Effects of the chitin synthesis inhibitor buprofezin on survival and development of immatures of Chrysoperla rufilabris (Neuroptera: Chrysopidae)

Effects of buprofezin (Applaud), a chitin synthesis inhibitor, on survival and development of eggs, three instars, and pupae of Chrysoperla rufilabris (Burmeister) were determined in the laboratory. Buprofezin at three tested concentrations (100, 500, and 1,000 mg [AI]/liter) did not affect the viability and development of eggs when the eggs were treated, or third instars and pupae when those stages were treated. Although the degree of effects by buprofezin on larvae varied with instar, buprofezin at the higher concentrations (500 and 1,000 mg [AI]/liter) reduced survival rates 17-47% and prolonged the overall development from first instars to adult emergence by 2 or 3 d when first instars were treated, indicating that the first instar is the most vulnerable stage. When second instars were treated, the survival of C. rufilabris from second instars to pupae was not significantly affected. However, the developmental time from second instar to adult emergence was longer in the treatments with the highest concentration (1,000 mg [AI]/liter) than that with the lowest concentration (100 mg [AI]/liter). The compatibility of buprofezin with natural enemies in integrated pest management programs is discussed.

The clinical presentation of uppermost cervical disc protrusion

OBJECT

The purpose of this study is to clarify the clinical presentation of the C2-C3 cervical herniation disc.

SUMMARY OF BACKGROUND DATA

Uppermost cervical disc protrusion is an uncommon condition. The pattern of large central fragments of nucleus impinging on the highest cervical disc region is often poorly localized according to its clinical presentation.

METHODS

Eight patients treated with anterior cervical discectomy with fusion for C2-C3 disc herniation participated in a detailed clinical and radiologic review to determine early detection and clarify potential hazards. Each patient's neurologic function was tested and recorded successively by a team of physicians and qualified physiotherapists.

RESULTS

Reviewing the symptomatology, most patients presented ascending radicular symptoms secondary to trivial trauma, characterized by suboccipital pain, loss of hand dexterity, and paresthesia over face and unilateral lateral arm. Six (75%) patients had remarkable improvement postoperatively in neurologic function, except for some residual sensory embarrassment in at least 6 months follow-up.

CONCLUSIONS

Clinical neurologic examination provides a less precise anatomic basis, to point to a particular upper cervical disc protrusion. Nonspecific neck and shoulder pain, a variety of cervical radiculopathy, and myelopathy may present. However, this rare spondylotic pattern is usually characterized by impairment of motor and sensory function more in the upper extremities than lower extremities and mostly starting following trauma. Radiculopathy generally outweighs the cord sign. Cruciate paralysis associated with vague diffuse and patch regions of hypesthesia over perioral distribution may help to localize this upper cervical lesion. The present study demonstrates that early detection and adequate anterior decompression may provide excellent outcome.

Correlation of homocytsteine levels with the extent of coronary atherosclerosis in patients with low cardiovascular risk profiles

Elevation of homocysteine is now known as an independent risk factor for vascular diseases. However, influences of homocysteine to the extent of coronary atherosclerosis in patients with different coronary risk profiles have not been studied. In this study, we used angiographic "diffuse score" and "clinical vessel score" to evaluate the extent of coronary atherosclerosis, and examined the correlation between levels of serum total homocysteine and angiographic scores among patients with high- and low-risk profiles. Seventy consecutive patients (58 men and 12 women, mean age 50 years) undergoing selective coronary angiography for the first time were recruited for this study. Patients were divided into high-risk (risk factor > or =3, n = 35) and low-risk (risk factor <3, n = 35) groups. Linear regression analysis revealed that levels of serum homocysteine were only significantly correlated with diffuse (r = 0.217, p = 0.007) and clinical vessel (r = 0.078, p = 0.037) scores in low-risk patients. These correlations could not be observed in diffuse (r = 0.070, p = 0.319) and clinical vessel (r = -0.001, p = 0.970) scores in the high-risk group. In conclusion, levels of homocysteine correlated with the extent of coronary atherosclerosis only among patients with low cardiovascular risk profiles.

Effects of a nitric oxide scavenger, carboxy-PTIO, on isoflurane MAC and cerebellar nitric oxide synthase activity in rats

Recent studies have indicated that nitric oxide may play a role in inhalation anaesthesia. Inhibition of nitric oxide synthase reduces the minimum alveolar concentration (MAC) for inhalation anaesthetics and decreases cerebellar nitric oxide synthase (NOS) activity in rats. In this study, we have explored further the role of nitric oxide in isoflurane anaesthesia by examining the effects of a nitric oxide scavenger, 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (carboxy-PTIO 0.075-0.6 mg kg-1) on MAC values and cerebellar NOS activity in rats. Bolus injection of carboxy-PTIO at doses greater than 0.15 mg kg-1 reduced the MAC value of isoflurane (mean 1.36 (SEM 0.07)% at 0.15 mg kg-1, 1.39 (0.14)% at 0.3 mg kg-1 and 1.31 (0.06)% at 0.6 mg kg-1 vs control value of 1.61 (0.19)%. Administration of carboxy-PTIO 0.125 and 0.15 mg kg-1 resulted in increased cerebellar NOS activity during isoflurane anaesthesia (P < 0.05). These findings suggest that the level of nitric oxide may set a baseline from which isoflurane then acts.

Recombinant protein composed of Pseudomonas exotoxin A, outer membrane proteins I and F as vaccine against P. aeruginosa infection

We have constructed a chimeric protein composed of the receptor binding and membrane translocation domains of Pseudomonas exotoxin A (PE) with the outer membrane proteins I and F, together designated as PEIF. The potential of PEIF as a vaccine against Pseudomonas infection was evaluated in BALB/c mice and New Zealand white rabbits. We examined titers of anti-PE and anti-OprF antibodies, and the ability both to neutralize PE cytotoxicity and to increase opsonophagocytic uptake of Pseudomonas aeruginosa strain PAO1, serogroups 2 and 6. The results showed that PEIF can induce antibodies not only to neutralize the PE cytotoxicity but also to promote the uptake of various strains of P. aeruginosa by murine peritoneal macrophages. In a burned mouse model, PEIF afforded significant protection against infection by the homologous P. aeruginosa strain PAO1, heterologous serogroup 2, and the PE hyperproducing strain PA103. These observations thus indicate that PEIF may be used as a novel vaccine against P. aeruginosa infection.

Presentation of autoantibody to proliferating cell nuclear antigen in patients with chronic hepatitis B and C virus infection

OBJECTIVES

To study the association of antibodies to proliferating cell nuclear antigen (PCNA) in patients with chronic hepatitis B (HBV) and C (HCV) virus infection.

METHODS

Sera from 243 patients with chronic HBV infection; 379 patients with chronic HCV infection; 80 patients with systemic lupus erythematosus (SLE); 28 patients with rheumatoid arthritis; 15 patients with Sjogren's syndrome; eight with polymyositis; eight with primary biliary cirrhosis; and 33 healthy control subjects were tested for the presentation of anti-PCNA antibodies by enzyme linked immunosorbent assay (ELISA) and immunoblotting using recombinant PCNA as antigen. The distribution of immunoglobulin isotypes of anti-PCNA antibody was measured by ELISA assay.

RESULTS

By ELISA, anti-PCNA antibodies were detected in 30 (12.3%) patients with chronic HBV infection, 71 (18.7%) patients with chronic HCV infection, and five (6.3%) patients with SLE. The inhibition of binding with these sera by purified PCNA was shown to exceed 71%. By immunoblotting, the frequency of anti-PCNA in patients with chronic HBV and HCV infection was 17 of 243 (7%) and 41 of 379 (11%), respectively. Absorption studies on indirect immunofluorescence showed the typical nuclear speckled staining pattern by anti-PCNA sera was abolished by preincubation of sera with PCNA. Anti-PCNA antibody was not detected in sera from patients with autoimmune diseases except SLE. Anti-PCNA antibodies in patients with chronic HBV and HCV infection were predominantly IgG.

CONCLUSION

These data suggest that anti-PCNA antibody are also present in patients with chronic HBV and HCV infection. Anti-PCNA antibody may not be specific for SLE.

A nontoxic Pseudomonas exotoxin A induces active immunity and passive protective antibody against Pseudomonas exotoxin A intoxication

Pseudomonas exotoxin A (PE) is one of the most potent cytotoxic agents produced by Pseudomonas aeruginosa. In this study, we examined the possibility of using PE with a deletion of 38 carboxyl-terminal amino acid residues, designated PE(Delta576-613), for active immunization against PE-mediated disease. We first examined the toxic effects of PE and PE(Delta576-613) on 5- and 9-week-old ICR mice. The results show that the subcutaneous administration of PE(Delta576-613) at a dose of 250 microg was still nontoxic to 5- and 9-week-old ICR mice, while native PE was lethal at a dose of 0.5 and 1 microg, respectively. PE(Delta576-613) was then used to immunize ICR mice. The minimum dose of PE(Delta576-613) that could effectively induce anti-PE antibodies in 5- and 9-week-old ICR mice was found to be 250 ng. However, immunization with 250 ng PE(Delta576-613) failed to protect the immunized mice from a lethal dose of PE. The effective immunization dose of PE(Delta576-613) that could protect mice against a 2 microg PE challenge was found to be 15 microg. In addition, sera obtained from PE(Delta576-613)-immunized ICR mice were able to neutralize PE intoxication and effectively protect mice from PE. Thus, PE(Delta576-613) may be used as an alternative route to new PE vaccine development.

Magnetic resonance of the hepatic veins with angular reconstruction: application in living-related liver transplantation

BACKGROUND

Preoperative mapping of the hepatic venous system of the partial liver graft is indispensable to the success of living-related liver transplantation. We assessed the accuracy of magnetic resonance (MR) venography with angular reconstruction in depicting the tributaries of the middle hepatic vein and left hepatic vein in the donors, which was essential in graft retrieval and venoplasty.

METHODS

Nineteen living-related liver transplantation donors underwent a pretransplantation survey, including sonography and MRI for hepatic venous evaluation. T1-weighted images were reconstructed manually, using the inferior vena cava as a fixed point for tilting to produce an oblique plane image where both the middle hepatic vein and left hepatic vein could be demonstrated draining into the inferior vena cava. The reconstructed images of the hepatic veins were compared with preoperative sonography, intraoperative sonography, and operative findings.

RESULTS

Preoperative sonography and MR findings correlated well with the operative findings in the major hepatic veins. The MR venography of the ramification of the hepatic veins has an accuracy of 93%, the sonography, 84%. Sonography is slightly inferior in the evaluation of the hepatic vein in segment 4 and the left superior hepatic vein, with an accuracy of 73% and 67%, respectively.

CONCLUSION

MR venography with angular reconstruction is accurate in depicting the complex distribution of the hepatic veins of the left liver, providing important information for decision making as to the cutting plane during graft retrieval and the method of venoplasty and anastomosis. Thus, unnecessary blood loss could be avoided and vascular complications could be prevented, as these conditions would be unacceptable for a healthy living donor. We propose that MR venography, a rapid and reliable technique, is an appropriate alternative examination or complementary modality to sonography in the pretransplantation evaluation of the living donor.

The dose effect of propofol on cerebrovascular reactivity to carbon dioxide in rabbits

BACKGROUND

Propofol has several properties beneficial to intracranial operation such as reduction in cerebral metabolic rate and cerebral blood flow (CBF) in a dose-dependent manner while leaving autoregulation intact. Several studies have demonstrated that the responsiveness of CBF to changes in arterial carbon dioxide tension (PaCO2) is maintained during propofol anesthesia in both humans and animals. These studies showed a significant difference in the CBF-CO2 reactivity slope between awake and propofol anaesthetized groups, but no comparison with different doses of propofol was made. To determine the dose effect of propofol on cerebrovascular CO2 reactivity, we used laser Doppler flowmetry (LDF) to detect the changes of CBF during propofol anesthesia.

METHODS

Ten rabbits were studied using LDF on the parietal cortex. After surgical preparation, anesthesia was maintained with 66% N2O in O2, morphine 10 mg/kg and pancuronium. Three experimental conditions were studied sequentially with intravenous administration of the following drugs: (1) normal saline (control), (2) propofol 20 mg/kg/h i.v., (3) propofol 40 mg/kg/h i.v. Mean arterial pressure, rectal temperature and hematocrit were kept constant. The arterial carbon dioxide tension (PaCO2) was adjusted to three levels during each condition: 20-25 mmHg (hypocapnia), 35-40 mmHg (normocapnia) and 45-50 mmHg (hypercapnia). CBF was measured continuously and recorded after the target PaCO2 had been reached.

RESULTS

There were no differences among all conditions in mean arterial pressure and heart rate. The changes of CBF as PaCO2 increased at the three different CO2 levels during each of the conditions were significantly different. The slope of CBF-CO2 reactivity among three different propofol doses was not significantly different.

CONCLUSIONS

These data indicate that cerebral vasomotor responsiveness to CO2 during propofol anesthesia is preserved and that the slope of CBF-CO2 reactivity is independent of propofol doses as mean arterial blood pressure is maintained.

Stereoscopic ranging by matching image modulations

We apply an AM-FM surface albedo model to analyze the projection of surface patterns viewed through a binocular camera system. This is used to support the use of modulation-based stereo matching where local image phase is used to compute stereo disparities. The local image phase is an advantageous feature for image matching, since the problem of computing disparities reduces to identifying local phase shifts between the stereoscopic image data. Local phase shifts, however, are problematic at high frequencies due to phase wrapping when disparities exceed +/-pi. We meld powerful multichannel Gabor image demodulation techniques for multiscale (coarse-to-fine) computation of local image phase with a disparity channel model for depth computation. The resulting framework unifies phase-based matching approaches with AM-FM surface/image models. We demonstrate the concepts in a stereo algorithm that generates a dense, accurate disparity map without the problems associated with phase wrapping.

Bone marrow metastasis in nasopharyngeal cancer: early detection using EBER1 in situ hybridization

BACKGROUND

Previous studies have reported the abundant expression of EBER1 in primary nasopharyngeal carcinoma (NPC) metastatic to lymph nodes and bone marrow (BM). This study was done to research the use of EBER1 in situ hybridization to detect micrometastasis in the marrow of NPC patients.

PATIENTS AND METHODS

A total of 41 patients who underwent BM biopsy either for routine pretherapeutic evaluation or suspected bone marrow metastasis were enrolled for study. Thirty-two patients underwent BM biopsy for routine staging examination (Group I) and 10 were examined for unexplained cytopenia, leukoerythroblastosis, disseminated intravascular coagulation, or extensive bone metastasis (Group II). The authors applied EBER1 in situ hybridization to investigate the expression of EBER1 in 42 BM specimens. Examinations were performed on paraffin embedded tissues using polymerase chain reaction-derived, digoxigenin-labeled EBER1 DNA probes.

RESULTS

Eight of 42 specimens (19%) were positive for BM metastasis. Just one (3%) had bone marrow involvement in Group I. However, seven (70%) were positive in Group II. All but one of them with bone marrow metastasis showed positive EBER1 in situ hybridization in the BM. Another patient suspected of having BM metastasis was negative for cytokeratin, but was positive for EBER1 in situ hybridization.

CONCLUSION

Routine bone marrow study is not recommended in the staging of NPC, since only 3% of patients had BM metastasis. EBER1 in situ hybridization of marrow specimens cannot detect malignant cells earlier in NPC, but can be usefully applied to cases of equivocal marrow metastasis.

Subarachnoid fentanyl with diluted small-dose bupivacaine for cesarean section delivery

BACKGROUND

The use of neuraxial opioid was very popular in recent years, and they may augment the analgesia produced by local anesthetic through direct binding with the spinal opioid receptors. Hemodynamic stability is very important during Cesarean section. Theoretically, the reduction of local anesthetic by addition of fentanyl would provide better hemodynamic stability and good anesthetic status.

METHODS

Thirty healthy parturients undergoing Cesarean section were assessed in a randomized fashion. They were divided into two groups. Each subject received 5 mg hyperbaric bupivacaine plus 25 micrograms fentanyl (0.5 ml) and cerebrospinal fluid (CSF) 0.6 ml (Group M + F) or 8 mg hyperbaric bupivacaine plus 0.5 ml of CSF (Group M). The effects of hemodynamic stability, side effects, and complete analgesic duration were observed.

RESULTS

It was disclosed that the hemodynamic status was more stable in group M + F. The incidence of nausea and vomiting appeared to be not statistically significant between groups. The incidence of pruritus was apparently higher in group M + F (93.5% vs. 0) but the incidence of shivering was much lower in group M + F (0 vs. 33.3%). The complete analgesic duration was longer in group M + F (146 +/- 47 min vs. 104 +/- 44 min). There were no significant differences in the anesthetic and surgical status, 1-min and 5-min Apgar scores, and the time of regression of sensory level to T10.

CONCLUSIONS

The combination of small-dose bupivacaine with fentanyl could provide more stable hemodynamic status, longer postoperative analgesia, and lower incidence of shivering. The incidence of pruritus in group M + F was high, but it was usually mild.

Extracellular zinc ion inhibits ClC-0 chloride channels by facilitating slow gating

Extracellular Zn2+ was found to reversibly inhibit the ClC-0 Cl- channel. The apparent on and off rates of the inhibition were highly temperature sensitive, suggesting an effect of Zn2+ on the slow gating (or inactivation) of ClC-0. In the absence of Zn2+, the rate of the slow-gating relaxation increased with temperature, with a Q10 of approximately 37. Extracellular Zn2+ facilitated the slow-gating process at all temperatures, but the Q10 did not change. Further analysis of the rate constants of the slow-gating process indicates that the effect of Zn2+ is mostly on the forward rate (the rate of inactivation) rather than the backward rate (the rate of recovery from inactivation) of the slow gating. When ClC-0 is bound with Zn2+, the equilibrium constant of the slow-gating process is increased by approximately 30-fold, reflecting a 30-fold higher Zn2+ affinity in the inactivated channel than in the open-state channel. As examined through a wide range of membrane potentials, Zn2+ inhibits the opening of the slow gate with equal potency at all voltages, suggesting that a two-state model is inadequate to describe the slow-gating transition. Following a model originally proposed by Pusch and co-workers (Pusch, M., U. Ludewig, and T.J. Jentsch. 1997. J. Gen. Physiol. 109:105-116), the effect of Zn2+ on the activation curve of the slow gate can be well described by adding two constraints: (a) the dissociation constant for Zn2+ binding to the open channel is 30 microM, and (b) the difference in entropy between the open state and the transition state of the slow-gating process is increased by 27 J/ mol/ degreesK for the Zn2+-bound channel. These results together indicate that extracellular Zn2+ inhibits ClC-0 by facilitating the slow-gating process.

Combination of bupivacaine scalp circuit infiltration with general anesthesia to control the hemodynamic response in craniotomy patients

BACKGROUND

Sudden and overwhelming increases in blood pressure (BP) and heart rate (HR) during incision of the scalp may give rise to morbidity or mortality in patients with intracranial pathology undergoing neurosurgery. A modification of the method proposed by Labat to abate this circumstantiality was applied in a group of patients receiving craniotomy. The modified method was to combine scalp circuit infiltration of local anesthetic with general anesthesia to control the hemodynamic response to craniotomy.

METHODS

Twenty-six patients scheduled to undergo craniotomy were randomly divided into two groups. Patients whose conditions or their current medication that might affect the stability of hemodynamics were excluded. In group A patients (N = 16) 25-30 ml of 0.25% bupivacaine was used for scalp circuit infiltration on the operation side, while in those of group B (N = 10) the same volume of 0.9% normal saline was used. After induction, anesthesia was maintained with 0.6% to 1.2% end-tidal isoflurane (ET-Iso) and 50% N2O in oxygen (N2O:O2 = 2 l/min:2 l/min). The end-tidal CO2 was kept within the range of 25-30 mmHg. BP and HR were recorded every five min before incision and then every two min after incision until one hour after induction. ET-Iso was also recorded every two min throughout a period of sixty min. If the BP and HR increased above 20% of the baseline (10 min before incision), thiopental 2.5 mg/kg and fentanyl 2 micrograms/kg were administered. If hypertension became sustained, the isoflurane concentration was adjusted until an acceptable level was obtained.

RESULTS

The mean BP during the surgery was 92 +/- 1 mmHg in group A and 92 +/- 7 mmHg in group B. The difference in BP between incision to 6 min after incision was statistically significant (P < 0.05). The mean HR during surgery was 101 +/- 5 beats/min in group B and 91 +/- 2 beats/min in group A, the difference of which was not statistically significant. All of the patients in group B required a deepened anesthesia to keep the BP and HR within the normal range, but no patient in group A had such need. The average concentration of ET-Iso during the 60 min period was 0.95 +/- 0.12% in group B and 0.41 +/- 0.01% in group A, respectively. The difference was statistically significant (P < 0.05).

CONCLUSIONS

Our results showed that scalp circuit infiltration with 0.25% bupivacaine significantly improved the cardiovascular stability and reduced the requirement of isoflurane during craniotomy. The routine use of bupivacaine scalp circuit infiltration in patients undergoing craniotomy should be considered.

The role of decompression for acute incomplete cervical spinal cord injury in cervical spondylosis

STUDY DESIGN

A prospective study was conducted in 37 patients with cervical spondylosis with incomplete cord injury to assess the role of decompression in these patients.

OBJECTIVES

To evaluate surgical and nonsurgical outcomes in patients with pre-existing cervical spondylosis of the spine, in whom an incomplete spinal cord syndrome developed after a minor neck injury.

SUMMARY OF BACKGROUND DATA

The benefits of surgical treatment of incomplete cord injury with cervical spondylosis is controversial but remains a treatment option. The results of this study clarified the benefits of surgery in such patients.

METHODS

Radiographic findings and outcomes based on post-spinal injury motor function score were compared retrospectively in 37 patients with cervical spondylosis. Sixteen patients were treated operatively and 21 were treated nonoperatively.

RESULTS

The neurologic conditions of 13 of the 16 patients (81.2%) treated surgically improved within 2 days of surgery. Comparing the improvement of the two groups at defined intervals, there were statistically significant differences (P < 0.006) between the surgical and nonsurgical patients at 1-month and 6-month follow-ups. Nevertheless, 13 of the 21 patients (62%) treated nonoperatively had recovered to at least muscle Grade 3 at the 2-year follow-up, but their recovery was slower than that of the surgical group.

CONCLUSION

Although neurologic improvement after an incomplete spinal cord injury when no bony lesion was present was slow during the first few months after trauma, more than 60% of the patients showed neurologic recovery with a muscle grade higher than 3 at 2-year follow-up. Surgical decompression, however, was associated with immediate neurologic improvement, faster recovery of neurologic function, early mobilization, better long-term neurologic outcome, briefer hospital stays, and fewer complications related to long confinements in bed than was nonoperative treatment.

Post-transplant changes of segment 4 after living related liver transplantation

The purpose of this study was to evaluate the outcome of the medial segment of the graft after living related liver transplantation (LRLT). Of the 12 pediatric recipients who underwent LRLT, 2 received whole left liver graft, 1 left lateral segment graft, and 9 extended left lateral segment grafts. The hepatic veins of the donor were reviewed and the volume of the medial segment and left lateral liver was measured before and 6 months after liver transplantation. The flow velocity and direction of the portal vein in the medial segment graft was also evaluated by Doppler ultrasound. The grafted livers of all recipients showed a substantial increase in volume of 9-120% 6 months after LRLT. For the left lateral segment, an increase in volume was found in all cases ranging from 21 to 245%. For the medial segment, volume increases of 5-48% were found in seven cases with normal hepatopetal flow detected inside the segment 4 intrahepatic portal vein. In four cases, the partial medial segment graft of the extended left lateral liver graft decreased in volume from 33 to 69%. Among these four cases, slow flow (n = 2) and hepatofugal flow (n = 1) were also detected in the intrahepatic portal vein of the medial segment. Mapping of the tributary of the hepatic veins of the graft revealed inadequate venous drainage of the partial segment 4 graft, which may be considered as the cause of the atrophic change of the partial segment 4 graft. In conclusion, different regenerative rates between the left lateral segment and the medial segment were noted, with a greater rate in the left lateral segment. The venous drainage of the medial segment is of primary concern in the determination of the outcome of the regeneration. Atrophic change occurs when inadequate hepatic venous drainage is encountered. Therefore, if an extended left lateral liver graft is required, the corresponding draining veins of the partial medial segment must be preserved. Otherwise, whole left liver or left lateral segment graft would be a better choice.

NitroG-L-arginine methyl ester decreases minimum alveolar concentration of isoflurane and reduces brain nitric oxide synthase activity in rats

BACKGROUND

Nitric Oxide (NO), an endogenous messenger produced by the enzyme nitric oxide synthase (NOS), is recently introduced to be involved in inhalational anesthesia. We have previously reported that a specific NOS inhibitor, nitroG-L-arginine methyl ester (L-NAME), reduces the value of minimum alveolar concentration (MAC) for isoflurane anesthesia in rabbits. The purpose of this study is to evaluate the effects of the NOS inhibitor, L-NAME, on isoflurane MAC and NOS activity in rats.

METHODS

Adult Wistar rats receiving isoflurane inhalation were randomly divided into two groups, with eight rats in each group. In the study group, L-NAME 30 mg/kg was given 60 min before the inhalation of isoflurane. Normal saline was given to the control group instead. The data of MAC, blood pressure (BP), and heart rate (HR) were recorded. The vital signs, such as EtCO2, PaO2, and temperature, were maintained within normal ranges. The activity of NOS in cerebellum was assessed by measuring the conversion of L-[3H] arginine to L-[3H] citrulline. All data were presented as mean +/- SD. Statistical analysis was performed using Student's t-test, where P < 0.05 was considered significant.

RESULTS

In the presence of L-NAME (30 mg/kg), the MAC for isoflurane was markedly reduced from 1.6 +/- 0.20% (study group) to 1.0 +/- 0.09% (control group) (P < 0.05). The activity of cNOS in cerebellum was 220.09 +/- 23.64 (pmol/mg protein/30 min) in the control group, and in contrast a sharp reduction as low as to 115.40 +/- 24.85 (pmol/mg protein/30 min) was seen in the study group.

CONCLUSIONS

The involvement of NO in the mechanism of isoflurane anesthesia can be demonstrated by the fact that the NOS inhibitor, L-NAME reduces the level of MAC and the cerebral NOS activity in rats.

Intraoperative Doppler ultrasound in liver transplantation

The purpose of this study was to determine the utility of intraoperative Doppler ultrasound for the diagnosis and reduction of the vascular complications in liver transplantation. This study included 19 pediatric and 5 adult patients. In the pediatric group, 12 patients received living related liver transplantation (LRLT), two splitting liver transplantation (SLT), three reduced-size liver transplantation (RLT) and two full-size pediatric liver transplants (FPLT). The hemodynamics and waveform of the hepatic vein, portal vein and hepatic artery were evaluated by intraoperative Doppler ultrasound (US) after reperfusion of the graft. Unsatisfactory hemodynamics was identified in nine cases, including decrease hepatic venous flow (6-9 cm/s) with non-pulsative flat waveform (adults, n = 2 and LRLT, n = 2); portal vein thrombosis (LRLT, n = 1); decrease portal flow (8 mL/min/kg) (LRLT, n = 1); occlusion of the portal vein (SLT, n = 1); poor arterial flow with dampened artery waveform (FPLT, n = 2). These abnormalities were all successfully re-reconstructed by surgical procedures and achieved a graft survival rate of 100%. Two late vascular complications including hepatic venous thrombosis and recurrent portal vein stenosis with splenorenal shunt were discovered 1 month later. They were treated effectively by surgical thrombolectomy and percutaneous balloon dilatation and metallic coils embolization respectively. Three patients died of non-vascular complications and all patients who underwent LRLT survived with a resultant 87.5% overall survival rate. In conclusion, intraoperative Doppler US is efficient in detecting abnormal hepatic hemodynamics, which permits early intervention and hence a better prognosis for the patients. Re-reconstructive procedures were monitored closely under Doppler US guidance until proper flow and wave-form were established. This reduces post-transplant vascular complications and thereby eliminates the likelihood of a lethal complication that might call for re-transplantation.

Functional co-assembly among subunits of cyclic-nucleotide-activated, nonselective cation channels, and across species from nematode to human

Cyclic-nucleotide-activated, nonselective cation channels have a central role in sensory transduction. They are most likely tetramers, composed of two subunits (alpha and beta or 1 and 2), with the former, but not the latter, being able to form homomeric cyclic-nucleotide-activated channels. Identified members of this channel family now include, in vertebrates, the rod and cone channels mediating visual transduction and the channel mediating olfactory transduction, each apparently with distinct alpha- and beta-subunits. Homologous channels have also been identified in Drosophila melanogaster and Caenorhabditis elegans. By co-expressing any combination of two alpha-subunits, or alpha- and beta-subunits, of this channel family in HEK 293 cells, we have found that they can all co-assemble functionally with each other, including those from fly and nematode. This finding suggests that the subunit members so far identified form a remarkably homogeneous and conserved group, functionally and evolutionarily, with no subfamilies yet identified. The ability to cross-assemble allows these subunits to potentially generate a diversity of heteromeric channels, each with properties specifically suited to a particular cellular function.

Efficacy of surgical treatment in traumatic central cord syndrome

BACKGROUND

Controversy surrounds the treatment of traumatic central cord syndrome (TCCS), as there are strong advocates for nonsurgical treatment for most patients. However, conservative treatment has been shown to yield a longer period of discomfort from pain and weakness in certain cases.

METHODS

In a retrospective review of 114 patients presenting with acute or chronic TCCS from 1988-94, four different age groups were separately observed under different treatments. Motor and sensory recovery were assessed.

RESULTS

Better results were achieved in younger patients, with or without radiographic abnormalities, and in patients with clinically correlated encroaching cord lesions who received early surgical decompression.

CONCLUSIONS

Surgical intervention for TCCS must be addressed with careful clinical and radiographic survey. Removal of offending lesions in the subacute period results in significant motor and sensory improvement in short-term and long-term follow-up.