Stable Serum Concentrations Research Articles

Clinical efficacy of buprenorphine after oral dosing in rats undergoing major surgery.

Serum corticosterone, serum buprenorphine, body weight change, consumption of food and water and behaviour-based pain assessment were measured in catheterised and non-catheterised male Wistar rats undergoing myocardial infarct (MI) surgery under general anaesthesia following buprenorphine dosing by subcutaneous (Bup-SC, 0.05 mg/kg) and oral (Bup-O, 0.4 mg/kg) routes. Buprenorphine was dosed subcutaneously at half an hour before and 8, 16 and 24 hours after surgery (Bup-SC), orally at one hour before surgery (Bup-O1) or at one hour before and 12 hours after surgery (Bup-O2) in catheterised rats and at one hour before and 24 hours after surgery (Bup-O24) in non-catheterised rats. Serum corticosterone, body weight changes and food and water consumption were not significantly different between treatments in catheterised rats. Bup-SC resulted in rapidly decreasing serum concentrations below the clinically effective concentrations (1 ng/mL) already at two hours after the first dose. Bup-O provided significantly higher and slowly decreasing serum concentrations, at or above clinically effective concentrations, for 24 hours (Bup-O1) and 42 hours (Bup-O2) after surgery. In non-catheterised rats, body weight development and food consumption were significantly higher in Bup-O24 rats compared to Bup-SC rats. The results indicate that a SC buprenorphine dose of 0.05 mg/kg every eight hours provides long periods of serum concentrations below clinically effective levels, and that a higher dose and/or more frequent dosage are required to provide stable serum concentrations at or above clinically effective levels. A single oral buprenorphine dose of 0.4 mg/kg provides clinically effective and stable serum concentrations for 24 hours in rats after MI surgery.

Goserelin/PLGA solid dispersion used to prepare long-acting microspheres with reduced initial release and reduced fluctuation of drug serum concentration in vivo

To prepare Goserelin (GOS) loaded long-acting microspheres with reduced initial release and prolonged drug release time of GOS, GOS/PLGA solid dispersion (by hot-melt extrusion, HME) was dissolved/dispersed in dichloromethane (DCM) to prepare microspheres by O/W method. From results of molecular dynamics simulation, PLGA and GOS molecules completely and uniformly dissolved and dispersed in DCM, respectively. In F5 microspheres (prepared by HME-O/W method), GOS existed as molecular or amorphous state, but not aggregation. Burst release of F5 microspheres (2.75%) was similar with Zoladex™ implant (0.39%) and less than F10 microspheres (prepared by S/O/W method, 25.92%). After lag phase, GOS released rapidly from F5 microspheres and the cumulative release on the 45th days was 95.14%. After injection of F5 microspheres, GOS serum concentration was relative steady at the range of 27.64–175.27 ng/mL for nearly 35 days. AUC(0-35 day) of F5 microspheres was almost 2 times that of F10 microspheres. Pharmacodynamics study also showed potential effect of F5 microspheres on inhibiting the secretion of testosterone in male rats. HME-O/W method is potential to establish long-acting PLGA microspheres (loading water-soluble drug), exhibiting stable drug serum concentration in vivo, and without large concentration fluctuation or serious pain/side effects.

ACE2-IgG1 fusions with improved in vitro and in vivo activity against SARS-CoV-2

SummarySARS-CoV-2, the etiologic agent of COVID-19, uses ACE2 as a cell entry receptor. Soluble ACE2 has been shown to have neutralizing antiviral activity but has a short half-life and no active transport mechanism from the circulation into the alveolar spaces of the lung. To overcome this, we constructed an ACE2-human IgG1 fusion protein with mutations in the catalytic domain of ACE2. A mutation in the catalytic domain of ACE2, MDR504, significantly increased binding to SARS-CoV-2 spike protein, as well as to a spike variant, in vitro with more potent viral neutralization in plaque assays. Parental administration of the protein showed stable serum concentrations with excellent bioavailability in the epithelial lining fluid of the lung, and ameliorated lung SARS-CoV-2 infection in vivo. These data support that the MDR504 hACE2-Fc is an excellent candidate for treatment or prophylaxis of COVID-19 and potentially emerging variants.

Thermosensitive Polyester Hydrogel for Application of Immunosuppressive Drug Delivery System in Skin Allograft.

Tacrolimus (FK506) is a common immunosuppressive drug that is capable of suppressing acute rejection reactions, and is used to treat patients after allotransplantation. A stable and suitable serum concentration of tacrolimus is desirable for better therapeutic effects. However, daily drug administration via oral or injection routes is quite inconvenient and may encounter drug overdose or low patient compliance problems. In this research, our objective was to develop an extended delivery system using a thermosensitive hydrogel of poly ethylene glycol, D,L-lactide (L), and ϵ-caprolactone (CL) block copolymer, mPEG-PLCL, as a drug depot. The formulation of mPEG-PLCL and 0.5% PVP-dissolved tacrolimus was studied and the optimal formulation was obtained. The in vivo data showed that in situ gelling is achieved, a stable and sustained release of the drug within 30 days can be maintained, and the hydrogel was majorly degraded in that period. Moreover, improved allograft survival was achieved. Together, these data imply the potential of the current formulation for immunosuppressive treatments.

P57. ERAS vs non-ERAS: protocol implementation resulted in significant outcomes improvement in patients undergoing lumbar spine fusion

BACKGROUND CONTEXT Effective management of common adverse events (AE) immediately after lumbar fusion, ie, uncontrolled pain, nausea and vomiting, and urinary retention, is imperative to facilitate discharge. Persisting, intolerable symptoms prolong hospitalization. Enhanced Recovery After Surgery (ERAS) has shown improved outcomes across a variety of surgical population, results in spine surgery is limited. PURPOSE To compare measurable outcomes before and after ERAS implementation. STUDY DESIGN/SETTING Retrospective study. PATIENT SAMPLE Patients undergoing lumbar fusion. OUTCOME MEASURES Pain scores, opioid consumption, AEs and length of stay (LOS). METHODS A comprehensive Spine ERAS clinical pathway was developed. Associated policies and order sets were established. Printed and electronic education resources were produced. The program was fully implemented after a 3-month trial. With IRB approval, a retrospective review of pre-post ERAS consecutive patients was completed. Pre-ERAS (Non-ERAS) patients received traditional care; ERAS patients were treated with evidence-based care pathways including preoperative optimization; screening and prophylaxis treatment of anemia, infection and postoperative nausea and vomiting (PONV); standardized anesthetic, pre-emptive multi-modal analgesia (MMA) and Tranexamic Acid (TXA) use; interventions to promote metabolic status and return to normal function i.e. early catheter removal, mobilization, and diet resumption. Supplemental opioid was changed from patient-controlled analgesia (PCA) with a short acting opioid ie, hydromorphone, to intraoperative intravenous methadone. The intermittent demand dosing from PCA causes significant fluctuation in serum opioid concentration resulting in either inadequate pain control or over sedation. Methadone was preferred due to its long duration and stable serum concentration. Demographics, surgical details, hospitalization, medications and AEs were compared. All opioids were converted to morphine milligram equivalents (MME). Data was analyzed with analysis of variance, Wilcoxon, chi-square, and/or Spearman correlation tests. RESULTS A total of 146 ERAS and 192 Non-ERAS (n-338) patients were included in this series. Patients during the trial period were excluded. Both groups were similar with regards to age, gender, BMI, ASA score, surgery and baseline opioid use (all p>0.05). Preoperative baseline pain scores were comparable between cohorts (ERAS 4.5 vs Non-ERAS 4.2, p=0.401). Comparing cohorts, significant reductions in pain scores were observed in the post-anesthesia care unit (p=0.004) and 24-48 hours post-operatively (p CONCLUSIONS ERAS implementation in lumbar fusion resulted in significant reduction in pain scores, total opioid consumption, hypotension, urinary retention and LOS. A smaller percentage of patients received transfusion. FDA DEVICE/DRUG STATUS Hydromorphone (Approved for this indication), Methadone HCl (Approved for this indication), Tranexamic Acid (Approved for this indication), Patient-Controlled Analgesia (PCA) Pump (Approved for this indication).

Development of an Image-Guided Orthotopic Xenograft Mouse Model of Endometrial Cancer with Controllable Estrogen Exposure.

Endometrial cancer (EC) is the most common gynaecological malignancy in Western society and the majority of cases are estrogen dependent. While endocrine drugs proved to be of insufficient therapeutic value in the past, recent clinical research shows promising results by using combinational regimens and pre-clinical studies and identified potential novel endocrine targets. Relevant pre-clinical models can accelerate research in this area. In the present study we describe an orthotopic and estrogen dependent xenograft mouse model of EC. Tumours were induced in one uterine horn of female athymic nude mice using the well-differentiated human endometrial adenocarcinoma Ishikawa cell line—modified to express the luciferase gene for bioluminescence imaging (BLI). BLI and contrast-enhanced computed-tomograph (CE-CT) were used to measure non-invasive tumour growth. Controlled estrogen exposure was achieved by the use of MedRod implants releasing 1.5 μg/d of 17β-estradiol (E2) in ovariectomized mice. Stable E2 serum concentration was demonstrated by LC-MS/MS. Induced tumours were E2 responsive as increased tumour growth was observed in the presence of E2 but not placebo, assessed by BLI, CE-CT, and tumour weight at sacrifice. Metastatic spread was assessed macroscopically by BLI and histology and was seen in the peritoneal cavity, in the lymphovascular space, and in the thoracic cavity. In conclusion, we developed an orthotopic xenograft mouse model of EC that exhibits the most relevant features of human disease, regarding metastatic spread and estrogen dependency. This model offers an easy to manipulate estrogen dosage (by simply adjusting the MedRod implant length), image-guided monitoring of tumour growth, and objectively measurable endpoints (including tumour weight). This is an excellent in vivo tool to further explore endocrine drug regimens and novel endocrine drug targets for EC.

Effect of the CYP3A5, CYP3A4, CYP3A7, ABCB1, POR and NR1I2 genes in the pharmacokinetics of tacrolimus in a pediatric cohort with stable serum concentrations after renal transplantation: study protocol.

Effect of the CYP3A5, CYP3A4, CYP3A7, ABCB1, POR and NR1I2 genes in the pharmacokinetics of tacrolimus in a pediatric cohort with stable serum concentrations after renal transplantation: study protocol.

The pharmacokinetics of methamphetamine self-administration in male and female rats

BackgroundBecause methamphetamine (METH) pharmacokinetics after single iv doses show significant differences between male and female rats, we hypothesized that pharmacokinetic differences in METH disposition could be a contributing factor to the patterns of METH self-administration behaviors in rats. MethodsFor the studies, we used a passive (non-contingent) METH dosing schedule consisting of 27 METH iv bolus injections (0.048mg/kg) over 2h derived from a previous active (contingent) METH self-administration behavioral study in male rats. After METH dosing of male and female Sprague-Dawley rats (n=5/group), METH and amphetamine serum concentrations were determined by LC–MS/MS. Pharmacokinetic analysis, including predictive mathematical simulations of the data, was then conducted. ResultsMale and female rats achieved relatively stable METH serum concentrations within 20min, which remained constant from 20 to 120min. While not statistically different, METH clearance and volume of distribution values for females were 25% and 33% lower (respectively) than males. Linear regression analysis of predicted METH concentrations from pharmacokinetic simulations versus observed concentrations showed a substantially better correlation with male data than female data (r2=0.71 vs. 0.56; slope=0.95 vs. 0.45, respectively). At 120min, the time of predicted peak METH serum concentrations, female values were 42% higher than expected, while male values were within 3%. ConclusionsUnlike METH male pharmacokinetic data, the female data was less predictable during multiple METH administrations and produced overall higher than expected METH concentrations. These findings demonstrate that METH pharmacokinetics could contribute to differences in METH self-administration behaviors in rats.

Implementation of a protocol for administration of vancomycin by continuous infusion: pharmacokinetic, pharmacodynamic and toxicological aspects

Optimising antibiotic administration is critical when dealing with pathogens with reduced susceptibility. Vancomycin activity is dependent on the area under the concentration–time curve over 24h at steady-state divided by the minimum inhibitory concentration (AUC/MIC), making continuous infusion (CI) or conventional twice daily administration pharmacodynamically equipotent. Because CI facilitates drug administration and serum level monitoring, we have implemented a protocol for CI of vancomycin by: (i) examining whether maintaining stable serum concentrations (set at 25–30mg/L based on local susceptibility data of Gram-positive target organisms) can be achieved in patients suffering from difficult-to-treat infections; (ii) assessing toxicity (n=94) and overall efficacy (n=59); and (iii) examining the correlation between AUC/MIC and the clinical outcome in patients for whom vancomycin was the only active agent against a single causative pathogen (n=20). Stable serum levels at the expected target were obtained at the population level (loading dose 20mg/kg; infusion of 2.57g/24h adjusted for creatinine clearance) for up to 44 days, but large intrapatient variations required frequent dose re-adjustments (increase in 57% and decrease in 16% of the total population). Recursive partitioning analysis of AUC/MIC ratios versus success or failure suggested threshold values of 667 (total serum level) and 451 (free serum level), corresponding to organisms with a MIC>1mg/L. Nephrotoxicity potentially related to vancomycin was observed in 10% of patients, but treatment had to be discontinued in only two of them.

The influence of liver and pancreas surgery on the thyroid function

BackgroundNowadays, the increasing number of oncologic patients with liver or pancreatic tumours are subjected to surgical treatment, as it can provide a long-term survival or sometimes cure. As a result, numerous new clinical questions regarding metabolic disturbances in these patients have been arisen. Among others, the impact of the pancreas and liver surgery extent in relation to the thyroid function remains to be elucidated.Materials and methodsThe study comprised 51 patients (25 men and 26 women, mean age ± SD 61.6 ± 10.4 yrs, mean ± SD) with pancreatic or liver tumours, qualified for abdominal operation. Serum levels of FT3, FT4 and TSH were measured on the day before (time “0”) and on the 1st, 3rd and 5th day after surgery in two (2) subgroups reflecting the extent of surgery: twenty seven (27) patients (14 men and 13 women, mean age ± SD 61.5 ± 11.8 yrs) after major surgery (Whipple’s surgery, right and left hemihepatectomy, segmentectomy of the liver, distal pancreatectomy, total duodenopancreatectomy) and twenty four (24) patients (11 men and 13 women, mean age ± SD 61.8 ± 8.9 yrs) after minor, palliative surgery (exploratory laparotomy, gastroenterostomy, triple by-pass, liver tumour embolization, hepaticojejunostomy). Additionally, the obtained results were analyzed in relation to the type of the disease (pancreatic surgery vs liver surgery).ResultsMean serum FT3 level decreased significantly during the study in major and minor surgery subgroups (p<0.001, in both) in comparison to the baseline values, accompanied by stable serum concentrations of TSH (NS) and FT4 (NS). The above decreasing tendency in FT3 concentrations was similar in both subgroups (NS), the same as were unchanged levels of TSH (NS) and FT4 (NS). Mean FT4 concentration on the 3rd and 5th day after major surgery was lower in pancreatic tumour patients in comparison to liver tumour patients (p=0.002, p=0.032, respectively). Similarly, mean FT3 concentration on the 3rd day in minor surgery subgroup was lower in pancreatic tumour patients in comparison to liver tumour patients (p=0.015).DiscussionOur findings have confirmed essential reduction of FT3 values after abdominal surgery, independently of surgery extent. Additionally, pancreatic tumour patients are more likely to have lower FT3 and FT4 levels after surgery when compared to liver tumour patients.

Ovariectomy and 17&amp;beta;-estradiol Replacement in Rats and Mice: A Visual Demonstration

Estrogens are a family of female sexual hormones with an exceptionally wide spectrum of effects. When rats and mice are used in estrogen research they are commonly ovariectomized in order to ablate the rapidly cycling hormone production, replacing the 17β-estradiol exogenously. There is, however, lack of consensus regarding how the hormone should be administered to obtain physiological serum concentrations. This is crucial since the 17β-estradiol level/administration method profoundly influences the experimental results. We have in a series of studies characterized the different modes of 17β-estradiol administration, finding that subcutaneous silastic capsules and per-oral nut-cream Nutella are superior to commercially available slow-release pellets (produced by the company Innovative Research of America) and daily injections in terms of producing physiological serum concentrations of 17β-estradiol. Amongst the advantages of the nut-cream method, that previously has been used for buprenorphine administration, is that when used for estrogen administration it resembles peroral hormone replacement therapy and is non-invasive. The subcutaneous silastic capsules are convenient and produce the most stable serum concentrations. This video article contains step-by-step demonstrations of ovariectomy and 17β-estradiol hormone replacement by silastic capsules and peroral Nutella in rats and mice, followed by a discussion of important aspects of the administration procedures.

Methanol Ingestion

Methanol Ingestion

Rat brain and serum lithium concentrations after acute injections of lithium carbonate and orotate

Eight hours after intraperitoneal injections of 1.0, 2.0, and 4.0m equiv Li kg-1, the serum and brain lithium concentrations of rats were significantly greater after lithium orotate than after lithium carbonate. While little serum lithium remained at 24 h after injection of 2.0 m equiv kg-1 lithium carbonate, two-thirds of the 2 h serum lithium concentration was present 24h after lithium orotate. Furthermore, the 24 h brain concentration of lithium after lithium orotate was approximately three times greater than that after lithium carbonate. These data suggest the possibility that lower doses of lithium orotate than lithium carbonate may achieve therapeutic brain lithium concentrations and relatively stable serum concentrations.

The Contraceptive Vaginal Ring in Women With Renal and Liver Transplantation: Analysis of Preliminary Results

Introduction Vaginal administration seems to be the best route to achieve steady and precise doses of contraceptive hormones, resulting in stable serum concentrations and low exposure. The aim of this study was to evaluate the contraceptive efficacy, cycle control, tolerability and acceptability of a contraceptive vaginal ring (NuvaRing) in renal and liver transplant recipients. Material and Methods Renal or liver transplant recipients, asking for contraception, were enrolled into the study. The duration of treatment was 12 cycles, with each vaginal ring releasing an average of 120 mg etonogestrel and 15 mg ethinylestradiol daily. Study visits were scheduled at screening, in the first week following cycles 3, 6, and 12 (172 cycles). Results Among 17 females included into the study: were 9 renal (mean age, 30 ± 7.2 years) and 8 liver transplant recipients (mean age, 32.6 ± 6.6 years). At the onset of therapy all patients showed at least 6 months of stable graft function with no signs of allograft rejection. The mean posttransplant follow-up was 4 ± 3.6 and 5.3 ± 2.1 years for women with renal and hepatic transplantations respectively ( P = NS). The immunosuppressive therapy was not changed for any patient. We demonstrated good cycle control: 162 cycles did not exhibit any bleeding; 7 cycles, only spotting episodes, whereas 2 cycles had 1 bleeding episode during the ring period. The estrogen-related adverse events (nausea and breast tenderness) were reported in 2 patients. One patient experienced significant bleeding related to thrombocytopenia. Discussion Nuvaring, in our preliminary findings, may be considered to be an highly effective contraceptive method for female transplant recipients that additionally regulate menstrual bleeding and seems to positively influence well-being. Vaginal administration may diminish the chance of drug interactions and therefore be safer for patients.

Accidental methanol ingestion: Case report

BackgroundThe incidence of methanol (CH3OH) intoxication differs enormously from country to country. Methanol intoxication is extremely rare in the Dutch population. Even a low dose can already be potentially lethal. Patients are conventionally treated with hemodialysis. Therefore we'd like to present a report of a foreign sailor in Rotterdam who accidentally caused himself severe methanol intoxication, with a maximum measured concentration of 4.4 g/L.Case presentationThe patient presented with hemodynamic instability and severe metabolic acidosis with pH 6.69. The anion gap was 39 mmol/L and the osmol gap 73 mosmol/kg. Treatment with ethanol and continuous venovenous hemodiafiltration (CVVH-DF) was initiated. Despite the hemodynamic instability it is was possible to achieve rapid correction of pH and methanol concentration with CVVH-DF while maintaining a stable and therapeutic ethanol serum concentration. Despite hemodynamic and acid-base improvement, our patient developed massive cerebral edema leading to brain death. Permission for organ donation was unfortunately not ascertained.ConclusionsWe conclude that in a hemodynamic instable situation high methanol concentrations and methanol-induced derangements of homeostasis are safely and effectively treated with CVVH-DF and that severe cerebral edema is another possible cause of death rather than the classical bleeding in the putamen area.

Doxofylline: The next generation methylxanthine

Methylxanthines are widely used in the treatment of asthma. Being one of the few drugs that can be administered orally, they are especially helpful in resource restricted settings. Theophylline, the commonly used methylxanthine drug is associated with a wide range of adverse effects accounting for the poor compliance and high drop-out rates. Moreover, a narrow therapeutic index warrants routine monitoring of its levels in the blood. Doxofylline, a new methylxanthine derivative, is shown to have similar efficacy with significantly less side effects in both animal studies as well as human adults. However, there is a paucity of studies in children with asthma. Retrospective data suggest that 11% patients experienced some side effects, but only 5% reported moderate side effects. Available evidence suggests that it improves spirometric parameters in children with asthma as compared to placebo. Extrapolating data from adult patients, it may be used in place of theophylline as an add on therapy in step 3 and step 4 in children with asthma. Dosage recommended for children> 6 yrs of age is 6 mg/Kg/dose BID. Doxofylline produces stable serum concentrations, hence plasma monitoring is required only in patients with hepatic insufficiency and intolerance to xanthine drugs.

Paliperidone ER: a review of the clinical trial data.

Paliperidone extended-release tablet (paliperidone ER; INVEGA()) is an oral antipsychotic for the treatment of schizophrenia. The recommended dose range is 3-12 mg per day. Paliperidone ER utilizes the OROS((R)) delivery system, which allows for once-daily dosing. Its pharmacokinetic profile results in a more stable serum concentration. Paliperidone is 9-hydroxyrisperidone, the chief active metabolite of risperidone. It undergoes limited hepatic metabolism, thereby minimizing the risks of hepatic drug-drug and drug-disease interactions. Three 6-week trials in patients with acute schizophrenia reported that paliperidone ER was effective, well tolerated, and produced clinically meaningful improvements in personal and social functioning compared with placebo. Post-hoc analysis of these trials in various populations, including recently diagnosed, elderly and more severely ill patients, those with sleep disturbances and those with predominant negative symptoms demonstrated improvement as well. Paliperidone ER was also significantly better than placebo in the prevention of symptom recurrence in a 6-month maintenance study. The most common clinically relevant adverse events associated with paliperidone ER were extrapyramidal symptoms, tachycardia and somnolence. The incidence of Parkinsonism, akathisia and use of anticholinergic medications increased in a dose-related manner. Further, modest QTc interval prolongation was observed but did not produce clinical symptoms. Similar to risperidone, paliperidone ER is associated with increases in serum prolactin levels. Overall, paliperidone ER was effective, well tolerated and provides a new treatment option for patients with schizophrenia.

Continuous versus intermittent infusion of temocillin, a directed spectrum penicillin for intensive care patients with nosocomial pneumonia: stability, compatibility, population pharmacokinetic studies and breakpoint selection

Temocillin, a 6alpha-methoxy-penicillin stable towards most beta-lactamases (including extended-spectrum beta-lactamase), is presented as an alternative to carbapenems for susceptible Enterobacteriaceae in microbiological surveys. We aimed at documenting its potential clinical usefulness in intensive care (IC) patients using pharmacokinetic/pharmacodynamic approaches applied to conventional (twice daily) and continuous infusion (CI) modes of administration. (i) In vitro evaluation of temocillin stability and compatibility with other drugs under conditions pertinent of CI in IC patients; (ii) pharmacokinetic study in patients treated by CI (4 g/day; n = 6) versus [twice daily (2 g every 12 h); n = 6]; (iii) population pharmacokinetic analysis of twice daily with Monte Carlo simulations to determine 95% probability of target attainment (PTA(95)) versus MIC (based on time above MIC > or = 40% for measured free drug). Temocillin was stable at 37 degrees C in 8.34% solutions for 24 h and compatible with flucloxacillin and aminoglycosides, but not with several other antibiotic and non-antibiotic drugs. With CI, stable total serum concentrations were 73.5 +/- 3.0 mg/L (SEM) and free concentration 29.3 +/- 2.8 mg/L. With twice daily, Cmax (total drug) was 147 +/- 12.3 mg/L (SEM; free drug: 50.3 +/- 15.8 mg/L), lowest trough (total drug) 12.3 mg/L, and PTA(95) (free drug) obtained for MIC < or = 8 mg/L. Temocillin (4 g/day) by CI yields stable free serum concentrations above the current breakpoint (16 mg/L), although individual variations may suggest lowering the breakpoint to 8 mg/L (as for twice daily) unless the daily dose or the frequency of administration is increased.

Effects of estradiol with oral or intravaginal progesterone on risk markers for breast cancer in a postmenopausal monkey model

To evaluate the effects of oral estradiol given with either oral or intravaginal micronized progesterone (P4) on risk biomarkers for breast cancer in a postmenopausal monkey model. This experiment was a two-way crossover study in which 20 ovariectomized adult female cynomolgus macaques were treated (in equivalent doses for women) with oral estradiol (1 mg/d) + oral micronized P4 (200 mg/d) or intravaginal P4 delivered by Silastic rings (6- to 10-mg/d release rate). Hormone treatments lasted 2 months and were separated by a 1-month washout period. The primary outcome measure was breast epithelial proliferation. Serum P4 concentrations were significantly greater in subjects receiving oral P4 (10.9 ng/mL) compared with intravaginal P4 (3.8 ng/mL) at 2 to 3 hours after oral dosing (P<0.0001) but not at 24 to 28 hours after oral dosing (2.9 ng/mL for oral P4 vs 3.2 ng/mL for intravaginal P4 at 2 months, P=0.19). Serum estradiol concentrations were significantly lower after oral P4 than after intravaginal P4 (P<0.05 for all time points). Oral P4 resulted in significantly decreased body weight (-2.5%) compared with intravaginal P4 (+3.6%) (P=0.0001). Markers of breast proliferation, sex steroid receptor expression, and endometrial area did not differ significantly between oral P4 and intravaginal P4 treatments (P>0.1 for all). Despite different pharmacodynamic profiles, oral and intravaginal P4 had similar effects on biomarkers in the postmenopausal breast.

Re-Induction as a Possible Alternative Modality of Dose Escalation of Infliximab: A Prospective Evaluation in a Small Series of Psoriatic Patients

Infliximab is an anti-tumour necrosis factor-alpha chimeric monoclonal antibody which is highly effective in psoriasis, as well as in other indications. In clinical practice, some patients may require dose escalation to overcome a reduction of the extent and/or duration of response during regular maintenance treatment, possibly due to the loss of stable serum concentrations of the drug. Common strategies of dose escalation are the increase of dose per infusion and the decrease of interval between infusions. Here we report the results of re-induction therapy with infliximab used as a dose escalation strategy in 9 patients whose psoriasis relapsed during maintenance treatment with infliximab 5 mg/kg every 8 weeks. Re-induction was well tolerated and capable of restoring response in 8 of these patients.