Relationship between dexamethasone added to periarticular anesthetic infiltration and postoperative nausea and vomiting following total knee arthroplasty under general anesthesia: a retrospective observational study.

BACKGROUND: Periarticular anesthetic infiltration (PAI) with a corticosteroid is a modality for pain control following total knee arthroplasty (TKA). Systemic corticosteroids are an established antiemetic for the prophylaxis of postoperative nausea and vomiting (PONV). The purpose of this retrospective observational study was to elucidate the relationship between dexamethasone added to PAI and PONV in patients who underwent TKA. METHODS: Data from 435 patients who received PAI using ropivacaine with or without dexamethasone were reviewed. The primary outcome was the incidence of PONV within 24 h following TKA. The incidence of deep incisional and organ/space surgical site infection (SSI) within the first year was also assessed. RESULTS: The overall incidence of PONV was 23.2%. A multivariate logistic regression analysis showed that dexamethasone added to PAI was independently associated with a reduced incidence of PONV (adjusted odds ratio, 0.23; 95% confidence interval, 0.12-0.44, P < 0.001). The incidence of PONV and rescue analgesic requirements within 24 h were lower in patients who received PAI with dexamethasone than in those who received PAI alone (19.5% vs 49.1%, P < 0.001, 7.9% vs 29.1%, P < 0.001, respectively). SSI developed in one out of the 55 patients who received PAI alone, but in none of those who received PAI with dexamethasone. CONCLUSIONS: Dexamethasone added to PAI for postoperative pain management was independently associated with a lower risk of PONV within 24 h of TKA.

[Acute Tongue Swelling Immediately after Extubation of the Trachea in a Patient Undergoing Bipolar Hip Arthroplasty under General Anesthesia].

An 81-year-old woman underwent bipolar hip arthroplasty in the left lateral position under general anesthesia. Her trachea was intubated with a standard tube and a rolled gauze pad was placed between the left lingual margin and buccal wall. Surgery lasting for 49 minutes and anesthesia were uneventful until extubation in the supine position. After the extubation she gradually developed tongue swelling and finally required a temporary supraglottic airway to avoid airway obstruction. The swelling was localized to the tongue and disappeared completely in a day. There were no specific factors for tongue swelling except for the tracheal tube and gauze pad in this case. Airway management with a tracheal tube may potentially cause acute life-threatening tongue swelling after surgery of a relatively short duration.

Survival of yeasts stored after freeze-drying or liquid-drying.

We investigated the survival mechanisms of freeze-dried or liquid-dried (L-dried) yeast cells in ampoules. Type strains of various yeasts were freeze-dried or L-dried and sealed in ampoules under high vacuum (< 1 Pa) or low vacuum (4.8 x 10(4) Pa), then stored at 37 degrees C (accelerated storage test) for up to 17 weeks. Among strains in each of the genera Saccharomyces, Saccharomycopsis, Debaryomyces, and Pichia, survival rates immediately after freeze-drying varied more widely than those after L-drying. Freeze-dried cells stored at 4.8 x 10(4) Pa had lower survival rates than those stored at < 1 Pa. L-dried cells stored at 4.8 x 10(4) Pa also had lower survival rates than those stored at < 1 Pa, but the decrease in survival was not as marked as in freeze-dried cells. Strains that had high survival rates immediately after freeze-drying tended to have small cells, to be osmotolerant, and to be able to utilize many kinds of carbohydrates. L-dried cells of most Candida strains had stable survival rates regardless of the vacuum pressure. In basidiomycetous yeasts, strains forming extracellular polysaccharides had markedly lower survival.

Lower intracuff pressure of laryngeal mask airway in the lateral and prone positions compared with that in the supine position.

We compared the intracuff pressure (ICP) of a laryngeal mask airway (LMA) in the lateral and prone positions with that in the supine position. One hundred and eight patients, weighing 50-70 kg, scheduled for elective orthopedic and plastic surgery, were assigned to three groups, based on their body position during surgery. General anesthesia was induced and then a size 4 deflated LMA was inserted in each patient in the supine (group 1; n = 42), lateral (group 2; n = 45), or prone position (group 3; n = 21). The LMA cuff was inflated with 15 ml of air. Anesthesia was maintained without nitrous oxide, and the ICP was measured until LMA removal in the supine position. ICP in groups 2 and 3 was significantly lower than that in group 1 from immediately after insertion to the end of surgery. After surgery, turning from the lateral (group 2) or prone (group 3) position to the supine position significantly raised the ICP. Because the ICP is related to the seal pressure of the LMA and postoperative pharyngolaryngeal morbidity, we recommend evaluating and adjusting the ICP appropriately in each body position.

Survival of freeze-dried bacteria.

The aim of this study was to investigate the survival of freeze-dried bacterial species stored at the International Patent Organism Depository (IPOD) and to elucidate the characteristics affecting survival. Bacterial strains were freeze-dried, sealed in ampoules under a vacuum (<1 Pa), and stored in the dark at 5 degrees C. The survival of a variety of species following storage for up to 20 years was analyzed. The survival of freeze-dried species was analyzed in terms of two stages, freeze-drying and storing. Nonmotile genera showed relatively high survival after freeze-drying. Motile genera with peritrichous flagella showed low survival rates after freeze-drying. Vibrio and Aeromonas, which produce numerous flagella, showed very low survival rates. In Lactobacillus, non-trehalose-fermenting species showed better survival rates after freeze-drying than did fermenting species, and those species with teichoic acid in the cell wall showed lower survival rates during storage than species with teichoic acid in the cell membrane. Human pathogenic species of Corynebacterium, Bacillus, Streptococcus, and Klebsiella showed lower survival rates during storage than nonpathogenic species within the same genus. Among Pseudomonas species, P. chlororaphis, the only species tested that forms levan from sucrose, showed the lowest survival rate during storage in the genus. Survival rates of Gram-negative species during storage tended to be lower than those of Gram-positive species, though Chryseobacterium meningosepticum had stable survival during storage. The conclusion is that smooth cell surfaces (i.e., no flagella) and lack of trehalose outside the cytoplasm improved survival rates after freeze-drying. Because desiccation is important for survival during storage, the presence of extracellular polysaccharides or teichoic acids is disadvantageous for long-term survival. The lower survival rates of freeze-dried Gram-negative bacteria compared with those of Gram-positive bacteria may be attributed to the thinner peptidoglycan layer and the presence of lipopolysaccharides on the cell wall in the former species.

Anti-atherosclerotic effect of cilostazol in apolipoprotein-E knockout mice.

To investigate whether cilostazol (CAS 73963-72-1), a selective phosphodiesterase 3 inhibitor, reduces the progression of atherogenic diet-induced atherosclerosis, cilostazol was orally administered twice a day for 4 weeks to male apolipoprotein-E knockout (ApoE KO) mice. In serial sections of the aortic root, the atherosclerotic lesion ratios in the cilostazol-treated groups (32.5 +/- 3.3% for 100 mg/kg, 29.0 +/- 2.9% for 300 mg/kg) were significantly and dose-dependently smaller than that of the control group (40.2 +/- 3.7%). Cilostazol also significantly reduced the expression of vascular cell adhesion molecule-1 (VCAM-1) and monocyte/macrophage accumulation in the aortic root and increased high-density lipoprotein(HDL) cholesterol levels in plasma. These results suggest that cilostazol suppresses the progression of atherosclerosis in ApoE KO mice by inhibiting adhesionand infiltration of monocytes and reducing cholesterol accumulation in atherosclerotic lesion.

OPC-28326, a selective femoral arterial vasodilator, augments ischemia induced angiogenesis.

OPC-28326, 4-(N-methyl-2-phenylethylamino)-1-(3,5-dimethyl-4-propionyl-aminobenzoyl) piperidine hydrochloride monohydrate, is a newly developed selective peripheral vasodilator and increases blood flow to lower extremities with alpha2-adrenergic antagonist property. Here, we investigated the effect of OPC-28326 on ischemia-induced angiogenesis. OPC-28326 enhanced tube formation by human aortic endothelial cells (HAECs). Moreover, OPC-28326 enhanced the number of microvessels sprouting from aortic rings embedded in collagen gel. OPC-28326 markedly induced phosphorylation of endothelial nitric oxide synthase (eNOS) in HAECs via phosphatidylinositol-3 kinase PI3K/Akt (PI3K/Akt) pathway. Next, the angiogenic effect of OPC-28326 was evaluated in a mouse hindlimb ischemia model. Blood flow recovery to the ischemic leg was significantly enhanced by OPC-28326. Furthermore, anti-CD31 immunostaining revealed that OPC-28326 increased capillary density in the ischemic muscle. However, OPC-28326 failed to promote blood flow recovery in ischemic hindlimb in eNOS-deficient mice. These results suggest that OPC-28326 promotes angiogenesis, which was associated with activation of eNOS via PI3K/Akt pathway. OPC-28326 might be promising to treat patients with ischemic vascular diseases.

Impaired expression of importin/karyopherin beta1 leads to post-implantation lethality.

Importin beta1 (Impbeta)/karyopherin beta1 (Kpnb1) mediates the nuclear import of a large variety of substrates. This study aimed to investigate the requirement for the Kpnb1 gene in mouse development, using a gene trap line, B6-CB-Ayu8108(GtgeoIMEG) (Ayu8108(geo)), in which the trap vector was inserted into the promoter region of the Kpnb1 gene, but in reverse orientation of the Kpnb1 gene. Ayu8108(geo/geo) homozygous embryos could develop to the blastocyst stage, but died before embryonic day 5.5, and expression of the Kpnb1 gene in homozygous blastocysts was undetectable. We also replaced the betageo gene with Impbeta cDNA through Cre-mediated recombination to rescue Impbeta expression. Homozygous mice for the rescued allele Ayu8108(Impbeta/Impbeta) were born and developed normally. These results demonstrated that the cause of post-implantation lethality of Ayu8108(geo/geo) homozygous embryos was impaired expression of the Kpnb1 gene, indicating indispensable roles of Impbeta1 in early development of mice.

Survival curves for microbial species stored by freeze-drying.

The survival of a variety of species of microorganism following storage for up to 20 years has been analyzed. The organisms were freeze-dried, sealed in ampoules under vacuum (<1 Pa) and stored in the dark at 5 degrees C. The yeast that was tested, Saccharomyces cerevisiae, showed only 8% survival when recovered shortly after freeze-drying, but subsequent loss during storage was the least among all the tested microorganisms. The decrease in the logarithm of survival per year (log survival) was -0.010, which corresponds to a survival rate of 97.7% per year. The Gram-negative bacteria tested, Escherichia coli, Pseudomonas putida, and Enterobacter cloacae, showed 42.6, 33.5, and 50.8% survival shortly after freeze-drying, which was higher than the corresponding survival of S. cerevisiae, but the subsequent loss during storage was greater than S. cerevisiae, the log survival figures being -0.041, -0.058, and -0.073 per year. These values correspond to survival rates of 91.0, 87.5, and 84.5% each year. The Gram-positive bacteria tested, Lactobacillus acidophilus and Enteroccoccus faecium, showed 62.5 and 85.2% survival shortly after freeze-drying, which was even higher than that of the Gram-negative species, and these organisms also showed better survival during storage than Gram-negative bacteria; their log survival rates were -0.018 and -0.016 per year, which corresponded to survival rates of almost 96% per year. Comparison of these results with other published data for different drying conditions suggests that survival during storage is strongly influenced by the degree of vacuum under which the ampoules were sealed. The excellent survival after freeze-drying of each species might be attributable to the high level of desiccation and to sealing under vacuum.

Characterization of an exchangeable gene trap using pU-17 carrying a stop codon-beta geo cassette.

We have developed a new exchangeable gene trap vector, pU-17, carrying the intron-lox71-splicing acceptor (SA)-beta geo-loxP-pA-lox2272-pSP73-lox511. The SA contains three stop codons in-frame with the ATG of beta galactosidase/neomycin-resistance fusion gene (beta geo) that can function in promoter trapping. We found that the trap vector was highly selective for integrations in the introns adjacent to the exon containing the start codon. Furthermore, by using the Cre-mutant lox system, we successfully replaced the beta geo gene with the enhanced green fluorescent protein (EGFP) gene, established mouse lines with the replaced clones, removed the selection marker gene by mating with Flp-deleter mice, and confirmed that the replaced EGFP gene was expressed in the same pattern as the beta geo gene. Thus, using this pU-17 trap vector, we can initially carry out random mutagenesis, and then convert it to a gain-of-function mutation by replacing the beta geo gene with any gene of interest to be expressed under the control of the trapped promoter through Cre-mediated recombination.

[A case of intraoperative hyperkalemia probably due to preoperative feeding with a liquid enteral formulation].

A 67-year-old man with no remarkable preanesthetic complications underwent esophagectomy. The patient was fed only with a liquid enteral formulation (Ensure Liquid) for 5 days immediately before the operative day. His serum potassium level before Ensure Liquid administration was 4.1 mEq x l(-1). The first blood analysis at 30 min after the initiation of the surgery revealed an increase in serum potassium level (5.9-6.1 mEq x l(-1)) without any conceivable cause during the anesthetic management. A glucose-insulin infusion treatment lowered the serum potassium level to the normal range. The serum potassium level re-increased to 6.4 mEq x l(-1) 4 days after the initiation of jejunal feeding with Ensure Liquid and then returned to the normal range after the termination of Ensure Liquid administration. The patient's perioperative course suggests that the preoperative Ensure Liquid administration is a probable cause of the intraoperative hyperkalemia in this case.

A method for evaluating drug effects on intermittent claudication using a treadmill in rats with unilateral hindlimb artery occlusion.

INTRODUCTION: We have developed an in vivo experimental model for evaluating peripheral arterial insufficiency and predicting the efficacy of drugs on intermittent claudication (IC). We found that rats that had been running normally on a treadmill developed a gait disturbance when a hindlimb artery was unilaterally occluded. We hypothesized that the distance run before gait disturbance developed (DGD) in rats with occlusion of a hindlimb artery might be an appropriate index of the severity of peripheral insufficiency, and that the model might serve as a test bed for evaluating drug efficacy. To prove this hypothesis, we examined whether DGD was determined by severity of hindlimb ischemia. Furthermore, we also examined whether cilostazol, which has been proved to have ameliorative effects in patients with IC, increased DGD. METHODS: To vary the severity of ischemia, either the superficial femoral artery, the distal portion of the iliac artery, or the proximal portion of iliac artery was unilaterally occluded. After a recovery period, these rats were subjected to a treadmill test (15 m/min and 15% incline) to determine DGD and examine the effect of cilostazol on DGD. RESULTS: DGD was the longest and shortest in rats with superficial femoral artery and proximal portion of iliac artery occlusion, respectively. Intermediate DGD was observed in rats with distal portion of iliac artery occlusion. These data suggest that DGD is correlated with the severity of hindlimb ischemia. Two weeks or longer administration of cilostazol 30 and 100 mg/kg twice a day evoked a significant increase in DGD. DISCUSSION: Peripheral arterial insufficiency and its modulation by drugs can be evaluated in rats with unilateral hindlimb artery occlusion, on a treadmill, by measuring DGD.

Novel selective hindlimb vasodilators: synthesis and biological activity of 1-acyl-4-aminopiperidine derivatives.

A series of 6-(4-amino-1-piperidinyl)carbonyl-2(1H)-quinolinones, and their open form derivatives, were synthesized and evaluated for their ability to stimulate femoral artery blood flow (FBF) in the canine hindlimb. All members of this series stimulated FBF, and subsequent experiments revealed that selected members of this series produced minimal changes in coronary blood flow or systemic blood pressure. Compound 25 was the most promising agent in this respect, and clinical trials are now ongoing to evaluate the effectiveness of this drug as a novel treatment for intermittent claudication and Raynaud's phenomenon.

Effect of oral OPC-28326, a selective femoral arterial vasodilator, on hindlimb subcutaneous tissue temperature in conscious dogs under buprenorphine sedation.

In dogs, rectal temperature was decreased to about 36 degrees C at 2 to 2.5 h after sedation with buprenorphine (0.3 mg/body, i.m.), and hindlimb subcutaneous tissue temperature (T(SC)) in the thigh decreased in a similar manner. T(SC) in the dorsum of the foot showed a greater decrease than that in the thigh. OPC-28326 (4-(N-methyl-2-phenylethylamino)-1-(3,5-dimethyl-4-propionyl-aminobenzoyl) piperidine hydrochloride monohydrate) at doses of 0.3, 1.0 and 3.0 mg/kg, p.o. inhibited the buprenorphine-induced decrease in T(SC) in the dorsum dose-dependently, but had little effect on that in the thigh or rectal temperature. In conclusion, T(SC) in the extremities were more sensitive to core temperature and peripheral circulation.