Management and Outcome of COVID-19 Infection Using Nirmatrelvir/Ritonavir in Kidney Transplant Patients

BACKGROUND

Nirmatrelvir/ritonavir has been shown to reduce the risk of COVID-19 related complications in patients at high risk for severe COVID-19. However, clinical experience of nirmatrelvir/ritonavir in the transplant recipient population is scattered due to the complex management of drug-drug interactions with calcineurin inhibitors. We describe the clinical experience with nirmatrelvir/ritonavir at The Ottawa Hospital kidney transplant program.

METHODS

Patients who received nirmatrelvir/ritonavir between April and June 2022 were included and followed up 30 days after completion of treatment. Tacrolimus was withheld for 24 hours and resumed 72 hours after the last dose of nirmatrelvir/ritonavir (on Day 8) based on drug level the day before. The first 30 patients had their dose adjusted according to drug levels performed twice in the first week and as needed thereafter. Subsequently, a simplified algorithm with less frequent calcineurin inhibitor level monitoring was implemented. Outcomes including tacrolimus level changes, serum creatinine and acute kidney injury (AKI, defined as serum creatinine increase by 30%) and clinical outcomes were described globally and compared between algorithms.

RESULTS

Fifty-one patients received nirmatrelvir/ritonavir. Tacrolimus levels drawn at the first timepoint, 7 days after withholding of calcineurin inhibitor and 2 days after discontinuing nirmatrelvir/ritonavir were within the therapeutic target in 17/44 (39%), subtherapeutic in 21/44(48%) and supratherapeutic in 6/44 (14%). Two weeks after, 55% were within the therapeutic range, 23% were below, and 23% were above it. The standard and simplified algorithms provided similar tacrolimus level (median 5.2 ug/L [4.0, 6.2] versus 4.8 ug/L [4.3, 5.7] p=0.70). There were no acute rejections or other complications.

CONCLUSIONS

Withholding tacrolimus starting the day before initiation of nirmatrelvir/ritonavir with resumption 3 days after completion of therapy resulted in a low incidence of supratherapeutic levels but a short period of subtherapeutic levels for many patients. AKI was infrequent. The data are limited by the small sample size and short follow-up.

The changing landscape in nephrology education in India

Digital tools have revolutionized education in nephrology in India. All forms of in-person learning are moving online. Social media have taken over the world, with clinicians learning and promoting multidirectional education methods. E-learning is better equipped to keep up with the rapid pace of new knowledge generation and dissemination. The use of digital multimedia tools to enhance rapid learning is backed by science, viz., dual-coding theory. Digital tools such as Twitter, blogs, podcasts, YouTube, and Nephrology Simulator (NephSIM) have had an impact in facilitating nephrology education among medical professionals and the general public. Digital tools, such as NephMadness, have resulted in the gamification of nephrology learning. Social media usage by the nephrology community in India is growing at a rapid pace. Everyday Cases in Nephrology (#ECNeph), a monthly Twitter-based discussion focused on academically challenging clinical cases, has its origins in India. The Women in Nephrology, India (WIN-India) initiative is very active in facilitating digital education in India and has, in a short space of time, created phenomenal momentum. Furthermore, non-governmental organizations in India, such as the Kidney Warriors Foundation and the Multi Organ Harvesting Aid Network (MOHAN) Foundation, have successfully tapped into social media to educate and aid kidney disease patients. All technologies come with some drawbacks. Despite their acceptance and validation, digital tools have their own pitfalls. These relate to (1) accessibility and connectivity, (2) accuracy of the scientific information, (3) social media noise, and (4) patient privacy. All pitfalls of digital education can be addressed by avoiding excessive social media overload and adopting an appropriate peer-review process. It is advisable to seek written consent from patients whenever patient data are posted online, to avoid privacy issues.

Gender disparities in the treatment of aortic stenosis – an analysis of the united states national inpatient sample (2009–2018)

Introduction

Gender disparity in the management of a variety of cardiovascular disorders has been well established. Studies have shown that women are less likely to undergo surgical aortic valve replacement (SAVR), and have higher mortality and health care cost in the management of aortic stenosis (AS). The impact of transcatheter aortic valve replacement (TAVR) on this gender disparity has not been well established.

Purpose

We sought to examine the impact of gender on outcomes following aortic valve replacement for AS in the era of routine transcatheter valve replacement.

Methods

We used the National Inpatient Sample (2009–18), a representative probability sample of the United States, to study visits for all aortic valve replacements and in-hospital outcomes as a function of gender. Survey estimation commands were used to provide national estimates.

Results

There were an estimated 431,344 SAVR and 189,137 TAVR inpatient visits during the periods of 2009–18 and 2011–18, respectively with a higher representation of women in the TAVR cohort (46.4% [95% CI, 45.9%-46.9%]) than SAVR (36.8% [95% CI, 36.4%-37.2%]). Women were slightly older with higher prevalence of uncomplicated hypertension (HTN) and pulmonary circulation disorders. However, women exhibited a lower prevalence of complicated HTN, complicated diabetes mellitus, prior percutaneous coronary intervention, prior coronary artery bypass grafting, peripheral vascular disease and renal failure. In-hospital mortality was higher in women after SAVR (3.8%±0.1 vs 2.7%±0.07, p<0.001) and TAVR (2.4%±0.1 vs 1.7%±0.1, p<0.001) compared to men. Female SAVR patients had higher rates of permanent pacemaker (PPM) implantation, stroke and significant bleeding (5.9%±0.1 vs 5%±0.1, 2.8%±0.1 vs 2.3%±0.07, and 37.8%±0.8 vs 29.8%±0.6; p<0.001, respectively) but lower rates of acute kidney injury (AKI) (16.4%±0.3 vs 20.3%±0.3, p<0.001). In addition, women undergoing TAVR had higher rates of stroke and significant bleeding (2.4%±0.1 vs 1.6%±0.09 and 28.7%±0.6 vs 22%±0.5; p<0.001 respectively) but lower rates of PPM and AKI (9.5%±0.3 vs 10.7%±0.2 and 11.3%±0.3 vs 13.4%±0.3; p<0.001, respectively). There was a reduction in mortality, compared to the early TAVR era, for all groups during the study period, particularly in female TAVR patients (from approximately 5.2% to 1.7%). In-hospital mortality for women was lower after TAVR than SAVR, both after multivariable adjustment (OR = 0.33, 95% CI 0.24–0.45) and propensity matching (mean difference 1.28%±0.49).

Conclusions

TAVR appears to have narrowed the gender disparity in the management of AS. Although women continue to have a higher in-hospital mortality following both TAVR and SAVR compared to men, TAVR is associated with a lower inpatient mortality in women compared to SAVR. Thus, TAVR may represent a bridge for the gender gap in aortic valve replacement.

Funding Acknowledgement

Type of funding sources: None.

Is HRCT reliable in determining disease activity in pulmonary tuberculosis?

Aims and Objectives The purpose of our study is to [1] determine the activity of disease based on the HRCT findings (2) to define indications for the use of HRCT in evaluation of Pulmonary TB and (3) to determine whether additional information provided by HRCT alters clinical management of the disease. Materials and Methods The present study was carried out at Shree Sayajirao General Hospital (SSGH), Baroda, Gujarat, India from January 2002 to December 2002. Twenty five patients with sputum positive post-primary pulmonary TB were studied prospectively with chest radiographs and HRCT. The diagnosis of active TB was based on detection of acid-fast bacilli in sputum. None of the patients in our study population was HIV positive. All patients underwent x-ray chest and HRCT chest (Philips Tomoscan, Best, Netherlands). The pattern, extent and severity of HRCT findings were recorded and compared with the plain x-ray findings. The gathered information and investigations were subjected to statistical analysis. Results Our study population consisted of sputum positive (AFB positive) 25 patients, 22 of them were newly diagnosed/suspected post-primary tuberculosis (GROUP 1) and 3 of them had taken six months of AKT (GROUP 2). Our study included 22 males and 3 females with average age of 38 years (range, 14-65 years.) In total chest radiographic signs of active tuberculosis were seen in twelve (48%) patients. HRCT showed evidences of active tuberculosis in all 22 patients of newly diagnosed tuberculosis; and in 2 out of 3 patients with prior history of AKT. Thus, total of 24 (96%) patients had evidence of active pulmonary TB on HRCT. One patient with prior history of AKT showed evidence of pulmonary Koch′s sequel. Conclusion Although chest radiography remains the foremost imaging technique in the evaluation of pulmonary TB, HRCT can be useful in certain circumstances and can provide important information in the diagnosis and management of the disease. HRCT is helpful in the distinction of active form inactive TB. HRCT is better than plain chest radiograph in identification of extent of pulmonary TB, especially subtle areas of consolidation, cavitation, bronchogenic and miliary spread. HRCT is recommended when the radiographic findings are normal or inconclusive and tuberculosis is suspected clinically for the confirmation of diagnosis and determination of activity.

POS0442 RELATIONSHIP BETWEEN PARAOXONASE-1 GENOTYPE, ACTIVITY AND MAJOR ADVERSE CARDIOVASCULAR EVENTS IN PATIENTS WITH RHEUMATOID ARTHRITIS RECEIVING TOFACITINIB

Background:

Paraoxonase-1 (PON1) is a high-density lipoprotein (HDL)-associated enzyme with paraoxonase, lactonase and arylesterase activities.1 PON1 contributes to the antioxidant properties of HDL, and is being investigated for its atheroprotective properties.1 Patients (pts) with rheumatoid arthritis (RA) who are homozygous for the RR genotype of the Q192R gene polymorphism on PON1 (rs662) have increased paraoxonase activity, and lower risk of carotid plaques, vs those with QQ or QR genotypes.2 Tofacitinib is an oral Janus kinase inhibitor for the treatment of RA.

Objectives:

To investigate the relationship between PON1 genotype/activity and risk of major adverse cardiovascular events (MACE) in the tofacitinib RA clinical programme.

Methods:

In this post hoc analysis, data were pooled from pts enrolled in nine Phase 2/3 studies of tofacitinib in RA. Enzyme activities in pt plasma samples were measured at individual study baseline (BL) and at follow-up visits using three substrates: paraoxon (paraoxonase activity), dihydrocoumarin (lactonase activity) and phenylacetate (arylesterase activity). The effect of the PON1 Q192R genotype (QQ, QR or RR) on BL paraoxonase/lactonase/arylesterase activity was assessed using linear regression for each study, with age and sex as covariates, and then fixed-effect meta-analysis assessed effects across studies. The risk of MACE by enzyme activity was determined using Cox proportional hazards regression stratified by clinical studies. Univariate regression against BL enzyme activity and other risk factors, as well as both minimally and fully adjusted multivariable regressions against time-varying enzyme activity, are presented.

Results:

The analysis included 1969 pts with RA who received ≥1 dose of tofacitinib and had PON1 activity measures available at BL; 39 pts had ≥1 MACE event. Compared with the QQ genotype, the RR genotype had a highly significant positive association with BL paraoxonase activity, and a highly significant negative association with BL lactonase and arylesterase activity (Table 1). A univariate analysis identified several BL covariates significantly associated with risk of MACE (Figure 1a). Time-varying models found a highly significant association of increased paraoxonase activity over time with lower risk of future MACE, even after controlling for low-density lipoprotein or HDL cholesterol levels, and other traditional cardiovascular (CV) risk factors identified in univariate analysis (Figure 1b), with similar findings for lactonase and arylesterase (data not shown).

Table 1.

Effect of PON1 genotype (RR vs QQ) on BL enzyme activity

nEstimate95% CIp valueCochran’s Q testParaoxonase12291.0350.93, 1.141<0.00010.209Lactonase1188-0.375-0.505, -0.246<0.00010.025Arylesterase1231-1.016-1.382, -0.649<0.00010.251

Fixed-effects model; estimate >0 favours RR genotype and <0 favours QQ genotype

BL, baseline; CI, confidence interval

Conclusion:

Higher activity of the HDL-associated protein PON1 over time was associated with a significantly reduced risk of future MACE in pts with RA receiving tofacitinib, after controlling for traditional CV risk factors and cholesterol levels. Further investigation of PON1 as a novel functional lipid biomarker to assess CV risk in pts with RA is warranted.

References:

[1]Mackness & Mackness. Gene 2015; 567: 12-21.

[2]Charles-Schoeman et al. Arthritis Rheum 2013; 65: 2765-2772.

Acknowledgements:

Study sponsored by Pfizer Inc. Medical writing support was provided by Jennifer Higginson, CMC Connect, and funded by Pfizer Inc.

Disclosure of Interests:

Christina Charles-Schoeman Consultant of: AbbVie, Gilead, Pfizer Inc, Regeneron-Sanofi, Grant/research support from: AbbVie, Bristol-Myers Squibb, Pfizer Inc, Craig Hyde Shareholder of: Pfizer Inc, Employee of: Pfizer Inc, Shunjie Guan Shareholder of: Pfizer Inc, Employee of: Pfizer Inc, Neil Parikh: None declared, Jennifer Wang: None declared, Ani Shahbazian: None declared, Lori Stockert Shareholder of: Pfizer Inc, Employee of: Pfizer Inc, John Andrews Shareholder of: Pfizer Inc, Employee of: Pfizer Inc

OP0280-PARE A MINDFULNESS PROGRAM DOSING STUDY TO EVALUATE IMPROVEMENT IN EMOTIONAL DISTRESS AMONG PEOPLE WITH RHEUMATIC DISEASE

Background:

Mindfulness-based interventions for chronic pain and emotional distress have increased in popularity as complementary therapies among people living with rheumatic and musculoskeletal disease (RMD).1,2 Despite growing evidence that mindfulness meditation reduces pain and anxiety associated with RMD, more research is needed to specify the optimal duration of mindfulness training necessary to be effective for short- and long-term benefit.

Objectives:

To evaluate and compare the effectiveness of full-length versus brief mindfulness training programs for improving anxiety among people living with RMD.

Methods:

Adult US participants (pts) within the ArthritisPower registry were invited to participate in the Healthy Mind Healthy You study comparing the effectiveness of two online mindfulness training programs of different lengths accessed via the MoodNetwork platform. The full-length mindfulness based cognitive therapy program lasted 8 weeks, while the brief evidence-based mindfulness program lasted 3 weeks. Pts were randomized to one of the two programs and completed assessments every two weeks during the program and then every four weeks during the 12-week follow-up period. Assessments included World Health Organization-Five Well-Being Index (WHO-5), Five Facet Mindfulness Questionnaire (FFMQ), Perceived Stress Scale (PSS), and two measures of emotional distress, PROMIS Short Forms for Anxiety and Depression. Analyses compared demographic characteristics and assessment scores by program length.

Results:

324 pts completed assessments at baseline and 70 pts completed them at week 8, an attrition rate of 78% in each of the program arms. The majority of pts were female, White, with 67% between the ages of 45-64 years. No statistically significant differences were observed at baseline between participants randomized to each of the two programs, and in their assessment scores at week 8 (Table 1); PROMIS Anxiety and Depression scores improved from baseline to week 8 for pts in both programs (Figure 1). Overall, mean (SD) PROMIS Depression scores improved from 58.4 (7.7) at baseline to 55.4 (7.2) at week 8 (p=0.018), a meaningfully important difference, among the 70 pts reporting scores at both time points.

Table 1.

Assessment Scores at Baseline and Week 8, Mean (SD)

BaselineWeek 8All (n=324)8-week course (n=163)3-week course (n=161)p-valueAll (n=70)8-week course (n=35)3-week course (n=35)p-valueWHO-5 b10.6 (4.9)10.4 (4.8)10.9 (5.0)0.37812.0 (5.1)12.5 (5.5)11.6 (4.7)0.488FFMQ c42.7 (6.1)42.7 (6.1)42.7 (6.1)0.93239.2 (5.7)38.9 (6.1)39.4 (5.3)0.741PSS d18.7 (7.5)19.2 (6.8)18.3 (8.2)0.30416.6 (7.3)15.7 (7.8)17.6 (6.8)0.291PROMIS Depression e56.5 (8.3)57.3 (8.0)55.7 (8.6)0.09755.1 (8.5)54.8 (9.3)55.5 (7.8)0.735PROMIS Anxiety f58.7 (8.2)59.0 (8.2)58.4 (8.1)0.47055.4 (7.2)54.6 (7.4)56.1 (7.1)0.404

a denotes use of Fisher’s Exact Test b Range 0 (worse) to 25 (better), c Range 3 (worse) to 15 (better), d Range 0 (better) to 40 (worse), e Range 24.7 (better) to 63.5 (worse), f Range 25.7 (better) to 62.0 (worse)

Conclusion:

People living with RMD who are part of a real-world US registry are willing to participate in an online mindfulness training program study, but may require additional support to remain engaged and adherent throughout the program and to participate to study conclusion. Participation in a mindfulness training program, whether full-length or brief, appears to improve symptoms of emotional distress among people with RMD.

References:

[1]Zhou, B. et al. Comp. Ther. in Clin. Prac. 2020; 39:1-7

[2]Reiner, K. et al. Pain Medicine. 2013; 14(2): 230-242

Acknowledgements:

The authors would like to thank ArthritisPower members for participating in the study, and the Healthy Mind Healthy You study team at Massachusetts General Hospital (see MoodNetwork.org) for leading it. The study was funded by the Patient-Centered Outcomes Research Institute (XPPRN-1512-33786).

Disclosure of Interests:

Julia Thompson: None declared, Nupur Parikh: None declared, Kelly Gavigan: None declared, Shilpa Venkatachalam: None declared, W. Benjamin Nowell Grant/research support from: Full-time employee of Global Healthy Living Foundation, an independent nonprofit organization, which has received funding to conduct research; Principal Investigator for studies with grant support from AbbVie, Amgen and Eli Lilly.

Management of anesthesia for cesarean delivery in a patient with an unruptured intracranial aneurysm

Headaches are a common symptom during pregnancy. The thunderclap headache is a sudden onset headache reaching maximal intensity within seconds to minutes. It is typically a subarachnoid hemorrhage caused by rupture of an intracranial aneurysm or arteriovenous malformation. Physiologic changes of pregnancy, such as increased cardiac output and plasma volume, may increase the risk of aneurysmal rupture. The relationship between the mode of delivery and incidence of rupture is not well defined. In this case report, we discuss the anesthetic management for cesarean delivery of a parturient with an unruptured aneurysm, located on the left ophthalmic-internal carotid artery. The delivery options and anesthetic technique used are presented, together with a review of published literature.

Medical students and interns' knowledge about and attitude towards homosexuality

Background and Rationale:

Medical professionals’ attitude towards homosexuals affects health care offered to such patients with a different sexual orientation. There is absence of literature that explores the attitudes of Indian medical students or physicians towards homosexuality.

Aim:

This study aimed to evaluate Indian medical students and interns’ knowledge about homosexuality and attitude towards homosexuals.

Materials and Methods:

After IEC approval and written informed consent, a cross-sectional study was conducted on a purposive sample of undergraduate medical students and interns studying in one Indian medical college. The response rate was 80.5%. Only completely and validly filled responses (N = 244) were analyzed. The participants filled the Sex Education and Knowledge about Homosexuality Questionnaire (SEKHQ) and the Attitudes towards Homosexuals Questionnaire (AHQ). SEKHQ consisted of 32 statements with response chosen from ‘true’, ‘false’, or ‘don’t know’. AHQ consisted of 20 statements scorable on a 5-point Likert scale. Multiple linear regression was used to find the predictors of knowledge and attitude.

Results:

Medical students and interns had inadequate knowledge about homosexuality, although they endorsed a neutral stance insofar as their attitude towards homosexuals is concerned. Females had more positive attitudes towards homosexuals. Knowledge emerged as the most significant predictor of attitude; those having higher knowledge had more positive attitudes.

Conclusion:

Enhancing knowledge of medical students by incorporation of homosexuality related health issues in the curriculum could help reduce prejudice towards the sexual minority and thus impact their future clinical practice.

The increased cost of ventral hernia recurrence: a cost analysis

PURPOSE

Over 300,000 ventral hernia repairs (VHRs) are performed each year in the US. We sought to assess the economic burden related to ventral hernia recurrences with a focused comparison of those with the initial open versus laparoscopic surgery.

METHODS

The Premier Alliance database from 2009 to 2014 was utilized to obtain patient demographics and comorbid indices, including the Charlson comorbidity index (CCI). Total hospital cost and resource expenses during index laparoscopic and open VHRs and subsequent recurrent repairs were also obtained. The sample was separated into laparoscopic and open repair groups from the initial operation. Adjusted and propensity score matched cost outcome data were then compared amongst groups.

RESULTS

One thousand and seventy-seven patients were used for the analysis with a recurrence rate of 3.78 %. For the combined sample, costs were significantly higher during recurrent hernia repair hospitalization ($21,726 versus $19,484, p < 0.0001). However, for index laparoscopic repairs, both the adjusted total hospital cost and department level costs were similar during the index and the recurrent visit. The costs and resource utilization did not go up due to recurrence, even though these patients had greater severity during the recurrent visit (CCI score 0.92 versus 1.06; p = 0.0092). Using a matched sample, the total hospital recurrence cost was higher for the initial open group compared to laparoscopic group ($14,520 versus $12,649; p = 0.0454).

CONCLUSIONS

Based on our analysis, need for recurrent VHR adds substantially to total hospital costs and resource utilization. Following initial laparoscopic repair, however, the total cost of recurrent repair is not significantly increased, as it is following initial open repair. When comparing the initial laparoscopic repair versus open, the cost of recurrence was higher for the prior open repair group.

Phase II study of saracatinib (AZD0530) in patients with previously treated metastatic colorectal cancer

BACKGROUND

Src has a critical role in tumor cell migration and invasion. Increased Src activity has been shown to correlate with disease progression and poor prognosis, suggesting Src could serve as a therapeutic target for kinase inhibition. Saracatinib (AZD0530) is a novel selective oral Src kinase inhibitor.

METHODS

Metastatic colorectal cancer patients who had received one prior treatment and had measurable disease were enrolled in this phase 2 study. Saracatinib was administered at 175 mg by mouth daily for 28 day cycles until dose-limiting toxicity or progression as determined by staging every 2 cycles. The primary endpoint was improvement in 4 month progression-free survival. Design of Thall, Simon, and Estey was used to monitor proportion of patients that were progression free at 4 months. The trial was opened with plan to enroll maximum of 35 patients, with futility assessment every 10 patients.

RESULTS

A total of 10 patients were enrolled between January and November 2007. Further enrollment was stopped due to futility. Median progression-free survival was 7.9 weeks, with all 10 patients showing disease progression following radiographic imaging. Median overall survival was 13.5 months. All patients were deceased by time of analysis. Observed adverse events were notable for a higher than expected number of patients with grade 3 hypophosphatemia (n = 5).

CONCLUSION

Saracatinib is a novel oral Src kinase inhibitor that was well tolerated but failed to meet its primary endpoint of improvement in 4 month progression-free survival as a single agent in previously treated metastatic colorectal cancer patients.

Growth, Doping and Characterization of AlxGa1−xN Thin Film Alloys on 6H-SiC(0001) Substrates

Thin films of AlxGa1−xN (0.05 ≤ x ≤ 0.96) having smooth surfaces were deposited directly on both vicinal and on-axis 6H-SiC(0001) substrates. Cross-sectional TEM of Al0.13Ga0.87N revealed stacking faults near the SiC/Nitride alloy interface and numerous threading dislocations. EDX, AES and RBS were used to determine the compositions, which were paired with their respective CL near band-edge emission energies. A negative bowing parameter was determined. The CL emission energies were similar to the bandgap energies obtained by SE. FE-AES of the initial growth of Al0.2Ga0.8N revealed an aluminum rich layer near the interface. N-type (silicon) doping was achieved for AlxGa1−xN for 0.12 ≤ x ≤ 0.42. Al0.2Ga0.8N/GaN superlattices were fabricated with coherent interfaces. Additionally, HEMT structures using an AlN/GaN/AlN buffer structure were fabricated.

Effect of gender and geographic location on the expression of primary hyperparathyroidism

BACKGROUND

The effect of gender on the expression of primary hyperparathyroidism (PHPT) is not well characterized.

AIM

We therefore evaluated two Caucasian populations (US and Italian) of men and women with PHPT, matched for age and body mass index (BMI), in a cross-sectional retrospective observational study.

METHODS

We studied 74 US (23 men) and 126 Italian (42 men) patients evaluating main biochemical indices of the disease and bone mineral density (BMD) at the spine and proximal femur.

RESULTS

Mean serum calcium levels were higher both in Italian men compared to women (11.7 ± 1.22 mg/dl and 11.1 ± 0.83, p<0.01) and in Italian compared to US patients (11.3 ± 1.01 and 10.8 ± 0.58, p<0.001), with similar results for the serum ionized calcium. Mean serum PTH levels were not different either between the genders or between the countries. After controlling for BMI, the mean BMD at both the femoral neck and total hip in females US patients was significantly higher compared with Italian female patients.

CONCLUSION

Despite similar levels of circulating PTH, Italian patients have more pronounced effects of the disease as assessed by serum calcium and a more significant cortical involvement in women as assessed by BMD.

Effect of dual inhibition of the Src and insulin-like growth factor-1 receptor (IGF-1R) pathways on antitumor effects in prostate cancer (PCa)

21

Background: The Src and IGF-1R axes are aberrantly activated in both PCa and the microenvironment of bone metastases. Dasatinib and BMS-754807 are clinically promising small molecule inhibitors with high potency against Src family kinases and IGF-1R, respectively. The aim of this study was to establish antitumor co-operativity by combining IGF-1R and Src blockade in a preclinical PCa model.

Methods: LNCaP and PC3 cells were used as models for androgen-dependent and independent PCa, respectively. Inhibition of Src and IGF-1R pathways was accomplished by pharmacologic agents (dasatinib against Src and BMS-754807 against IGF-1R) as well as by shRNA. Serum IGF-1 levels were measured in patients (pts) with castration-resistant PCa (CRPC) treated with dasatinib and docetaxel in a phase II trial.

Results: Src inhibition decreased proliferation of PCa cells, and migration in modified Boyden Chamber and wound assays. In contrast, IGF-1R blockade induced apoptosis (increased Sub-G1 fraction cells, Annexin-V(+) cells and PARP cleavage). Phosphorylation of Akt was partially inhibited by either drug alone and almost completely abrogated by the combination. Intraprostatic injection of shIGF-1R or shSrc PC3 cells in nude mice led to an 83% and 60% decrease in tumor size compared to control shRNA, respectively. In both cell lines, all observed antitumor effects were enhanced when dual blockade was used, relative to blocking the Src or IGF-1R pathway alone. In 9/19 (47%) pts with CRPC, treatment with dasatinib resulted in a compensatory increase of serum IGF-1 levels.

Conclusions: Dual inhibition of Src and IGF-1R is effective and complementary in PCa, mediated, in part, through inhibition of the downstream target Akt. In about half of pts treated with dasatinib, an increase in soluble IGF-1 levels was observed, indicating there is a compensatory upregulation of survival pathways that might be abrogated by dual inhibition of Src and IGF-1R. The combination of dasatinib and BMS-754807 may be a rational therapeutic approach in PCa by blocking complementary processes of tumor growth and progression.

[Table: see text]

Doping of GaN by Ion Implantation: Does it Work?

Epitaxially grown GaN by metal organic chemical vapor deposition (MOCVD) on SiC were implanted with 100 keV Si+ (for n-type) and 80 keV Mg+ (for p-type) with various fluences from 1×1012 to 7×1015 ions/cm2 at liquid nitrogen temperature (LT), room temperature (RT), and 700 °C (HT). High temperature (1200 °C and 1500 °C) annealing was carried out after capping the GaN with epitaxial AIN by MOCVD to study damage recovery. Samples were capped by a layer of AIN in order to protect the GaN surface during annealing. Effects of implant temperature, damage and dopant activation are critically studied to evaluate a role of ion implantation in doping of GaN. The damage was studied by Rutherford Backscattering/Channeling, spectroscopic ellipsometry and photoluminescence. Results show dependence of radiation damage level on temperature of the substrate during implantation: implantations at elevated temperatures up to 550 °C decrease the lattice disorder; “hot implants” above 550 °C can not be useful in doping of GaN due to nitrogen loss from the surface. SE measurements have indicated very high sensitivity to the implantation damage. PL measurements at LT of 80 keV Mg+ (5×1014 cm-2) implanted and annealed GaN showed two peaks : one ∼100 meV and another ∼140 meV away from the band edge.

Revealing the 3D internal structure of natural polymer microcomposites using X-ray ultra microtomography

Properties of composite materials are directly affected by the spatial arrangement of reinforcement and matrix. In this research, partially hydrolysed cellulose microcrystals were used to fabricate polycaprolactone microcomposites. The spatial distribution of cellulose microcrystals was characterized by a newly developed technique of X-ray ultra microscopy and microtomography. The phase and absorption contrast imaging of X-ray ultra microscopy revealed two-dimensional and three-dimensional information on CMC distribution in polymer matrices. The highest contrast and flux (signal-to-noise ratio) were obtained using vanadium foil targets with the accelerating voltage of 30 keV and beam current of >200 nA. The spatial distribution of cellulose microcrystals was correlated to the mechanical properties of the microcomposites. It was observed that heterogeneous distribution and clustering of cellulose microcrystals resulted in degradation of tensile strength and elastic modulus of composites. The utilization of X-ray ultra microscopy can open up new opportunities for composite researchers to explore the internal structure of microcomposites. X-ray ultra microscopy sample preparation is relatively simple in comparison to transmission electron microscopy and the spatial information is gathered at much larger scale.

Long-term prospective follow-up of intracranial aneurysms treated with endovascular coiling using contrast-enhanced MR angiography

BACKGROUND AND PURPOSE

Catheter angiography has been the criterion standard for follow-up evaluation of coiled intracranial aneurysms. In our center, CE-MRA has been used to evaluate aneurysm recanalization. Our aim was to investigate the feasibility and usefulness of a CE-MRA protocol for following patients with intracranial aneurysms treated with endovascular coiling.

MATERIALS AND METHODS

From September 2003 to December 2006, 134 aneurysms were treated by endovascular coiling in 124 patients by using detachable coils. These patients were followed with CE-MRA at 3 months, 15 months, and 3 and 5 years. MRAs were analyzed by 2 interventional neuroradiologists. Findings were assigned to 3 categories: complete obliteration (class 1), residual neck (class 2), and residual aneurysm (class 3).

RESULTS

Initially, CE-MRA demonstrated 67 (50%) complete obliterations (class 1), 57 (41.79%) residual necks (class 2), and 8 (5.97%) residual aneurysms (class 3). No patient experienced rebleed during the follow-up period. A total of 214 patient-years of follow-up were obtained (range, 0-53 months). Two (1.49%) patients died after the follow-up, and 11 (8.21%) patients were lost to follow-up. On follow-up, 76 (56.72%) patients showed stable results. Fifty-six (41.79%) aneurysms showed change in their obliteration pattern. Of these 56, 47 demonstrated recanalization and 9 (6.72%) showed further obliteration. Most of the aneurysms that showed change in their obliteration remained stable on follow-up. Only 11 (8.21% of the total and 23.4% of those who showed recanalization) patients underwent recoiling or clipping.

CONCLUSIONS

CE-MRA can be used in routine practice to follow-up aneurysm recanalization noninvasively. CE-MRA permits close-interval follow-up and may show more filling of the aneurysm neck or sac than DSA.