Pregabalin reduces post-operative pain after mastectomy: a double-blind, randomized, placebo-controlled study

BACKGROUND

Pregabalin is used for the treatment of neuropathic pain and has shown analgesic efficacy in post-operative pain. The aim of this randomized, double-blinded, placebo-controlled trial (Clinical Trials.gov ID NCT00938548) was to investigate the efficacy and safety of pregabalin for reducing post-operative pain in patients after mastectomy.

METHODS

Eighty-four women scheduled for elective mastectomy were randomly assigned to groups that received either pregabalin (75 mg) or placebo, 1 h before surgery and 12 h after the initial dose. Assessments of pain [verbal numerical rating scale (VNRS), at rest and with arm abduction] and side effects were performed at 1, 6, 24 and 48 h post-operatively. After discharge from the hospital, pain was assessed by telephone interview at post-operative 1 week and 1 month.

RESULTS

VNRS scores for pain at rest were lower in the pregabalin group (n=42) than the placebo group (n=42) at 1, 24 and 48 h post-operatively (P<0.05). VNRS scores for pain with arm abduction were lower in the pregabalin group (n=42) than the placebo group (n=42) at 1 and 24 h, and 1 week post-operatively (P<0.05). Incidences of side effects such as nausea and vomiting, headache, dizziness and blurred vision were similar in both groups.

CONCLUSION

Perioperative administration of pregabalin for a single day (75 mg twice daily) was easy, safe and effective in reducing post-operative pain in patients undergoing mastectomy.

Fenofibrate lowers abdominal and skeletal adiposity and improves insulin sensitivity in OLETF rats

The effect of peroxisome proliferator-activated receptor (PPAR)-alpha activators on the liver is well established, but the other effects on muscle and adipose tissue about lipid metabolism and insulin sensitivity are not clear. We investigated whether PPAR-alpha activation affects adiposity of skeletal muscle as well as adipose tissue and improves insulin sensitivity in spontaneous type 2 diabetes model, Otsuka Long-Evans Tokushima Fatty (OLETF) rats. Thirty-three weeks of aged, 20 male OLETF rats were divided into two groups. Control group (n=10) was fed with chow and treatment group (n=10) with chow contained fenofibrate for 7 weeks. At the age of 40 weeks, all rats were examined with MRI, intravenous glucose tolerance test, and then sacrificed for measurement of fat mass and RNA analyses. The total fat (the sum of subcutaneous, mesenteric, epididymal, and retroperitoneal fat pads) measured by dissection was significantly reduced in treatment group. The signal intensity of muscular adiposity was significantly decreased in treatment group. The mRNA levels of FAT/CD36 and mitochondrial carnitine palmitoyltransferase I (M-CPT I) in liver were remarkably increased. Fasting plasma insulin and leptin levels, insulin response after intravenous glucose loading and homeostasis model assessment insulin resistance (HOMA(IR)) index were lowered in treatment group. Fenofibrate increase mitochondrial fatty acid beta-oxidation in liver but not in skeletal muscle and lower the plasma levels of triglyceride and free fatty acid. It might result in reduction of adiposity of truncal adipose tissue and skeletal muscle. We suggest that reduction of adiposity in trunk and skeletal muscle might improve insulin sensitivity.

Micellar effect on the photolysis of hydrogen peroxide

Photolysis experiments were performed to quantify the effect of three anionic surfactants on the photolysis of hydrogen peroxide (H2O2) at the ambient laboratory temperature of 22+/-1 degrees C. H2O2 photolysis in water, methanol, and surfactant monomeric solution was also conducted to compare the photochemical reactivity of H2O2 in different media. Photolysis rates were highest for water, followed by micellar solutions, and lowest for methanol. The results show that the photochemical reactivity of H2O2 is less favorable in organic solvent than in water and surfactant micelles affect H2O2 photolysis. Retarded photolysis of H2O2 in micellar solutions implies that a fraction of H2O2 dissolved in water partitions into micellar pseudophase of surfactant. H2O2 partitioned into micelles has less photochemical reactivity and thus photolysis rate was retarded in the presence of micelles. Photolysis inhibitory level by micelles was shown to be dependent on the kinds of surfactants used in this study. In addition, the inhibitory effect by surfactant monomers was negligible due to the absence of micelles.

Application of pulsed Doppler ultrasound for the evaluation of small intestinal motility in dogs

The purpose of this study was to verify whether small intestinal peristalsis could be observed and quantitatively assessed using pulsed-Doppler ultrasound. Pulsed-Doppler ultrasound was used to evaluate small intestinal peristalsis after a meal in ten normal dogs and ten sedated dogs. The small intestinal peristalses were measured 0, 1, 3, 6, 9, 12, and 24 hours after a 24-hour fast and after feeding. The number of small intestinal peristalsis were 0.133/min, 0.100/min, 0.033/min, 0.167/min, 0.070/min, 0.067/min, and 0.100/min in the fasted dogs, and 1.667/ min, 0.933/min, 1.133/min, 1.234/min, 1.933/min, 1.533/ min, and 0.533/min in fed dogs, respectively. In the dogs sedated with xylazine HCl, the number of small intestinal peristalsis was significantly reduced (p<0.01). However, in the dogs treated with ketamine HCl and acepromazine, the number of small intestinal peristalsis remained unchanged. Therefore, it can be concluded that pulsed-Doppler ultrasound allows graphic visualization of the intestinal movements, which can be subjected to qualitative and quantitative analysis, and may be suitable for a non-invasive study of small intestinal motility.

[Estimates of breeding value of Inner Mongolia cashmere goats using animal model BLUP method]

In this study, single trait animal model of best linear unbiased prediction (BLUP) procedures was used to obtain estimates of 3,981 Inner Mongolia cashmere goats' breeding value for body weight and cashmere yield. The data were collected during 1989-1998 at Arbas cashmere goats farm, Etuoke banner, Inner Mongolia. Multiple traits of BLUP were used to get estimates of total breeding values (TBV) of all goats. The model included age and sex-herd-year as fixed effects, and individual additive effect and individual permanent environment as random effects. The selection based on breeding value and phenotypic value was compared. The results showed as following: (1) There was a large difference between weaning weight selection and TBV selection of ram lamb; (2) The difference between phenotypic selection and TBV selection of gimmer hogg reached a significant level (P < 0.01); (3) The difference between phenotypic selection and TBV selection of ram hogg reached a significant level (P < 0.01); (4) Rank correlation between body weight selection and body weight' EBV selection and that between cashmere yield selection and cashmere yield' EBV selection were not significant (P > 0.05). The study concluded precision of individual phenotypic selection was low and animal model BLUP was suitable to select Inner Mongolia cashmere goats. At last, this study gave a series of methods of selecting sires based on objective reality.

[Application of the polymerase chain reaction to the epidemiological study of amoebiasis]

The polymerase chain reaction (PCR) has been used in studying the pathogenicity of Entamoeba histolytica in a rural community in Shandong province. Formalin-fixed stool samples were used for extraction of DNA. The PCR amplifications were performed using two sets of primer that discriminate between pathogenic and nonpathogenic E. histolytica. All of the 32 cases of cyst carrier diagnosed microscopically were identified as positive. Three groups were defined through PCR analysis: 6 cases (18.8%) were positive for pathogenic but negative for nonpathogenic, 25 cases (78.1%) were negative for pathogenic but positive for nonpathogenic, and only one case (3.1%) was positive for both pathogenic and nonpathogenic. The cases found to be pathogenic by PCR were also closely correlated with their clinical manifestations (diarrhea) (OR = 31.5, P < 0.005). All of the control cases showed negative reaction to PCR. PCR has also been used to study the epidemiology of amoebiasis in a small population group with 40 persons in the same province. Both positive rates by PCR on pathogenic and nonpathogenic were 10%. The results showed that this new technique can be applied in the field for the epidemiological studies of pathogenic and nonpathogenic E. histolytica.