Diet, caloric restriction, and the rodent bioassay

The diet can significantly alter the results of toxicity and carcinogenicity studies. Ad libitum (AL) overfeeding of excessive calories to sedentary adult rodents is one of the most poorly controlled variables affecting the current rodent bioassay. AL-overfed rodents develop an early onset of adverse metabolic events, endocrine- disruptive degenerative diseases, and tumors that result in early morbidity and mortality. AL food consumption is extremely variable, but has a strong correlation with adult body weight, obesity, and survival. AL feeding of diets with modified protein, fiber, and energy content are not as effective as simple, moderate dietary (caloric) restriction (DR) in controlling these study variables. Moderate DR (70-75% of adult AL) is operationally simple and controls adult body weights, prevents obesity, and improves health and survival by reducing or delaying diet- related endocrine, renal, and cardiac diseases. Moderate DR provides a uniform rodent model, increases treatment exposure time, and increases the statistical sensitivity of these chronic bioassays to detect true treatment effects. Feeding a balanced diet by a moderate DR regimen of 70-75% of the maximum, unrestricted adult AL food intake is recommended for conducting well-controlled toxicity and carcinogenicity studies.      

Uterine leiomyomas: correlation of MR, histopathologic findings, and symptoms

Magnetic resonance (MR) imaging, symptoms, and pathologic findings were correlated in 59 uterine leiomyomas from 23 patients. The tumors varied from less than 1 cm to 18 cm in diameter. Fifty-seven leiomyomas were identified in the corpus uterus, one was located within the broad ligament, and another was detected in the cervix. Among the corpus lesions, 9 were correctly identified on MR images as subserosal and 37 as intramural. Of 11 tumors assigned at surgery to the submucosal group, 10 had been accurately defined with MR. On MR, myomas associated with hypermenorrhea produced an anatomic disruption of the "junctional zone" (the low-intensity band seen at the myometrium-endometrium junction on T2 contrast images). Long TR (2 sec) and TE (56 msec) parameters (T2 contrast images) yielded the best contrast resolution between leiomyoma and surrounding myometrium. Correlation of MR with histologic features demonstrated 2 groups of lesions. Leiomyomas free of degenerative changes emitted homogeneous signals of low intensity. Contrast between tumor and myometrium was -16% on the T1 contrast image and increased to -44 +/- 16% on the T2 contrast image. Leiomyomas with hyaline, myxomatous, or fatty degeneration demonstrated various degrees of inhomogeneity, best seen on images obtained with long TR and TE. It is concluded that MR is an accurate modality for imaging uterine leiomyomas, since it clearly demonstrates tumor number, size, location, and the presence and extent of degeneration.     

A prospective study of pregravid oral contraceptive use and risk of hypertensive disorders of pregnancy

Oral contraceptive use is associated with hypertension, dyslipidemias, and insulin resistance, all of which also characterize hypertensive disorders of pregnancy. In this prospective cohort study, the association of oral contraceptive use before pregnancy and the risk of gestational hypertension and preeclampsia was assessed. Between 1991 and 1995, 3973 nulliparous women who reported their first pregnancy lasting > or = 6 months were studied. Pregravid exposures were collected by biennial mailed questionnaires, and cases were confirmed by medical record review. Recent oral contraceptive use was defined as use within 2 years of pregnancy. Proportional hazards analysis was used to adjust for potential confounding variables. During the 4 years of follow-up, 133 (3.3%) women with gestational hypertension and 62 (1.6%) with preeclampsia were identified. Twenty-five percent of women who did not develop these disorders were recent users of oral contraceptives, compared with 19% (p = 0.11) of women who developed gestational hypertension and 30% (p = 0.38) who developed preeclampsia. Mean duration of prior oral contraceptive use was similar for cases and noncases. Compared with never and past users, the multivariate relative risk among recent users for developing gestational hypertension was 0.7 (95% confidence interval (CI), 0.4-1.0) and for preeclampsia was 1.3 (95% CI, 0.8-2.4). Among recent users who had used oral contraceptives for > or = 8 years, the relative risk for gestational hypertension was 0.6 (95% CI, 0.3-1.2) and for preeclampsia was 2.1 (95% CI, 1.1-4.2). When the analysis was restricted to women who had never smoked, the risk for gestational hypertension was 0.2 (95% CI, 0.1-0.9) and for preeclampsia was 4.1 (95% CI, 1.9-8.7). Thus, recent use of oral contraceptives was associated with a reduced risk for developing gestational hypertension. In contrast, there was a suggestion that recent use was associated with an increased risk of developing preeclampsia, but only among women who had used these agents for > or = 8 years.     

A Prospective Study of the Intake of Vitamins C and B6, and the Risk of Kidney Stones in Men

Purpose

The association between the intake of vitamins C and B6, and kidney stone formation was examined.

Materials and Methods

We conducted a prospective study of the relatioship between the intake of vitamins C and B6 and the risk of symptomatic kidney stones in a cohort of 45,251 men 40 to 75 years old with no history of kidney calculi. Vitamin intake from foods and supplements was assessed using a semiquantitative food frequency questionnaire completed in 1986.

Results

During 6 years of followup 751 incident cases of kidney stones were documented. Neither vitamin C nor vitamin B6 intake was significantly associated with the risk of stone formation. For vitamin C the age-adjusted relative risk for men consuming 1,500 mg. daily or more compared to less than 250 mg. daily was 0.78 (95 percent confidence interval 0.54 to 1.11). For vitamin B6 the age-adjusted relative risk for men consuming 40 mg. daily or more compared to less than 3 mg. daily was 0.91 (95 percent confidence interval 0.64 to 1.31). After adjusting for other potential stone risk factors the relative risks did not change significantly.

Conclusions

These data do not support an association between a high daily intake of vitamin C or vitamin B6 and the risk of stone formation, even when consumed in large doses.     

Cost-Effectiveness and Value of Information Analysis of Brief Interventions to Promote Physical Activity in Primary Care

Background

Brief interventions (BIs) delivered in primary care have shown potential to increase physical activity levels and may be cost-effective, at least in the short-term, when compared with usual care. Nevertheless, there is limited evidence on their longer term costs and health benefits.

Improving response rates using a monetary incentive for patient completion of questionnaires: an observational study

Background

Poor response rates to postal questionnaires can introduce bias and reduce the statistical power of a study. To improve response rates in our trial in primary care we tested the effect of introducing an unconditional direct payment of £5 for the completion of postal questionnaires.

Methods

We recruited patients in general practice with knee problems from sites across the United Kingdom. An evidence-based strategy was used to follow-up patients at twelve months with postal questionnaires. This included an unconditional direct payment of £5 to patients for the completion and return of questionnaires. The first 105 patients did not receive the £5 incentive, but the subsequent 442 patients did. We used logistic regression to analyse the effect of introducing a monetary incentive to increase the response to postal questionnaires.

Results

The response rate following reminders for the historical controls was 78.1% (82 of 105) compared with 88.0% (389 of 442) for those patients who received the £5 payment (diff = 9.9%, 95% CI 2.3% to 19.1%). Direct payments significantly increased the odds of response (adjusted odds ratio = 2.2, 95% CI 1.2 to 4.0, P = 0.009) with only 12 of 442 patients declining the payment. The incentive did not save costs to the trial – the extra cost per additional respondent was almost £50.

Conclusion

The direct payment of £5 significantly increased the completion of postal questionnaires at negligible increase in cost for an adequately powered study.     

Control of head lice with a coconut-derived emulsion shampoo

Objective   To evaluate a novel coconut-derived emulsion (CDE) shampoo against head lice infestation in children.
Design   A school trial in which pupils were treated on days 0 and 7 and checked on days 8 and 15 and a family trial where product was applied by parents three times in 2 weeks or used as a cosmetic shampoo and checked on days 14 and days 70.
Setting   UK schools in Bristol and Western-super-Mare and families in Northern Somerset.
Main outcome measure   Numbers of children free from infestation after treatment.
Results   In the school trial, percentage cures at day 8 were 14% (permethrin, n  = 7) and 61% (CDE, n  = 37). In the family trial where all family members were treated, cure rate was 96% ( n  = 28), and if the shampoo was subsequently used as a cosmetic shampoo, only 1 of 12 children became re-infested after 10 weeks.
Conclusion   CDE shampoo is a novel effective method of controlling head lice and used after treatment as a cosmetic shampoo can aid in the reduction of re-infestation.     

深低温+100%甘油+RPMI 1640合成细胞培养液保存羊膜联合角膜缘干细胞移植在眼表重建中的应用

目的:评价深低温 100%甘油 RPMI1640合成细胞培养液保存羊膜联合角膜缘干细胞移植在重建眼表结构中的治疗效果。方法:①实验对象:选取解放军南京军区福州总医院眼科中心2000～2006年收治的严重眼表烧伤患者29例34眼。实验经医学伦理委员会批准,剖腹产孕妇的胎盘由本院妇产科提供,孕妇均签署知情同意书。离体6h以内的同种异体新鲜角膜由福建省红十字会提供。②实验方法:钝性分离羊膜与绒毛膜,将羊膜上皮面朝上平铺于去除胶面的眼科手术薄膜纸片上,剪成3cm×4cm大小,置于100%甘油 RPMI1640合成细胞培养液各5mL的无菌小瓶中,-80℃冷藏备用。在供体眼球角膜缘前1mm处透明角膜上、角膜缘后2mm处巩膜上作适当深度的环形划界,然后剖出带有浅层基质的角膜缘上皮移植片备用。严重眼表烧伤组织,将备好的羊膜植片上皮面朝上平铺于眼表面,依结膜缺损区大小修剪,缝合固定于近角膜缘的浅层巩膜上,使羊膜紧贴于角膜表面,然后将羊膜边缘与球结膜对位缝合。再将备好的角膜缘上皮移植片与植床角膜缘对位固定缝合。此外,4眼伴轻度眼睑闭合不全者同时行眼睑缘粘连性缝合。结果:严重眼表烧伤患者29例34眼中,除眼睑缘粘连性缝合的4眼外,余30眼(88.24%)术后7～14d角膜水肿消退,14～21d上皮修复角膜全表面,结膜表面光滑,无感染发生;术后3～6个月角膜新生血管明显减少,角膜透明度改善,视力提高3～5行;经过22.8个月随访,眼表面稳定。睑缘粘连性缝合的4眼(11.76%)发生羊膜植片急性排斥反应,羊膜融解,改行深板层角膜移植,2个月后观察眼表亦光滑,无睑球粘连发生。结论:深低温 100%甘油 RPMI1640合成细胞培养液保存羊膜联合角膜缘干细胞移植手术,既发挥了羊膜的生物学特性,又提供了角膜缘活性细胞,能快速、稳定促进角膜更新机制的恢复,加速角膜表面重新上皮化,是治疗严重眼表烧伤有效、可行的手术方式。