Diploid species phylogeny and evolutionary reticulation indicate early radiation of Ephedra in the Tethys coast

Reconstructing a robust species phylogeny and disentangling the evolutionary and biogeographic history of the gymnosperm genus Ephedra, which has a large genome and rich polyploids, remain a big challenge. Here we reconstructed a transcriptome-based phylogeny of 19 diploid Ephedra species, and explored evolutionary reticulations in this genus represented by 50 diploid and polyploid species, using four low-copy nuclear and nine plastid genes. The diploid species phylogeny indicates that the Mediterranean species diverged first, and the remaining species split into three clades, including the American species (Clade A), E. rhytidosperma, and all other Asian species (Clade B). The single-gene trees placed E. rhytidosperma sister to Clade A, Clade B, or Clades A + B in similar proportions, suggesting that radiation and gene flow likely occurred in the early evolution of Ephedra. In addition, reticulate evolution occurred not only among the deep nodes, but also in the recently evolved South American species, which further caused difficulty in phylogenetic reconstruction. Moreover, we found that allopolyploid speciation was pervasive in Ephedra. Our study also suggests that Ephedra very likely originated in the Tethys coast during the late Cretaceous, and the South American Ephedra species have a single origin by dispersal from Mexico or North America.

Development of the first PCR for detection of Psoroptes ovis var. cuniculi infection and its comparison to microscopic examination and serological assay in rabbits

Psoroptes mites are the common ecto-parasites of wild and domestic animals worldwide, which causes considerable economic losses in livestock industry. Microscopy is deemed to be the 'gold standard' for the diagnosis of Psoroptes mite infection but it has poor sensitivity for low mite infections and/or sub-clinical infections. To overcome these shortcomings, we screened four genes to develop a sensitive and specific PCR for the detection of Psoroptes mite infection in rabbits, and confirmed its practicability in detecting early infection and monitoring treatment outcome with traditional microscopy and serological tests. Results showed that PCR assay targeting ITS2 (ITS2-PCR) had a high specificity and sensitivity (detection limit: 40.3 pg/μL DNA) for detecting P. ovis DNA. In rabbits artificially infected with P. ovis, all three diagnostic tests showed the same detection rate from 14 days post infection (dpi) to 42 days dpi. However, these diagnostic tests behave differently at 7 dpi and after treatment: at 7 dpi, the detection rate of ITS2-PCR was higher than rPsoSP3-based iELISA and traditional microscopy (ITS2-PCR: 88.9%, rPsoSP3-iELISA: 77.7%, microscopy: 33.3%); at 7 days post treatment (dpt), positivity rates of ITS2-PCR and microscopy rapidly decreased to 0.00% and 11.1%, whereas rPsoSP3-iELISA remained 100% positive rate. Furthermore, the comprehensive comparisons of diagnostic performance and features of three diagnostic tests at 7 dpi were performed. Compared to ITS2-PCR or rPsoSP3-iELISA, microscopy had the lowest sensitivity, and the agreement between these assays was low (κ < 0.3). Field study showed that ITS2-PCR showed a higher detection rate than microscopy (19.4% and 11.1%, respectively). Our results suggested that the ITS2-PCR developed in this study provided a new laboratory tool for diagnosis of P. ovis var. cuniculi infection, and it had advantages over microscopic examination in detection low-level mite infections and serological assay in monitoring treatment outcome.

Gapless genome assembly of azalea and multi-omics investigation into divergence between two species with distinct flower color

The genus Rhododendron (Ericaceae), with more than 1000 species highly diverse in flower color, is providing distinct ornamental values and a model system for flower color studies. Here, we investigated the divergence between two parental species with different flower color widely used for azalea breeding. Gapless genome assembly was generated for the yellow-flowered azalea, Rhododendron molle. Comparative genomics found recent proliferation of long terminal repeat retrotransposons (LTR-RTs), especially Gypsy, has resulted in a 125 Mb (19%) genome size increase in species-specific regions, and a significant amount of dispersed gene duplicates (13 402) and pseudogenes (17 437). Metabolomic assessment revealed that yellow flower coloration is attributed to the dynamic changes of carotenoids/flavonols biosynthesis and chlorophyll degradation. Time-ordered gene co-expression networks (TO-GCNs) and the comparison confirmed the metabolome and uncovered the specific gene regulatory changes underpinning the distinct flower pigmentation. B3 and ERF TFs were found dominating the gene regulation of carotenoids/flavonols characterized pigmentation in R. molle, while WRKY, ERF, WD40, C2H2, and NAC TFs collectively regulated the anthocyanins characterized pigmentation in the red-flowered R simsii. This study employed a multi-omics strategy in disentangling the complex divergence between two important azaleas and provided references for further functional genetics and molecular breeding.

Potential allopolyploid origin of Ericales revealed with gene-tree reconciliation

Few incidents of ancient allopolyploidization (polyploidization by hybridization or merging diverged genomes) were previously revealed, although there is significant evidence for the accumulation of whole genome duplications (WGD) in plants. Here, we focused on Ericales, one of the largest and most diverse angiosperm orders with significant ornamental and economic value. Through integrating 24 high-quality whole genome data selected from ~ 200 Superasterids genomes/species and an algorithm of topology-based gene-tree reconciliation, we explored the evolutionary history of in Ericales with ancient complex. We unraveled the allopolyploid origin of Ericales and detected extensive lineage-specific gene loss following the polyploidization. Our study provided a new hypothesis regarding the origin of Ericales and revealed an instructive perspective of gene loss as a pervasive source of genetic variation and adaptive phenotypic diversity in Ericales.

Floral nectary, nectar production dynamics, and floral reproductive isolation among closely related species of Pedicularis

Floral nectar is thought to be one of the most important rewards that attract pollinators in Pedicularis; however, few studies have examined variation of nectary structure and/or nectar secretion in the genus, particularly among closely related species. Here we investigated nectary morphology, nectar quality, and nectar production dynamics in flowers of Pedicularis section Cyathophora. We found a conical floral nectary at the base of the ovary in species of the rex-thamnophila clade. Stomata were found on the surface of the nectary, and copious starch grains were detected in the nectary tissues. In contrast, a semi-annular nectary was found in flowers of the species of the superba clade. Only a few starch grains were observed in tissues of the semi-annular nectary, and the nectar sugar concentration in these flowers was much lower than that in the flowers of the rex-thamnophila clade. Our results indicate that the floral nectary has experienced considerable morphological, structural, and functional differentiation among closely related species of Pedicularis. This could have affected nectar production, leading to a shift of the pollination mode. Our results also imply that variation of the nectary morphology and nectar production may have played an important role in the speciation of sect. Cyathophora.

Molecular phylogeny of Asian Meconopsis based on nuclear ribosomal and chloroplast DNA sequence data

The taxonomy and phylogeny of Asian Meconopsis (Himalayan blue poppy) remain largely unresolved. We used the internal transcribed spacer (ITS) region of nuclear ribosomal DNA (nrDNA) and the chloroplast DNA (cpDNA) trnL-F region for phylogenetic reconstruction of Meconopsis and its close relatives Papaver, Roemeria, and Stylomecon. We identified five main clades, which were well-supported in the gene trees reconstructed with the nrDNA ITS and cpDNA trnL-F sequences. We found that 41 species of Asian Meconopsis did not constitute a monophyletic clade, but formed two solid clades (I and V) separated in the phylogenetic tree by three clades (II, III and IV) of Papaver and its allies. Clade V includes only four Asian Meconopsis species, with the remaining 90 percent of Asian species included in clade I. In this core Asian Meconopsis clade, five subclades (Ia-Ie) were recognized in the nrDNA ITS tree. Three species (Meconopsis discigera, M. pinnatifolia, and M. torquata) of subgenus Discogyne were imbedded in subclade Ia, indicating that the present definition of subgenera in Meconopsis should be rejected. These subclades are inconsistent with any series or sections of the present classifications, suggesting that classifications of the genus should be completely revised. Finally, proposals for further revision of the genus Meconopsis were put forward based on molecular, morphological, and biogeographical evidences.

Phylogeographic evidence for a link of species divergence of Ephedra in the Qinghai-Tibetan Plateau and adjacent regions to the Miocene Asian aridification

The Qinghai-Tibetan Plateau (QTP) has become one of the hotspots for phylogeographical studies due to its high species diversity. However, most previous studies have focused on the effects of the Quaternary glaciations on phylogeographical structures and the locations of glacial refugia, and little is known about the effects of the aridization of interior Asia on plant population structure and speciation. Here the chloroplast DNA (cpDNA) trnT-trnF and trnS-trnfM sequences were used to investigate the differentiation and phylogeographical history of 14 Ephedra species from the QTP and northern China, based on a sampling of 107 populations. The phylogeographical analysis, together with phylogenetic reconstruction based on combined four cpDNA fragments (rbcL, rpl16, rps4, and trnS-trnfM), supports three main lineages (eastern QTP, southern QTP, and northern China) of these Ephedra species. Divergence of each lineage could be dated to the Middle or Late Miocene, and was very likely linked to the uplift of the QTP and the Asian aridification, given the high drought and/or cold tolerance of Ephedra. Most of the Ephedra species had low intraspecific variation and lacked a strong phylogeographical structure, which could be partially attributed to clonal reproduction and a relatively recent origin. In addition, ten of the detected 25 cpDNA haplotypes are shared among species, suggesting that a wide sampling of species is helpful to investigate the origin of observed haplotypes and make reliable phylogeographical inference. Moreover, the systematic positions of some Ephedra species are discussed.

Phylogenetic relationships and generic delimitation of Eurasian Aster (Asteraceae: Astereae) inferred from ITS, ETS and trnL-F sequence data

BACKGROUND AND AIMS

The classification and phylogeny of Eurasian (EA) Aster (Asterinae, Astereae, Asteraceae) remain poorly resolved. Some taxonomists adopt a broad definition of EA Aster, whereas others favour a narrow generic concept. The present study aims to delimit EA Aster sensu stricto (s.s.), elucidate the phylogenetic relationships of EA Aster s.s. and segregate genera.

METHODS

The internal and external transcribed spacers of nuclear ribosomal DNA and the plastid DNA trnL-F region were used to reconstruct the phylogeny of EA Aster through maximum parsimony and Bayesian analyses.

KEY RESULTS

The analyses strongly support an Aster clade including the genera Sheareria, Rhynchospermum, Kalimeris (excluding Kalimeris longipetiolata), Heteropappus, Miyamayomena, Turczaninowia, Rhinactinidia, eastern Asian Doellingeria, Asterothamnus and Arctogeron. Many well-recognized species of Chinese Aster s.s. lie outside of the Aster clade.

CONCLUSIONS

The results reveal that EA Aster s.s. is both paraphyletic and polyphyletic. Sheareria, Rhynchospermum, Kalimeris (excluding K. longipetiolata), Heteropappus, Miyamayomena, Turczaninowia, Rhinactinidia, eastern Asian Doellingeria, Asterothamnus and Arctogeron should be included in Aster, whereas many species of Chinese Aster s.s. should be excluded. The recircumscribed Aster should be divided into two subgenera and nine sections. Kalimeris longipetiolata, Aster batangensis, A. ser. Albescentes, A. series Hersileoides, a two-species group composed of A. senecioides and A. fuscescens, and a six-species group including A. asteroides, should be elevated to generic level. With the Aster clade, they belong to the Australasian lineages. The generic status of Callistephus should be maintained. Whether Galatella (including Crinitina) and Tripolium should remain as genera or be merged into a single genus remains to be determined. In addition, the taxonomic status of A. auriculatus and the A. pycnophyllus-A. panduratus clade remains unresolved, and the systematic position of some segregates of EA Aster requires further study.

Great genetic differentiation among populations of Meconopsis integrifolia and its implication for plant speciation in the Qinghai-Tibetan Plateau

The complex tectonic events and climatic oscillations in the Qinghai-Tibetan Plateau (QTP), the largest and highest plateau in the world, are thought to have had great effects on the evolutionary history of the native plants. Of great interest is to investigate plant population genetic divergence in the QTP and its correlation with the geologic and climatic changes. We conducted a range-wide phylogeographical analysis of M. integrifolia based on the chloroplast DNA (cpDNA) trnL-trnF and trnfM-trnS regions, and defined 26 haplotypes that were phylogenetically divided into six clades dated to the late Tertiary. The six clades correspond, respectively, to highly differentiated population groups that do not overlap in geographic distribution, implying that the mountain ranges acting as corridors or barriers greatly affected the evolutionary history of the QTP plants. The older clade of M. integrifolia only occurs in the southwest of the species' range, whereas the distributions of younger clades extend northeastward in the eastern QTP, suggesting that climatic divergence resulting from the uplift of the QTP triggered the initial divergence of M. integrifolia native to the plateau. Also, the nrDNA ITS region was used to clarify the unexpected phylogenetic relationships of cpDNA haplotypes between M. integrifolia and M. betonicifolia. The topological incongruence between the two phylogenies suggests an ancestral hybridization between the two species. Our study indicates that geographic isolation and hybridization are two important mechanisms responsible for the population differentiation and speciation of Meconopsis, a species-rich genus with complex polyploids.

Comparative characterization of stem cells from human exfoliated deciduous teeth and dental pulp stem cells

OBJECTIVE

This study focused on the characterization of stem cells from human exfoliated deciduous teeth (SHED) in comparison with dental pulp stem cells (DPSCs) to certify SHED as a key element in tissue engineering.

METHODS

In the present study, SHED and DPSCs were assayed for their cell surface antigens and proliferation by measuring the cell cycles, growth rates, Ki67-positive efficiencies, and colony-forming units (CFUs). The evaluation of multi-differentiation was performed using alizarin red and oil red O and real-time PCR in vitro. The mineralization capability of the cells was examined in vivo by implanting with ceramic bovine bone (CBB) into subcutaneous of immunocompromised mice for 8weeks. A three-dimensional pellet cultivation system is proposed for SHED and DPSCs to recreate the biological microenvironment that is similar to that of a regenerative milieu.

RESULTS

SHED showed a higher proliferation rate and differentiation capability in comparison with DPSCs in vitro, and the results of the in vivo transplantation suggest that SHED have a higher capability of mineralization than the DPSCs. The mRNA expression levels of inflammatory cytokines, including matrix metalloproteinase-1 (MMP1), tissue inhibitors of metalloproteinase-1 (TIMP1), matrix metalloproteinase-2 (MMP2), tissue inhibitors of metalloproteinase-2 (TIMP2) and interleukin-6 (IL-6) were higher in SHED than that in DPSCs. In addition, the expression levels of Col I and proliferating cell nuclear antigen (PCNA) in SHED sheets were significantly higher than those in DPSCs sheets.

CONCLUSIONS

This study systematically demonstrated the differences in the growth and differentiation characteristics between SHED and DPSCs. Consequently, SHED may represent a suitable, accessible and potential alternative source for regenerative medicine and therapeutic applications.

Inhibition of RANK/RANKL signal transduction pathway: a promising approach for osteoporosis treatment

Osteoporosis is a bone disease causing impaired bone strength. It is characterized by increased osteoclast formation or enhanced bone resorption, leading to an increased risk of fragility fractures. Its prevalence increases with age. The advent of an aging population suggests that progressively more individuals will develop this disease in the aging population. A number of drugs for the prevention and treatment of osteoporosis act by inhibiting bone resorption. However, the effectiveness of osteoporosis treatment in clinical practice is limited. Since the osteoclast is the only cell in the body that is capable of resorbing bone, understanding its biology will be necessary for developing a new therapeutic approach for osteoporosis. Recently, it was discovered that the receptor activator of nuclear factor kappaB (RANK)/RANK ligand (RANKL)/osteoprotegerin (OPG) system is an important signal transduction pathway that regulates osteoclast formation. The binding of OPG to RANKL inhibits the binding between RANKL and RANK; this, in turn, prevents osteoclast precursors from differentiating and fusing to form mature osteoclasts. Therefore, the inhibition of the RANK/RANKL pathway inhibits osteoclast formation, differentiation, activation, and bone resorption. A potential clinical antiresorptive therapy can be developed by using an anti-RANKL monoclonal antibody, such as denosumab, that binds to RANKL with high affinity and specificity and blocks RANKL-RANK interactions.

[Effects and molecular mechanism of nicotine on odontoblasts]

OBJECTIVE

To observe the effects of nicotine on the proliferation of odontoblasts and explore the possible mechanism.

METHODS

Odontoblasts MDPC-23 were cultured, inoculated and divided into two groups randomly. With no stimuli added for the control group, the experimental group was stimulated by 100 microg/mL nicotine. After 8 hours, 10 micromol/L BrdU was added to label cells at S stage in cell cycle. 24 hours later, odontoblasts were fixed and immunofluorescence staining was performed with specific mouse BrdU antibody. After counterstaining with propidium iodide, BrdU positive cells were arbitrarily scored microscopically by an independent estimation conducted three times, and the corresponding total cell number in the same vision were counted in both groups. BrdU positive cell rates were calculated and compared statistically. At the same time, odontoblasts MDPC-23 were cultured and stimulated by 100 microg/mL nicotine, the dynamic Ca2+ concentration inside the cytoplasm were detected immediately by a confocal laser scanning microscope.

RESULTS

The ratio of S stage cells in the experimental group was 36.3% significantly lower than that (48.2%) in the control group. After the addition of 100 microg/mL nicotine, the Ca2+ concentration inside the cytoplasm rose rapidly, sustained at a high level for a short time and then relapsed gradually.

CONCLUSION

Nicotine had inhibitory effects on the proliferation of odontoblasts MDPC-23, which might be related to the increased Ca2+ concentration in the cytoplasm.

Identification of a novel missense mutation of MSX1 gene in Chinese family with autosomal-dominant oligodontia

OBJECTIVES

Oligodontia is defined as the congenital absence of 6 or more permanent teeth excluding the third molar. The occurrence of non-syndromic still remains poorly understood, but in recent years some cases have been reported where mutations or polymorphisms of PAX9 and MSX1 had been associated with non-syndromic oligodontia. The objective of the present work was to study the phenotype and genotype of three generations of a Han Chinese family affected by non-syndromic autosomal-dominant oligodontia.

DESIGN

We examined all individuals of the oligodontia family by clinical and radiographic examinations. Based on clinical manifestations, candidate genes MSX1 and PAX9 were picked up to analyse and screen mutations.

RESULTS

Dental evaluation showed that the most commonly missing teeth are the mandibular second premolars, followed by the maxillary second premolars and maxillary lateral incisors, and subsequently the maxillary first premolars. The probability of missing a particular type of tooth is not always bilaterally symmetrical, and differences exist between maxilla and mandible. PCR-SSCP analysis and DNA sequencing revealed a novel missense mutation c.662C>A in a highly conserved homeobox sequence of MSX1 and a known polymorphisms c.347C>G.

CONCLUSION

Our finding suggests the missense transversion (c.662C>A) and the polymorphisms (c.347C>G) may be responsible for oligodontia phenotype in this Chinese family.

[Regulation of osteopontin expression in odontoblasts by upstream stimulatory factor 1]

OBJECTIVE

To investigate the regulation effects of upstream stimulatory factor 1 (USF1) on osteopontin expression in odontoblasts.

METHODS

Odontoblast MDPC-23 was cultured and stably transfected with PCMV-USF1 or A-USF plasmids. Total RNA was extracted and osteopontin expression examined by semi-quantitative RT-PCR. Gray value of osteopontin was measured and statistic analysis performed.

RESULTS

Clones of stable PCMV-USF1 and A-USF plasmids transfection were obtained. Compared with the control, osteopontin was upregulated in PCMV-USF1 transfection group, and downregulated in A-USF transfection group.

CONCLUSIONS

Upstream stimulatory factor 1 could regulate the osteopontin expression in odontoblasts, which could be blocked partly by A-USF.

[Expression, subcellular localization and nuclear translocation of transcription factor up stream stimulatory factor-1 in odontoblasts]

OBJECTIVE

To examine the expression and subcellular localization of transcription factor USF1 in odontoblasts and investigate whether nuclear translocation occurs under stimuli.

METHODS

Odontoblasts MDPC-23 were cultured on coverslips and divided into 2 groups. Group 1 received no stimuli, and group 2 was stimulated by nicotine with various concentrations respectively for 1h. Then the mountings of odontoblasts were prepared and immunocytochemical staining was performed with specific USF1 antibody via SABC method. Hela cells were used as positive control.

RESULTS

The staining was positive in the cytoplasm of odontoblasts in group 1, but in the nuclei of Hela cells and in 100 mg/L nicotine-stimulated odontoblasts in group 2.

CONCLUSIONS

There exists USF1 protein in odontoblasts, which locates in the cytoplasm and could translocate into nuclei under the stimulation of nicotine.

Leiomyosarcoma in the nasopharynx: MR imaging findings

The MR imaging findings of a leiomyosarcoma arising from the nasopharynx are presented. To our knowledge, this is the first MR imaging description of this entity.

Squeeze maneuver: an easy way to manage radiological contrast-medium extravasation

BACKGROUND

Contrast-medium extravasation injuries may be self-limited to catastrophic. Adequate prophylactic measures are enforced when risk factors for extravasation are present, and prompt treatment can avoid serious complications.

PURPOSE

To describe the squeeze maneuver, an effective method for the treatment of symptomatic contrast-medium extravasation.

MATERIAL AND METHODS

Over a 3-month period, eight patients with >50 ml contrast-medium extravasation resulting in vascular compromise of the fingers were managed with the squeeze maneuver as follows. The intravenous catheter used for contrast-medium injection was removed, and the skin around the insertion site was cleaned with povidone-iodine. An 18-gauge needle was then used to puncture five to eight openings near the catheter insertion site as deeply as possible. We then began squeezing from the periphery of the swelling toward the needle holes. As the contrast medium drained, it was swabbed away with iodine-soaked cotton swabs.

RESULTS

In all eight patients, the maneuver was successful with immediate resolution of the vascular compromise.

CONCLUSION

The squeeze maneuver provides an easy way to manage radiological contrast-medium extravasation and can be performed immediately in the CT suite.

[Neural engineering and neural prostheses]

The motivation of the brain-computer interface (BCI) research and its potential applications are introduced in this paper. Some of the problems in BCI-based medical device developments are also discussed.

Reflex regulation of antagonist muscles for control of joint equilibrium position

A systems model of spinal neuro-musculo-skeletal system (alpha - gamma model) is developed to investigate the plausible roles of spinal proprioceptive feedback in movement control. The model is composed of a joint, a pair of antagonist muscles, length and velocity feedback from muscle spindle, as well as spinal stretch reflex, reciprocal inhibition and recurrent inhibition of Renshaw cells. A descending command modulates the background activation of alpha motoneuron pools in combination with these reflex activities. A static gamma command controls the fusimotor contraction of the spindle. Simulation results reveal that the equilibrium joint angle is linearly correlated to the level of static gamma fusimotor activity of the spindle for a wide range of external loading conditions and reflex gains, suggesting that these spinal reflexes may contribute to regulate the equilibrium position of the joint. Sensitivity analysis further shows that reflex gains and other central commands alter the quasi-linear relation in regular fashions. The reciprocal inhibition gain changes the slope of the linear theta(eq) - gamma curve; and the descending alpha excitation, the stretch reflex gain, and the external load all shift the theta(eq) - gamma curve in parallel. These results imply that reflex gains and descending alpha commands may be coordinated to maintain a unique theta(eq) - gamma curve while providing the flexibility to counteract external loads, to execute a movement, or to regulate additional muscle variables. Dynamic simulation suggests that control of a class of movements can be achieved with a triphasic, alpha pulse and a continuous gamma signal. The model study supports the notion of a dual strategy for controlling trajectories via a feedforward alpha command and for regulating the final equilibrium positions via a feedback gamma command.

Are modified procedures significantly better than conventional procedures in percutaneous transhepatic treatment for complicated right hepatolithiasis with intrahepatic biliary strictures?

BACKGROUND

Conventional percutaneous procedures for treating patients with recurrent hepatolithiasis associated with complicated intrahepatic biliary strictures require multiple dilation sessions before stone extraction. We modified the approach, reducing the number of dilation sessions required and using newer lithotripsy and irrigation methods. We suggest that the modified procedures are superior to conventional management and demonstrate their utility in clearing hepatolithiasis.

METHODS

Percutaneous transhepatic stricture dilation and cholangioscopic lithotripsy were performed to treat patients with right recurrent hepatolithiasis with complicated intrahepatic biliary strictures. Conventional methods were used in 40 patients (Group A). Modified methods, including simplification of tract establishment and stricture dilation and electrohydraulic lithotripsy (EHL) were used in 60 patients (Group B).

RESULTS

Group B patients had fewer complications (massive hemobilia: 0% versus 15%, P = 0.0032, cholangitis: 0% versus 17.5%, P=0.0012), tolerated the procedures better (intolerable pain: 0% versus 12.5%, P=0.0087), had a higher rate of success (residual stones: 3.3% versus 20%, P=0.0132; remaining asymptomatic and stone-free: 81% versus 50%, P = 0.0021), a shorter hospital stay (17.8 +/- 4.4 days versus 36.2 +/- 5.5 days, P < 0.001) and lower overall expense (USD 2689 versus USD 3848) than Group A patients.

CONCLUSION

We believe that the modified methods are superior to conventional treatment in that they effectively decrease procedural complications and cost, and significantly improve treatment results.

The benefits of a second transhepatic route in failed percutaneous management of difficult intrahepatic biliary strictures with recurrent hepatolithiasis

Percutaneous stricture dilatation and cholangioscopic lithotomy has become a mainstay in the treatment of patients with recurrent hepatolithiasis associated with intrahepatic biliary strictures. In a consecutive series of 125 patients who underwent percutaneous management of recurrent hepatolithiasis from 1987 to 1999, there were 15 patients in whom the procedure failed to clear the stones. A second percutaneous transhepatic route was established for subsequent treatment. A reappraisal of its indications and efficacy was done. Treatment through a second route was helpful for patients with bilateral strictures, angulated duct, difficult strictures, large impacted stones, a subcutaneous jejunal limb, or hemobilia developing in the first route. Strictures remained impacted in 1 of the 15 patients (failure rate, 7%), with the remaining having complete clearance of stones. Cholangitis occurred in two patients; no other complications were encountered. A second percutaneous route is very helpful for the management of complicated hepatolithiasis and biliary stricture.

Percutaneous transhepatic cholangioscopy in the treatment of complicated intrahepatic biliary strictures and hepatolithiasis with internal metallic stent

For recurrent hepatolithiasis coexisting with a complicated long-segment intrahepatic biliary stricture, repeated surgeries, balloon dilation of the stricture, and external-internal stenting may still fail to solve the problem. We tried using a Gianturco-Rosch metallic Z internal stent (Wilson-Cook Medical, Inc., Bloomington, IN, USA) with the aid of percutaneous transhepatic cholangioscopy (PTCS) to treat such patients. Eight patients had a Z stent placed through a percutaneous transhepatic biliary drainage tract. Immediately after stent placement, PTCS was inserted via the percutaneous transhepatic biliary drainage route and a part of the wire skirt not firmly anchored in one of the eight patients was detected. It was successfully repositioned using PTCS. Recurrent cholangitis developed in three patients 6, 7, and 30 months, respectively, after stent placement. PTCS was undertaken again through a reestablished percutaneous transhepatic biliary drainage route and revealed sludge in their stent lumens. We cleared it by PTCS. No further cases of cholangitis occurred in later follow-up. PTCS is useful in ensuring adequate stent position, diagnosing and treating the causes of recurrent cholangitis, and prolonging the function of stents.

Alterations of p16/MTS1 gene in oral squamous cell carcinomas from Taiwanese

To determine the alterations of the p16/MTS1 gene in oral squamous cell carcinoma (OSCC), we examined in Taiwanese patients the mutation, deletion and methylation of p16/MTS1 in primary OSCCs associated mostly with betel quid (BQ)/tobacco use. Among 110 tumors undergoing mutational analyses, seven (6%) showed mutations in exon 2 or the intron 1/exon 2 splice site. All but one mutation disrupted the encoded proteins. Base transitions represented the vast majority (6/7) of the mutations identified in BQ/tobacco consuming subjects. It was noted that 15/56 (27%) tumors examined by restriction fragment methylation analysis revealed a significant level of methylation in different loci of exon 1 as compared with the respective non-cancerous tissue. Mutation of p16/MTS1 was exclusively identified in carcinomas of buccal mucosa, whereas methylation of the p16/MTS1 promoter region occurred preferentially in carcinomas of the tongue (54%) rather than at other sites (22%). Homozygous deletion was not found in 56 paired samples examined, nor was hemizygous deletion indicated in 12 informative cases. The results indicated aberrant methylation and mutation as the molecular abnormality of p16/MTS1 in the OSCC from Taiwanese.

Occlusion of azygos vein via direct percutaneous puncture of innominate vein following cavopulmonary anastomosis

A 2-year-10-month-old boy was diagnosed with a complex congenital heart disease: right atrial isomerism, left superior vena cava (LSVC), complete atrioventricular septal defect, secundum type atrial septal defect, transposition of the great arteries with pulmonary atresia, patent ductus arteriosus, absence of a right superior vena cava (RSVC), and dextrocardia. He had received a left Blalock-Taussig (BT) shunt at the age of 3 months and a left bidirectional Glenn shunt one year after BT shunt. Progressive cyanosis was noted after the second operation and cardiac catheterization showed a functional Glenn shunt with an engorged azygos vein, which was inadvertently skipped for ligation. Because of the absence of RSVC, transcatheter occlusion of the azygos vein was performed successfully via direct puncture of the innominate vein.

Percutaneous transhepatic placement of metallic stents in the treatment of complicated intrahepatic biliary stricture with hepatolithiasis: a preliminary report

OBJECTIVE

We aimed to study the effect of the metallic modified Gianturco-Rosch Z-stent in the management of refractory intrahepatic long-segment biliary strictures with hepatolithiasis.

METHODS

Six symptomatic patients with hepatolithiasis and coexisting intrahepatic long-segment biliary strictures, who failed to respond to the silastic external-internal biliary stenting, were selected. The metallic modified Gianturco-Rosch Z-stent was placed via percutaneous transhepatic cholangiography at the strictured site. Patients were followed regularly to evaluate for recurrence of cholangitis, stones, or strictures.

RESULTS

No complications were observed during the procedures. No recurrent strictures or formed calculi were found in these six patients during follow-up periods of 29 to 64 months. However, cholangitis and intrahepatic biliary muddy sludge occurred at 7 and 30 months in two patients after the placement of the metallic Z-stent. Percutaneous transhepatic cholangioscopy was used to clear sludge completely.

CONCLUSIONS

Our experience suggests that the metallic stent is a well-tolerated and promising alternative in the management of refractory intrahepatic long-segment biliary strictures with hepatolithiasis. Though biliary sludge may develop, it can be detected and cleared early. Repeated surgery can thus be avoided.

Synthesis and decomposition of transient-evoked otoacoustic emissions based on an active auditory model

In this paper, transient-evoked otoacoustic emissions (TEOAE's) are synthesized by an active auditory model, and decomposed by continuous wavelet transform (CWT) to study the frequency-latency relationship and the generation of TEOAE signals. The controlled voltage sources that relate to the mobile mechanism of the outer hair cells (OHC's) are proposed to serve as the generation sources of TEOAE signals. The state-variable method is adopted to calculate the auditory model. The mother wavelet used in CWT is selected on basis of the model. The results of this study show that the simulated TEOAE signal is similar to the clinically detected ones not only in the time-domain waveform, but also in the frequency-latency relationship. It seems to be clear that the generation of TEOAE signals is related to the same active mechanism as the cochlear sharp frequency selectivity.

Are expandable metallic stents better than conventional methods for treating difficult intrahepatic biliary strictures with recurrent hepatolithiasis?

BACKGROUND

Conventional methods for treating patients with recurrent hepatolithiasis associated with complicated intrahepatic biliary strictures include balloon dilatation of the intrahepatic biliary strictures, lithotripsy, and the clearance of difficult stones as completely as possible, with the placement of an external-internal stent for at least 6 months. After these modalities are used, symptomatic refractory strictures remain. Recently we used internal Gianturco-Rosch metallic Z stents to treat patients who had refractory strictures.

OBJECTIVE

To compare therapeutic results and complications of an internal expandable metallic Z stent with those of repeated external-internal stent placement.

STUDY DESIGN

Case-control study.

SETTING

A referral center.

PATIENTS

From January 1992 to December 1996, 18 patients with recurrent hepatolithiasis and complicated intrahepatic biliary strictures underwent percutaneous dilatation of stricture and transhepatic percutaneous cholangioscopic lithotomy for recurrent stones. After their stones were completely cleared, their biliary strictures failed to dilate satisfactorily. The patients were randomly enrolled into 2 groups: group A (7 patients), who received an expandable metallic Z stent, and group B (11 patients), who had repeated placement of external-internal stents.

INTERVENTIONS

Percutaneous stricture dilatation, electrohydraulic lithotripsy, balloon dilatation, percutaneous transhepatic cholangioscopic lithotomy, and biliary stenting by a Silastic external-internal catheter or a modified Gianturco-Rosch expandable metallic Z stent (for an internal stent).

MAIN OUTCOME MEASURES

The number of procedures, days in hospital, procedure-related complications, incidents of stone recurrence and recurrence of cholangitis, readmissions to the hospital, treatment sessions required, and mortality rate. Patients' limitations in ordinary activities were also compared.

RESULTS

The follow-up period ranged from 28 to 60 (40.7+/-12.7 [mean +/- SD]) months in group A and from 28 to 49 (36.0+/-7.2) months in group B. Fewer group A patients (3 [43%]) than group B patients (8 [73%]) tended to have recurrent cholangitis and to require readmission to the hospital, but this was not statistically significant (P = .33). When their cumulative probability of a first episode of cholangitis during follow-up was compared, however, it was significantly lower in patients treated with a metallic stent (P = .04). Compared with group B patients, group A patients had less frequent recurrence of stones (0% vs 64%; P = .01), fewer procedures for the clearance of biliary stones or sludge (1.7+/-2.2 vs 6.4+/-4.3; P = .03), and shorter hospital stays (8.0+/-11.5 days vs 17.0+/-12.0 days; P = .07). No patients in group A experienced limitation in ordinary activities, whereas 7 patients in group B did (P<.02).

CONCLUSIONS

Compared with the repeated placement of external-internal stents, the use of a metallic internal stent effectively decreases stone recurrence, simplifies further procedures, and is more convenient. Its use is suggested as an alternative choice in the treatment of recurrent hepatolithiasis with refractory intrahepatic biliary strictures.

A fast recursive-least-squares adaptive notch filter and its applications to biomedical signals

A fast recursive-least-squares (FRLS) adaptive notch filter (ANF) for cancellation of sinusoidal interference from recorded biomedical signals is investigated. The FRLS ANF is derived by making an approximation to the conventional recursive-least-squares (RLS) ANF for computation economy. It outperforms the commonly adopted least-mean-squares (LMS) ANF, demonstrating a rapid and bandwidth-insensitive initial convergence. A novel application of the FRLS ANF is for the elimination of the tonal artefact in distortion product otoacoustic emission (DPOAE) signals.

Metastatic hepatocellular carcinoma presenting as hemocholecyst with perforation: a case report

In case of hepatocellular carcinoma (HCC), the gallbladder is less frequently involved and metastasis to the gallbladder, together with its significant clinical manifestations, is rarely discussed in the literature in detail. HCC with metastasis to the gallbladder, initially presenting as gallbladder intraluminal hemorrhage and perforation, has not been previously reported. We present a case of HCC disclosed by emergency cholecystectomy for hemocholecyst with perforation. Evaluation of the possible metastatic mechanisms is also discussed.

Widely tunable spectrum translation and wavelength exchange by four-wave mixing in optical fibers

By a suitable choice of the wavelengths of two pumps and one signal about the zero-dispersion wavelength of a fiber, it is possible to generate mainly one four-wave-mixing product (idler) whose spectrum is a translated version of that of the signal; no spectral inversion or phase conjugation is involved. Unit conversion efficiency can in principle be obtained. Complete exchange of power between two wavelengths can be implemented. One can adjust the wavelengths of the signal and the idler at will over tens of nanometers, while maintaining high conversion efficiency, by suitably tuning the pumps. For fixed pump wavelengths, the signal bandwidth scales linearly with pump power and can reach several nanometers for pump powers of the order of several watts in silica fibers or less in highly nonlinear fibers.

Broadband fiber-optical parametric amplifiers and wavelength converters with low-ripple Chebyshev gain spectra

Theory predicts that a two-pump fiber optical parametric amplifier or wavelength converter operated near the fiber zero-dispersion wavelength can exhibit a gain spectrum approximated by a Chebyshev polynomial of order 8. Under realistic conditions of pump spacing and fiber dispersion, very low-gain ripple can be obtained over a large bandwidth. For example, a dispersion-shifted fiber can provide a signal amplifier with a gain of 20 dB with 0.2-dB uniformity over a 45-nm bandwidth. Potential limitations are discussed.

Watershed infarction of spinal cord after the embolization of bronchial artery: a case report

A case of watershed infarction in the spinal cord is reported. The patient underwent bronchial artery embolization for control of massive hemoptysis. The bronchial arteriogram was carefully examined and focused on blood supply to the spinal cord prior to embolization. Acute paraparesis followed the embolization procedure even though there was no visible spinal supply on the arteriogram. Magnetic resonance imaging showed a hyperintensity lesion over the watershed region which is located at the central portion of the upper thoracic cord. This case is reported to emphasize the significant role which angiographically invisible small vessels can play in the blood supply to the spinal cord. The vascular system of the spinal cord and the prevention of spinal cord ischemia secondary to embolization are further discussed here.

Reappraisal of the systematic management of complicated hepatolithiasis with bilateral intrahepatic biliary strictures

OBJECTIVE

To compare the results, limitations, and complications of the surgical treatment of bilateral hepatolithiasis and intrahepatic biliary strictures with left hepatectomy and without left hepatectomy.

DESIGN

Case-controlled study.

SETTING

Referral center.

PATIENTS

During a 12-year period, 103 patients with bilateral hepatolithiasis and intrahepatic biliary strictures underwent surgical treatment. Group A (n = 73) received left hepatic resection (lateral segmentectomy or lobectomy) and postoperative biliary dilatation with residual stone extraction. Group B (n = 30) underwent the same procedures except for left hepatectomy.

INTERVENTIONS

Left lateral segmentectomy or left lobectomy, choledocholithotomy, postoperative cholangioscopic treatments (electrohydraulic lithotripsy, other lithotripsy, lithotomy, balloon dilatation, etc. via T tube or precutaneous transhepatic route).

MAIN OUTCOME MEASURES

Days of hospitalization, incidence of major and minor complications, mortality rates, and the rates of residual stones and stone recurrence were compared.

RESULTS

Group A and B had similarly low postoperative 1-month mortality rates of 5.5% and 6.7%, respectively. The main cause of death in both groups was uncontrollable septicemia. The main major complications in group A were intra-abdominal abscess and upper gastrointestinal bleeding; the major complication in group B was massive hemobilia. Group B had a significantly higher overall rate of complications (53.3% vs 23.3%, P < .01) and a longer hospital stay than group A (median, 72 days vs 28 days, P < .03). When complications were classified as major or minor, only minor complications showed a significant difference (30% vs 13.7%, P = .05). After using biliary stricture dilatation and stone extraction, the rate of residual stones in the right lobe was similar in both groups, but patients in group B had a significantly higher rate of residual stones (12.5% vs 0%, P < .02) and stone recurrence in the left lobe (19% vs 0%, P < .003) than those in group A.

CONCLUSIONS

Partial resection of the left lobe in cases of bilateral hepatolithiasis and biliary strictures can effectively simplify problems in the treatment of bilateral hepatolithiasis and intrahepatic biliary strictures. In addition, not only were surgical complications not increased, but a decrease in complications from postoperative manipulations for stone clearance was noted in our series.

Management of symptomatic polycystic liver disease: laparoscopy adjuvant with alcohol sclerotherapy

An 81 year old woman with extensive polycystic liver disease received laparoscopic unroofing and fenestration, followed by 95% ethanol sclerotherapy, resulting in almost complete disappearance of the cysts. Such a procedure can avoid complications of both the multi-segmental liver resections and extensive fenestrations, and untoward reactions from a large amount of alcohol. In addition, it can achieve a satisfactory result. It is suggested that this procedure could be a safe and effective alternative to traditional open surgery in selective patients.

Coexisting sharp ductal angulation with intrahepatic biliary strictures in right hepatolithiasis

OBJECTIVE

To investigate the clinical characteristics of a coexisting sharp ductal angulation (< 90 degrees) with biliary stricture and to evaluate the difficulties it imposes in the management of retained or recurrent hepatolithiasis.

DESIGN

Case-controlled study.

SETTING

A referral center.

PATIENTS

Eighteen consecutive patients having right-sided hepatolithiasis and a coexisting sharp ductal angulation associated with biliary stricture (group 1) were compared with 84 patients matched with sex, age, and conditions of hepatolithiasis and intrahepatic biliary stricture(s) but no sharp angulated duct (group 2).

INTERVENTION

Postoperative cholangioscopic management (electrohydraulic lithotripsy or other lithotripsy, lithotomy, balloon dilation, biopsy, etc, via T-tube tract or percutaneous transhepatic route).

MAIN OUTCOME MEASURES

Sessions of manipulations, incidence of complications associated with interventions or disease, and mortality were compared.

RESULTS

Patients of group 1 needed more sessions of postoperative manipulation of stones and strictures (13.7 +/- 4.2 vs 8.0 +/- 2.3; P < .001). During management, there was a significantly increased vulnerability of severe and/or recurrent cholangitis (66.7% vs 9.5%; P < .001), septic shock (77.8% vs 11.9%; P < .001), liver abscess (55.6% vs 7.1%; P < .001), or massive hemobilia (33.3% vs 7.4%) in group 1 than in group 2. Their risks of coexisting secondary biliary cirrhosis (55.6% vs 9.5%; P < .001) and/or cholangiocarcinoma (16.6% vs 2.4%; P < .04) and mortality (27.8% vs 4.8%; P < .01) were also significantly higher in group 1.

CONCLUSION

Our results suggest that the coexisting sharp ductal angulation with biliary strictures in right-sided hepatolithiasis is a distinct difficult clinical entity in the field of biliary tract calculi.

Embolization of the major aorto--pulmonary collateral artery in tetralogy of Fallot: report of one case

A boy with tetralogy of Fallot diagnosed in infancy, presented for definitive correction at the age of 5 years and 3 months. He had undergone bilateral Blalock-Taussig shunts twice at 1 and 2 years of age, respectively. Cardiac catheterization and angiography prior to total correction revealed a major aorto-pulmonary collateral artery arising from the thoracic aorta and supplying the right upper lung. Embolization of the collateral artery with two platinum coils (via catheterization) was performed. The successful embolization exempted the patient from the risky ligation of the deeply located collateral artery.

Use of computed tomography to detect hepatic portal venous gas and intestinal intramural gas: a case report

Hepatic portal venous gas and intestinal intramural gas were demonstrated by computed tomography (CT) in a case of ischemic bowel disease. The patient died on the day following the examination.

Non-surgical retrieval of intravascular foreign body: experience of 12 cases

An intravascular foreign body is an iatrogenic complication that occurs during arterial or venous catheterization or interventional procedures. The foreign body could either be a catheter fragment, a dislodged coil, or a steel guide wire. From January 1987 to December 1992, 12 cases of intravascular foreign-body removals were performed by a percutaneous method at Mackay Memorial Hospital. Of the 12 cases, five were dislodged steel guide wires, four were broken CVP catheters, two were dislodged coils, and one was Port-A fragment. The techniques we used were the loop-snare technique (two cases) and stone basket retriever (10 cases). Eleven cases of intravascular foreign bodies were removed by non-surgical percutaneous retrieval but one case was a failure due to improper extraction of a dislodged steel guide wire. The patient received surgical extraction by regional venotomy finally. No major complications were noted during or after these procedures.

Repeat operation for nodular recurrent hepatocellular carcinoma within the cirrhotic liver remnant: a comparison with transcatheter arterial chemoembolization

Management of recurrent hepatocellular carcinoma in a cirrhotic liver remnant is a difficult but challenging problem. To investigate the difference in survival between treatment by repeat resection and treatment by transcatheter arterial chemoembolization (TAE), a retrospective controlled study was conducted. Four patients with nodular recurrence received limited second operations which included right hepatic segmentectomy (2 patients), left lateral segmentectomy (1 patient), and subsegmental wedge resection (1 patient). Eight matched patients received a total of 16 repeated sessions of chemoembolizations. Complications of the TAE group consisted of gastrointestinal bleeding (2 patients), acute pancreatitis (1 patient), and acute cholecystitis (1 patient). No complication developed in the resection group. The 4 patients undergoing a second operation have survived 21, 26, 34, and 54 months after repeat surgery. Seven (87.5%) of the 8 patients receiving TAE died 4 to 11 months after TAE. The resection group survived significantly longer than the TAE group (p < 0.01). Our results suggest that it is more advisable to perform a second operation than to undertake chemoembolizations for patients with cirrhosis and nodular recurrent hepatocellular carcinoma with acceptable functional liver reserve.

Bile duct stents in the management of hepatolithiasis with long-segment intrahepatic biliary strictures

Biliary stricture represents a challenging problem in the treatment of hepatolithiasis because of its association with treatment failure and stone recurrence. The long-segment type of stricture is difficult to manage and is likely to recur. To investigate the necessity for biliary stenting after balloon dilatation therapy, 20 consecutive patients with long-segment strictures who had 22 stents (group 1) were compared with ten patients who refused stenting (group 2). The long-segment strictures in group 1 were located on the right side in 80 per cent of patients, on the left side in 10 per cent, and were bilateral in 10 per cent. The stents, varying from 8 to 12 Fr, were retained for at least 6 months. They were inserted through the routes of a matured T tube track (five cases), percutaneous transhepatic track (14 cases), a jejunal limb (two cases) and a fistula (one case). Complications of stenting consisted of dislodgement (one case), haemobilia (two cases), cholangitis (two cases) and intrahepatic abscess (one case). The cumulative probability of stricture recurrence in group 1 was 10 per cent, 15 per cent and 21 per cent at 2, 3 and 4 years, respectively, whereas in group 2 it was 80 per cent at 2 years (P less than 0.003). The results suggest that intrahepatic biliary stenting after balloon dilatation appears necessary and helpful in the management of hepatolithiasis with long-segment biliary strictures.

Gentamicin-induced alterations of succinic dehydrogenase activity in the organ of Corti as revealed by non-decalcified frozen sections of the guinea pig's cochlea

The distribution of succinic dehydrogenase (SDH) activity and the changes of SDH activity after injection of gentamicin (GM) were observed in the organ of Corti using non-decalcified frozen sections of the guinea pig's cochlea. The distribution of SDH activity was found to increase from the apex to the basal turn. At each turn, SDH activity of the inner hair cells, the inner supporting cells and the nerve endings surrounding the supporting cell and on the hair cells presented a greater activity than that found in the outer hair cells, adjacent Deiter's cells and associated nerve endings. It was further observed that GM had a greater effect on SDH activity in the basal turn than the other turns. At each turn, a more sensitive area of response to GM was found on the nerve endings one each hair cell, especially on the outer hair cells of the basal turn.

Dilatation of intrahepatic biliary strictures in patients with hepatolithiasis

To investigate the role of balloon dilatation in the management of complicated hepatolithiasis with intrahepatic biliary stricture, 57 consecutive patients who received 208 sessions of dilatation in addition to the usual treatment were analyzed. The strictures were located in the right intrahepatic ducts (84.2%), left intrahepatic ducts (12.3%), or both (3.5%). Dilatation began 3-4 weeks after surgery. The routes of dilatation included the matured T-tube tract (3 cases), percutaneous transhepatic biliary drainage tracts (42 cases), and both (12 cases). The immediate overall success rate of complete stone clearance increased significantly from 0% predilatation to 94.7% postdilatation. The main complications of dilatation therapy consisted of septicemia (10.5%), hemobilia (10.5%), and mild diarrhea (80%). Eight patients (14%) with long-segment strictures received 11 postdilatation biliary stentings. Complications were 1 patient with occlusion and 2 patients with "spontaneous" hemobilia. Severe multiple strictures and coexistent secondary biliary cirrhosis were the contributing factors to complications. During the follow-up of 3.4 +/- 1.2 years, recurrence of strictures was found in 4 patients. Two of them belonged to the stenting group. The cumulative probability of restricture was low: 4% at 2 years, 6% at 2.5 years, and 8% at 3 years. We conclude that in complicated cases of hepatolithiasis with intrahepatic biliary stricture, dilatation and stenting are good adjuvant therapies.

A technique for temporal bone sections using non-decalcified frozen guinea pig cochleas: a study of succinic dehydrogenases

We have developed a technique for sectioning temporal bones and have studied non-decalcified frozen guinea pig cochleas to localize succinic dehydrogenases. The technique is simple and practicable. The 6-microns sections used preserve both fine cochlear structure and satisfactory histochemical localization for identifying the succinic dehydrogenases. The technique can also be extended to immunological test, detecting transmitters and investigating enzymes in the cochlea.

Stability of perfluorocarbon blood substitutes determined by sedimentation field-flow fractionation

It is shown that the method known as sedimentation field-flow fractionation, which has been applied to the separation and characterization of many industrial and biological particles and recently to emulsions, can be used to obtain high-resolution droplet diameter profiles for perfluorocarbon blood substitutes. Following a description of the methodology, experiments are described for two commercial perfluorocarbon emulsions, Fluosol-DA 20% and Fluosol-43. The droplet diameter profiles for both of these blood substitutes are shown to shift to noticeably higher diameter values in less than 2 months. The diameter at the profile peak for Fluosol-DA 20%, for example, shifts from 0.19 to 0.27 micron in 56 days.