Fabrication and characterization of high-T(c) YBa(2)Cu(3)O(7-x) nanoSQUIDs made by focused ion beam milling

We have fabricated high-T(c) nanoscale superconducting quantum interference devices (nanoSQUIDs) with a hole size of 250 nm × 250 nm based on a 100 nm bridge at 77 K by focused ion beam milling and ion implantation. At 78 K, the curve of the voltage branch became roughly linear and agreed with the Josephson-like behavior. The sample exhibited strong flux flow behavior at temperatures under 76 K. The voltage flux characteristic curves, V -I(mod), of the nanoSQUID at different bias currents at 78 K were observed. Typically, critical currents of 15 µA and peak-to-peak values of the voltage flux transfer function of 3.7 µV were measured. The measured data strongly suggest that the weak link structure could be a superconducting metal with a critical temperature T(c)' smaller than that (T(c)) of other YBa(2)Cu(3)O(7-x) (YBCO) films. This fabrication method of combining a nanobridge and ion implantation can improve the yield of nanojunctions and nanoSQUIDs.

Imaging of human aortic atherosclerotic plaques by polarization-sensitive optical coherence tomography

Optical coherence tomography (OCT) is analogous to ultrasound imaging except that it uses infrared light instead of sound. Polarization-sensitive optical coherence tomography (PS-OCT) combines the advantages of OCT and provides additional image contrast of the tested sample. We demonstrate this technique for imaging of back-reflected light, birefringence, and fast-axis orientation simultaneously in different kinds of atherosclerosis plaque. This in vitro study suggests birefringence changes in plaque are due to the prominent deposition of collagen or cholesterol by correlating PS-OCT images with histology. Thus the combination of high resolution structural imaging and birefringence detection make PS-OCT a potentially powerful tool for early assessment of atherosclerosis appearance and prediction of plaque rupture.

Effects of butorphanol and carprofen on the minimal alveolar concentration of isoflurane in dogs

OBJECTIVE

To evaluate the effects of butorphanol and carprofen, alone and in combination, on the minimal alveolar concentration (MAC) of isoflurane in dogs.

DESIGN

Randomized complete-block crossover study.

ANIMALS

6 healthy adult dogs.

PROCEDURE

Minimal alveolar concentration of isoflurane was determined following administration of carprofen alone, butorphanol alone, carprofen and butorphanol, and neither drug (control). Anesthesia was induced with isoflurane in oxygen, and MAC was determined by use of a tail clamp method. Three hours prior to induction of anesthesia, dogs were fed a small amount of canned food without any drugs (control) or with carprofen (2.2 mg/kg of body weight [1 mg/lb]). Following initial determination of MAC, butorphanol (0.4 mg/kg [0.18 mg/lb], i.v.) was administered, and MAC was determined again. Heart rate, respiratory rate, indirect arterial blood pressure, endtidal partial pressure of CO2, and saturation of hemoglobin with oxygen were recorded at the time MAC was determined.

RESULTS

Mean +/- SD MAC of isoflurane following administration of butorphanol alone (1.03 +/- 0.22%) or carprofen and butorphanol (0.90 +/- 0.21%) were significantly less than the control MAC (1.28 +/- 0.14%), but MAC after administration of carprofen alone (1.20 +/- 0.13%) was not significantly different from the control value. The effects of carprofen and butorphanol on the MAC of isoflurane were additive. There were not any significant differences among treatments in regard to cardiorespiratory data.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that administration of butorphanol alone or in combination with carprofen significantly reduces the MAC of isoflurane in dogs; however, the effects of butorphanol and carprofen are additive, not synergistic.

Comparison of anesthetic and cardiorespiratory effects of diazepam-butorphanol-ketamine, acepromazine-butorphanol-ketamine, and xylazine-butorphanol-ketamine in ferrets

Ten ferrets were used in a crossover study to determine the sedative effects of intramuscularly administered diazepam (3 mg/kg body weight)-butorphanol (0.2 mg/kg body weight)-ketamine (15 mg/kg body weight); acepromazine (0.1 mg/kg body weight)-butorphanol (0.2 mg/kg body weight)-ketamine (15 mg/kg body weight); and xylazine (2 mg/kg body weight)-butorphanol (0.2 mg/kg body weight)-ketamine (15 mg/kg body weight). All of the ferrets became laterally recumbent following the administration of each drug combination. The xylazine-butorphanol-ketamine combination induced significantly longer (p less than 0.05) durations of tail-clamp analgesia (mean+/-standard deviation [SD], 81.0+/-19.1 min versus 20.5+/-25.4 min and 30.0+/-26.9 min), dorsal recumbency (mean+/-SD, 94.6+/-13.6 min versus 75. 6+/-34.7 min and 55.2+24.8 min), and muscle relaxation suitable for endotracheal intubation (mean+/-SD, 67.1+/-23.0 min versus 7.0+/-22.1 min and 9.5+/-15.4 min) than the diazepam-butorphanol-ketamine and acepromazine-butorphanol-ketamine combinations, respectively. The recovery time from dorsal recumbency to standing was not significantly different among the three treatment groups. The heart rate was significantly lower in the xylazine-butorphanol-ketamine group; however, systolic blood pressure was not significantly different among the treatment groups. Ventilatory function was more depressed in the diazepam-butorphanol-ketamine and xylazine-butorphanol-ketamine groups than in the acepromazine-butorphanol-ketamine group. A period (approximately 45 minutes) of hypoxia was observed in the xylazine-butorphanol-ketamine-treated ferret. Of the three combinations evaluated in ferrets, xylazine-butorphanol-ketamine was concluded to be the most effective anesthetic combination. However, hypoxemia and ventricular arrhythmias were observed in the xylazine-butorphanol-ketamine-treated ferrets, so the effectiveness of the xylazine-butorphanol-ketamine combination should be weighed against its cardiorespiratory side effects.

Noninvasive glucose monitoring in vivo with an optical heterodyne polarimeter

An amplitude-sensitive optical heterodyne polarimeter was set up to monitor noninvasively the aqueous glucose concentration in a rabbit's eye. A Zeeman laser in conjunction with a Glan-Thompson analyzer was used to generate an optical heterodyne signal. The amplitude of the heterodyne signal linearly related to the optical rotation angle of the aqueous glucose. The concentration of the aqueous glucose in a rabbit's eyeball was measured in vivo. There was a 30-min time delay between observations of aqueous glucose and blood glucose. The detection capability and the reproducibility of the experiment are demonstrated and discussed.

Comparison of sedative and cardiorespiratory effects of diazepam, acepromazine, and xylazine in ferrets

The sedative and cardiorespiratory effects of an intramuscular injection of diazepam (3 mg/kg body weight), acepromazine (0.1 mg/kg body weight), or xylazine (2 mg/kg body weight) in ferrets (n = 10, crossover design) was evaluated. Time from injection to assuming lateral recumbency was not significantly different between the three drugs. Duration of recumbency expressed as mean+/-standard deviation was significantly longer with xylazine (68.3+/-20.8 min) than with diazepam (43.2+/-8.2 min) or acepromazine (49.8+/-11.2 min). Sedation was graded to be the best in the xylazine-treated ferrets and worst in the diazepam-treated ferrets. Analgesia was judged only to be present following xylazine injection. Systolic blood pressure, oxyhemoglobin saturation, and end-expired carbon dioxide (CO2) were similar with all three drugs. It was concluded that, at the doses administered, xylazine provided better chemical restraint in the healthy ferret than either acepromazine or diazepam.

Evaluation of sedative and cardiorespiratory effects of diazepam-butorphanol, acepromazine-butorphanol, and xylazine-butorphanol in ferrets

Ten ferrets were used in a crossover study to determine the sedative effects of intramuscularly (IM) administered diazepam (3 mg/kg body weight)-butorphanol (0.2 mg/kg body weight), acepromazine (0.1 mg/kg body weight)-butorphanol (0.2 mg/kg body weight), or xylazine (2.0 mg/kg body weight)-butorphanol (0.2 mg/kg body weight). All ferrets became laterally recumbent following the administration of each drug combination. The xylazine-butorphanol combination caused a significantly longer (p less than 0.05) duration of analgesia than the diazepam-butorphanol and acepromazine-butorphanol combinations. None of the ferrets could be intubated with any of the drug combinations. The time from induction to recovery was significantly shorter in the acepromazine-butorphanol-treated ferrets. A significantly lower heart rate was observed in the xylazine-butorphanol-treated ferrets; however, an acceptable systolic blood pressure was maintained. Ventilatory function was more depressed in the diazepam-butorphanol- and xylazine-butorphanol-treated ferrets than in the acepromazine-butorphanol-treated ferrets. Xylazine-butorphanol was found to be the best combination for use in ferrets.

Comparison of anesthetic and cardiorespiratory effects of tiletamine-zolazepam-xylazine and tiletamine-zolazepam-xylazine-butorphanol in ferrets

Nine ferrests were used in a crossover study to determine the anesthetic effects of intramuscular (i.m.) administration of a low dose of tiletamine-zolazepam (1.5 mg/kg body weight)-xylazine (1.5 mg/kg body weight); a high dose of tiletamine-zolazepam (3 mg/kg body weight)-xylazine (3 mg/kg body weight); and tiletamine-zolazepam (1.5 mg/kg body weight)-xylazine (1.5 mg/kg body weight)-butorphanol (0.2 mg/kg body weight). All ferrets became laterally recumbent within two minutes following the administration of each drug combination. The tiletamine-zolazepam-xylazine-butorphanol combination induced significantly longer (p less than 0.05) durations of tail clamp analgesia (mean +/- standard deviation [SD], 90.0 +/- 17.1 min versus 17.8 +/- 15.8 min and 41.9 +/- 26.3 min) and endotracheal intubation (mean +/- SD, 84.8 +/- 21.7 min versus 5.2 +/- 10.3 min and 26.3 +/- 29.8 min) than the low-dose tiletamine-zolazepam-xylazine and high-dose tiletamine-zolazepam-xylazine combinations, respectively. Heart rates and the times from dorsal recumbency to standing were not significantly different among the three treatment groups. However, systolic blood pressure was significantly lower in the tiletamine-zolazepam-xylazine-butorphanol group. Ventilatory function was more depressed in the tiletamine-zolazepam-xylazine-butorphanol group than in the low-dose tiletamine-zolazepam-xylazine and high-dose tiletamine-zolazepam-xylazine groups. A short period of hypoxia was observed in the tiletamine-zolazepam-xylazine-butorphanol-treated ferrets. Tiletamine-zolazepam-xylazine-butorphanol was found to be the best of the three combinations evaluated in these ferrets. The addition of butorphanol to the low-dose tiletamine-zolazepam-xylazine combination greatly enhanced the duration of analgesia, endotracheal intubation, and dorsal recumbency. However, since hypoxemia occurred during the tiletamine-zolazepam-xylazine-butorphanol anesthesia, oxygen (O2) insufflation is recommended. Doubling the dose of the low-dose tiletamine-zolazepam-xylazine increased the duration of analgesia and endotracheal intubation without prolonging the recovery when compared to the low-dose tiletamine-zolazepam-xylazine group.

Modulation of microsomal cytochrome P450 by Scutellariae Radix and Gentianae scabrae Radix in rat liver

The present study has determined the effects of Scutellariae Radix (Huangqin) and Gentianae scabrae Radix (Longdan) on liver microsomal cytochrome P450 (P450)-dependent mono-oxygenases using rats pretreated with crude extracts of medicinal herbs. Scutellariae Radix resulted in a 53% decrease of pentoxyresorufin O-dealkylase activity in liver microsomes. In contrast, Gentianae scabrae Radix caused a 50% increase of benzo(a)pyrene hydroxylase activity. Immunoblotting analysis of liver microsomes revealed that Scutellariae Radix induced and suppressed the levels of P450 1A and 2B proteins, respectively. Scutellariae and Gentianae scabrae Radixes had no effects on microsomal aniline hydroxylase activity and P450 2E1 protein.