Social correlates of leisure-time sedentary behaviours in Canadian adults

Research on the correlates of sedentary behaviour among adults is needed to design health interventions to modify this behaviour. This study explored the associations of social correlates with leisure-time sedentary behaviour of Canadian adults, and whether these associations differ between different types of sedentary behaviour. A sample of 12,021 Canadian adults was drawn from the 2012 Canadian Community Health Survey, and analyzed using binary logistic regression to model the relationships that marital status, the presence of children in the household, and social support have with overall time spent sitting, using a computer, playing video games, watching television, and reading during leisure time. Covariates included gender, age, education, income, employment status, perceived health, physical activity level, body mass index (BMI), and province or territory of residence. Extensive computer time was primarily negatively related to being in a common law relationship, and primarily positively related to being single/never married. Being single/never married was positively associated with extensive sitting time in men only. Having children under 12 in the household was protective against extensive video game and reading times. Increasing social support was negatively associated with extensive computer time in men and women, while among men increasing social support was positively associated with extensive sitting time. Computer, video game, television, and reading time have unique correlates among Canadian adults. Marital status, the presence of children in the household, and social support should be considered in future analyses of sedentary activities in adults.

Targeting Aldose Reductase: A Novel Strategy in Treating Endocrine Resistance Using Combination Therapy

Breast cancer is the most commonly diagnosed form of cancer in women. Among breast cancer patients about 2/3 are initially hormone sensitive or estrogen receptor (ER) positive and respond to endocrine therapy. Aromatase inhibitors (AI's) are superior class of hormonal therapeutic agents effectively control ER positive breast cancer in postmenopausal women. Acquired resistance to AI's is expected to be an emerging serious problem in clinics and recent studies have shown that tumors use adaptive signaling mechanisms to overcome AI sensitivity. Thus there is an urgent need for newer treatment modalities. Combination of endocrine and non endocrine agents that block these signaling pathways may prevent or delay the adaptive mechanism and thereby onset of resistance to hormonal therapy. In our study we have found that Fidarestat, an aldose reductase (enzyme which catalyzes the rate limiting step of glucose to fructose or sorbitol formation in polyol pathway) inhibitor effectively re-sensitize letrozole resistant LTLT-Ca breast cancer cells to letrozole. 1µM of fidarestat + 1uM letrozole was found very effective in inducing maximum cell death in LTLT-Ca cells when compared to fidarestat alone. The combination treatment not only restored ER-α levels but also down regulated HER2/MAPK signaling proteins. Aldose reductase siRNA (100nM)- treated MCF-7/Aro and MCF-7 cells upregulated ER-α in western blot and ER-functionality assays. On the other hand in aldose reductase-siRNA- treated LTLT-Ca cells, ER-α levels were down- regulated as in fidarestat treatment. Pretreatment of LTLT-Ca with fidarestat for one week showed reduced proliferation of cells and the effect was maintained until four passages with 1µM letrozole alone. Fidarestat treatment up-regulated E2-mediated transcription in LTLT-Ca cells. In order to enhance the efficacy and targeted delivery of fidarestat in LTLT–Ca cells we have used a nanoparticle-based therapeutic formulation. Folate receptor, highly expressed on epithelial carcinomas, could be a potential molecular target for tumor selective drug delivery. Physcio-chemically well characterized Fidarestat–folate nanoparticles (FFNP's) were prepared to increase the tumor selective intracellular delivery. FFNP's were found superior in exerting cytotoxicity when compared to fidarestat alone. Combination therapy was equally effective in controlling LTLT-Ca cell growth using xenograft model. Taken together, the increased glucose metabolism in LTLT-Ca cells may be critically contributing to chemotherapeutic resistance by increasing drug metabolism and decreasing uptake. Hence targeting aldose reductase in endocrine resistance may be attractive alternative to increase the sensitivity of hormonal therapy.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 67.

Morphine, opioids, and the feline pulmonary vascular bed

BACKGROUND

Opioid-induced vasodepressor responses have been reported in a variety of species and laboratory models. The aim of this study was to ascertain the relative potencies of different clinically relevant opioids compared with traditional vasodepressor agents in the feline pulmonary vascular bed. A second aim was to study the effects of morphine and to identify the receptors involved in the mediation or the modulation of these effects.

METHODS

This was a prospective vehicle-controlled study involving an intact chest preparation of adult mongrel cats. The effects of various opioids, morphine, fentanyl, remifentanil, sufentanil, and meperidine were compared with other vasodepressor agents. Additionally, the effects of L-N(5)-(1-iminoethyl) ornithine hydrochloride (L-NIO) (nitric oxide synthase inhibitor), nimesulide [selective cyclooxygenase (COX)-2 inhibitor], glibenclamide (ATP-sensitive K+ channel blocker), naloxone (non-selective opioid receptor antagonist), and diphenhydramine (histamine H(1)-receptor antagonist) were investigated on pulmonary arterial responses to morphine and other selected agonists in the feline pulmonary vascular bed. The systemic pressure and lobar arterial perfusion pressure were continuously monitored, electronically averaged, and recorded.

RESULTS

In the cat pulmonary vascular bed of the isolated left lower lobe, morphine, remifentanil, fentanyl, sufentanil, and meperidine induced a dose-dependent moderate vasodepressor response and it appeared that sufentanil was the most potent on a nanomolar basis. The effects of morphine were not significantly altered after administration of L-NIO, nimesulide, and glibenclamide. However, the vascular responses to morphine were significantly attenuated following administration of naloxone and diphenhydramine.

CONCLUSION

The results of the present study suggest that sufentanil appears to have slightly more potency and morphine the least of the five opioid agonists studied on a nanomolar basis. Morphine-induced vasodilatory responses appeared to be mediated or modulated by both opioid receptor and histamine-receptor-sensitive pathways.

347 ARTIFICIAL INSEMINATION OF LACTATING HOLSTEIN COWS WITH SEXED SPERM

The recommended use of sexed sperm has been limited to heifers. The objective of this field trial was to determine pregnancy rates in lactating dairy cows following artificial insemination of 2 or 10 � 106 sexed or 10 � 106 unsexed frozen/thawed sperm. Sperm were separated into X chromosome-bearing populations at rates of 3000-5000/s, on the basis of DNA content, with a flow cytometer/sperm sorter operating at 40 psi and using 150 mW of laser intensity. Sperm were sorted, collected and cryopreserved in a Tris-based medium. Holstein cows, averaging 2.4 lactations (range: 1-9), were presynchronized with prostaglandin F2� (PGF)2�; (25 mg) i.m. at 40-58 days in milk (DIM) (average, 44 days). A second dose of PGF2� (25 mg) i.m. was administered 14 days later. All cows were screened with ultrasound 14 days later, and those with normal ovarian and uterine status were used for this study. Qualifying cows received 100 �g gonadotropin-releasing hormone (GnRH) i.m. (average, 72 DIM) and 25 mg PGF2� i.m. 7 days later, and then 100 �g GnRH i.m. 2 days after the prostaglandin. Cows (n = 172) were fixed-timed inseminated 16-19 h after the last GnRH treatment, balanced over three sperm insemination treatments, two Holstein bulls, and two inseminators. Both 32-day pregnancy and 60-day fetal sex were determined using ultrasound. Cows carrying fetuses identified as dying at the 32-day ultrasound check were considered not pregnant. Data were subjected to ANOVA. Effects of sperm treatment, bulls, inseminators, and subsequent interactions on pregnancy rate were not significant (P > 0.05). The 32-day pregnancy rate and 95% confidence interval for 10 � 106 unsexed, 10 � 106 sexed, and 2 � 106 sexed inseminates were 55.6 (42.5-68.6), 43.9 (31.6-57.0), and 40.4% (28.4-53.6), respectively. Additionally, DIM or cow parity did not affect pregnancy rate (P > 0.05). Fetal death (<32 days) for unsexed inseminates was 5.5% (two pregnancies) compared to 9.5% (four pregnancies) for pooled sexed inseminates (P > 0.05). There were four confirmed pregnancies of sexed sperm that also aborted between Days 32-60. Fetal sex ratio was significantly altered (P < 0.05) for sexed (93% female fetuses) compared to unsexed (52% female fetuses) inseminates. Pregnancy rate in these selected lactating cows inseminated with sexed sperm was not significantly lower (P > 0.05) than that for unsexed sperm. However, these results should be viewed cautiously due to the limited numbers of cows used. Successful use of sexed sperm in dairy cows, which approached an elective waiting period of 80 DIM, was achieved with cows that were selected for reproductive status prior to insemination.

Update on medications used to treat gastrointestinal disease in children

Progress in the pharmacotherapy of pediatric gastrointestinal diseases continued during 1998 despite ongoing obstacles encountered by clinicians and researchers. The major change involved warnings that cisapride, a widely used prokinetic agent, could cause potentially fatal arrythmias in susceptible people. The risk for children is unclear and a consensus of prescribing guidelines is needed. Excellent pediatric-oriented reviews have been published that summarize our knowledge of proton pump inhibitors, probiotics, 5-hydroxtryptamine-3 (5-HT3) antagonists, and the treatment of gastrointestinal infections and chronic abdominal pain. Triple medication therapy for the eradication of Helicobacter pylori is now the standard of care, but the optimal combination and duration of therapy needs to be determined. Also described are interesting developments requiring further confirmation: the treatments of infectious diarrhea with zinc; achalasia and Hirschsprung's disease with botulinum toxin; weight loss with megestrol acetate; and sialorrhea with glycopyrollate.

Validation of nonoperative management of occult vascular injuries and accuracy of physical examination alone in penetrating extremity trauma: 5- to 10-year follow-up

PURPOSE

To establish by long-term follow-up the safety and efficacy of nonoperative management of clinically occult arterial injuries and the use of physical examination (PE) alone in determining treatment of penetrating extremity trauma (PET).

METHODS

Two groups of patients were studied: (1) all patients with PET, arterial abnormalities on arteriograms, and no hard signs of vascular injury treated nonoperatively from 1986 to 1989; and (2) all patients with PET to the extremities managed by PE alone from 1989 to 1991. Telephone contact, PE, and duplex ultrasonography (US) were attempted in all group 1 patients, and telephone interviews were attempted in all group 2 patients.

RESULTS

Group 1 had 43 patients with 44 clinically occult penetrating injuries to extremity arteries. Arteriography identified 21 intimal flaps/irregularities, 19 narrowings, 2 pseudoaneurysms, and 1 arteriovenous fistula. Four patients (9%) had clinical deterioration within 1 month and required surgery, with good results. Twenty-three of the other 39 patients (58%) were able to be contacted, and 17 (43%) with 18 injuries underwent PE and US. All were asymptomatic and had normal PE, and one had mild residual narrowing on US. The other 6 patients (four in prison, two out of state) reported no symptoms of vascular insufficiency and never sought medical attention for vascular problems. Mean follow-up was 9.1 years (range, 8.6-11.1 years). Group 2 had 287 patients (309 injuries) with PET treated by observation based on PE alone. Four patients (1.3%) required delayed surgery within the first week, and 78 with 90 injuries (29%) were able to be contacted. No patient reported any vascular symptoms or ever saw a physician for vascular problems. Mean follow-up was 5.4 years (range, 2.2-6.0 years).

CONCLUSION

This is the first long-term follow-up of nonoperative management of clinically occult arterial injuries of the extremities and the use of PE alone in the initial management of PET. The results show these approaches to be safe, effective, and now a proven standard of care.

Mitoxantrone, vincristine, and 5-fluorouracil with leucovorin modulation as induction chemotherapy prior to high-dose intensification in metastatic breast cancer

We treated 39 women with newly diagnosed stage IV breast cancer with a new regimen of mitoxantrone 18 mg/m2 on days 1, 29, 57, vincristine 1.4 mg/m2 (maximum 2.0 mg) on days 1, 8, 15, 22, 29, 36, 43, 50, and 5-fluorouracil 375 mg/m2 on days 15-20, 43-47, 71-75 with leucovorin modulation 500 mg/m2 before each 5FU infusion (MVF). This regimen was utilized as an initial cytoreductive or induction program for these patients prior to high-dose intensification with autologous stem cell rescue. Ten patients (25%) obtained a clinical complete response and six patients (15%) obtained a partial response for an overall response rate of 40%. In addition, 10 patients had evaluable disease that was improved or stable (primarily bone and/or bone marrow metastases) after MVF induction. Thus, 26 patients (65%) were eligible for high-dose intensification with autologous stem cell rescue after MVF induction. Toxicity was primarily a mild mucositis and more commonly peripheral neuropathy. MVF therapy is an active treatment program for metastatic breast cancer but the neurotoxicity makes it difficult to recommend for widespread use.

Nutrition, infant feeding and post-partum amenorrhoea in rural Bangladesh

The duration of amenorrhoea among a group of chronically malnourished women in a rural area of Bangladesh is examined by application of multivariate hazard models with time-varying covariates, including the influence of maternal nutrition, seasonality and patterns of infant feeding. Both maternal weight at pregnancy termination and the pattern of infant feeding affected the length of post-partum amenorrhoea. Analyses focused on season of birth showed the importance of differences by education in infant feeding.