IntroductionThe aim of this study was to compare the fracture resistance of upper premolars undergoing root canal treatment that had been temporarily restored with 4 different temporary filling materials.MethodsThis study was based on 120 extracted upper premolars. Eight teeth were left intact and served as the negative control group. Mesio-occluso-distal cavities with 2 different designs were prepared for the rest of the teeth (for group 1 a width of one third of the intercuspal distance and for group 2 a width of two thirds of the intercuspal distance). Then, the endodontic access cavities were prepared, and the root canals instrumented with Revo-S rotary files (MicroMega, Besancon, France). Thereafter, a total of 16 teeth consisting of 8 each from group 1 and group 2 served as the positive control group and did not have any temporary filling material. The teeth were randomly divided into 4 subgroups (n = 12) according to the temporary filling material: Cavit G (3M ESPE, St Paul, MN), Coltosol F (Coltène/Whaledent AG, Altstätten, Switzerland), Intermediate Restorative Material (Dentsply Sirona, Konstanz, Germany), or DiaTemp (DiaDent Europe BV, Almere, Netherlands). Each specimen was then subjected to a fracture resistance test using a universal testing machine until the fracture occurred. The force required to fracture each specimen was recorded, and the data were statistically analyzed.ResultsThe negative control group showed the highest fracture resistance values compared with the other groups, whereas the positive control groups showed the lowest fracture resistance values. There were no statistically significant differences in the fracture resistance of upper premolar teeth undergoing root canal treatment among Cavit G, Intermediate Restorative Material, Coltosol F, and DiaTemp, regardless of the cavity width (P > .05).ConclusionsThe cavity design was found to be an effective factor on the fracture resistance of upper premolar teeth undergoing root canal treatment. The temporary filling materials tested did not affect the fracture resistance. 相似文献
The purpose of this study was to elucidate the involvement of Mate1 in the tubular secretion of trimethoprim and saturation of Mate1-mediated efflux to address the mechanisms underlying the pharmacokinetic drug interactions with trimethoprim. Trimethoprim is a more potent inhibitor of MATE2-K than MATE1 with Ki values (μM) of 0.030–0.28 and 2.4–5.9, respectively. Trimethoprim is a substrate of human MATE1 and MATE2-K with Km values of 2.3 ± 0.9 and 0.018 ± 0.004 μM, and mouse Mate1, but not human OCT2, mouse Oct1 and Oct2. Pyrimethamine significantly reduced the renal clearance (CLR) of trimethoprim (mL/min/kg) from 40.0 ± 5.1 to 20.1 ± 3.7 (p < 0.05). Trimethoprim was given to mice at three infusion rates (150, 500, and 1500 nmol/min/kg). Together with an increase in the plasma concentrations of trimethoprim, the CLR (mL/min/kg) of trimethoprim decreased to 25.9 ± 3.2, 13.5 ± 5.7, and 8.92 ± 1.50 at the respective rates. Trimethoprim decreased the CLR of rhodamine 123 in an infusion rate-dependent manner: 11.5 ± 1.3 (control), 5.17 ± 1.55, 1.31 ± 0.50, and 0.532 ± 0.180. These results suggest that Mate1 mediates the tubular secretion of trimethoprim, and at therapeutic doses, MATEs-mediated efflux can be saturated, and thereby, cause drug interactions with other MATE substrates. 相似文献
There is a relationship between arterial blood pressure, cardiac output and vascular resistance described mathematically, that helps us to understand short-term control of blood pressure in terms of a hydraulic system. Arterial baroreceptors are specialized sensors which mediate a rapid response to sudden changes in pressure through interaction with the autonomic nervous system. This in turn influences heart rate, inotropic state and vascular tone, altering distribution of blood between arterial and venous systems, thus compensating for acute changes in total blood volume. Total blood volume is controlled predominantly by the kidney, with the renin–angiotensin–aldosterone system acting as both the ‘sensor’ of blood pressure/volume (via renin release in the juxtaglomerular apparatus) and the ‘effector’ of blood pressure/volume (via aldosterone secretion by the adrenal cortex). Overall control is shared; the baroreceptors being responsible for mediating short-term changes, and renal mechanisms determining the long-term control of blood pressure. These systems have to be adaptable in order to deal with physiological variation in the delivery of blood to tissues from rest to exercise, and with the large shifts in blood volume seen in acute haemorrhage. Pathophysiological changes in these systems lead to maladaptive responses, with systemic hypertension the most commonly seen. 相似文献
Metformin, a drug for type 2 diabetes mellitus, has shown therapeutic effects for various cancers. However, it had no beneficial effects on the survival rate of human malignant mesothelioma (HMM) patients. The present study was performed to elucidate the underlying mechanism of metformin resistance in HMM cells. Glucose‐starved HMM cells had enhanced resistance to metformin, demonstrated by decreased apoptosis and autophagy and increased cell survival. These cells showed abnormalities in mitochondria, such as decreased ATP synthesis, morphological elongation, altered mitochondrial permeability transition pore and hyperpolarization of mitochondrial membrane potential (MMP). Intriguingly, Mdr1 was significantly upregulated in mitochondria but not in cell membrane. The upregulated mitochondrial Mdr1 was reversed by treatment with carbonyl cyanide m‐chlorophenyl hydrazone, an MMP depolarization inducer. Furthermore, apoptosis and autophagy were increased in multidrug resistance protein 1 knockout HMM cells cultured under glucose starvation with metformin treatment. The data suggest that mitochondrial Mdr1 plays a critical role in the chemoresistance to metformin in HMM cells, which could be a potential target for improving its therapeutic efficacy. 相似文献
AimsGlucose tolerance abnormalities are frequently observed in patients with chronic liver disease (CLD). Insulin resistance (IR) has been suggested to be a major factor responsible for these abnormalities in CLD. However studies relating IR with severity of CLD are scarce in Nigeria. This study assessed insulin resistance and glucose tolerance abnormalities in CLD and their relationship with the severity of CLD in a tertiary hospital in South-West, Nigeria.MethodsThis cross sectional study involved 100 subjects with CLD. Ethical clearance was obtained and informed consent was granted by participants. Participants were interviewed using a structured proforma; physical examination and relevant investigations were performed. Insulin resistance was measured using the homeostasis model assessment (HOMA-IR) Data was analysed using Statistical Package for Social Sciences version 20.0 and p value of <0.05 was considered significant.ResultsMean age of the study participants was 51.9 ± 11.9 years, and mean duration of CLD was 15.9 ± 5.8 months. Glucose tolerance abnormalities were present in 66 subjects (66%) and increased from 16.1% in Child Pugh's class A to 90.0% in class C.HOMA-IR positively correlated with age, body mass index, serum blood glucose, duration and severity of CLD. Increasing age, presence of hepatocellular carcinoma, Child Pugh's class B and class C were associated with glucose tolerance abnormalities.ConclusionGlucose tolerance abnormalities and insulin resistance were highly prevalent among chronic liver disease subjects studied and seemed to parallel the severity of CLD, determined by the Child Pugh's score. 相似文献
Introduction: Despite the potency of current antiretrovirals, some patients continue to struggle with the management of the treatment of HIV due to drug resistance-associated mutations. The underlying causes of these developments are usually drug adherence and drug availability as well as the economic affordability of those potent drugs in low to middle-income countries as well as in some industrialised countries. Viral replication, despite therapy, varies by region from 5 to 28. Non-adherence includes a variety of behaviours with different clinical implications. Addressing non-adherence and choosing new regimens based on a strategic vision may aid overall treatment strategies in the future.
Areas covered: The authors review the literature derived from Embase, MEDLINE and the main international congresses on transmitted and selected drug resistance to HIV therapeutics. They also consider the pharmacological aspects of antiretroviral therapy including the genetic barrier, convenience, potency, drug-drug interactions and tolerability are discuss prospective randomized or observational clinical trials on salvage therapy.
Expert opinion: Preventive intervention is the most efficient way to reduce the selection and transmission of drug-resistant mutations. While subjects with no current available options may benefit from new compounds (ibalizumab and fostemsavir), strategies should be implemented to spare as many patients as possible from drug resistance. 相似文献
Potential associations of vegetarian diet patterns with fasting insulin (FI) and insulin sensitivity remain unclear. We aimed to investigate whether vegetarian diets were associated with FI and insulin sensitivity in a cross-sectional study in Chinese vegetarians and matched omnivores and then to test whether it is independent of body mass index (BMI).
Methods and results
This study included 279 vegetarians (73 vegans, 206 lacto-ovo-vegetarians) and 279 age- and sex-matched omnivores. Fasting blood glucose (FG) and FI concentrations were measured, and β-cell function (HOMA-β) and insulin resistance index (HOMA-IR) were used to evaluate insulin sensitivity. All blood glucose and insulin sensitivity indices were naturally log-transformed, and multiple-linear regression was used to determine the association between vegetarian diet patterns and insulin sensitivity after adjusting for confounders including BMI, visceral fat area, physical activity, sedentary time, income, alcohol consumption, and daily dietary intakes of macronutrients. Compared to omnivores, both vegan diet [β = ?0.25, 95% CI: (?0.38, ?0.14)] and lacto-ovo-vegetarian diet [β = ?0.10, 95% CI: (?0.18, ?0.01)] were negatively associated with HOMA-IR after adjusting for BMI. Vegan diet remained negatively associated with FI [β = ?0.16, 95% CI: (?0.30, ?0.01)] and HOMA-IR [β = ?0.17, 95% CI: (?0.32, ?0.03)] after adjusting for all confounders.
Conclusion
Vegetarian diet, especially vegan diet, is negatively associated with FI and IR, independent of BMI. 相似文献