Renal function in patients during and after hypotensive anesthesia with sevoflurane

STUDY OBJECTIVES: To evaluate renal function during and after hypotensive anesthesia with sevoflurane compared with isoflurane in the clinical setting. DESIGN: Randomized, prospective study. SETTING: Inpatient surgery at Rosai Hospital. PATIENTS: 26 ASA physical status I and II patients scheduled for orthopedic surgery. INTERVENTIONS: Patients received isoflurane, nitrous oxide (N2O), and fentanyl (Group I = isoflurane group; n = 13) or sevoflurane, N2O, and fentanyl (Group S = sevoflurane group; n = 13). Controlled hypotension was induced with either isoflurane or sevoflurane to maintain mean arterial pressure at 60 mmHg for 120 minutes. MEASUREMENTS AND MAIN RESULTS: Measurements included serum inorganic fluoride (previously speculated to influence renal function), creatinine clearance (CCr; to assess renal glomerular function), urinary N-acetyl-beta-D-glucosaminidase (NAG; to assess renal tubular function), blood urea nitrogen (BUN), and serum creatinine (as clinical renal function indices). Serum fluoride, CCr, and NAG were measured before hypotension, 60 minutes, and 120 minutes after the start of hypotension, 30 minutes after recovery of normotension, and on the first postoperative day. BUN and serum creatinine were measured preoperatively and on the third and seventh postoperative days. Minimum alveolar concentration times hour was 3.6 +/- 1.8 in Group I and 4.0 +/- 0.7 in Group S. In both groups, BUN and serum creatinine did not change, and CCr significantly decreased after the start of hypotension. In Group I, serum fluoride and NAG did not change. In Group S, serum fluoride significantly increased after the start of hypotension compared with prehypotension values and compared with Group I values. In addition, NAG significantly increased at 120 minutes after the start of hypotension and at 30 minutes after recovery of normotension, but returned to prehypotension values on the first postoperative day. CONCLUSIONS: Two hours of hypotensive anesthesia with sevoflurane under 5 L/min total gas flow in patients having no preoperative renal dysfunction transiently increased NAG, which is consistent with a temporary, reversible disturbance of renal tubular function.     

Beneficial effects of acetazolamide on paroxysmal attacks of girdle sensation in multiple sclerosis

A 56-year-old woman with a 40-year history of multiple sclerosis (MS) developed paroxysmal attacks of girdle sensation in the Th5-6 dermatomes. The attacks lasted 20-60 minutes and occured up to three times per week. T2-weighted MR imaging of the spinal cord showed high intensity area from Th5 to Th8. Electrocardiography, echocardiography and laboratory findings did not indicate ischemic heart disease; therefore, the paroxysms were attributed to the spinal cord lesions. Attacks were successfully suppressed by acetazolamide 250 mg/day. Although carbamazepine is frequently used to treat paroxysmal attacks in MS, we would like to suggest that acetazolamide may also be beneficial in some patients with paroxysmal symptoms.     

Contribution of parenchymal and non-parenchymal liver cells to the clearance of hepatocyte growth factor from the circulation in rats

PURPOSE: The distribution of 125I-hepatocyte growth factor (HGF) to either liver parenchymal cells (PC) or non-parenchymal cells (NPC) was investigated in rats. METHODS: After injection of a trace amount of 125I-HGF, the distribution of radioactivity determined by microautoradiography closely resembled that of 125I-epidermal growth factor which distributes mainly to PC. RESULTS: The uptake clearance of 125I-HGF estimated by determining the radioactivity of isolated liver cells was three times higher for PC than for NPC. This suggests that HGF distributes mainly to PC at relatively low doses. On the other hand, the uptake clearance by PC fell on coadministering an excess (80 micrograms/kg) of unlabeled HGF, while no change was observed for NPC, indicating that a saturable process for the hepatic handling of HGF exists only in PC where the HGF receptor is expressed. CONCLUSIONS: At such a dose the uptake clearance was comparable for both PC and NPC showing that HGF distributes to both cell types although NPC have few HGF receptors. Since the distribution to NPC was relatively non-specific and heparin-sensitive, it may be that heparin-like substances, which are believed to exist on PC and/or the extracellular matrix, also exist on NPC.     

Cerebrospinal fluid tissue factor and thrombin-antithrombin III complex as indicators of tissue injury after subarachnoid hemorrhage

BACKGROUND AND PURPOSE: No marker that reflects and predicts brain injury due to subarachnoid hemorrhage (SAH) and cerebral vasospasm has been reported. We hypothesized that membrane-bound tissue factor (mTF) and thrombin-antithrombin III complex (TAT) in the cerebrospinal fluid (CSF) of patients with SAH become markers indicating brain injury. To evaluate the hypothesis, we correlated levels of mTF and TAT in the CSF of patients with SAH with clinical severity, the degree of SAH, and outcome. METHODS: We assayed CSF mTF, TAT and myelin basic protein (MBP) in patients with SAH at intervals that included days 0 to 4 and days 5 to 9 after ictus. Classification of clinical severity of disease on admission was based on Hunt and Hess grade, degree of SAH on CT on Fisher's grading, and outcome 3 months after SAH on the Glasgow Outcome Scale. RESULTS: In the interval from days 0 to 4, mTF and TAT correlated with Hunt and Hess and Fisher grades, and occurrence of cerebral infarction due to vasospasm. Only mTF correlated significantly in this period with outcome. TAT, mTF, and MBP all correlated significantly with each other. From days 5 to 9, only mTF correlated with cerebral infarction, infarction volume, MBP levels, and outcome. CONCLUSIONS: Both mTF and TAT reflected brain injury from SAH and predicted vasospasm, though mTF was more sensitive and a better predictor of outcome. Unlike mTF, TAT did not correlate with vasospasm during the interval when it most commonly occurs, which raised doubt about thrombin activation as a cause.     

Study of the structure and properties of TAPO-5 molecular sieve

The conditions under which some of the Ti⁴⁺ ions in TAPO-5 (a titanium containing aluminophosphate) can be reduced to Ti³⁺ whilst leaving the crystal and pore structure of the molecular sieve intact, have been studied. ESR spectroscopy was used to probe the local geometry round the Ti³⁺, and was found that this was in a distorted octahedral coordination. The heteroatom was therefore present in a separate microphase locate inside the micropores, in particles too small to be detectable by X-ray diffraction. Two titanium sites were identified. It was found that reduction of Ti⁴⁺ involved the lattice oxygens, whilst on exposure to air Ti³⁺ was oxidised via an electron-transfer mechanism which resulted in the formation of a Superoxide.On leave from the Department of Applied Chemistry and Material Technology, Shizuoka University, 3-5-1 Johoku, Hamamatsu 432, Japan     

A full-wave analysis of offset reflector antennas with polarizationgrids

A full-wave analysis is presented of offset reflector antennas with polarization grids which uses the equivalent grating approach proposed by the authors (ibid., vol.AP-35, p.367-71, Apr. 1987). Two types of antenna are compared: one has a parallel straight strip grating (grid A) and the other has a curved strip grating (grid B) whose pattern is designed so that the antenna system does not generate a cross-polarized component. The key future method is the definition of the equivalent grid. This method quantitatively evaluates the scattering, includes a physical interpretation of the phenomena and gives a physical interpretation of the phenomena and gives a suggestion for the design of the strip patterns. Cross-population suppression effects are quantitatively evaluated as functions of the strip parameters, the size and the location of the grid. It is noted that the cross-polar peaks of the patterns with grid A move with the tilt angle of the grid. The mechanism of this movement is also explained     

Quench detection method without a central voltage tap by calculating active power

In this paper, we present an electric quench detection method without a central voltage tap which may cause the short-circuit of the lead-wires from the voltage taps in the quench detection of a large AC superconducting coil. In this method, an inductive voltage detection coil is used instead of the central voltage tap. The inductive voltage detection coil is electrically insulated from a superconducting coil and therefore the lead-wires do not break down. Through the quench detection tests for a Bi-2223/Ag HTS coil, we show the feasibility of the proposed method for detecting the quench of the large AC superconducting coil.     

A piezoelectric micromotor using in-plane shearing of PZT elements

A torsional micromotor, 3/spl times/4/spl times/8.5mm, was developed using planar bulk lead zirconium titantate placed upon a small rectangular prism made from phosphor bronze, with a tapered conical horn and a machined interior. By using a new measurement technique, the torque and efficiency versus speed were measured at several combinations of applied voltage and preload. At 87.1-mN preload, up to 0.1-N/spl middot/mm torque and 425r/min in both directions were obtained by driving the system at resonance, 186.3kHz for counter-clockwise rotation, and 240.6kHz for clockwise rotation, while the overall efficiency peaked at slightly above 40%.