Dose-dependent incidence of agranulocytosis in patients treated with methimazole and propylthiouracil

Agranulocytosis is a serious adverse effect of methimazole (MMI) and propylthiouracil (PTU), and although there have been reports suggesting a dose-dependent incidence in relation to both drugs, the evidence has not been conclusive. The objective of our study was to determine whether the incidences of agranulocytosis induced by MMI and PTU exhibit dose-dependency. The subjects were 27,784 patients with untreated Graves' disease, 22,993 of whom were on an antithyroid drug treatment regimen for more than 90 days. Within this subset, 18,259 patients had been treated with MMI, and 4,734 had been treated with PTU. The incidence of agranulocytosis according to dose in the MMI group was 0.13% at 10 mg/day, 0.20% at 15 mg/day, 0.32% at 20 mg/day, and 0.47% at 30 mg/day, revealing a significant dose-dependent increase. In the PTU group, there were 0 cases of agranulocytosis at doses of 125 mg/day and below, 0.33% at 150 mg/day, 0.31% at 200 mg/day, and 0.81% at 300 mg/day, also revealing a significant dose-dependent increase. The incidence of agranulocytosis at MMI 15 mg and PTU 300 mg, i.e., at the same potency in terms of hormone synthesis inhibition, was 0.20% and 0.81%, respectively, and significantly higher in the PTU group. Our findings confirm a dose-dependent increase in the incidence of agranulocytosis with both drugs, but that at comparable thyroid hormone synthesis inhibitory doses PTU has a considerably higher propensity to induce agranulocytosis than MMI does.

Dose-dependent effect on skin permeation of polar and non-polar compounds

The study of the relationship between the amount of drug applied to the skin and fraction of drug absorbed can improve our understanding of finite-dose percutaneous absorption in the development of topical products and risk assessment of hazardous chemical exposure. It has been previously shown that an increase in the dose applied to the skin leads to a decrease in the fraction of drug permeated the skin (dose-dependent effect). The objective of this research was to examine the dose-dependent effect using permeants of varying physiochemical properties. The dose-dependent effect was studied using human epidermal membrane under finite dose conditions in Franz diffusion cell with model permeants at doses ranging from 0.1 to 200 μg. The dose-dependent effect was evident with model permeants caffeine, corticosterone, dexamethasone, and estradiol, consistent with the relationship of decreasing fraction of dose permeated the skin at increasing the applied dose. However, no significant dose-dependent effect was observed for the polar model permeants urea, mannitol, tetraethyl ammonium, and ethylene glycol, suggesting different transport mechanisms for these permeants. It was also found that, at relatively high doses, estradiol, dexamethasone, and corticosterone could increase the permeation of polar and lipophilic permeants, which could counter the dose-dependent effect under the conditions studied.

Characterization of vagus nerve stimulation-induced pupillary responses in epileptic patients

BACKGROUND

Modulation of the locus coeruleus (LC)-noradrenergic system is a key mechanism of vagus nerve stimulation (VNS). Activation of the LC produces pupil dilation, and the VNS-induced change in pupil diameter was demonstrated in animals as a possible dose-dependent biomarker for treatment titration.

OBJECTIVE

This study aimed to characterize VNS-induced pupillary responses in epileptic patients.

METHODS

Pupil diameter was recorded in ten epileptic patients upon four stimulation conditions: three graded levels of VNS intensity and a somatosensory control stimulation (cutaneous electrical stimulation over the left clavicle). For each block, the patients rated the intensity of stimulation on a numerical scale. We extracted the latency of the peak pupil dilation and the magnitude of the early (0-2.5 s) and late components (2.5-5 s) of the pupil dilation response (PDR).

RESULTS

VNS elicited a peak dilation with longer latency compared to the control condition (p = 0.043). The magnitude of the early PDR was significantly correlated with the intensity of perception (p = 0.046), whereas the late PDR was not (p = 0.19). There was a significant main effect of the VNS level of intensity on the magnitude of the late PDR (p = 0.01) but not on the early PDR (p = 0.2). The relationship between late PDR magnitude and VNS intensity was best fit by a Gaussian model (inverted-U).

CONCLUSIONS

The late component of the PDR might reflect specific dose-dependent effects of VNS, as compared to control somatosensory stimulation. The inverted-U relationship of late PDR with VNS intensity might indicate the engagement of antagonist central mechanisms at high stimulation intensities.

[Clinical aspects and care of radiogenic treatment side effects on the eye]

Malignant tumors of the eye can be successfully treated with radiotherapy, which, however, can lead to radiogenic side effects in the surrounding healthy tissues. A  distinction can be made between two forms of irradiation, external radiotherapy (teletherapy) and brachytherapy with a radiation source close to the tumor. The radiation dose is important for the occurrence of side effects. Acute damage usually results from inflammatory processes initiated at the cellular level. In contrast, late side effects are rather due to the reaction of the tissue with repair and remodeling processes . Acute side effects often resolve completely, especially under corresponding treatment, whereas late side effects tend to be irreversible. The aim of this article is to present risk factors as well as the clinical signs of periocular and ocular radiogenic side effects for the relevant tissue structures of the eye in a narrative review to facilitate ophthalmologic follow-up and, if necessary, treatment measures for these patients during everyday practice.

Dose-dependent and strain-dependent anti-obesity effects of Lactobacillus sakei in a diet induced obese murine model

BACKGROUND

Overweight and abdominal obesity, in addition to medical conditions such as high blood pressure, high blood sugar and triglyceride levels, are typical risk factors associated with metabolic syndrome. Yet, considering the complexity of factors and underlying mechanisms leading to these inflammatory conditions, a deeper understanding of this area is still lacking. Some probiotics have a reputation of a relatively-long history of safe use, and an increasing number of studies are confirming benefits including anti-obesity effects when administered in adequate amounts. Recent reports demonstrate that probiotic functions may widely differ with reference to either intra-species or inter-species related data. Such differences do not necessarily reflect or explain strain-specific functions of a probiotic, and thus require further assessment at the intra-species level. Various anti-obesity clinical trials with probiotics have shown discrepant results and require additional consolidated studies in order to clarify the correct dose of application for reliable and constant efficacy over a long period.

METHODS

Three different strains of Lactobacillus sakei were administered in a high-fat diet induced obese murine model using three different doses, 1 × 1010, 1 × 109 and 1 × 108 CFUs, respectively, per day. Changes in body and organ weight were monitored, and serum chemistry analysis was performed for monitoring obesity associated biomarkers.

RESULTS

Only one strain of L. sakei (CJLS03) induced a dose-dependent anti-obesity effect, while no correlation with either dose or body or adipose tissue weight loss could be detected for the other two L. sakei strains (L338 and L446). The body weight reduction primarily correlated with adipose tissue and obesity-associated serum biomarkers such as triglycerides and aspartate transaminase.

DISCUSSION

This study shows intraspecies diversity of L. sakei and suggests that anti-obesity effects of probiotics may vary in a strain- and dose-specific manner.

Benzodiazepines and risk of pneumonia in schizophrenia: a nationwide case-control study

OBJECTIVES

To investigate the relationship between benzodiazepine and risk of developing pneumonia in patients with schizophrenia, whose benzodiazepine dosage and usage frequency was higher than that of the general population.

METHODS

We conducted a nested case-control study to assess the association between benzodiazepine use and pneumonia among patients with schizophrenia. By using the Taiwan National Health Insurance Research Database, we identified a schizophrenia cohort comprising 34,929 patients during 2000-2010. Within the schizophrenia cohort, 2501 cases of pneumonia and 9961 matched control patients (1:4 ratio) were identified. Benzodiazepine exposure was categorized by drug, treatment duration, and daily dose. Conditional logistic regression models were used to examine the association between benzodiazepine exposure and the risk of pneumonia.

RESULTS

The current use (within 30 days) of midazolam led to the highest pneumonia risk (adjusted risk ratio = 6.56, P < 0.001), followed by diazepam (3.43, P < 0.001), lorazepam (2.16, P < 0.001), and triazolam (1.80, P = 0.019). Furthermore, nearly all the benzodiazepines under current use had a dose-dependent effect on pneumonia risk. The risk of pneumonia was correlated with the affinities of γ-aminobutyric acid A α1, α2, and α3 receptors.

CONCLUSIONS

Benzodiazepines had a dose-dependent relationship with pneumonia in patients with schizophrenia. The differences in risk and mechanism of action of the individual drugs require further investigation. Clinicians should be aware of the early signs of pneumonia in patients with schizophrenia receiving benzodiazepines.

Dose-dependent effect of parathyroid hormone on fracture healing and bone formation in mice

BACKGROUND

Parathyroid hormone (PTH) is the only clinically approved osteoanabolic drug for osteoporosis treatment. However, PTH is not established for the treatment of fracture healing, and doses of PTH diverge significantly between different studies. We hypothesized that the effect of PTH on promoting fracture healing and bone formation is dose dependent.

MATERIALS AND METHODS

In vivo, mice were treated with PTH (10, 40, and 200 μg/kg) in a closed femoral fracture model. Fracture healing was analyzed after 4 weeks. The fourth lumbar vertebra was analyzed to assess systemic effects. In addition, osteoblasts from calvaria of mice were treated in vitro with PTH doses of 10^-5-50 nM, and their differentiation was analyzed after 26 days.

RESULTS

In vivo, PTH dose-dependently stimulated bone formation in the fracture callus and the vertebral body. However, PTH treatment did not increase biomechanical stiffness of the fractured femora in a dose-dependent manner. The increased bone formation in the 200 μg/kg group was associated with a depletion of osteoclasts, indicating diminished bone remodeling. Of interest, in vitro, we observed diminished mineralization with the highest doses of PTH in osteoblast cultures.

CONCLUSIONS

PTH dose-dependently stimulates bone formation in vivo. However, during fracture healing, this did not result in a dose-dependent increase of the mechanical stiffness of the fracture callus. Taken together, our in vivo and in vitro data indicate that the dose-dependent effects of PTH during fracture healing are based on the actions on multiple cell types, thereby influencing not only bone formation but also osteoclastic callus remodeling.

Immediate Dose-Response Effect of High-Energy Versus Low-Energy Extracorporeal Shock Wave Therapy on Cutaneous Microcirculation

Elucidation of the precise mechanisms and therapeutic options of extracorporeal shock wave therapy (ESWT) is only at the beginning. Although immediate real-time effects of ESWT on cutaneous hemodynamics have recently been described, the dose response to different ESWT energies in cutaneous microcirculation has never been examined. Thirty-nine Sprague-Dawley rats were randomly assigned to three groups that received either focused high-energy shock waves (group A: total of 1000 impulses, 10 J) to the lower leg of the hind limb, focused low-energy shock waves (group B: total of 300 impulses, 1 J) or placebo shock wave treatment (group C: 0 impulses, 0 J) using a multimodality shock wave delivery system (Duolith SD-1 T-Top, Storz Medical, Tägerwilen, Switzerland). Immediate microcirculatory effects were assessed with the O2C (oxygen to see) system (LEA Medizintechnik, Giessen, Germany) before and for 20 min after application of ESWT. Cutaneous tissue oxygen saturation increased significantly higher after high-energy ESWT than after low-energy and placebo ESWT (A: 29.4% vs. B: 17.3% vs. C: 3.3%; p = 0.003). Capillary blood velocity was significantly higher after high-energy ESWT and lower after low-energy ESWT versus placebo ESWT (group A: 17.8% vs. group B: -22.1% vs. group C: -5.0%, p = 0.045). Post-capillary venous filling pressure was significantly enhanced in the high-energy ESWT group in contrast to the low-energy ESWT and placebo groups (group A: 25% vs. group B: 2% vs. group C: -4%, p = 0.001). Both high-energy and low-energy ESWT affect cutaneous hemodynamics in a standard rat model. High-energy ESWT significantly increases parameters of cutaneous microcirculation immediately after application, resulting in higher tissue oxygen saturation, venous filling pressure and blood velocity, which suggests higher tissue perfusion with enhanced oxygen saturation, in contrast to low-energy as well as placebo ESWT. Low-energy ESWT also increased tissue oxygen saturation, albeit to a lower extent, and decreases both blood velocity and venous filling pressure. Low-energy ESWT reduced tissue perfusion, but improved oxygen saturation immediately after the application.

A push-button: Spodoptera exigua oviposition on Nicotiana attenuata dose-independently primes the feeding-induced plant defense

Insect oviposition on a plant often precedes the attack by herbivorous larvae. We recently discovered that oviposition by Spodoptera exigua moths on the desert tobacco Nicotiana attenuata primes the induction of 2 defense traits, a phenylpropanoid and activity of protease inhibitors, in response to larval feeding. Oviposition-experienced plants suffer a reduced feeding damage by less and smaller larvae than unexperienced control plants. The increased resistance of oviposition-experienced plants requires the plant's ability to activate its biosynthesis of phenylpropanoids via a Myb transcription factor. Oviposition by S. exigua on N. attenuata is highly variable with respect to the amount, distribution and localization of the eggs on the plant. This raises the question, whether the plant's priming of herbivore defense depends on the egg number and localization. S. exigua moths prefer the oldest leaves for oviposition and yet prime defense-induction in the larval attacked young systemic leaves. Neither the levels of the primed defense traits, nor the affected larval mortality correlate with the number of eggs a plant previously received. This suggests that upon S. exigua oviposition, N. attenuata is shifted - independently of the egg-dose - into a primed state that is responding stronger to the feeding larvae than unprimed plants.

One-Year Follow-Up of Serum Prolactin Level in Schizophrenia Patients Treated with Blonanserin: A Case Series

In our previous study, a prolactin elevation was more frequently in risperidone than in blonanserin; however, it was more often in blonanserin than in olanzapine. Therefore, while a rate of PRL rising is low to moderate, hyperprolactinemia is a considerable adverse effect in the blonanserin treatment. In this study, to examine detailed characteristics of hyperprolactinemia of blonanserin, we analyzed the prolactin data in six schizophrenic patients who were switched to blonanserin from other antipsychotics and followed for one year. As a result, blonanserin dose was clearly associated with serum prolactin level. The average prolactin level was almost normal when the mean blonanserin dosage was 8.0 mg/day. Regardless of the dose decrease of blonanserin, there were no remarkable changes in symptoms and social functions. Based on our findings, we conclude that low dose blonanserin medication may be useful for schizophrenia maintenance treatment without hyperprolactinemia and a high rate of relapse.

Dose-dependent model of caffeine effects on human vigilance during total sleep deprivation

Caffeine is the most widely consumed stimulant to counter sleep-loss effects. While the pharmacokinetics of caffeine in the body is well-understood, its alertness-restoring effects are still not well characterized. In fact, mathematical models capable of predicting the effects of varying doses of caffeine on objective measures of vigilance are not available. In this paper, we describe a phenomenological model of the dose-dependent effects of caffeine on psychomotor vigilance task (PVT) performance of sleep-deprived subjects. We used the two-process model of sleep regulation to quantify performance during sleep loss in the absence of caffeine and a dose-dependent multiplier factor derived from the Hill equation to model the effects of single and repeated caffeine doses. We developed and validated the model fits and predictions on PVT lapse (number of reaction times exceeding 500 ms) data from two separate laboratory studies. At the population-average level, the model captured the effects of a range of caffeine doses (50-300 mg), yielding up to a 90% improvement over the two-process model. Individual-specific caffeine models, on average, predicted the effects up to 23% better than population-average caffeine models. The proposed model serves as a useful tool for predicting the dose-dependent effects of caffeine on the PVT performance of sleep-deprived subjects and, therefore, can be used for determining caffeine doses that optimize the timing and duration of peak performance.