Is There a Dose-Response Relationship of Cement Volume With Cement Leakage and Pain Relief After Vertebroplasty?

The aim of this study was to determine if there were dose–response relationships of cement volume with cement leakage and pain relief after percutaneous vertebroplasty (PVP) for osteoporosis vertebral compression fractures (OVCFs). We collected the patient and procedural characteristics on 108 patients with OVCFs in our hospital who received PVP. Univariate and multivariate analyses were performed to explore the relationships between these potential influential variables and cement leakage and pain relief at 1 month postoperatively. Multivariate linear and logistic regression analyses were conducted with the pain score reduction and the bone cement leakage as dependent variables and the potential risk factors as independent variables, respectively. The results showed that the independent risk factors for the pain relief were the cement volume injected and fracture age, and for bone cement leakage were the cement volume injected and low-viscosity cement. In conclusion, the present study indicated that there were positive dose–response correlation relationships of cement volume with the incidence of cement leakage and the degree of pain relief after PVP, respectively. Thus, the cement should be injected into the vertebrae as much as possible during the PVP procedure.

Robot-assisted gait training might be beneficial for more severely affected children with cerebral palsy

PURPOSE

Robot-assisted gait training (RAGT) can complement conventional therapies in children with cerebral palsy. We investigated changes in walking-related outcomes between children with different Gross Motor Function Classification System (GMFCS) levels and the dose-response relationship.

METHODS

Data from 67 children (3.9-19.9 years) with GMFCS levels II-IV were evaluated retrospectively. Every child received RAGT with the Lokomat complementing a multidisciplinary rehabilitation program. Changes in various walking-related outcomes were assessed.

RESULTS

Walking-related outcomes did not improve differently between GMFCS level groups. Significant within-group improvements were mainly observed in children with GMFCS level IV. A dose-response relationship was present for children with GMFCS levels III and IV.

CONCLUSIONS

Our results indicated that, although children with a GMFCS level IV walked less during an average Lokomat session, they experienced significant improvements in walking-related outcomes. Further, training dose correlated with changes in walking-related outcomes. However, between-group differences in changes in walking-related outcomes were not significant.

Study on 2-arylthio-5-iodo pyrimidine derivatives as novel nonnucleoside inhibitors against hepatitis B virus DNA replication

BACKGROUND

Novel nonnucleoside hepatitis B virus inhibitors have been recently developed for the reason of drug-resistant mutations and adverse effects of nucleoside analogs. In this study, two series of 2-arylthio-5-iodo pyrimidine analogs were firstly reported as potential anti-HBV agents.

METHODOLOGY

Target compounds were prepared according to two high-yielded synthetic routes, and their anti-HBV activities were evaluated on Hep2.2.15 and HepAD38 cell lines, respectively. To probe the mechanism of active agents, a cell-based (Huh-7) study of biochemical markers (e.g., HBeAg, HBsAg, intracellular HBV DNA and pgRNA) was performed. Furthermore, the pharmacophore models were constructed for future optimization of lead compounds.

CONCLUSION

2-Arylthio-5-iodo pyrimidine derivatives firstly proved to be effective against HBV, which paves the way for future development of nonnucleoside anti-HBV agents.

Methods for meta-analysis of pharmacodynamic dose-response data with application to multi-arm studies of alogliptin

Standard methods for meta-analysis of dose-response data in epidemiology assume a model with a single scalar parameter, such as log-linear relationships between exposure and outcome; such models are implicitly unbounded. In contrast, in pharmacology, multi-parameter models, such as the widely used E_max model, are used to describe relationships that are bounded above and below. We propose methods for estimating the parameters of a dose-response model by meta-analysis of summary data from the results of randomized controlled trials of a drug, in which each trial uses multiple doses of the drug of interest (possibly including dose 0 or placebo). We assume that, for each randomized arm of each trial, the mean and standard error of a continuous response measure and the corresponding allocated dose are available. We consider weighted least squares fitting of the model to the mean and dose pairs from all arms of all studies, and a two-stage procedure in which scalar inverse-variance meta-analysis is performed at each dose, and the dose-response model is fitted to the results by weighted least squares. We then compare these with two further methods inspired by network meta-analysis that fit the model to the contrasts between doses. We illustrate the methods by estimating the parameters of the E_max model to a collection of multi-arm, multiple-dose, randomized controlled trials of alogliptin, a drug for the management of diabetes mellitus, and further examine the properties of the four methods with sensitivity analyses and a simulation study. We find that all four methods produce broadly comparable point estimates for the parameters of most interest, but a single-stage method based on contrasts between doses produces the most appropriate confidence intervals. Although simpler methods may have pragmatic advantages, such as the use of standard software for scalar meta-analysis, more sophisticated methods are nevertheless preferable for their advantages in estimation.

Multiple contrast type tests for the evaluation of animal carcinogenicity studies

The Cochran-Armitage (CA) test is frequently used for testing the dose-response relationship in tumor incidence. This test is based on a weighted linear regression of proportions. It is well known that the CA test lacks power for nonlinear tumor outcomes. For general shape of outcomes, Hothorn and Bretz (2000) proposed a multiple contrast (MC) test. This test suggests the use of the maximum over several single contrasts, where each of them is chosen appropriately to cover a specific dose-response shape. In this work, two new test procedures are proposed and they are compared to the CA and MC tests using power.

A dose-ranging trial to optimize the dose of rifampin in the treatment of tuberculosis

RATIONALE

Rifampin at a dose of 10 mg/kg was introduced in 1971 based on pharmacokinetic, toxicity, and cost considerations. Available data in mice and humans showed that an increase in dose may shorten the duration of tuberculosis treatment.

OBJECTIVES

To evaluate the safety and tolerability, the pharmacokinetics, and the extended early bactericidal activity of increasing doses of rifampin.

METHODS

Patients with drug-susceptible tuberculosis were enrolled into a control group of eight patients receiving the standard dose of 10 mg/kg rifampin, followed by consecutive experimental groups with 15 patients each receiving rifampin 20, 25, 30, and 35 mg/kg, respectively, for 14 days. In all patients isoniazid, pyrazinamide, and ethambutol were added in standard doses for the second 7 days of treatment. Safety, pharmacokinetics of rifampin, and fall in bacterial load were assessed.

MEASUREMENTS AND MAIN RESULTS

Grade 1 and 2 adverse events were equally distributed between the five dose groups; there were five grade 3 events of which one was a possibly related hepatotoxicity. Areas under the time-concentration curves and peak serum concentrations of rifampin showed a more than proportional increase with dose. The daily fall in bacterial load over 14 days was 0.176, 0.168, 0.167, 0.265, and 0.261 log10 colony-forming units/ml sputum in the 10, 20, 25, 30, and 35 mg/kg groups, respectively.

CONCLUSIONS

Two weeks of rifampin up to 35 mg/kg was safe and well tolerated. There was a nonlinear increase in exposure to rifampin without an apparent ceiling effect and a greater estimated fall in bacterial load in the higher dosing groups. Clinical trial registered with www.clinicaltrials.gov (NCT 01392911).

Dose-Related Differences in Effectiveness of Human Papillomavirus Vaccination Against Genital Warts: A Nationwide Study of 550,000 Young Girls

BACKGROUND

Reducing the number of doses in the human papillomavirus (HPV) vaccination regimen from 3 to 2 could increase coverage rates. In this cohort study, we assessed the risk of genital warts (GWs) according to timing and number of doses of quadrivalent HPV vaccine.

METHODS

From population-based registries, we identified all girls in Denmark born during 1985-1999, for whom information on HPV vaccinations was retrieved. The cohort was followed for GW occurrence during 2006-2012. Incidence rate ratios (IRRs) were calculated by Poisson regression to determine differences in GW rates by number of vaccine doses.

RESULTS

Of the 550,690 girls in the cohort, 361 734 had been vaccinated. Of these, 25.9% had been vaccinated twice and 58.8% 3 times. The risk of GWs decreased significantly with each additional dose of vaccine. For girls who received 2 doses, extension of the interval between doses reduced the incidence of GWs. In comparison with a 2-month interval, the incidence of GWs was reduced by 45% (95% confidence interval [CI], 20%-62%), 55% (95% CI, 35%-69%), and 63% (95% CI, 44%-75%), with an interval of 4, 5, and 6 months, respectively. The IRR of 2 vs 3 doses was close to 1, with an interval of about 6 months between the first 2 doses.

CONCLUSIONS

With the original vaccine schedule, completion of 3 doses seems to be required to obtain full protection against GWs. A 2-dose regimen may be as effective if the dosing interval is extended to around 6 months, although the long-term effectiveness of this regimen is unknown.

Detecting impairment: sensitive cognitive measures of dose-related acute alcohol intoxication

The cognitive impairment that results from acute alcohol intoxication is associated with considerable safety risks. Other psychoactive substances, such as medications, pose a similar risk to road and workplace safety. However, there is currently no legal limit for operating vehicles or working while experiencing drug-related impairment. The current study sought to identify a brief cognitive task sensitive to a meaningful degree of impairment from acute alcohol intoxication to potentially stand as a reference from which to quantify impairment from other similar substances. A placebo-controlled single-blind crossover design was employed to determine the relative sensitivity of four commonly-administered cognitive tasks (Compensatory Tracking Task, Digit Symbol Substitution Test, Brief Stop Signal Task and Inspection Time Task) to alcohol-related impairment in male social drinkers at ~0.05% ascending breath alcohol concentration (BrAC), ~0.08% peak BrAC and 0.05% descending BrAC. The Inspection Time Task was identified as the most sensitive task, detecting a medium to large magnitude increase in impairment (g ≈ 0.60) at 0.05% ascending and descending BrAC, and a large magnitude effect size (g = 0.80) at 0.08% peak BrAC. The remaining tasks failed to demonstrate sensitivity to dose-dependent and limb-dependent changes in alcohol-induced impairment. The Inspection Time Task was deemed the most sensitive task for screening alcohol-related impairment based on the present results. Confirmation of equivalence with other drug-related impairment and sensitivity to alcohol-induced impairment in real-world settings should be established in future research.

Differences in rates of radiation-induced true and false rib fractures after stereotactic body radiation therapy for Stage I primary lung cancer

The purpose of this study was to analyze the dosimetry and investigate the clinical outcomes of radiation-induced rib fractures (RIRFs) after stereotactic body radiotherapy (SBRT). A total of 126 patients with Stage I primary lung cancer treated with SBRT, who had undergone follow-up computed tomography (CT) at least 12 months after SBRT and who had no previous overlapping radiation exposure were included in the study. We used the Mantel-Haenszel method and multiple logistic regression analysis to compare risk factors. We analyzed D(0.5 cm(3)) (minimum absolute dose received by a 0.5-cm(3) volume) and identified each rib that received a biologically effective dose (BED) (BED3, using the linear-quadratic (LQ) formulation assuming an α/β = 3) of at least 50 Gy. Of the 126 patients, 46 (37%) suffered a total of 77 RIRFs. The median interval from SBRT to RIRF detection was 15 months (range, 3-56 months). The 3-year cumulative probabilities were 45% (95% CI, 34-56%) and 3% (95% CI, 0-6%), for Grades 1 and 2 RIRFs, respectively. Multivariate analysis showed that tumor location was a statistically significant risk factor for the development of Grade 1 RIRFs. Of the 77 RIRFs, 71 (92%) developed in the true ribs (ribs 1-7), and the remaining six developed in the false ribs (ribs 8-12). The BED3 associated with 10% and 50% probabilities of RIRF were 55 and 210 Gy to the true ribs and 240 and 260 Gy to the false ribs. We conclude that RIRFs develop more frequently in true ribs than in false ribs.

Peretinoin after curative therapy of hepatitis C-related hepatocellular carcinoma: a randomized double-blind placebo-controlled study

BACKGROUND

Effective prophylactic therapies have not been established for hepatocellular carcinoma recurrence. Peretinoin represents one novel option for patients with hepatitis C virus-related hepatocellular carcinoma (HCV-HCC), and it was tested in a multicenter, randomized, double-blind, placebo-controlled study.

METHODS

Patients with curative therapy were assigned to one of the following regimens: peretinoin 600, 300 mg/day, or placebo for up to 96 weeks. The primary outcome was recurrence-free survival (RFS).

RESULTS

Of the 401 patients initially enrolled, 377 patients were analyzed for efficacy. The RFS rates in the 600-mg group, the 300-mg group, and the placebo group were 71.9, 63.6, and 66.0 % at 1 year, and 43.7, 24.9, and 29.3 % at 3 years, respectively. The primary comparison of peretinoin (300 and 600-mg) with placebo was not significant (P = 0.434). The dose-response relationship based on the hypothesis that "efficacy begins to increase at 600 mg/day" was significant (P = 0.023, multiplicity-adjusted P = 0.048). The hazard ratios for RFS in the 600-mg group vs. the placebo group were 0.73 [95 % confidence interval (CI) 0.51-1.03] for the entire study period and 0.27 (95 % CI 0.07-0.96) after 2 years of the randomization. Common adverse events included ascites, increased blood pressure, headache, presence of urine albumin, and increased transaminases.

CONCLUSIONS

Although the superiority of peretinoin to placebo could not be validated, 600 mg/day was shown to be the optimal dose, and treatment may possibly reduce the recurrence of HCV-HCC, particularly after 2 years. The efficacy and safety of peretinoin 600 mg/day should continue to be evaluated in further studies.

Pilot dose-response trial of i.v. ketamine in treatment-resistant depression

OBJECTIVES

Research studies have reported impressive antidepressant effects with ketamine but significant knowledge gaps remain over the best method of administering ketamine, and the relationships between dose, antidepressant response and adverse effects.

METHODS

In this pilot dose-finding study, the efficacy and tolerability of ketamine given by rapid intravenous (i.v.) infusion were assessed in a double-blind, placebo-controlled, crossover design, in four subjects with treatment- resistant depression. Each subject received up to four i.v. doses of ketamine (0.1, 0.2, 0.3, 0.4 mg/kg), given over 2-5 min, 1 week apart, and one randomly inserted placebo treatment.

RESULTS

Three of four subjects achieved antidepressant response (≥ 50% decrease in Montgomery-Asberg Depression Rating Scale scores), two at the minimum 0.1 mg/kg dose, though all relapsed within a week. For two subjects, the greatest improvement occurred at the highest dose received. Rapid infusion over 2 min led to significant adverse psychotomimetic effects which also increased proportionately with ketamine dosage.

CONCLUSIONS

This is the first trial to present dose-response data of ketamine efficacy and psychomimetic effects in depressed subjects. Antidepressant efficacy may be dose-related. Psychotomimetic effects were dose-related. Rapid infusion over 2 min may not be a feasible clinical approach to treatment, given poor tolerability.

A dose and time response Markov model for the in-host dynamics of infection with intracellular bacteria following inhalation: with application to Francisella tularensis

In a novel approach, the standard birth–death process is extended to incorporate a fundamental mechanism undergone by intracellular bacteria, phagocytosis. The model accounts for stochastic interaction between bacteria and cells of the immune system and heterogeneity in susceptibility to infection of individual hosts within a population. Model output is the dose–response relation and the dose-dependent distribution of time until response, where response is the onset of symptoms. The model is thereafter parametrized with respect to the highly virulent Schu S4 strain of Francisella tularensis, in the first such study to consider a biologically plausible mathematical model for early human infection with this bacterium. Results indicate a median infectious dose of about 23 organisms, which is higher than previously thought, and an average incubation period of between 3 and 7 days depending on dose. The distribution of incubation periods is right-skewed up to about 100 organisms and symmetric for larger doses. Moreover, there are some interesting parallels to the hypotheses of some of the classical dose–response models, such as independent action (single-hit model) and individual effective dose (probit model). The findings of this study support experimental evidence and postulations from other investigations that response is, in fact, influenced by both in-host and between-host variability.

Maternal blood manganese level and birth weight: a MOCEH birth cohort study

BACKGROUND

Manganese (Mn) is an essential trace element for humans and animals, but excess intake of Mn can lead to adverse developmental outcome. Few studies have investigated the effects of deficiency or excess of Mn on the human foetus. In this study, we assessed the quantitative relationship between maternal blood Mn and birth weight of a newborn.

METHODS

We performed analysis on 331 full-term, live birth singleton mother-infant pairs enrolled from July 2007 to December 2009 in the Mother and Children's Environmental Health (MOCEH) study in Korea. A questionnaire on general characteristics, a review of medical records, and maternal whole blood Mn analysis were performed at full-term pregnancy. We evaluated the relationship between maternal blood level of Mn and the birth outcome using logistic regression and generalised additive model.

RESULTS

The mean Mn concentration in whole maternal blood was 22.5 μg/L. We found a curvilinear relationship between maternal blood Mn and birth weight after adjusting for potential confounders. Birth weight peaked at the maternal blood Mn level of 30 and 35 μg/L. An increased probability of birth weight below 3000 g was observed at both below 16.9 μg/L (odds ratio = 2.77, 95% CI: 0.89-8.65) and above 26.9 μg/L of maternal blood Mn level (odds ratio = 2.66, 95% CI: 0.84-8.08).

CONCLUSIONS

Our study found that both extreme level of maternal Mn level was associated with lower birth weight outcome in a nonlinear fashion.

Obesity survival paradox in pneumonia: a meta-analysis

BACKGROUND

It is unclear whether an 'obesity survival paradox' exists for pneumonia. Therefore, we conducted a meta-analysis to assess the associations between increased body mass index (BMI), pneumonia risk, and mortality risk.

METHODS

Cohort studies were identified from the PubMed and Embase databases. Summary relative risks (RRs) with their corresponding 95% confidence intervals (CIs) were calculated using a random effects model.

RESULTS

Thirteen cohort studies on pneumonia risk (n = 1,536,623), and ten cohort studies on mortality (n = 1,375,482) were included. Overweight and obese individuals were significantly associated with an increased risk of pneumonia (RR = 1.33, 95% CI 1.04 to 1.71, P = 0.02, I(2) = 87%). In the dose-response analysis, the estimated summary RR of pneumonia per 5 kg/m(2) increase in BMI was 1.04 (95% CI 1.01 to 1.07, P = 0.01, I(2) = 84%). Inversely, overweight and obese subjects were significantly associated with reduced risk of pneumonia mortality (RR = 0.83, 95% CI 0.77 to 0.91, P < 0.01, I(2) = 34%). The estimated summary RR of mortality per 5 kg/m(2) increase in BMI was 0.95 (95% CI 0.93 to 0.98, P < 0.01, I(2) = 77%).

CONCLUSIONS

This meta-analysis suggests that an 'obesity survival paradox' exists for pneumonia. Because this meta-analysis is based on observational studies, more studies are required to confirm the results.

External beam radiotherapy for painful bone metastases from hepatocellular carcinoma: multiple fractions compared with an 8-Gy single fraction

External beam radiotherapy (EBRT) for hepatocellular carcinoma (HCC) bone metastases has not been popular in palliative therapy, and optimum dose schedules have not been decided because of limited published reports. We here evaluated the palliative effect of EBRT for HCC bone metastases and compared the dose-response relationship between multiple fractions (MFs) and an 8-Gy single fraction (SF). Twenty-eight patients (42 sites) with painful bone metastases who received EBRT and were analyzed retrospectively. Eight patients (12 sites) received SF. Of the remaining 20 patients (30 sites), 10 received MFs at moderate doses (20-30 Gy; 17 sites) and 10 received MFs at high doses (36-52 Gy; 13 sites). Overall response was achieved at 83% (35) of all sites; 75% (9) and 87% (26) for the SF and MF patients (88%, moderate dose; 85%, high dose), respectively. No significant differences in overall response were observed between each fraction schedule. Response duration was significantly longer for the high-dose MF patients than for the SF patients and moderate-dose MF patients (P < 0.05). SF was as effective as MF radiotherapy in terms of pain relief, but high-dose MF delivery relieved pain for a significantly longer duration.

A meta-analysis on dose-response relationship between night shift work and the risk of breast cancer

This study aimed to conduct a systematic review to sum up evidence of the associations between different aspects of night shift work and female breast cancer using a dose-response meta-analysis approach. We systematicly searched all cohort and case-control studies published in English on MEDLINE, Embase, PSYCInfo, APC Journal Club and Global Health, from January 1971 to May 2013. We extracted effect measures (relative risk, RR; odd ratio, OR; or hazard ratio, HR) from individual studies to generate pooled results using meta-analysis approaches. A log-linear dose-response regression model was used to evaluate the relationship between various indicators of exposure to night shift work and breast cancer risk. Downs and Black scale was applied to assess the methodological quality of included studies. Ten studies were included in the meta-analysis. A pooled adjusted relative risk for the association between 'ever exposed to night shift work' and breast cancer was 1.19 [95% confidence interval (CI) 1.05-1.35]. Further meta-analyses on dose-response relationship showed that every 5-year increase of exposure to night shift work would correspondingly enhance the risk of breast cancer of the female by 3% (pooled RR = 1.03, 95% CI 1.01-1.05; Pheterogeneity < 0.001). Our meta-analysis also suggested that an increase in 500-night shifts would result in a 13% (RR = 1.13, 95% CI 1.07-1.21; Pheterogeneity = 0.06) increase in breast cancer risk. This systematic review updated the evidence that a positive dose-response relationship is likely to present for breast cancer with increasing years of employment and cumulative shifts involved in the work.

Enhancing the clinical activity of sorafenib through dose escalation: rationale and current experience

Sorafenib is an oral multitargeted tyrosine and serine/threonine kinase inhibitor approved for the treatment of advanced renal cell and hepatocellular carcinoma. An understanding of its dose-toxicity relationship has paved the way for trials seeking to enhance its clinical activity through the exploration of alternative dosing strategies. In this article, we review the dose-toxicity relationship of sorafenib observed during its phase I and early phase II testing, explore its toxicity profile at the recommended dose and schedule, discuss the evidence for dose escalation to higher levels, and examine the preliminary evidence for clinical activity of this strategy. Owing to a temporal relationship between toxicity and dose, it may be possible in select patients to escalate sorafenib to doses beyond those currently employed. However, because of the potential for increased toxicity, sorafenib dose escalation should currently be performed only in the context of a clinical trial.

I-131 dose response for incident thyroid cancers in Ukraine related to the Chornobyl accident

BACKGROUND

Current knowledge about Chornobyl-related thyroid cancer risks comes from ecological studies based on grouped doses, case-control studies, and studies of prevalent cancers.

OBJECTIVE

To address this limitation, we evaluated the dose-response relationship for incident thyroid cancers using measurement-based individual iodine-131 (I-131) thyroid dose estimates in a prospective analytic cohort study.

METHODS

The cohort consists of individuals < 18 years of age on 26 April 1986 who resided in three contaminated oblasts (states) of Ukraine and underwent up to four thyroid screening examinations between 1998 and 2007 (n = 12,514). Thyroid doses of I-131 were estimated based on individual radioactivity measurements taken within 2 months after the accident, environmental transport models, and interview data. Excess radiation risks were estimated using Poisson regression models.

RESULTS

Sixty-five incident thyroid cancers were diagnosed during the second through fourth screenings and 73,004 person-years (PY) of observation. The dose-response relationship was consistent with linearity on relative and absolute scales, although the excess relative risk (ERR) model described data better than did the excess absolute risk (EAR) model. The ERR per gray was 1.91 [95% confidence interval (CI), 0.43-6.34], and the EAR per 10⁴ PY/Gy was 2.21 (95% CI, 0.04-5.78). The ERR per gray varied significantly by oblast of residence but not by time since exposure, use of iodine prophylaxis, iodine status, sex, age, or tumor size.

CONCLUSIONS

I-131-related thyroid cancer risks persisted for two decades after exposure, with no evidence of decrease during the observation period. The radiation risks, although smaller, are compatible with those of retrospective and ecological post-Chornobyl studies.

Subclinical hypothyroidism after radioiodine exposure: Ukrainian-American cohort study of thyroid cancer and other thyroid diseases after the Chornobyl accident (1998-2000)

BACKGROUND

Hypothyroidism is the most common thyroid abnormality in patients treated with high doses of iodine-131 (131I). Data on risk of hypothyroidism from low to moderate 131I thyroid doses are limited and inconsistent.

OBJECTIVE

This study was conducted to quantify the risk of hypothyroidism prevalence in relation to 131I doses received because of the Chornobyl accident.

METHODS

This is a cross-sectional (1998-2000) screening study of thyroid diseases in a cohort of 11,853 individuals < 18 years of age at the time of the accident, with individual thyroid radioactivity measurements taken within 2 months of the accident. We measured thyroid-stimulating hormone (TSH), free thyroxine, and antibodies to thyroid peroxidase (ATPO) in serum.

RESULTS

Mean age at examination of the analysis cohort was 21.6 years (range, 12.2-32.5 years), with 49% females. Mean 131I thyroid dose was 0.79 Gy (range, 0-40.7 Gy). There were 719 cases with hypothyroidism (TSH > 4 mIU/L), including 14 with overt hypothyroidism. We found a significant, small association between (131)I thyroid doses and prevalent hypothyroidism, with the excess odds ratio (EOR) per gray of 0.10 (95% confidence interval, 0.03-0.21). EOR per gray was higher in individuals with ATPO < or = 60 U/mL compared with individuals with ATPO > 60 U/mL (p < 0.001).

CONCLUSIONS

This is the first study to find a significant relationship between prevalence of hypothyroidism and individual (131)I thyroid doses due to environmental exposure. The radiation increase in hypothyroidism was small (10% per Gy) and limited largely to subclinical hypothyroidism. Prospective data are needed to evaluate the dynamics of radiation-related hypothyroidism and clarify the role of antithyroid antibodies.

Similar analgesic effect after popliteal fossa nerve blockade with 0.375% and 0.75% bupivacaine

This study tested the hypothesis that increasing the concentration of bupivacaine from 0.375 to 0.75% would increase the duration of postoperative analgesia by 3 h. Seventy patients scheduled for hospital admission after foot or ankle surgery gave consent to enter this prospective randomized trial. Patients were randomly assigned to receive a popliteal fossa block (posterior approach) using 30 cc of either 0.375% or 0.75% bupivacaine, with epinephrine. Patients also received a neuraxial anesthetic and postoperative intravenous patient-controlled analgesia. Patient characteristics, duration of analgesia, pain scores, use of analgesic medications, and side effects of analgesic therapy were determined. Duration of analgesia was similar with both concentrations of bupivacaine (0.375% 14 +/- 8 h, 0.75% 13 +/- 6 h; mean +/- SD). Pain scores were the same for both groups on the first postoperative day (3 of 10 at rest, 5 with therapy). Analgesic use and side effects attributable to pain management did not differ between groups. In conclusion, postoperative analgesia was not affected by the concentration of bupivacaine used for the nerve block. There was no benefit to increasing the concentration of bupivacaine above 0.375% for single-injection popliteal fossa nerve blockade when performed for postoperative analgesia.

Estradiol and Bisphenol A stimulate androgen receptor and estrogen receptor gene expression in fetal mouse prostate mesenchyme cells

BACKGROUND

Hormonal alterations during development have lifelong effects on the prostate gland. Endogenous estrogens, including 17beta-estradiol (E(2)), and synthetic estrogenic endocrine disruptors, such as bisphenol A (BPA), have similar effects on prostate development. Increasing exposure to estrogens within the low-dose, physiologic range results in permanent increases in the size and androgen responsiveness of the prostate, whereas exposure within the high-dose, pharmacologic range has the opposite effects.

OBJECTIVES

We tested the hypothesis that the low-dose effects of estrogens on the developing prostate are associated with increased expression of androgen receptor (Ar) and estrogen receptor 1 (alpha) (Esr1) genes in mesenchyme cells.

METHODS

Ar and Esr1 mRNA levels were quantified in primary cultures of fetal mouse prostate mesenchyme cells treated with E(2) and BPA.

DISCUSSION

Ar and Esr1 mRNA expression increased in response to E(2), with thresholds of 0.001 and 0.037 nM, respectively; and in response to BPA, with a threshold of 1 nM for both mRNAs. We did not observe the expected inhibition of Ar mRNA expression by pharmacologic levels of E(2) relative to unexposed cells.

CONCLUSIONS

The observed induction of gene expression occurred at concentrations within the range of free E(2) previously shown to permanently increase prostate size, thus supporting the involvement of direct effects of estrogens on gene expression in prostate mesenchyme. The effects of BPA occurred within the range of concentrations currently measured in human serum, demonstrating the vulnerability of developing tissues to xenoestrogens.

Arsenic cancer risk confounder in southwest Taiwan data set

Quantitative analysis for the risk of human cancer from the ingestion of inorganic arsenic has been based on the reported cancer mortality experience in the blackfoot disease (BFD) -endemic area of southwest Taiwan. Linear regression analysis shows that arsenic as the sole etiologic factor accounts for only 21% of the variance in the village standardized mortality ratios for bladder and lung cancer. A previous study had reported the influence of confounders (township, BFD prevalence, and artesian well dependency) qualitatively, but they have not been introduced into a quantitative assessment. In this six-township study, only three townships (2, 4, and 6) showed a significant positive dose-response relationship with arsenic exposure. The other three townships (0, 3, and 5) demonstrated significant bladder and lung cancer risks that were independent of arsenic exposure. The data for bladder and lung cancer mortality for townships 2, 4, and 6 fit an inverse linear regression model (p < 0.001) with an estimated threshold at 151 microg/L (95% confidence interval, 42 to 229 microg/L) . Such a model is consistent with epidemiologic and toxicologic literature for bladder cancer. Exploration of the southwest Taiwan cancer mortality data set has clarified the dose-response relationship with arsenic exposure by separating out township as a confounding factor. Key words: arsenic, blackfoot disease, bladder cancer, cancer risk, confounder, dose-response relationship, southwest Taiwan, threshold model.

Blood pressure response to conventional and low-dose enalapril in chronic renal failure

AIMS

In chronic renal failure, the clearance of most ACE inhibitors including enalapril is reduced. Hence, with conventional dosage, plasma enalaprilat may be markedly elevated. It is unclear whether this excess of drug exposure affords an improved control of blood pressure. The aim of the present study was to evaluate short-term blood pressure response to two different plasma levels of enalaprilat.

METHODS

As part of an open, randomized, controlled trial of the effect of high and low dosage of enalapril on the progression of renal failure, short-term blood pressure response was evaluated. Data were analysed in all patients completing 3 months of follow-up. The patients were allocated to two trough plasma concentrations of enalaprilat, either above 50 ng ml(-1) (high) (n = 17) or below 10 ng ml(-1) (low) (n = 18), and the daily dose of enalapril titrated accordingly.

RESULTS

Median (range) glomerular filtration rate (GFR) at baseline was 18 (7.9) in the high enalaprilat concentration group and 17 (7.3) ml min(-1) 1.73 m(2) in the low concentration group (NS). Nine patients in each group were on treatment with enalapril at baseline with a median daily dose of 5 mg in both the high (5-10) and low (2.5-20) concentration group. At 3 months' follow-up, the dose was 10 (2.5-30) and 1.9 (1.25-5) mg (P < 0.0001), respectively. After 3 months median trough concentrations of enalaprilat were 82.5 (22-244) ng ml(-1) and 9.1 (2.5-74.8) ng ml(-1) (P < 0.002). At baseline the median systolic blood pressures in the two groups were 140 (110-200) and 133 (110-165), in the high and low enalaprilat concentration groups, respectively, and after 3 months they were 135 (105-170) and 130 (105-170) mmHg (NS). Median diastolic blood pressure was 80 mmHg in each group both at baseline (65-100) and at follow-up (60-95) (NS). There was no difference between the groups in concomitant antihypertensive treatment (number of patients treated, mean daily dose) during the observation period. Proteinuria remained stable during the study period in both groups; patients in the high concentration group had higher plasma potassium concentrations at day 90 and patients in the low group experienced a slight increase in GFR.

CONCLUSIONS

In moderate to severe chronic renal insufficiency the same degree of blood pressure control was achieved on low as well as moderate daily doses of enalapril. This was irrespective of concomitant antihypertensive treatment.