Core-shell inversion by pH modulation in dynamic covalent micelles

Dynamic covalent surfactants have been obtained by the reversible condensation of a hydrophobic aldehyde (ended by an ionic tip) with various neutral polyethylene glycol based hydrophilic amines. In water, the duality between the two hydrophilic domains (charged and neutral) leads to their segregation when the surfactants are self-assembled within micelles. Depending on the number of polyethylene glycol units, a core-shell inversion leading to a switching orientation of the ionic tips from the inside to the outside of the micelles has been demonstrated by a combination of scattering techniques. In competition experiments, when several amines of different pKas and hydrophilic polyethylene glycol chains are competing for the same aldehyde, it becomes possible to trigger this core-shell inversion by pH modulation and associated dynamic constitutional reorganization.

Quantifying spillover spreading for comparing instrument performance and aiding in multicolor panel design

After compensation, the measurement errors arising from multiple fluorescences spilling into each detector become evident by the spreading of nominally negative distributions. Depending on the instrument configuration and performance, and reagents used, this "spillover spreading" (SS) affects sensitivity in any given parameter. The degree of SS had been predicted theoretically to increase with measurement error, i.e., by the square root of fluorescence intensity, as well as directly related to the spectral overlap matrix coefficients. We devised a metric to quantify SS between any pair of detectors. This metric is intrinsic, as it is independent of fluorescence intensity. The combination of all such values for one instrument can be represented as a spillover spreading matrix (SSM). Single-stained controls were used to determine the SSM on multiple instruments over time, and under various conditions of signal quality. SSM values reveal fluorescence spectrum interactions that can limit the sensitivity of a reagent in the presence of brightly-stained cells on a different color. The SSM was found to be highly reproducible; its non-trivial values show a CV of less than 30% across a 2-month time frame. In addition, the SSM is comparable between similarly-configured instruments; instrument-specific differences in the SSM reveal underperforming detectors. Quantifying and monitoring the SSM can be a useful tool in instrument quality control to ensure consistent sensitivity and performance. In addition, the SSM is a key element for predicting the performance of multicolor immunofluorescence panels, which will aid in the optimization and development of new panels. We propose that the SSM is a critical component of QA/QC in evaluation of flow cytometer performance.

Cardiac characterization of 16 patients with large NF1 gene deletions

The aim of this study was to characterize cardiac features of patients with neurofibromatosis 1 (NF1) and large deletions of the NF1 gene region. The study participants were 16 patients with large NF1 deletions and 16 age- and sex-matched NF1 patients without such deletions. All the patients were comprehensively characterized clinically and by echocardiography. Six of 16 NF1 deletion patients but none of 16 non-deletion NF1 patients have major cardiac abnormalities (p = 0.041). Congenital heart defects (CHDs) include mitral insufficiency in two patients and ventricular septal defect, aortic stenosis, and aortic insufficiency in one patient each. Three deletion patients have hypertrophic cardiomyopathy. Two patients have intracardiac tumors. NF1 patients without large deletions have increased left ventricular (LV) diastolic posterior wall thickness (p < 0.001) and increased intraventricular diastolic septal thickness (p = 0.001) compared with a healthy reference population without NF1, suggestive of eccentric LV hypertrophy. CHDs and other cardiovascular anomalies are more frequent among patients with large NF1 deletion and may cause serious clinical complications. Eccentric LV hypertrophy may occur in NF1 patients without whole gene deletions, but the clinical significance of this finding is uncertain. All patients with clinical suspicion for NF1 should be referred to a cardiologist for evaluation and surveillance.

Amine-reactive dyes for dead cell discrimination in fixed samples

Amine-reactive dyes, also known as LIVE/DEAD fixable dead cell stains, are a class of viability dyes suitable for identifying dead cells in samples that will be fixed. These dyes cross the cell membranes of dead cells, and react with free amines in the cytoplasm. Live cells exclude these dyes because their cell membranes are intact, and free dye is washed away after staining. Notably, the reaction is irreversible; therefore, when cells are fixed and permeabilized (as with intracellular staining procedures), the bound dye remains associated with the dead cells (unlike other viability dyes). Since amine-reactive dyes are fluorescent when excited by lasers, dead cells can be identified by flow cytometry. This unit describes procedures, troubleshooting, and outcomes for using the two most commonly used amine-reactive dyes, ViViD and Aqua Blue.

Neuro-kardio-fazio-kutane Syndrome

Neuro-kardio-fazio-kutane („neuro-cardio-facio-cutaneous“: NCFC) Syndrome wurden in den letzten Jahren als eine Gruppe von angeborenen Erkrankungen definiert, deren phänotypische Überschneidungen eine gemeinsame pathogenetische Grundlage haben. Erkrankungen aus diesem phänotypischen Spektrum gehen mit einer Überfunktion des RAS-MAPK-Signalwegs (RAS: „rat sarcoma“, MAPK mitogenaktivierte Proteinkinase) einher. Zu den neuro-kardio-fazio-kutanen Erkrankungen gehören das Noonan-, das LEOPARD-, das kardio-fazio-kutane („cardio-facio-cutaneous“: CFC) und das Costello-Syndrom, die Neurofibromatose Typ 1 sowie das Legius-Syndrom. Für eine sachgerechte medizinische Diagnostik und Behandlung sowie die notwendige psychosoziale Betreuung von Betroffenen und deren Familien ist das Zusammenwirken verschiedener Fachdisziplinen notwendig.

Comparison of laboratory colonies and field populations of Tamarixia radiata, an ectoparasitoid of the Asian citrus psyllid, using internal transcribed spacer and cytochrome oxidase subunit I DNA sequences

The genetic diversity of Tamarixia radiata Waterston (Hymenoptera: Eulophidae) laboratory colonies derived from collections in China, northern Vietnam, Pakistan, and a mixed colony from Taiwan and southern Vietnam was evaluated using the internal transcribed spacer (ITS) region 1, ITS-2, and the 5' end of the cytochrome oxidase subunit I gene. The strains share the same ITS sequence, consistent with the morphological hypothesis that the collections represent a single species. The COI marker was variable and could distinguish the northern Vietnam and Pakistan colonies from each other and from the other colonies. Comparison of COI sequences from field-collected populations of Puerto Rico, Guadeloupe, and Texas indicates that Florida is not a likely source of the introduction into Puerto Rico but is a likely source of the introduction into Texas.

Quality assurance for polychromatic flow cytometry

This protocol outlines a three-part quality assurance program to optimize, calibrate and monitor flow cytometers used to measure cells labeled with five or more fluorochromes (a practice known as polychromatic flow cytometry). The initial steps of this program (system optimization) ensure that the instrument's lasers, mirrors and filters are optimally configured for the generation and transmission of multiple fluorescent signals. To determine the sensitivity and dynamic range of each fluorescence detector, the system is then calibrated by measuring fluorescence over a range of photomultiplier tube (PMT) voltages by determining the PMT voltage range and linearity (Steps 2-10) and validating the PMT voltage (Steps 11-17). Finally, to ensure consistent performance, we provide procedures to monitor the precision, accuracy and sensitivity of fluorescence measurements over time. All three aspects of this program should be performed upon installation, or whenever changes occur along the flow cytometer's optical path. However, only a few of these procedures need to be carried out on a routine basis.

Amine reactive dyes: An effective tool to discriminate live and dead cells in polychromatic flow cytometry

Membrane-damaged cells caused by either mechanical trauma or through normal biological processes can produce artifacts in immunophenotyping analysis by flow cytometry. Dead cells can nonspecifically bind monoclonal antibody conjugates, potentially leading to erroneous conclusions, particularly when cell frequencies are low. To date, DNA intercalating dyes (Ethidium monoazaide (EMA), Propidium Iodide, 7AAD, etc.) or Annexin V have been commonly used to exclude dead cells; however, each suffer from technical problems. The first issue with such dyes is the dependence on a consistent dead cell source for fluorescence compensation. Another major issue is the stability of the staining; except for EMA, fixation and permeablization used for intracellular staining procedures can cause loss of fluorescence. EMA requires a UV exposure to covalently bond to DNA; while this dye is effective and is not affected by intracellular treatments it is weakly fluorescent. Here we report on the optimization of a new class of viability dyes, the amine reactive viability dyes (ViD) as a dead cell exclusion marker. The inclusion of ViD into the staining panel was found to be simple, reproducible and can have a significant benefit on the accuracy of identifying appropriate cell populations. We show the fluorescence of cells stained with these dyes correlates with traditional dead cell discriminating markers, even after fixation and permeabilization. Amine reactive viability dyes are a powerful tool for fluorescence immunophenotyping experiments.

Photodynamic therapy with topical methyl aminolaevulinate for 'difficult-to-treat' basal cell carcinoma

BACKGROUND

Basal cell carcinoma (BCC) may be difficult to treat by conventional means, particularly if the lesions are large or located in the mid-face (H-zone). Photodynamic therapy (PDT) using topical methyl aminolaevulinate (MAL) may be a good noninvasive option for these patients.

OBJECTIVES

To investigate the efficacy and safety of PDT using MAL for BCCs defined as 'difficult to treat', i.e. large lesions, in the H-zone, or in patients at high risk of surgical complications.

METHODS

This was a prospective, multicentre, noncomparative study. Patients were assessed 3, 12 and 24 months after the last PDT treatment. One hundred and two patients with 'difficult-to-treat' BCC were treated with MAL PDT, using 160 mg g(-1) cream and 75 J cm(-2) red light (570-670 nm), after lesion preparation and 3 h of cream exposure. Results Ninety-five patients with 148 lesions were included in the per protocol analysis. The histologically confirmed lesion complete response rate at 3 months was 89% (131 of 148). At 12 months, 10 lesions had reappeared, and therefore the cumulative treatment failure rate was 18% (27 of 148). At 24 months, an additional nine lesions had reappeared, resulting in a cumulative treatment failure rate of 24% (36 of 148). The estimated sustained lesion complete response rate (assessed using a time-to-event approach) was 90% at 3 months, 84% at 12 months and 78% at 24 months. Overall cosmetic outcome was judged as excellent or good in 79% and 84% of the patients at 12 and 24 months, respectively. Follow-up is continuing for up to 5 years.

CONCLUSIONS

MAL PDT is an attractive option for 'difficult-to-treat' BCC. Because of the excellent cosmetic results, the treatment is particularly well suited for lesions that would otherwise require extensive surgical procedures.

[Dacryolithiasis: diagnosis using nasal endoscopy]

PURPOSE

The purpose of this study was to assess the value of two new clinical findings for the diagnosis of dacryolithiasis discovered with nasal endoscopy: anatomical abnormalities of the Hasner valve (HV) and mucopurulent discharge visible at this valve. The value of these findings is compared with other clinical and radiological signs of dacryolithiasis. A hypothesis is developed as to the responsibility of the HV in the formation of dacryolithiasis.

METHOD

This study was prospective and based on 797 operations performed for epiphora: 647 endonasal dacryocystorhinostomies and 150 meatotomies of the HV, with systematic preoperative nasal videoendoscopy. Ninety dacryocystographies (DCGs) and 129 lacrimal computed tomographies (LCT) were preoperatively performed.

RESULTS

Dacryoliths were found in 55 of 797 patients (6.9%). The HV could be examined in 48 patients in the lithiasis group and in 687 patients in the control group. Mucopurulent discharge was observed in 22 patients with lithiasis (45.8%) and in 40 patients (5.8%) (p<10(-6)) of the control group. Anatomical abnormalities of the HV were found in 40 patients with dacryolithiasis (83.3%) as compared to 82 patients ing the control group (11.4%) (p<10(-6)). In 13 patients, the VH was very small (<2 mm), in 12 patients it was very long (>15 mm), and in 15 patients both abnormalities were observed. Other clinical signs were young age (mean, 48.2 years vs 59.1% in the control group) (p<0.05), a history of acute noninfectious dacryocystic retention (38.2% vs 9.5%) (p<10(-5)), partial obstruction of the lacrimal pathway (LP) (61.8% vs 30.5%) (p<10(-5)). The 28 LCTs that were performed in subjects who had lithiasis made it possible to diagnose 19 cases of dacryolithiasis and confirmed abnormalities of the HV causing narrowing of the LP in 20.

CONCLUSION

Dacryolithiasis is frequent and often misdiagnosed. When dacryolithiasis is suspected, a nasal videoendoscopic exam must be done to seek HV abnormalities and mucopurulent discharge at this valve. This latter finding, i.e., the association of mucopurulent discharge with a patent lacrimal system, has high specificity. The finding of numerous anatomical abnormalities of the HV may be an indication that congenital malformation of the HV is the cause of many cases of lithiasis.

A comparison of photodynamic therapy using topical methyl aminolevulinate (Metvix) with single cycle cryotherapy in patients with actinic keratosis: a prospective, randomized study

BACKGROUND

Actinic keratosis (AK) is a very common condition, which has the potential of progressing to squamous cell carcinoma. The present study is a prospective, randomized study comparing the lesion response, cosmetic outcome, patient satisfaction and tolerability of a new treatment modality, photodynamic therapy (PDT), using topical methyl aminolevulinate (Metvix), with the most commonly used standard therapy for AK, cryotherapy.

METHODS

A total of 204 patients with clinically diagnosed AK were randomized to either cryotherapy or PDT. The PDT patients were further assigned to an active or placebo group in a random, double-blind manner. Cryotherapy was performed using liquid nitrogen spray in a single freeze-thaw cycle. PDT was performed using 160 mg/g methyl aminolevulinate cream or placebo, a 3-hour application time, red light (570-670 nm) and a total light dose of 75 J/cm(2). PDT was repeated after 7 days. Two sessions of PDT were undertaken, as a previous study had shown a single session had similar efficacy to cryotherapy. Lesion response was assessed clinically after 3 months (complete response or non-complete response).

RESULTS

The lesion response rate was 91% in the methyl aminolevulinate PDT group, 68% in the cryotherapy group and 30% in the placebo PDT group. Methyl aminolevulinate PDT was statistically significantly better than both cryotherapy and placebo PDT in terms of response rates and cosmetic outcome. Most patients preferred PDT to other treatments.

CONCLUSIONS

PDT with methyl aminolevulinate is an excellent treatment option, particularly for patients with widespread damage or AK lesions in cosmetically sensitive areas.

Impaired adaptive resynthesis and prolonged depletion of hepatic mitochondrial DNA after repeated alcohol binges in mice

BACKGROUND & AIMS

A single dose of alcohol causes transient hepatic mitochondrial DNA (mtDNA) depletion in mice followed by increased mtDNA synthesis and an overshoot of mtDNA levels. We determined the effect of repeated alcohol binges on hepatic mtDNA in mice.

METHODS

Ethanol (5 g/kg) was administered by gastric intubation daily for 4 days, and mtDNA levels, synthesis, and integrity were assessed by slot blot hybridization, in organello [3H]deoxythymidine triphosphate incorporation, and long polymerase chain reaction analysis, respectively.

RESULTS

mtDNA levels were decreased for 48 hours after the last dose, with no overshoot phenomenon later on. Two and 24 hours after the fourth dose, long polymerase chain reaction experiments showed DNA lesions that blocked the progress of the polymerases and in organello mtDNA synthesis was decreased, although DNA polymerase gamma activity was unchanged with synthetic templates. Mitochondria exhibited ultrastructural abnormalities, and respiration was impaired 2 and 24 hours after the fourth binge. Cytochrome P450 2E1, mitochondrial generation of peroxides, thiobarbituric acid reactants, and ethane exhalation were increased.

CONCLUSIONS

After repeated doses of ethanol, the accumulation of unrepaired mtDNA lesions (possibly involving lipid peroxidation-induced adducts) blocks the progress of polymerase gamma on mtDNA and prevents adaptive mtDNA resynthesis, causing prolonged hepatic mtDNA depletion.

Quantification of sodium dodecyl sulfate in microliter-volume biochemical samples by visible light spectroscopy

A method for sodium dodecyl sulfate (SDS) quantitation in microliter-volume complex biochemical samples is described. The quantitation is based on the use of a dye, stains-all, the color of which changes from intense fuchsia to yellow upon addition of SDS. We show that this color change is gradual and proportional to the amount of SDS added to the stains-all solution, thus allowing its use to reliably quantitate SDS in biochemical samples by means of a visible light spectrophotometer. A large number of compounds widely used in biochemistry are herein shown not to interfere with the SDS measurement when they are present in the sample at usual biochemical concentrations. Furthermore, linearity between the color change and the amount of SDS present in the sample is never impaired when huge amounts of these compounds are also present, thus making this quantitation method highly reliable with use of a calibration curve. The method allows easy and reliable quantitation of microgram amounts of SDS in microliter-volume biochemical samples.

Controlling electrophoretic trapping of circular DNA by addition of starch preparations to agarose gels

Starch preparations were added to agarose gels to enhance the electrophoretic trapping of circular plasmid DNA. The critical voltages required to trap the open circular (OC) and the supercoiled (SC) forms of a 13.1-kbp plasmid were measured in gels composed of agarose and added starch preparations. Modified starch preparations reduced the critical voltage required to trap the OC form of the plasmid to approximately one-third of the control value (in 1% agarose gels). Amylose (a fraction of starch with a low amount of branching) also reduced the critical voltage to trap the OC form in a similar manner. The critical voltage to trap the SC form of the plasmid was not significantly reduced by the starch preparations. The capacity to trap OC DNA was increased by the addition of higher amounts of the starch preparations added to the gels. Field inversion gel etectrophoresis was used to characterize the length of the traps in the gels. The starch preparations and amylose increased the trap lengths approximately twofold. The increased trap length correlated with the decreased critical voltage required to trap the OC form of the 13.1-kbp plasmid.