Acute pancreatitis associated with pembrolizumab-induced hypertriglyceridemia

INTRODUCTION

Acute pancreatitis (AP) following drug-induced hypertriglyceridemia is a rare clinical phenomenon. Immune checkpoint inhibitors have revolutionized treatment for a variety of solid organ and hematological malignancies. Pembrolizumab is a programmed cell death receptor-1 (PD-1) inhibitor that has shown promising responses in many advanced cancers. However, a constellation of immune-related adverse events has also been described. There are reports of pembrolizumab-induced hypertriglyceridemia, but AP as a result of this side effect remains an exceedingly rare clinical sequela.

CASE REPORT

We delineate a case of a patient with stage IVB non-small-cell lung cancer who developed progressive abdominal pain and nausea following administration of pembrolizumab for four months. Laboratory studies revealed increased serum lipase and triglyceride levels at 12,562 IU/L and 16,901 mg/dL, respectively. The diagnosis of AP was made based on the revised Atlanta classification criteria. After ruling out alternative causes, pembrolizumab-induced hypertriglyceridemia was considered the likely etiology of AP.

MANAGEMENT AND OUTCOME

The patient was transferred to the medical intensive care unit for close monitoring. Treatment was initiated with intravenous fluids, pain medications, and an insulin infusion. However, her hypertriglyceridemia levels remained persistently elevated, necessitating therapeutic apheresis. She recovered well with no complications after triglyceride apheresis.

DISCUSSION

AP following pembrolizumab-associated hypertriglyceridemia remains a rare clinicopathologic entity. Given the widespread clinical use of immune checkpoint inhibitors, knowledge of such rare adverse events is crucial. Evaluation of serum triglyceride levels before and after initiating pembrolizumab therapy may be mandated, especially in patients with metabolic comorbidities.

Phase II study of pembrolizumab and lenvatinib in advanced well-differentiated neuroendocrine tumors

BACKGROUND

Immune checkpoint inhibitors (CPIs) have not been shown to be active in well-differentiated neuroendocrine tumors (NETs), with response rates <5%. Lenvatinib is a multitargeted tyrosine kinase inhibitor which binds to vascular endothelial growth factor and fibroblast growth factor receptors and has demonstrated efficacy in pancreatic and gastrointestinal NETs [44% and 16% objective radiographic response rate (ORR), respectively]. The combination of antiangiogenic and CPI therapies can be synergistic. We therefore evaluated the combination of lenvatinib and pembrolizumab in well-differentiated gastrointestinal (GI) and thoracic NETs.

PATIENTS AND METHODS

A prospective, phase II trial evaluated patients with advanced GI/thoracic NETs (pancreatic NETs were excluded due to high response rate of lenvatinib monotherapy in this patient population), with evidence of progression within 8 months of study entry and at least two prior lines of systemic therapy. Patients received lenvatinib 20 mg daily and pembrolizumab 200 mg intravenously every 3 weeks until unacceptable toxicity or progression of disease. Primary endpoint was objective response rate, and an interim analysis was planned once 20 patients were enrolled. Four ORRs were required to continue enrollment.

RESULTS

Twenty patients were enrolled on protocol from April 2021 to January 2022 (nine small intestine, five lung, two thymic, two unknown primary, one cecal, one presacral primaries). Two patients (10%) achieved a partial response (atypical lung and small intestinal primaries). Median progression-free survival (PFS) was 8 months (95% confidence interval 5.8-10.2 months). Twelve (60%) patients experienced probably or definitely associated grade 3 adverse events (10 hypertension). Fourteen patients (70%) required dose reductions or discontinued one of the medications. Two patients discontinued treatment before radiographic assessment.

CONCLUSIONS

The combination of pembrolizumab and lenvatinib did not show sufficient response in patients with NETs to warrant continued enrollment on trial.

The Gastric Obstruction Due to Orbeez Beads Ingestion: A Case Report With Esophagogastroduodenoscopy Findings

Ingestion of non-food entities poses a critical risk, particularly in children and young adults. Mostly foreign bodies can safely pass through the gastrointestinal tract if they traverse the pylorus; however, ingestion of Orbeez beads can present as a unique challenge. Orbeez beads have the potential to absorb water and can expand in the stomach and small intestine, and can result in complications including constipation, intestinal obstruction, perforation, and peritonitis. Timely diagnosis and management are crucial to improve patient outcomes. We present a case of a 19-year-old male who ingested Orbeez beads and presented with nausea, vomiting, and abdominal pain. A non-contrast CT scan of the abdomen confirmed the foreign bodies. Fifty to seventy beads were successfully removed via esophagogastroduodenoscopy (EGD) without any complications, and the patient is currently doing well.

Isolated Colonic Histoplasmosis in Patients Undergoing Immunomodulator Therapy: A Systematic Review

Gastrointestinal histoplasmosis remains an inconspicuous clinicopathologic entity. It is predominantly considered a protean manifestation of disseminated disease. We hereby delineate a unique case of biopsy-proven isolated colonic histoplasmosis in a patient undergoing methotrexate therapy. Furthermore, we present the first systematic review of the MEDLINE, Google Scholar, Embase, and Scopus databases regarding isolated colonic histoplasmosis in adult patients receiving immunomodulator therapy (IMT). A total of 13 case reports (level of clinical evidence: IV) were identified. The mean age was 55.6 ± 11.1 years, with 9 (69.2%) cases reported in women. Patients with subclinical disease (5, 38.5%) were often incidentally diagnosed by screening colonoscopy. Symptomatic individuals predominantly presented with diarrhea (4, 30.8%), weight loss (3, 23.1%), and/or abdominal pain (3, 23.1%). IMT was mainly administered for liver transplant (4, 30.8%), renal transplant (4, 30.8%), and ulcerative colitis (2, 15.4%). Common colonoscopy features included colonic ulcerations (7, 53.8%), polyps or pseudopolyps (3, 23.1%), and/or mass-like lesions (3, 23.1%). Diagnosis was made by histology of colonic biopsy in 11 (84.6%) and resected specimens in 2 (15.4%) patients. Treatment consisted of a combination of amphotericin B with oral itraconazole in 6 (46.2%), oral itraconazole alone in 5 (38.5%), and amphotericin B alone in 2 (15.4%) patients. Complete clinical recovery was achieved in all patients. This article illustrates that isolated colonic involvement can be the only clinical presentation of histoplasmosis. It may masquerade as other bowel disorders, presenting diagnostic and therapeutic conundrums. Gastroenterologists should rule out colonic histoplasmosis in IMT recipients who develop unexplained colitis symptoms.

Kratom-induced common bile duct dilation

Kratom is an herb with opioid-like properties that has become readily available in the United States and is being used for self-management of pain and opioid withdrawal. We present a case of common bile duct dilation secondary to use of kratom. Our suspicion is that the mu-opioid agonism associated with kratom use resulted in effects similar to what might be seen in opiate-induced biliary ductal dilation.

Hematologic abnormalities as a marker of cirrhosis after Fontan completion

Background

More patients with functioning single ventricle are living into adulthood due to improved survival with the Fontan procedure. Therefore, screening and detection of late-stage complications such as Fontan Associated Liver Disease (FALD) has become increasingly important to improve outcomes. The role of hematologic abnormalities as a marker of cirrhosis in this population is evolving.

Purpose

We aimed to evaluate the value of hematologic parameters in predicting the presence of cirrhosis in the context of FALD.

Methods

This was a retrospective study of patients after Fontan completion who underwent liver biopsy between 2007 and 2019 at our institution. Biopsy slides were evaluated for the presence of cirrhosis by a single pathologist. Laboratory testing was recorded within 12 months of the liver biopsy. Univariable analysis was conducted with an alpha level of 0.05 for hypothesis testing.

Results

A total of 31 Fontan patients with liver biopsies were identified, of whom 7 patients were found to have cirrhosis (Table 1). Compared to patients with no cirrhosis on biopsy, cirrhotic patients tended to have lower hematologic counts including absolute lymphocyte count (0.78 vs 1.02, p=0.019), hemoglobin (12.5 vs 15.1, p=0.018), and platelets (131 vs 194, p=0.025). Notably, the MELD-XI score (Model for End-stage Liver Disease excluding INR) as well as its individual components, creatinine and total bilirubin, were not different between the groups.

Conclusion

Our data suggests that hematologic parameters including absolute lymphocyte count might be of value in predicting cirrhosis on liver biopsy following Fontan completion. Further research to validate these findings in other cohorts is warranted.

Funding Acknowledgement

Type of funding sources: None.

Rates and causes of readmissions following index admissions for Takotsubo syndrome-a meta-analysis of 118,941 index hospitalizations

Background

Rising trends in takotsubo syndrome (TTS)-related complications warrant data to identify the rate, causes and predictors of readmission on a large scale. We conducted the first-ever meta-analysis to evaluate the pooled rate of short-term and long-term readmissions after index TTS admissions.

Methods

PubMed/Medline, EMBASE and SCOPUS databases were systematically reviewed to find studies through October 2019 reporting rates and causes of readmission following index TTS admissions. Random effects models were used to estimate pooled rates and causes of readmissions and I2 statistics were used to report inter-study heterogeneity.

Results

A total of 16 cohorts with 118,941 TTS index admissions (mean age 65–75 yrs; female &gt;85%, median follow-up 272.5 days) revealed a 16.6% [95% CI-13.2%-20.3%, I2=99%] pooled rate of readmission. Short-term and long-term pooled readmission rates are displayed in Fig.1. The readmission rate was higher in cohorts with young patients (&lt;70 vs. &gt;70 yrs), smaller sample size (n&lt;100 vs. n&gt;100) and single-centres vs. multicentres. Studies published from the USA (16.4% vs. 14.9%) had a higher readmission rate as compared to Italy. The most frequent causes were cardiac (40.6%), respiratory (15.7%) and renal (7.0%). Among readmissions with cardiac diagnoses, heart failure was most common (40.1%).

Conclusions

This global meta-analysis revealed that the pooled rate of readmission following index TTS admissions was ∼17% and causes were mainly cardiac or respiratory.

Funding Acknowledgement

Type of funding source: None

On the residual six-fold astigmatism in DCOR/ASCOR

After the introduction of the hexapole C_s-correctors for scanning transmission electron microscopes (STEM), the next big step forward was the strong reduction of the six-fold astigmatism A₅ by means of an advanced hexapole design (DCOR/ASCOR). As a result all axial aberrations up to fifth order are sufficiently small to allow for large semi-aperture angles beyond 40 mrad for electron energies in the range of 30 to 300 kV without deterioration of the STEM resolution. In this paper we derive simple expressions for the optimum hexapole strength for minimum A₅ and the size of the residual A₅. Both quantities are intrinsic properties of the hexapoles and the transfer lens doublet in between. The optimum hexapole strength scales with the inverse of the electron wavelength, while the residual A₅ does not depend on the electron energy directly, but on the spherical aberration C_s of the pole piece. With the given properties of the DCOR/ASCOR and typical values of C_s in the range of 0.5 to 2.7 mm, at all acceleration voltages A₅ remains in the range from 0.03 to 0.4 mm, the latter even for a large-gap pole piece.

Changes in the Visual Threshold as a Function of Subception

In a previous paper (Dixon, 1958b) one of the authors reported an experiment which suggested that apparent changes in the threshold for one eye occur as a function of the emotionality of stimulus material presented below threshold to the other eye. The following experiment describes an attempt to investigate further the validity of this conclusion. The results are consistent with those from the previous research.

Follow-up Care for Survivors of Prostate Cancer - Clinical Management: a Program in Evidence-Based Care Systematic Review and Clinical Practice Guideline

AIMS

This clinical practice guideline was developed to provide evidence-based guidance on the frequency by which prostate-specific antigen (PSA) levels should be tested in men after curative-intent treatment for prostate cancer and to define the most appropriate diagnostic testing if biochemical recurrence occurs.

MATERIALS AND METHODS

An electronic search using OVID was used to systematically search the MEDLINE and EMBASE databases for systematic reviews and primary literature. A systematic review and practice guideline was written, reviewed and approved by the Guideline Development Group (GDG) and Program in Evidence-Based Care Report Approval Panel. External review by three prostate experts was completed, as well as an online consultation with healthcare professionals who were intended users of the guideline.

RESULTS

Three systematic reviews and seven primary studies were included in the evidence base. All identified literature reported on diagnostic imaging properties of diagnostic tests following biochemical recurrence.

CONCLUSIONS

Due to a lack of empirical research, few evidenced-based recommendations could be made with respect to a follow-up schedule of PSA testing for prostate cancer survivors following curative-intent treatment, or detailing diagnostic testing upon detection of biochemical recurrence. Accordingly, the GDG focused substantial effort on critical examination of the identified evidence, existing clinical practice guidelines and on obtaining clinical expertise consensus using a modified Delphi method. Overall, the recommendations embedded in this guideline reflect the best practice to date for the efficient and effective clinical follow-up care of prostate cancer survivors.

In vitro and in vivo investigation for optimization of niosomal ability for sustainment and bioavailability enhancement of diltiazem after nasal administration

Diltiazem hydrochloride (DTZ) is a calcium channel antagonist depicted by extensive first pass metabolism and low oral bioavailability. The aim of this work was to develop niosomes for potential nasal delivery of DTZ. Niosomes protect hydrophilic drugs inside their core while nasal route offers both rapid onset and evasion of first-pass metabolism. Niosomes were prepared using a combination of Span 60 or Brij-52 with cholesterol (CHOL) in different molar ratios followed by determination of entrapment efficiency, particle size and in vitro drug release. A parallel design was adopted to evaluate the pharmacokinetic performance of DTZ-loaded niosomes in male Wistar rats. Non-compartmental analysis was performed where C_max, T_max, t_1/2, MRT, area under the release curve (AUC) and K_e were assessed. The prepared niosomes were spherical with mean particle size 0.82-1.59 μm. Span 60-cholesterol niosomes (1:1 molar ratio) showed the highest entrapment and release efficiencies. In vivo study revealed an increase in MRT, t_1/2 and AUC with a decrease in K_e. In conclusion, nasal niosomal formulation of DTZ expressed suitable pharmacokinetic parameters and bioavailability through prolonged duration of action inside the body as well as low rate of elimination depicting a promising alternate to the conventional oral route.

Adjuvant sunitinib following chemoradiotherapy and surgery for locally advanced esophageal cancer: a phase II trial

The prognosis for locally advanced esophageal cancer is poor despite the use of trimodality therapy. In this phase II study, we report the feasibility, tolerability and efficacy of adjuvant sunitinib. Included were patients with stage IIa, IIB or III cancer of the thoracic esophagus or gastroesophageal junction. Neoadjuvant therapy involved Irinotecan (65 mg/m² ) + Cisplatin (30 mg/m² ) on weeks 1 and 2, 4 and 5, 7 and 8 with concurrent radiation (50Gy/25 fractions) on weeks 4-8. Sunitinib was commenced 4-13 weeks after surgery and continued for one year. Sixty-one patients were included in the final analysis, 36 patients commenced adjuvant sunitinib. Fourteen patients discontinued sunitinib due to disease recurrence (39%) within the 12-month period, 12 (33%) discontinued due to toxicity, and 3 (8%) requested cessation of therapy. In the overall population, median survival was 26 months with a 2 and 3-year survival rate of 52% and 35%, respectively. The median survival for the 36 patients treated with sunitinib was 35 months and 2-year survival probability of 68%. In a historical control, a prior phase II study with the same trimodality therapy (n = 43), median survival was 36 months, with a 2-year survival of 67%. Initiation of adjuvant sunitinib is feasible, but poorly tolerated, with no signal of additional benefit over trimodality therapy for locally advanced esophageal cancer.

Analysis of β-Subunit-dependent GABAA Receptor Modulation and Behavioral Effects of Valerenic Acid Derivatives

Valerenic acid (VA)-a β2/3-selective GABA type A (GABAA) receptor modulator-displays anxiolytic and anticonvulsive effects in mice devoid of sedation, making VA an interesting drug candidate. Here we analyzed β-subunit-dependent enhancement of GABA-induced chloride currents (IGABA) by a library of VA derivatives and studied their effects on pentylenetetrazole (PTZ)-induced seizure threshold and locomotion. Compound-induced IGABA enhancement was determined in oocytes expressing α1β1γ2S, α1β2γ2S, or α1β3γ2S receptors. Effects on seizure threshold and locomotion were studied using C57BL/6N mice and compared with saline-treated controls. β2/3-selective VA derivatives such as VA-amide (VA-A) modulating α1β3γ2S (VA-A: Emax = 972 ± 69%, n = 6, P < 0.05) and α1β2γ2S receptors (Emax = 1119 ± 72%, n = 6, P < 0.05) more efficaciously than VA (α1β3γ2S: VA: Emax = 632 ± 88%, n = 9 versus α1β2γ2S: VA: Emax = 721 ± 68%, n = 6) displayed significantly more pronounced seizure threshold elevation than VA (saline control: 40.4 ± 1.4 mg/kg PTZ versus VA 10 mg/kg: 49.0 ± 1.8 mg/kg PTZ versus VA-A 3 mg/kg: 57.9 ± 1.9 mg/kg PTZ, P < 0.05). Similarly, VA's methylamide (VA-MA) enhancing IGABA through β3-containing receptors more efficaciously than VA (Emax = 1043 ± 57%, P < 0.01, n = 6) displayed stronger anticonvulsive effects. Increased potency of IGABA enhancement and anticonvulsive effects at lower doses compared with VA were observed for VA-tetrazole (α1β3γ2S: VA-TET: EC50 = 6.0 ± 1.0 μM, P < 0.05; VA-TET: 0.3 mg/kg: 47.3 ± 0.5 mg/kg PTZ versus VA: 10 mg/kg: 49.0 ± 1.8 mg/kg PTZ, P < 0.05). At higher doses (≥10 mg/kg), VA-A, VA-MA, and VA-TET reduced locomotion. In contrast, unselective VA derivatives induced anticonvulsive effects only at high doses (30 mg/kg) or did not display any behavioral effects. Our data indicate that the β2/3-selective compounds VA-A, VA-MA, and VA-TET induce anticonvulsive effects at low doses (≤10 mg/kg), whereas impairment of locomotion was observed at doses ≥10 mg/kg.

Incidence of contrast-induced nephropathy in kidney transplant recipients

Contrast-induced nephropathy (CIN) is responsible for one-third of acute kidney injuries (AKI) in the hospital setting. The incidence of CIN varies from 3% to 30%, depending on the preexisting risk factors, with higher incidence noted with diabetes mellitus, chronic kidney disease, and older age. Though CIN risk factors are common in kidney transplant recipients (KTRs), data about incidence of CIN in this population are sparse.

METHODS

We retrospectively analyzed 124 consecutive patients transplanted at our center between January 2002 and December 2013 and received iodinated intravascular contrast with stable kidney function prior to contrast administration. CIN was defined as either an absolute rise in serum creatinine of ≥ 0.5 mg/dL or a ≥ 25% drop in estimated glomerular filtration rate (eGFR) after contrast administration.

RESULTS

Seven of 124 (5.64%) patients developed CIN. Kidney function returned to baseline in 5 of the 7 patients within 3 weeks. In 2 patients serum creatinine remained elevated due to recurrent AKI episodes from other causes. Dialysis was not required in any patient. Calcineurin inhibitors (CNIs) were being used in 95% patients at the time of contrast administration. Diabetes mellitus, baseline serum creatinine, age, race, gender, and the use of ACE inhibitor, angiotensin receptor blocker, diuretic, or prophylaxis with intravenous hydration ± N-acetylcysteine did not affect the incidence of CIN.

CONCLUSION

Incidence of CIN in KTRs was low in our study (5.6%), much less than previously reported. This low incidence may be related to the high baseline eGFR (>70 mL/min/1.73 m(2)) and use of hypo-osmolar contrast in our patients. In KTRs with baseline eGFR >70 mL/min, the incidence of CIN is low despite the concurrent use of nephrotoxic CNI.

First case report of acute hemorrhagic leukoencephalitis following Plasmodium vivax infection

Acute hemorrhagic leukoencephalitis (AHLE, Hurst's disease) is a rare hyperacute variant of acute disseminated encephalomyelitis (ADEM) characterized by severe, rapidly progressive clinical illness and hemorrhagic necrosis of white matter. Like ADEM, it is often preceded by viral illness or vaccination. Plasmodium vivax infection is usually uncomplicated and non-fatal with only a handful of reports of central nervous system complications. In this article, we report a previously unknown association between AHLE and P. vivax infection.

Amantadine: the journey from fighting flu to treating Parkinson disease

OBJECTIVE

To explore how amantadine transitioned from an anti-flu drug to antiparkinsonian agent.

METHODS

A review of the historical literature on the use of amantadine from 1966 to the present was performed.

RESULTS

Amantadine was originally introduced and utilized as an antiviral medication. A single patient noticed relief in her Parkinson disease (PD) symptoms after taking amantadine for a flu infection, and this observation sparked an interest, and several important studies that eventually led to a new drug indication.

CONCLUSION

Amantadine has over the years fallen out of favor as a drug to address influenza infection; however, it has become part of the arsenal utilized for early symptomatic treatment of PD, as well an option for treating dyskinesia.

Characterization and role of NUMB in the human extravillous trophopblast

NUMB is a multifunctional protein involved in asymmetric cell differentiation, proliferation and maintenance. Four mammalian NUMB isoforms have been identified, which utilize the phosphotyrosine binding (PTB) domain and the proline rich region (PRR) domain to regulate cell growth and differentiation in the developing nervous system. The observation that a decrease in spongiotrophoblast number and thickness of placentae of null (Numb(-/-)) mouse embryos, which died at E10.5, suggests NUMB may play a role in placental development. In this study, we demonstrated for the first time, that NUMB isoforms 1, 2, 3, and 4 are present in the human placenta and the human extravillous trophoblast (EVT) cell line HTR8/SVneo. We report three novel isoforms, NUMB 7, 8, and 9, identified by cloning of RT-PCR products and sequencing. Corresponding sequences of novel isoforms were submitted to genebank (accession numbers for each new isoform: NUMB 7- EU265736, NUMB 8- EU265737 and NUMB 9-EU265738). Western blot analysis confirmed the presence of all NUMB isofoms in human placental samples in all trimesters and in EVT cells. NUMB immunosignals were extensively localized in human extravillous trophoblasts and decidual cells at the maternal-fetal interface. NUMB 8 appeared to be the predominant isoform in placental villi. Furthermore, cell migration studies revealed NUMB isoform 1 to be involved in EVT cell migration and NUMB isoforms 2 and 4 to induce EVT apoptosis.

Transmission electron microscopy at 20 kV for imaging and spectroscopy

The electron optical performance of a transmission electron microscope (TEM) is characterized for direct spatial imaging and spectroscopy using electrons with energies as low as 20 keV. The highly stable instrument is equipped with an electrostatic monochromator and a C(S)-corrector. At 20 kV it shows high image contrast even for single-layer graphene with a lattice transfer of 213 pm (tilted illumination). For 4 nm thick Si, the 200 reflections (271.5 pm) were directly transferred (axial illumination). We show at 20 kV that radiation-sensitive fullerenes (C(60)) within a carbon nanotube container withstand an about two orders of magnitude higher electron dose than at 80 kV. In spectroscopy mode, the monochromated low-energy electron beam enables the acquisition of EELS spectra up to very high energy losses with exceptionally low background noise. Using Si and Ge, we show that 20 kV TEM allows the determination of dielectric properties and narrow band gaps, which were not accessible by TEM so far. These very first results demonstrate that low kV TEM is an exciting new tool for determination of structural and electronic properties of different types of nano-materials.

In vitro characterization and release study of Ambroxol hydrochloride matrix tablets prepared by direct compression

A series of either hydrophilic or hydrophobic polymers were used to prepare controlled release Ambroxol hydrochloride (AMX) matrix tablets by direct compression. Both the compatibility and flow properties of AMX/polymer mixtures were investigated. The effect of the amount and type of polymer on the physical properties and in vitro drug release was studied and compared to commercially available Ambroxol(®) SR capsules. A kinetic study of the release profile of AMX from the prepared matrix tablets was performed. All excipients used in the study were compatible with the model drug. AMX/drug mixtures containing sodium alginate (NA) and hydroxypropylmethyl cellulose (HPMC) showed better flow properties than other polymers used in the study. The in vitro drug release studies showed that matrix tablets formulae containing 10% HPMC (S7) or a combination of 30% NA and 5% HPMC (Ah) exhibited a higher ability to control the release of AMX. The kinetic study revealed that a diffusion controlled mechanism prevailed except when carbopol was used. Formula Ah followed a non-fickian diffusion mechanism similar to Ambroxol(®) SR capsules. Both formulae S7 and Ah could be considered as potential candidates for formulation of AMX controlled release matrix tablets.

Polyimide Copolymers Containing Various Levels Of The 6F Moiety For High Temperature And Microelectronic Applications

Trifluoromethyl group-containing polyimides not only show extraordinary electrical properties, but they also exhibit excellent long-term thermo-oxidative stability. Among the most thermomechanically stable structural polyimides are those from 6F dianhydride (6FDA) and 6F diamines. The effects of substituting non-fluorine containing monomers such as BTDA, mPDA and 4,4′-DADPS for the hexafluoroisopropylidene monomers on the dielectric, thermo-oxidative, thermal and mechanical properties of the copolymers were studied.

Information transfer in a TEM corrected for spherical and chromatic aberration

For the transmission electron aberration-corrected microscope (TEAM) initiative of five U.S. Department of Energy laboratories in the United States, a correction system for the simultaneous compensation of the primary axial aberrations, the spherical aberration Cs, and the chromatic aberration Cc has been developed and successfully installed. The performance of the resulting Cc /Cs-corrected TEAM instrument has been investigated thoroughly. A significant improvement of the linear contrast transfer can be demonstrated. The information about the instrument one obtains using Young's fringe method is compared for uncorrected, Cs-corrected, and Cc /Cs-corrected instruments. The experimental results agree well with simulations. The conclusions might be useful to others in understanding the process of image formation in a Cc /Cs-corrected transmission electron microscope.

Novel homozygous mutation in DSP causing skin fragility-woolly hair syndrome: report of a large family and review of the desmoplakin-related phenotypes

Desmoplakin is an important cytoskeletal linker for the function of the desmosomes. Linking desmoplakin to certain types of cardiocutaneous syndromes has been a hot topic recently. Skin fragility-woolly hair syndrome is a rare autosomal recessive disorder involving the desmosomes and is caused by mutation in the desmoplakin gene (DSP). We report five members from a large family with skin fragility-woolly hair syndrome. The index is a 14-year-old girl with palmoplantar keratoderma, woolly hair, variable alopecia, dystrophic nails, and excessive blistering to trivial mechanical trauma. No cardiac symptoms were reported. Although formal cardiac examination was not feasible, the echocardiographic evaluation of the other two affected younger siblings was normal. Homozygosity mapping and linkage analysis revealed a high LOD score region in the short arm of chromosome 6 that harbors the DSP. Full sequencing of the DSP showed a novel homozygous c.7097 G>A (p.R2366H) mutation in all affected members, and the parents were heterozygous. This is the report of the third case/family of the skin fragility-woolly hair syndrome in the literature. We also present a clinical and molecular review of various desmoplakin-related phenotypes, with emphasis on onset of cardiomyopathy. The complexity of the desmoplakin and its variable presentations warrant introducing the term 'desmoplakinopathies' to describe all the phenotypes related to defects in the desmoplakin.

Current and future aberration correctors for the improvement of resolution in electron microscopy

The achievable resolution of a modern transmission electron microscope (TEM) is mainly limited by the inherent aberrations of the objective lens. Hence, one major goal over the past decade has been the development of aberration correctors to compensate the spherical aberration. Such a correction system is now available and it is possible to improve the resolution with this corrector. When high resolution in a TEM is required, one important parameter, the field of view, also has to be considered. In addition, especially for the large cameras now available, the compensation of off-axial aberrations is also an important task. A correction system to compensate the spherical aberration and the off-axial coma is under development. The next step to follow towards ultra-high resolution will be a correction system to compensate the chromatic aberration. With such a correction system, a new area will be opened for applications for which the chromatic aberration defines the achievable resolution, even if the spherical aberration is corrected. This is the case, for example, for low-voltage electron microscopy (EM) for the investigation of beam-sensitive materials, for dynamic EM or for in-situ EM.

Detection of single atoms and buried defects in three dimensions by aberration-corrected electron microscope with 0.5-A information limit

The ability of electron microscopes to analyze all the atoms in individual nanostructures is limited by lens aberrations. However, recent advances in aberration-correcting electron optics have led to greatly enhanced instrument performance and new techniques of electron microscopy. The development of an ultrastable electron microscope with aberration-correcting optics and a monochromated high-brightness source has significantly improved instrument resolution and contrast. In the present work, we report information transfer beyond 50 pm and show images of single gold atoms with a signal-to-noise ratio as large as 10. The instrument's new capabilities were exploited to detect a buried Sigma3 {112} grain boundary and observe the dynamic arrangements of single atoms and atom pairs with sub-angstrom resolution. These results mark an important step toward meeting the challenge of determining the three-dimensional atomic-scale structure of nanomaterials.