia in Rats: A Comparison with Gray Matter Injury

We quantitatively assessed both gray and white matter injury after spinal cord ischemia in rats, and the relationship between the magnitude of gray and white matter injury was determined. Twenty-five male rats were anesthetized with isoflurane, and spinal cord ischemia (SCI) was induced by balloon intraaortic occlusion combined with hypotension. The animals were randomly allocated to one of the following three groups: animals with SCI for 12 min (SCI-12; n = 8), 15 min (SCI-15; n = 9), or those with sham operation (n = 8). Twenty-four hours after reperfusion, hindlimb motor function was assessed using the Basso-Beattie-Bresnahan scale scoring. Gray matter damage was assessed on the basis of the number of normal neurons in the ventral horn. White matter damage was assessed on the basis of the extent of vacuolation and amyloid precursor protein immunoreactivity in the ventral and ventrolateral white matter. There were significantly less normal neurons in the SCI-15 group compared with those in the SCI-12 and sham groups (P < 0.05). There was a significant positive correlation between the Basso-Beattie-Bresnahan scores and the number of normal neurons. The percentages of vacuolation areas in the SCI-15 group were significantly larger compared with those in the SCI-12 and sham groups (30% +/- 10% versus 9% +/- 7%, 0% +/- 0%, P < 0.05). Immunohistochemical analysis revealed increased amyloid precursor protein immunoreactivity in the swollen axons, especially in the SCI-15 group. There was a significant negative correlation between the number of normal neurons and percentages of vacuolation areas. These results indicate that both gray and white matter were injured after SCI in rats and the degree of white mater injury was correlated with the severity of gray matter injury after a relatively short recovery period.

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.

[Spinal cord protection during descending thoracic and thoracoabdominal aortic surgery]

The incidence of postoperative paralysis after thoracic and thoracoabdominal aortic operations has decreased, but is still high in comparison with other operations. The analysis of the mechanism involved in the ischemic tolerance of the spinal cord could contribute to the protection of the spinal cord from ischemia. The identification of the Adamkiewicz artery and the predictive factors for postoperative paralysis in the preoperative period, the use of motor evoked potential, several adjuncts to keep the spinal cord circulation, the stabilization of the hemodynamics with good oxygenation, and hypothermia contribute to the prevention of the spinal cord ischemia. The anesthetics appropriate for the monitoring of the motor-evoked potential are propofol and fentanyl with or without ketamine. Among the anesthetic drugs, narcotics might exacerbate the motor function after the spinal cord ischemia. The analgesic drugs which do not aggravate the spinal cord dysfunction would be expected. Good cooperation of surgeons and anesthesiologists greatly contributes to the finding of the spinal cord ischemia during this operation.

The effects of the delta-opioid agonist SNC80 on hind-limb motor function and neuronal injury after spinal cord ischemia in rats

Recent investigation suggested neuroprotective efficacy of a delta-opioid agonist in the brain. We investigated the effects of intrathecal treatment with a delta-opioid agonist (SNC80) on spinal cord ischemia (SCI) in rats. SCI was induced with an intraaortic balloon catheter. The animals were randomly allocated to one of the following five groups: 1) SNC80 before 9 min of SCI (SNC-9; n = 12), 2) vehicle before 9 min of SCI (V-9; n = 12), 3) SNC80 before 11 min of SCI (SNC-11; n = 10), 4) vehicle before 11 min of SCI (V-11; n = 12), or 5) sham (n = 12). SNC80 (400 nmol) or vehicle was administered 15 min before SCI. Forty-eight hours after reperfusion, hind-limb motor function was assessed by using the Basso, Beattie, Bresnahan (BBB) scale (0 = paraplegia; 21 = normal) and histological assessment of the L4 and L5 spinal segments was performed. BBB scores in the SNC-9 group were higher compared with those in the V-9 group (P < 0.05), whereas there were no differences in BBB scores between the SNC-11 and V-11 groups. There were significantly more normal neurons in the SNC-9 and SNC-11 groups than in the V-9 and V-11 groups (P < 0.05). The results indicate that intrathecal treatment with the delta-opioid agonist SNC80 can attenuate hind-limb motor dysfunction and neuronal injury after SCI in rats.

Cyclooxygenase-2 expression in Schwann cells and macrophages in the sciatic nerve after single spinal nerve injury in rats

Recent evidence suggested that cyclooxygenase-2 (COX-2) expression in the peripheral nerve early after nerve injury might be involved in the development of neuropathic pain. Although previous investigators have demonstrated that COX-2 is expressed in peripheral nerve at a late phase (2-4 weeks) after nerve injury, COX-2 up-regulation at an early phase after nerve injury has not been determined. Using immunohistochemistry, we observed biphasic increases of COX-2 expression after L5 single spinal nerve injury. The first increment of COX-2 positive cells was noted 1 day after nerve injury and these cells co-expressed the Schwann cell marker S-100. A second increment was noted after 7-14 days and these cells co-expressed the macrophage marker ED-1. These results suggested that the cellular sources of COX-2 expression might be different between the early and late phases after nerve injury.

Double-stranded RNA activates RANTES gene transcription through co-operation of nuclear factor-kappaB and interferon regulatory factors in human airway epithelial cells

BACKGROUND

Regulated on activation, normal T cells expressed and secreted (RANTES) is a member of the CC chemokine family and contributes to viral-induced airway inflammation including exacerbations of asthma. Double-stranded RNA (dsRNA) is known to be synthesized during replication of many viruses and a ligand of Toll-like receptor 3. We hypothesized that dsRNA may mimic viral infection and induce RANTES expression in airway epithelial cells.

OBJECTIVE

We first confirmed that dsRNA up-regulated RANTES mRNA and protein synthesis in the airway epithelial cells. We next focused our studies on the transcriptional regulation of RANTES.

METHODS

Airway epithelial cell line BEAS-2B and normal human bronchial epithelial cells were used in vitro study. Levels of RANTES mRNA and protein expression were determined with RT-PCR and ELISA. Mechanisms of transcriptional regulation were assessed by electrophoretic mobility shift assay and dual luciferase assay using RANTES promoter-luciferase reporter plasmids.

RESULTS

Activation of nuclear factor-kappaB (NF-kappaB) was confirmed by nuclear protein binding to a DNA probe derived from the RANTES promoter. Activity of the RANTES promoter was increased by dsRNA. The stimulation with dsRNA was partially inhibited in plasmids mutated at either of the binding sites for NF-kappaB or IFN regulatory factors (IRFs). When both sites were mutated, the activation was totally abrogated.

CONCLUSION

These results imply that dsRNA activates NF-kappaB and IRFs and these transcription factors activate transcription of the RANTES promoter and its protein expression in airway epithelial cells.

Effect of isoflurane on neuronal apoptosis in rats subjected to focal cerebral ischemia

Although isoflurane can reduce ischemic neuronal injury after short postischemic recovery intervals, this neuroprotective efficacy is not sustained. Neuronal apoptosis can contribute to the gradual increase in infarct size after ischemia. This suggests that isoflurane, although capable of reducing early neuronal death, may not inhibit ischemia-induced apoptosis. We investigated the effects of isoflurane on markers of apoptosis in rats subjected to focal ischemia. Fasted Wistar-Kyoto rats were anesthetized with isoflurane and randomly allocated to awake (n = 40) or isoflurane (n = 40) groups. Animals in both groups were subjected to focal ischemia by filament occlusion of the middle cerebral artery for 70 min. Pericranial temperature was servo-controlled at 37 degrees C +/- 0.2 degrees C throughout the experiment. In the awake group, isoflurane was discontinued and the animals were allowed to awaken. In the isoflurane group, isoflurane anesthesia was maintained at 1.5 MAC (minimum alveolar anesthetic concentration). Animals were killed 7 h, 1 day, 4 days, or 7 days after reperfusion (n = 10/group/time point). The area of cerebral infarction was measured by image analysis in a hematoxylin and eosin stained section. In three adjacent sections, apoptotic neurons were identified by TUNEL staining and immunostaining for active caspase-9 and caspase-3. Infarct size was smaller in the isoflurane group than the awake group 7 h, 1 day, and 4 days after reperfusion (P < 0.05). However, this difference was absent 7 days after reperfusion. The number of apoptotic (TUNEL, caspase-3, and caspase-9 positive) cells 1 day after ischemia was significantly more in the awake versus isoflurane group. After a recovery period of 4 or 7 days, the number of apoptotic cells in the isoflurane group was more than in the awake group. After 7 days, the number of caspase-3 and -9 positive neurons was more in the isoflurane group (P < 0.05). The data indicate that isoflurane delays but does not prevent the development of cerebral infarction caused by ischemia. Isoflurane reduced the development of apoptosis early after ischemia but did not prevent it at later stages of postischemic recovery.

IMPLICATIONS

The effect of isoflurane on neuronal apoptosis was investigated in rats subjected to focal cerebral ischemia. In isoflurane-anesthetized animals, ischemia-induced apoptosis occurred during the later stages of postischemic recovery. Isoflurane did not inhibit postischemic neuronal apoptosis.

Peri-sciatic administration of indomethacin early after nerve injury can attenuate the development of tactile allodynia in a rat model of L5 single spinal nerve injury

To clarify the role of cyclooxygenase in the peripheral nerve on the development of neuropathic pain, we investigated the effects of peri-sciatic administration of indomethacin on the development of allodynia in a model of L5 single spinal nerve injury. Peri-sciatic administration of indomethacin (1 mg/kg) was performed 3, 24, or 72 h after nerve injury (n=6/each). In rats with indomethacin 3 or 24 h after nerve injury, ipsi-lateral paw withdrawal thresholds 7-35 days after nerve injury were significantly higher compared with those in the control group (n=6: without peri-sciatic treatment) (P<0.05). However, such efficacy was no longer apparent when indomethacin was administered 72 h after nerve injury. These results suggest that peri-sciatic administration of indomethacin early (less than 24 h) after nerve injury can attenuate the development of allodynia.

Localization of tumour necrosis factor-alpha converting enzyme in normal human skin

The tumour necrosis factor (TNF)-alpha converting enzyme (TACE) is a metalloproteinase-disintegrin that releases soluble TNF-alpha from cells by cleaving within the extracellular domain of membrane-bound pro-TNF-alpha. TACE knockout mice display a range of epithelial abnormalities. However, the localization of TACE in normal human skin is unclear. In this study, we examined the expression of TACE in normal skin by immunohistochemical analysis. The expression of TACE was seen throughout all layers of the epidermis, the hair follicles, eccrine ducts and glands, and sebaceous glands. There was also staining of blood vessels in the dermis. In particular, TACE was localized predominantly in mast cells, suggesting that these cells are an important source of TNF-alpha.

Intravenous administration of flurbiprofen does not affect cerebral blood flow velocity and cerebral oxygenation under isoflurane and propofol anesthesia

Flurbiprofen, a nonsteroidal antiinflammatory drug (NSAID), has been used to treat rheumatic and osteoarthritic pain and to reduce postoperative pain. Although other NSAIDs, such as indomethacin, reduce cerebral blood flow (CBF), the effect of flurbiprofen on CBF is unknown. In the present study, we investigated the effects of flurbiprofen on cerebral blood flow velocity (CBFV) and cerebral oxygenation under isoflurane or propofol anesthesia. Forty-eight patients undergoing orthopedic or abdominal surgery were enrolled. Patients were randomly allocated to receive either propofol (target control infusion: target site effect concentration 3 microg/mL) or isoflurane (1 MAC) for maintenance of anesthesia. In each group (n = 12), 1 mg/kg of flurbiprofen (PROP-F and ISO-F groups) or 0.1 mL/kg saline (PROP-S and ISO-S groups) was administered i.v. for 5 min. During and after the administration of flurbiprofen or saline, cerebral oxygenation variables (tissue oxygen index [TOI], total hemoglobin change [Delta cHb], oxygenated hemoglobin changes [Delta O(2)Hb], and deoxygenated hemoglobin changes [Delta HHb]), and middle cerebral artery flow velocity (Vmca) were measured using a cerebral oximeter (NIRO 300) and transcranial Doppler, respectively, from 5 min before study drug administration to 60 min post-administration. Before the administration of flurbiprofen, control values of TOI in the ISO-S and ISO-F groups were significantly higher than those in the PROP-S and PROP-F groups, respectively (ISO-S versus PROP-S, 67% +/- 4% versus 60% +/- 7%; IOS-F versus PROP-F, 69% +/- 4% versus 63% +/- 8%; P < 0.05). However, values of TOI, Delta cHb, Delta O(2)Hb, Delta HHb, and Vmca did not change significantly during and after the administration of flurbiprofen under propofol or isoflurane anesthesia, and these values were similar to those during and after the administration of saline in the same anesthesia group. These data indicate that flurbiprofen does not affect CBFV and cerebral oxygenation under propofol or isoflurane anesthesia.

IMPLICATIONS

Indomethacin, a nonsteroidal antiinflammatory drug (NSAID), has been demonstrated to reduce cerebral blood flow (CBF). The CBF effects of flurbiprofen, another NSAID, are unknown. We investigated cerebral blood flow velocity (CBFV) and cerebral oxygenation during and after the administration of flurbiprofen under isoflurane and propofol anesthesia. We found that flurbiprofen had no effect on CBFV and cerebral oxygenation.

Lytic infection of Epstein-Barr virus (EBV) in hemophagocytic syndrome associated with EBV-induced lymphoproliferative disorder

This report describes lytic infection with Epstein-Barr virus (EBV) in three cases of hemophagocytic syndrome (HPS) presumably associated with EBV-induced lymphoproliferative disorder. All cases were previously healthy females with ages ranging from 52 to 87 years who showed a fulminant clinical course with accompanying fever, liver dysfunction, and disseminated intravascular coagulation. Cases 1 and 2 showed proliferation of atypical T lymphocytes, and case 3 showed proliferation of atypical B lymphocytes. Hemophagocytic histiocytes were observed in the bone marrow, lymph nodes, spleen, and liver. Atypical lymphocytes in all cases showed a positive reaction for both EBV-encoded small RNA (EBER) indicating latent infection with EBV and immediate early mRNAs of the Bam HI fragment of lower stranded frame (BHLF), indicating lytic infection by in situ hybridization. Interestingly, BHLF-positive cells were predominant in all cases. It is possible that reactivation of EBV infection may be involved in triggering the induction of cytokines and abnormal activation of histiocytes.

[Retrospective analysis of postoperative nausea and vomiting after craniotomy]

BACKGROUND

Postoperative nausea and vomiting are important complications after craniotomy.

METHODS

One hundred and seventy eight patients who had undergone brain tumor resection at Nara Medical University were retrospectively divided to one of two groups; with or without PONV within 24 hours postoperatively. Variables compared between the groups include gender, age, weight, height, site of surgery (supratentorial versus infratentorial craniotomy), size of brain tumor, type of anesthesia (inhalation versus intravenous anesthesia with nitrous oxide), intraoperative fentanyl dose, duration of surgery as well as anesthesia, and intraoperative posture.

RESULTS

PONV occurred in 87 patients (49%). The incidence of PONV in patients undergoing infratentorial craniotomy was significantly higher than that in patients undergoing supratentorial craniotomy (75% vs 45%, P = 0.0011). There were no significant associations between PONV and other variables analyzed.

CONCLUSIONS

These results indicate that the incidence of PONV after brain tumor resection is high and infratentorial surgery is a risk factor for PONV. Strategies for the prevention of PONV after craniotomy are required.

Establishment and characterization of two cell lines (HEC-155, HEC-180) derived from uterine papillary serous adenocarcinoma

Uterine papillary serous adenocarcinoma (UPSC) is an uncommon histologic subtype of endometrial cancer that characteristically behaves aggressively with a poor prognosis. We established two novel cell lines derived from UPSC designated HEC-155 and HEC-180. Both cell lines have been growing steadily in monolayer cultures for over ten years. Overexpression of p53, Ki67 and p27 was detected in both cell lines by immunohistochemistry. Using a DNA sequencing technique, a point mutation of p53 was detected in exon 8, codon 286 in HEC-155 and in exon 6, codon 195 in HEC-180. These newly established cell lines should be useful for investigating the characteristics of UPSC.

Jugular Bulb Oxygen Saturation Under Propofol or Sevoflurane/Nitrous Oxide Anesthesia During Deliberate Mild Hypothermia in Neurosurgical Patients

Sevoflurane and propofol have been widely used as anesthetic agents for neurosurgery. Recent evidence has suggested that the influence of these anesthetics on cerebral oxygenation may differ. In the present study, the authors investigated jugular bulb oxygen saturation (SjO2) during propofol and sevoflurane/nitrous oxide anesthesia under mildly hypothermic conditions. After institutional approval and informed consent, 20 patients undergoing elective craniotomy were studied. Patients were randomly divided to the group S/N2O (sevoflurane/nitrous oxide/fentanyl anesthesia) or the group P (propofol/fentanyl anesthesia). After induction of anesthesia, the catheter was inserted retrograde into the jugular bulb and SjO2 was analyzed. During the operation, patients were cooled and tympanic membrane temperature was maintained at 34.5 degrees C. SjO2 was measured at normocapnia during mild hypothermia and at hypocapnia during mild hypothermia. There were no statistically significant differences in demographic variables between the groups. During mild hypothermia, SjO2 values were significantly lower in group P than in group S/N2O. The incidence of SjO2 less than 50% under mild hypothermic-hypocapnic conditions was significantly higher in group P than in group S/N2O. These results suggest that hyperventilation should be more cautiously applied during mild hypothermia in patients anesthetized with propofol and fentanyl versus sevoflurane/nitrous oxide/fentanyl.

Evaluation of Rapid Ischemic Preconditioning in a Rabbit Model of Spinal Cord Ischemia

Background

Rapid ischemic preconditioning (IPC) has been shown to reduce cellular injury after subsequent cardiac and cerebral ischemia. However, the data on rapid IPC of the spinal cord is limited. The authors investigated whether pretreatment with sublethal ischemia of spinal cord can attenuate neuronal injury after spinal cord ischemia in rabbits.

Methods

Forty-seven male New Zealand white rabbits were randomly assigned to one of three groups (n = 15 or 16 each). In the IPC(-) group, the infrarenal aorta was occluded for 17 min to produce spinal cord ischemia. In the IPC(+) group, 5 min of aortic occlusion was performed 30 min before 17 min of spinal cord ischemia. In the sham group, the aorta was not occluded. Hind limb motor function was assessed at 3 h, 24 h, 4 days, and 7 days after reperfusion using Tarlov scoring (0 = paraplegia; 4 = normal). Animals were killed for histopathologic evaluation at 24 h or 7 days after reperfusion. The number of normal neurons in the anterior spinal cord (L4-L6) was counted.

Results

Neurologic scores were significantly higher in the IPC(+) group than the IPC(-) group at 3 and 24 h after reperfusion (P &lt; 0.05). However, neurologic scores in the IPC(+) group gradually decreased and became similar to those in the IPC(-) group at 4 and 7 days after reperfusion. At 24 h after reperfusion, the numbers of normal neurons were significantly higher in the IPC (+) group than in the IPC(-) group (P &lt; 0.05) and were similar between the IPC(+) and sham groups. At 7 days after reperfusion, there was no difference in the number of normal neurons between the IPC(+) and IPC(-) groups.

Conclusion

The results indicate that rapid IPC protects the spinal cord against neuronal damage 24 h but not 7 days after reperfusion in a rabbit model of spinal cord ischemia, suggesting that the efficacy of rapid IPC may be transient.

Influence of Patient Variables and Sensor Location on Regional Cerebral Oxygen Saturation Measured by INVOS 4100 Near-Infrared Spectrophotometers

Cerebral oximeter based on near-infrared spectroscopy has been used as a continuous, noninvasive monitoring of regional cerebral oxygen saturation (rSO2). Although the absolute rSO2 values have a wide range of variability, the factors affecting a variability of rSO2 values have not been extensively investigated. The authors investigated the influence of patient variables and sensor location on rSO2 measured by the cerebral oximeter INVOS 4100 in 111 patients anesthetized with sevoflurane, fentanyl, and nitrous oxide in oxygen. The sensors for rSO2 measurements were applied on the right forehead (R), 1 cm lateral to R (R1), on the left forehead (L), 1 cm lateral to L (L1), and on the center of the forehead (C). The relationship between the rSO2 values and patient variables were also analyzed. Values of rSO2 at R1 and L1 were significantly lower than those at R and L, respectively. Values of rSO2 at C were significantly higher compared with those at other sites. There were no significant correlations between the rSO2 values and values of weight, height, and head size. Values of rSO2 were similar between males and females. A significant negative correlation between the rSO2 values and age and a positive correlation between the rSO2 values and hemoglobin concentration were observed. These data indicate that patient age, hemoglobin concentration at the measurement, and sensor location can affect rSO2 values.

Alteration in haemodynamics and pathological changes in the cardiovascular system during the development of Type 2 diabetes mellitus in OLETF rats

AIMS/HYPOTHESIS

The process of cardiovascular complications in Type 2 diabetes mellitus (DM) is unclear. We investigated pathophysiological changes of the heart and vessels in the Otsuka Long-Evans Tokushima Fatty (OLETF) rat Type 2 DM model during a long time period.

METHODS

Echocardiography was carried out at 22 and 62 weeks of age of OLETF ( n=10, each) and age-matched Long-Evans Tokushima Otsuka (LETO) rats ( n=10, each) as a reference. Haemodynamic measurements and histological examinations of the heart and the coronary and aortic vascular walls were done.

RESULTS

The left ventricular (LV) maximal -dP/dt was reduced in OLETF rats at 62 weeks (-1085+/-35 mmHg/s) less than that at 22 weeks (-1892+/-396 mmHg/sec, p<0.05) and in LETO rats at 62 weeks (-1306+/-200 mmHg/sec, p<0.05). Wall thickening of intramyocardial coronary arteries, capillary tortuosity and thickening of basement membrane were evident in OLETF rats at 62 weeks. Intimal and medial wall thickening of the aorta were prominent in OLETF rats at 62 weeks (15+/-2.2 and 90+/-6.6 micro m, in LETO rats at 62 weeks, 2+/-0.4 and 65+/-5.2 micro m, p <0.05, and in OLETF rats at 22 weeks, 7+/-4.6 and 71+/-6.0 micro m, p<0.05, respectively).

CONCLUSIONS/INTERPRETATION

In the Type 2 DM model, angiopathy, especially in coronary arteries including small vessels, as well as a LV relaxation abnormality, are induced in a late stage of DM. These are considered to be important complications in Type 2 DM.

The Lotus japonicus Sen1 gene controls rhizobial differentiation into nitrogen-fixing bacteroids in nodules

A Lotus japonicus mutant, Ljsym75, which forms ineffective symbiotic nodules and defines a new locus involved in the process of nitrogen fixation, was characterized in detail in order to identify the stage of developmental arrest of the nodules. No nitrogen-fixing activity was detectable in Ljsym75 nodules at any stage during plant development, and plant growth was markedly retarded. Ljsym75 plants formed twice as many nodules as the wild-type Gifu, and this phenotype was not influenced by the application of low concentrations of nitrate. Although the ineffective nodules formed on Ljsym75 were anatomically similar to effective Gifu nodules, Ljsym75 nodules senesced prematurely. Microscopic examination revealed that bacteria endocytosed into Ljsym75 nodules failed to differentiate into bacteroids. Moreover, the bacteria contained no nitrogenase proteins, whereas leghemoglobin was detected in the cytosol of the nodules. These results indicate that Ljsym75 is required for bacterial differentiation into nitrogen-fixing bacteroids in nodules, and thus the Ljsym75 gene was renamed sen1 (for stationary endosymbiont nodule). Linkage analysis using DNA markers showed that Sen1 is located on chromosome 4.