Thiopental dose requirements for induction of anaesthesia and subsequent endotracheal intubation in patients with complete spinal cord injuries.

BACKGROUND: Dose requirements of thiopental depend on patient characteristics and infusion rate. We determined thiopental dose requirements for induction of anaesthesia, and the effects of remifentanil on cardiovascular and bispectral index (BIS) responses to tracheal intubation in spinal cord-injured (SCI) patients undergoing general anaesthesia. METHODS: Twenty patients with traumatic complete SCI undergoing elective surgery were enrolled. Twenty patients without SCI served as control. Anaesthesia was induced with thiopental, followed by remifentanil 1 µg/kg and rocuronium 0.8 mg/kg, and maintained with 2% sevoflurane and 50% nitrous oxide in oxygen after tracheal intubation. Thiopental was administered at a rate of 50 mg/15 s until abolition of the eyelash reflex. Thiopental doses, BIS values, systolic arterial blood pressure (SAP), heart rate (HR) and plasma catecholamine concentrations were measured. RESULTS: Total thiopental dose required to abolish the eyelash reflex based on total body weight (BW) (5.26 ± 0.87 vs. 3.91 ± 1.07 mg/kg, P < 0.001) or lean BW (6.56 ± 1.37 vs. 5.24 ± 1.36 mg/kg, P < 0.01) were significantly smaller in the SCI group than in the control. SAP was decreased by induction of anaesthesia with thiopental and remifentanil, and increased by tracheal intubation in both groups. However, the peak SAP after intubation was smaller in the SCI patients. HR increased significantly above baseline values following intubation in both groups with no significant intergroup differences. Hypertension was more frequent in the control group. Norepinephrine concentrations remained unaltered following intubation in both groups. CONCLUSIONS: These results suggest that the dose requirements of thiopental for induction of general anaesthesia and subsequent tracheal intubation are reduced in the SCI patients.

Dose-related attenuation of cardiovascular responses to tracheal intubation by intravenous remifentanil bolus in severe pre-eclamptic patients undergoing Caesarean delivery.

BACKGROUND: The optimal dose of remifentanil to attenuate the cardiovascular responses to tracheal intubation in pre-eclamptic patients undergoing Caesarean delivery under general anaesthesia has not been established. We compared the effects of two low doses of remifentanil on the cardiovascular responses to tracheal intubation and neonatal outcomes. METHODS: Forty-eight women with severe pre-eclampsia were randomly assigned to receive either remifentanil 0.5 µg kg⁻¹ (R0.5 group, n=24) or 1 µg kg⁻¹ (R1.0 group, n=24) over 30 s before induction of anaesthesia using thiopental 5 mg kg⁻¹ and succinylcholine 1.5 mg kg⁻¹. Systolic arterial pressure (SAP), heart rate (HR), and plasma catecholamine concentrations were measured. Neonatal effects were assessed using Apgar scores and umbilical cord blood gas analysis. RESULTS: SAP was decreased by induction of anaesthesia and increased by tracheal intubation in both groups. The peak SAP after intubation was greater in the R0.5 group than in the R1.0 group, whereas it did not exceed baseline values in either group. HR increased significantly above baseline in both groups with no significant differences between the groups. Three subjects in the R1.0 group received ephedrine due to hypotension (SAP < 90 mm Hg). Norepinephrine concentrations remained unaltered after intubation and increased significantly at delivery with no significant differences between the groups. Neonatal Apgar scores and umbilical arterial and venous pH and blood gas values were comparable between the groups. CONCLUSIONS: Both doses of remifentanil effectively attenuated haemodynamic responses to tracheal intubation with transient neonatal respiratory depression in pre-eclamptic patients undergoing Caesarean delivery under general anaesthesia. The 1.0 µg kg⁻¹ dose was associated with hypotension in three of 24 subjects.

Altered cardiovascular responses to tracheal intubation in patients with complete spinal cord injury: relation to time course and affected level.

BACKGROUND: We determined cardiovascular responses to tracheal intubation in relation to the time since injury in patients with different levels of spinal cord injury. METHODS: Two hundred and fourteen patients with complete cord injury were studied. They were either quadriplegics (>C7, n=71) or paraplegics (20 yr. Twenty patients with no cord injury served as controls. Systolic arterial pressure (SAP), heart rate (HR), and plasma catecholamine concentrations were determined. RESULTS: Intubation did not affect SAP in the quadriplegics regardless of the time post-injury, but it significantly increased SAP in all paraplegics. Moreover, the pressor response was enhanced in the paraplegics who were 10 yr or more since injury (P<0.05). HR increased significantly in all groups; the magnitude of the increase was less only in acute quadriplegics compared with controls. Plasma concentrations of norepinephrine increased in every group except for the quadriplegics within 4 weeks of injury. The maximum increases in SAP, HR, and norepinephrine from awake baseline values were smaller in the quadriplegics than in the paraplegics (P<0.01). CONCLUSIONS: The cardiovascular and catecholamine responses to intubation change as a function of the time elapsed and the level of the cord injury. In this study, the pressor response to tracheal intubation was abolished in the quadriplegics but not in paraplegics; indeed, it was enhanced at 10 yr or more since injury in this group.

Cardiovascular and arousal responses to laryngoscopy and tracheal intubation in patients with complete spinal cord injury.

BACKGROUND: We aimed to determine whether the autonomic and arousal responses to laryngoscopy and tracheal intubation were altered in patients with spinal cord injury (SCI). METHODS: One hundred and sixteen patients with traumatic complete SCI were grouped according to the time elapsed after the injury (<3 days and >9 months) and the level of injury (above T5 and below T5): acute high (AH, n=25), chronic high (CH, n=26), acute low (AL, n=20), and chronic low (CL, n=45). Twenty-five patients without SCI served as a control group. Bispectral index (BIS) response, systolic arterial pressure (SAP), heart rate (HR), and plasma concentrations of catecholamines and arginine vasopressin were measured. RESULTS: Both CH and CL groups showed a greater reduction in BIS values after induction of anaesthesia with thiopental compared with controls (P<0.05). However, BIS values after intubation increased similarly in all groups from the value measured just before laryngoscopy. SAP increased in the AL and CL and control groups but not in the AH and CH groups. HR increased significantly in all groups; though to a lesser degree in the AH compared with the other groups. Plasma norepinephrine concentrations increased in all except the AH group, but vasopressin concentrations were unchanged. CONCLUSIONS: The arousal response to laryngoscopy and tracheal intubation as measured by BIS is not altered in SCI, but cardiovascular and catecholamine responses may be changed depending on time elapsed and the level of the injury. However, an identical dose of thiopental may reduce BIS value after intubation more profoundly in patients with chronic SCI.

Effects of remifentanil on cardiovascular and bispectral index responses to endotracheal intubation in severe pre-eclamptic patients undergoing Caesarean delivery under general anaesthesia.

BACKGROUND: We examined the effects of remifentanil on cardiovascular and bispectral index (BIS) responses to tracheal intubation and neonatal outcomes in pre-eclamptic patients undergoing Caesarean delivery under general anaesthesia. METHODS: Forty-two women with severe pre-eclampsia were randomly assigned to receive either remifentanil 1 microg kg(-1) (n=21) or saline (n=21) over 30 s before induction of anaesthesia using thiopentone 4 mg kg(-1) and suxamethonium 1.5 mg kg(-1). Mean arterial pressure (MAP), heart rate (HR) and BIS values as well as plasma catecholamine concentrations were measured. Neonatal effects were assessed using Apgar scores and umbilical cord blood gas analysis. RESULTS: Induction with thiopentone caused a reduction in MAP and BIS in both remifentanil and control groups. Following the tracheal intubation MAP and HR increased in both groups, the magnitude of which was lower in the remifentanil group. BIS values also increased, of which magnitude did not differ between the groups. Norepinephrine concentrations increased significantly following the intubation in the control, while remained unaltered in the remifentanil group. The neonatal Apgar scores at 1 min were significantly lower in the remifentanil group than in the control. However, Apgar scores at 5 min, and umbilical artery and vein blood gas values were similar between the groups. CONCLUSIONS: These results suggest that a single bolus of 1 microg kg(-1) remifentanil effectively attenuates haemodynamic but not BIS responses to tracheal intubation in pre-eclamptic patients undergoing Caesarean delivery under general anaesthesia. However, its use was associated with maternal hypotension and neonatal respiratory depression requiring resuscitation.

Anaesthetic requirement and stress hormone responses in patients undergoing lumbar spine surgery: anterior vs. posterior approach.

BACKGROUND: The intensity of nociceptive stimuli reflects the severity of tissue injury. The anaesthetic requirement and stress hormonal responses were determined to learn whether they differ according to different surgical approaches (anterior vs. posterior) during the spinal surgery. METHODS: Patients undergoing lumbar spine surgery without neurological deficits were divided into two groups: one having posterior (n=13) and the other having anterior fusion (n=13). The end-tidal sevoflurane concentrations (ET(SEVO)) required to maintain the bispectral index score at 40-50 were determined. Mean arterial pressure (MAP), heart rate (HR), central venous pressure (CVP), serum osmolality and plasma concentrations of catecholamines, cortisol and vasopressin (AVP) were measured. RESULTS: There were no differences in MAP, HR, CVP and serum osmolality between the groups. ET(SEVO) was higher in the anterior than in the posterior group (P<0.05). The plasma concentrations of norepinephrine and cortisol increased in both groups during the surgery, whereas those of epinephrine remained unchanged. AVP concentrations increased during the surgery in the anterior group, and remained unaltered in the posterior group. The anterior group needed more analgesics (P<0.01) during the first 1 h after the operation. CONCLUSIONS: The anterior approach required a deeper level of anaesthesia while undergoing spinal surgery and more use of post-operative analgesics than the posterior approach. It was also associated with a more pronounced AVP release during the surgery.

MRI study of the lumbar spine in achondroplasia. A morphometric analysis for the evaluation of stenosis of the canal.

We carried out an MRI study of the lumbar spine in 15 patients with achondroplasia to evaluate the degree of stenosis of the canal. They were divided into asymptomatic and symptomatic groups. We measured the sagittal canal diameter, the sagittal cord diameter, the interpedicular distance at the mid-pedicle level and the cross-sectional area of the canal and spinal cord at mid-body and mid-disc levels. The MRI findings showed that in achondroplasia there was a significant difference between the groups in the cross-sectional area of the body canal at the upper lumbar levels. Patients with a narrower canal are more likely to develop symptoms of spinal stenosis than others.

Binding and regulation of HIF-1alpha by a subunit of the proteasome complex, PSMA7.

The hypoxia-inducible factor-1alpha (HIF-1alpha) is an important transcription factor for cellular responses to oxygen tension. It is rapidly degraded under normoxic conditions by the ubiquitin-dependent proteasome pathway. Here we report a critical role of the 20S proteasome subunit PSMA7 in HIF-1alpha regulation. PSMA7 was found to interact specifically with two subdomains of HIF-1alpha. PSMA7 inhibited the transactivation function of HIF-1alpha under both normoxic and hypoxia-mimicking conditions. In addition, we show that the PSMA7-mediated regulation of HIF-1alpha activity is associated with the proteasome pathway.

Supracondylar osteotomy with Ilizarov fixation for elbow deformities in adults.

Stable fixation after a corrective supracondylar osteotomy in adults is difficult because of the irregularity of the area of bony contact, displacement of the fragments, the predominance of cortical bone, and the need for early mobilisation. We have used the Ilizarov apparatus for fixation in 15 patients who were treated by complex osteotomies with displacement of fragments for cubitus varus or valgus. Most patients with cubitus varus required medial displacement with rotation of the distal fragment. Those with cubitus valgus required lateral shift of the distal fragment to reduce the medial prominence of the elbow that would otherwise result. All osteotomies united within the expected time without loss of correction, despite early mobilisation. Complications related to the fixation were few and had resolved at the long-term follow-up.

Preventing collapse in early osteonecrosis of the femoral head. A randomised clinical trial of core decompression.

We performed a randomised trial on 37 hips (33 patients) with early-stage osteonecrosis (ON). After the initial clinical evaluation, including plain radiography and MRI, 18 hips were randomly assigned to a core-decompression group and 19 to a conservatively-treated group. All the patients were regularly followed up by clinical evaluation, plain radiography and MRI at intervals of three months. Hip pain was relieved in nine out of ten initially symptomatic hips in the core-decompression group but persisted in three out of four initially painful hips in the conservatively-treated group at the second assessment (p < 0.05). At a minimum follow-up of 24 months, 14 of the 18 core-decompressed hips (78%) and 15 of the 19 non-operated hips (79%) developed collapse of the femoral head. By survival analysis, there was no significant difference in the time to collapse between the two groups (log-rank test p = 0.79). Core decompression may be effective tin symptomatic relief, but is of no greater value than conservative management in preventing collapse in early osteonecrosis of the femoral head.

Antibiotic-impregnated cement beads in the treatment of chronic osteomyelitis.

Fifty-four patients with chronic osteomyelitis of the long bones were treated at Gyeong-Sang National University Hospital between 1985 and 1993 using the cement bead technique. We studied the results of thirty-one patients who were followed up for 3 years or more. The average duration of follow-up was 4 years and 2 months (range: 3 to 7 years). All of the patients were treated by a two-stage operation; primary saucerization with implantation of antibiotic-impregnated polymethylmethacrylate beads and secondary bone grafts. The most recent follow-up examinations and analyses revealed that 17 patients (55%) were completely free of infection. Ten patients (32%) required repeated procedures of curettage and/or bone grafting. Amputations were performed on 4 patients.

Fatal cerebral hemorrhage associated with autonomic hyperreflexia during surgery in the prone position in a quadriplegic patient: a case report.

Intracerebral hemorrhage is an unusual complication of autonomic hyperreflexia (AHR), which can be fatal if massive bleeding occurs with subsequent brain herniation. Episodes of AHR are most often triggered by bladder and rectal distention. We present a case of a 45-year-old quadriplegic male who suffered left basal ganglia and thalamic hemorrhage associated with AHR during surgery for pressure sore defects in the prone position under local anesthesia. Early recognition and removal of triggering factors of AHR failed to bring his blood pressure under control. The patient continued to deteriorate neurologically and died 9 days after the attack. A preventive measure rather than episodic treatment of AHR may be of paramount importance to avoid life-threatening complications, especially when a patient with a history of AHR is undergoing surgery in the prone position.

Decreased agglutinability of methoxy-polyethylene glycol attached red blood cells: significance as a blood substitute.

Human Rb(+) AB type red blood cells were modified with methoxy-polyethylene glycol (mPEG) in order to decrease agglutinabilities toward clinically important anti-A, anti-B and anti-D reagents. Attachment of mPEG to membrane proteins of the red blood cell was identified by the shift of well-known blood group active glycoprotein bands such as band 3, 4.5 and PAS-1 on the SDS-polyacrylamide gel electrophoresis. When 4mM concentration of mPEG was added to red blood cells, agglutination was minimum by a blood group typing and microwell agglutination tests. Antibody binding tests showed decreased antibody binding to blood group antigens after mPEG attachment. The decrease of both agglutinability and antibody binding was the result of mPEG attachment to blood group active glycoprotein of the cell membrane. The morphology of red blood cells after mPEG attachment was the usual discocytic cell. Oxygen equilibrium curves of the mPEG-attached red blood cells were similar to unmodified red blood cells. This approach to decrease agglutinability of the red blood cells toward blood group antibodies may be used to develop a universally transfusible blood substitute.

Borderline necrosis of the femoral head.

To determine whether the histologic lesions classified by the system of Arlet et al as Type 2 (granular necrosis of fatty marrow) and Type 3 (complete medullary and trabecular necrosis) always progress to Type 4 (complete necrosis with marginal medullary fibrosis and appositional new bone formation), 10 femoral heads (nine patients) were monitored for 4 years using serial magnetic resonance images. These femoral heads had been diagnosed histologically as having either Type 2 (seven hips) or Type 3 (three hips) necrosis on initial core biopsies. On the initial magnetic resonance image, none of the femoral heads showed any focal lesions indicative of osteonecrosis. In all instances, superselective angiography showed interruption of the superior retinacular artery, and the bone marrow pressure was elevated. During a followup period of 48 to 54 months, no patient had a reactive low signal intensity band develop on T1 weightings, as evidence of a reparative process around the necrotic portion of the lesion, or any other findings of osteonecrosis on magnetic resonance images. These findings suggest that some Type 2 and 3 lesions of Arlet et al may not develop an obvious reactive interface of reparative revascularization and thus may not progress to definite and classic Type 4 osteonecrosis. This study supports the hypothesis that there is an ischemic threshold between reversible intraosseous hypoxia (bone marrow edema syndrome) and irreversible intraosseous anoxia (classic bone infarction or osteonecrosis) and suggests that borderline necrosis occurs in the transition zone of this ischemic threshold and is nonprogressive.

Identification of the functional importance of valine-19 residue in streptokinase by N-terminal deletion and site-directed mutagenesis.

Streptokinase (SK) is a bacterial plasminogen activator of multi-domain structure. In deletion analysis of the N-terminal region of SK, the deletion of 20 amino acids (SK delta N20) resulted in the dramatic reduction of plasminogen activator activity compared to deletion of 7 (SK delta N7) and 13 amino acids (SK delta N13). The incubation time to reach maximal active site generation in an equimolar mixture of SK delta N20 and plasminogen was the same as that for wild-type SK. To identify the functional residues important in plasminogen activation, several site-directed mutations were introduced at the region spanning Ser16-Val20 of SK. The results showed that Val19 residue is important for the activity of the SK-plasminogen complex.

Recombinant hemoglobin(alpha 29leucine --> phenylalanine, alpha 96valine --> tryptophan, beta 108asparagine --> lysine) exhibits low oxygen affinity and high cooperativity combined with resistance to autoxidation.

Using our hemoglobin expression system in Escherichia coli, we have constructed three recombinant hemoglobins (rHbs) with amino acid substitutions located in the alpha(1)beta(1) and alpha(1)beta(2) subunit interfaces and in the distal heme pocket of the alpha-chain: rHb(alphaV96W, betaN108K), rHb(alphaL29F, alphaV96W, betaN108K), and rHb(alphaL29F). rHb(alphaV96W, betaN108K) exhibits low oxygen affinity and high cooperativity and also ease of autoxidation of the heme iron atoms from the Fe2+ state to the Fe3+ state. It has been reported by Olson and co-workers [Carver et al., (1992) J. Biol. Chem. 267, 14443-14450; Brantley et al. (1993) J. Biol. Chem. 268, 6995-7010] that a mutation at position 29 (B10, helix notation), e.g. , Leu --> Phe, can inhibit the autoxidation of the heme iron of myoglobin. We have introduced such a mutation into our rHb having low oxygen affinity and high cooperativity. This triply mutated rHb(alphaL29F, alphaV96W, betaN108K) is stabilized against autoxidation and azide-induced oxidation compared to the double mutant, rHb(alphaV96W, betaN108K), but still exhibits low oxygen affinity and good cooperativity. According to electron paramagnetic resonance results, the oxidized form of the triple mutant shows a high ratio of an anionic form of bishistidine hemichrome. Previous reports have suggested that this form does not have water present at the distal heme pocket. (1)H nuclear magnetic resonance spectra of the triple mutant in the ferric state also exhibit spectral features characteristic of hemichrome-type signals. We have carried out a series of biochemical measurements to characterize these three interesting rHbs and to compare them to human normal adult hemoglobin. These results provide new insights into the structure-function relationship of hemoglobin with amino acid substitutions in the alpha(1)beta(1) and alpha(1)beta(2) interfaces and in the heme pockets.

Spontaneous healing of an atrophic pseudoarthrosis during femoral lengthening. A case report with six-year follow-up.

A seven-year old girl developed an atrophic pseudoarthrosis at the midshaft of the femur with 8.5 cm of femoral shortening after an open type II fracture. During a femoral lengthening procedure, the pseudoarthrosis filled with spontaneous callus formation and bone union was obtained.

Molecular cloning and nucleotide sequence of Streptomyces griseus trypsin gene.

Streptomyces griseus trypsin (E.C. 3.4.21.4) is one of the major extracellular proteinase, which is secreted by S. griseus. The gene encoding S. griseus trypsin was isolated from a S. griseus genomic library by using a synthetic oligonucleotide probe. Fragments containing the gene for S. griseus trypsin were characterized by hybridization and demonstration of proteolytic activity in S. lividans. Deduced amino acid sequence from the nucleotide sequence suggests that S. griseus trypsin is produced as a precursor, consisting of three portions; an amino-terminal pre sequence (32 amino acid residues), a pro sequence (4 residues), and the mature trypsin. The S. griseus trypsin consists of 223 amino acids with a computed molecular weight of 23,112. The existence of proline at the pro and mature junction suggests that the processing of S. griseus trypsin is non-autocatalytic.

Crystallization and preliminary X-ray analysis of a thermoalkalophilic lipase from Bacillus stearothermophilus L1.

A thermoalkalophilic lipase from Bacillus stearothermophilus L1 (L1 lipase) was crystallized in two different crystal forms using a low concentration of the enzyme and a calcium-exchange process. The first, needle-like, crystal form, which diffracts to about 3.5 A, belongs to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 67.84, b = 72.96, c = 104.41 A. The second, monoclinic, crystal form, which behaves better than the first form for crystallographic analyses, belongs to the monoclinic space group C2 and has unit-cell parameters a = 119.62, b = 85.05, c = 98.36 A, beta = 99.73 degrees. From the monoclinic crystals, a native data set and a samarium-derivative data set were collected to 2.0 and 2.3 A resolution, respectively. The difference Patterson map between the two data sets shows strong heavy-atom peaks, indicating that the crystals are suitable for a high-resolution structure determination.

Iliacus hematoma and femoral nerve palsy after revision hip arthroplasty: a case report.

Femoral nerve palsy occurred in a 65-year-old man after he had undergone a revision total hip arthroplasty using cementless components. The magnetic resonance imaging scan showed a mass in the iliacus muscle. The mass showed increased signal intensity on T1-weighted and T2-weighted spin-echo images and contained linear septa and a nodule. The gadolinium-enhanced T1-weighted image showed a rim of significant enhancement in the nodule. The findings of magnetic resonance images were suggestive of iliacus hematoma and of liposarcoma. The patient underwent surgery, and the mass was identified as an iliacus hematoma. The femoral nerve was stretched by the hematoma. After removal of the hematoma, the nerve palsy was improved completely. Iliacus hematoma may occur after total hip arthroplasty, even without anticoagulant therapy. The hematoma might appear to be a liposarcoma on magnetic resonance imaging scans.