[Investigation and factor analysis of postoperative surgical site infections in emergency abdominal surgery in China from 2018 to 2021 based on Chinese SSI Surveillance]

Objective: We investigated the incidence of surgical site infection (SSI) following emergency abdominal surgery (EAS) in China and further explored its risk factors, providing a reference for preventing and controlling SSI after EAS. Methods: This was an observational study. Data of patients who had undergone EAS and been enrolled in the Chinese SSI Surveillance Program during 2018-2021were retrospectively analyzed. All included patients had been followed up for 30 days after surgery. The analyzed data consisted of relevant patient characteristics and perioperative clinical data, including preoperative hemoglobin, albumin, and blood glucose concentrations, American Society of Anesthesiologists (ASA) score, grade of surgical incision, intestinal preparation, skin preparation, location of surgical site, approach, and duration. The primary outcome was the incidence of SSI occurring within 30 days following EAS. SSI was defined as both superficial and deep incisional infections and organ/space infections, diagnoses being supported by results of microbiological culture of secretions and pus. Secondary outcomes included 30-day postoperative mortality rates, length of stay in the intensive care unit (ICU), duration of postoperative hospitalization, and associated costs. The patients were classified into two groups, SSI and non-SSI, based on whether an infection had been diagnosed. Univariate and multivariate logistic regression analyses were performed to identify risk factors associated with SSI following EAS. Results: The study cohort comprised 5491 patients who had undergone EAS, comprising 3169 male and 2322 female patients. SSIs were diagnosed in 168 (3.1%) patients after EAS (SSI group); thus, the non-SSI group consisted of 5323 patients. The SSIs comprised superficial incision infections in 69 (41.1%), deep incision infections in 51 (30.4%), and organ or space infections in 48 (28.6%). Cultures of secretions and pus were positive in 115 (68.5%) cases. The most frequently detected organism was Escherichia coli (47/115; 40.9%). There were no significant differences in sex or body mass index between the SSI and non-SSI groups (both P>0.05). However, the proportion of individuals aged 60 years or older was significantly greater in the SSI than in the non-SSI group (49.4% [83/168] vs. 27.5% [1464/5323), χ2=38.604, P<0.001). Compared with the non-SSI group, the SSI group had greater proportions of patients with diabetes (11.9% [20/168] vs. 4.8% [258/5323], χ2=16.878, P<0.001), hypertension (25.6% [43/168] vs. 12.2% [649/5323], χ2=26.562, P<0.001); hemoglobin <110 g/L (27.4% [46/168] vs. 13.1% [697/5323], χ2=28.411, P<0.001), and albuminemia <30 g/L (24.4% [41/168] vs. 5.9% [316/5323], χ2=91.352, P<0.001), and a reduced rate of preoperative skin preparation (66.7% [112/168] vs. 75.9% [4039/5323], χ2=7.491, P=0.006). Furthermore, fewer patients in the SSI group had preoperative ASA scores of between one and two (56.0% [94/168] vs. 88.7% [4724/5323], χ2=162.869, P<0.001) in the non-SSI group. The incidences of contaminated and infected incisions were greater in the SSI group (63.1% [106/168] vs. 38.6% [2056/5323], χ2=40.854, P<0.001). There was a significant difference in surgical site distribution between the SSI and non-SSI groups (small intestine 29.8% [50/168] vs. 10.6% [565/5323], colorectal 26.2% [44/168] vs. 5.6% [298/5 323], and appendix 24.4% [41/168] vs. 65.1% [3465/5323]) χ2=167.897, P<0.001), respectively. There was a significantly lower proportion of laparoscope or robotic surgery in the non-SSI group (24.4 % [41/168] vs. 74.2% [3949/5323], χ2=203.199, P<0.001); the percentage of operations of duration less than 2 hours was significantly lower in the SSI than non-SSI group (35.7% [60/168] vs. 77.4% [4119/5323], χ2=155.487, P<0.001). As to clinical outcomes, there was a higher 30-day postoperative mortality rate (3.0%[5/168] vs. 0.2%[10/5323], χ2=36.807, P<0.001) and higher postoperative ICU occupancy rate (41.7% [70/168] vs. 19.7% [1046/5323], χ2=48.748, P<0.001) in the SSI group. The median length of stay in the ICU (0[2] vs. 0[0] days, U=328597.000, P<0.001), median total length of stay after surgery (16[13] vs. 6[5] days, U=128146.000, P<0.001), and median hospitalization cost (ten thousand yuan, 4.7[4.4] vs. 1.7[1.8], U=175965.000, P<0.001) were all significantly greater in the SSI group. Multivariate logistic regression analysis revealed that the absence of skin preparation before surgery (OR=2.435,95%CI: 1.690-3.508, P<0.001), preoperative albuminemia <30 g/L (OR=1.680, 95%CI: 1.081-2.610, P=0.021), contaminated or infected incisions (OR=3.031, 95%CI: 2.151-4.271, P<0.001), and laparotomy (OR=3.436, 95% CI: 2.123-5.564, P<0.001) were independent risk factors of SSI. Operative duration less than 2 hours (OR=0.465, 95%CI: 0.312-0.695, P<0.001) and ASA score of 1-2 (OR=0.416, 95% CI: 0.289-0.601, P<0.001) were identified as independent protective factors for SSI. Conclusions: It is important to consider the nutritional status in the perioperative period of patients undergoing EAS. Preoperative skin preparation should be conducted and, whenever possible, laparoscope or robot-assisted surgery. Duration of surgery should be as short as possible while maintaining surgery quality and improving patient care.

Abstract 1676: A comprehensive whole blood CyTOF immune monitoring panel with expanded surface and intracellular markers using the Maxpar Direct Immune Profiling Assay

In-depth monitoring of the immune response to cancer and infection is vital to ascertain disease status and to assess immunotherapeutic options. Time-of-flight technology, the basis of CyTOF® mass cytometry, enables multiplex proteomic cellular phenotyping with 50 or more markers, making it ideal for comprehensive immune profiling. Unlike fluorescence-dependent approaches, which require signal compensation that makes the development of larger panels more challenging, CyTOF utilizes monoisotopic metal-tagged antibodies that exhibit minimal background signal, enabling the highest-resolution multiparametric landscape of a single cell. The Maxpar® Direct™ Immune Profiling Assay™ is a pre-titrated dried-down 30-antibody cocktail preparation for immune profiling of human whole blood or PBMC. This assay is used with Maxpar Pathsetter™ software, which resolves whole blood into 37 immune populations comprising major lineage populations and their subsets, such as CD4 Th subsets and B and T cell memory cells, as well as stratifications of myeloid populations. The resulting system is a simple sample-to-answer solution for immune monitoring studies. Here, we expanded the 30-marker assay with 14 additional antibodies comprising pertinent targets of immunotherapy, including the exhaustion markers PD-1, PD-L1, Tim-3 and CTLA-4, and co-stimulation markers 4-1BB and ICOS. We also demonstrated the compatibility of the assay with downstream intracellular staining for cytoplasmic markers IFN-γ, TNF-α, IL-2, perforin and granzyme B for assessment of cellular function in 4h PMA/ionomycin-stimulated whole blood cultures. Next, we modified the existing Pathsetter model to automate the analysis of whole blood stained with the expanded panel to generate reports on key immune cell populations, percentages of exhausted cells and cell subsets producing cytokines. Last, to demonstrate the ability of this expanded panel to identify antigen-specific T cell subsets accompanied by their in-depth phenotypic assessment, we tested this panel against CMV peptide-stimulated whole blood samples. We demonstrated the flexibility of the Maxpar Direct Immune Profiling Assay in panel customization and a streamlined workflow for automated analysis to enable comprehensive immune profiling of human whole blood. For Research Use Only. Not for use in diagnostic procedures.

Citation Format: Shariq Mujib, Stephen K. Li, Nick Zabinyakov, Christina Loh. A comprehensive whole blood CyTOF immune monitoring panel with expanded surface and intracellular markers using the Maxpar Direct Immune Profiling Assay [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1676.

[Clinical characteristics of recurrent appendicitis]

Objective: To analyze clinical characteristics of recurrent appendicitis. Methods: A retrospective cohort study was carried out. Clinical data of patients who underwent appendectomy due to acute appendicitis confirmed by pathology in the Affiliated Hospital of Qingdao University from January 2011 to December 2015 were analyzed retrospectively. Exclusion criteria: (1) age of less than 18 years;(2) chronic appendicitis; (3) periappendiceal abscess; (4) appendiceal mucocele or mucinous neoplasms; (5) appendiceal neuroendocrine tumors or cancers; (6) appendicitis during pregnancy; (7) concurrent AIDS, hematological disease, autoimmune disease, inflammatory bowel disease or advanced cancer; (8) other simultaneous surgery. A total of 373 patients were enrolled the study. These patients were divided into the recurrent group (133 cases) and the first episode group (240 cases) according to the previous history of antibiotic therapy for acute appendicitis. The prevalence of recurrent appendicitis was calculated, and the clinical characteristics were analyzed, including gender, age, comorbidities and preoperative CT images. Results: Of 373 patients, 209 were male and 164 were female, with a median age of 42 (18 to 88) years. Median recurrent time of the recurrent group was 4 (1 to 60) months. Compared to the first episode group, the recurrent group had higher proportion of age <50 years [71.4% (95/133) vs. 57.5% (138/240), χ(2)=7.081, P=0.008], higher proportion of concurrent diabetes [13.5% (18/133) vs. 5.4% (13/240), χ(2)=7.399, P=0.007], shorter onset time [(41.7±13.6) hours vs. (59.4±56.2) hours, t=-3.286, P=0.001], lower proportion of abdominal tension and rebound pain [57.9% (77/133) vs. 66.7% (160/240), χ(2)=5.065, P=0.024], lower score of modified Alvarado score [(5.6±1.9) point vs. (6.1±1.9) point, t=-2.417, P=0.016], lower WBC count [(10.5±4.6) ×10(9)/L vs. (11.5±4.5)×10(9)/L, t=-1.190, P=0.047], higher percentage of lymphocyte [(19.4±14.7)% vs. (16.1±13.3)%, t=2.069, P=0.039]. In the recurrent group, ratio of length of removed appendix ≥7 cm was higher as compared with the first episode group [44.4% (59/133) vs. 32.9% (79/240), χ(2)=4.808, P=0.028], while the ratio of complicated appendicitis was significantly lower [8.3% (11/133) vs. 22.9% (55/240), χ(2)=10.823, P=0.001]. CT images were available in 129 patients, intraluminal appendicoliths was found in 19 of 50 patients (38%) in the recurrent group, while in 16 of 79 patients (20.3%) in the first episode group, and there was statistically significant difference between the two groups (χ(2)=4.880, P=0.027). Conclusions: Clinical characteristics of recurrent acute appendicitis include age less than 50 years, concurrent diabetes, short onset time, less abdominal tension or rebound pain, low modified Alvarado score, low WBC count, high percentage of lymphocyte, appendix length longer than 7 cm, non-complicated appendicitis and intraluminal appendicoliths.

Patterns of COVID-19 on computed tomography imaging

PURPOSE

As the designated tertiary referral centre for infectious diseases in Hong Kong, our hospital received the city's first group of patients diagnosed with coronavirus disease 2019 (COVID-19). Herein, we studied the earliest patients admitted to our centre in order to clarify the typical radiological findings, particularly computed tomography (CT) findings, associated with COVID-19.

METHODS

From 22 January 2020 to 29 February 2020, 19 patients with confirmed COVID-19 underwent high-resolution or conventional CT scans of the thorax in our centre. The CT imaging findings of these patients with confirmed COVID-19 in Hong Kong were reviewed in this study.

RESULTS

Ground-glass opacities (GGO) with peripheral subpleural distribution were found in all patients (100%). No specific zonal predominance was observed. All lobes were involved in 16 (84.2%) patients, focal subsegmental consolidations were observed in 14 (73.7%) patients, and interlobular septal thickening was present in 12 (63.2%) patients. No mediastinal lymph node enlargement, centrilobular nodule, or pleural effusion was detected in any of the patients. Other imaging features present in several patients include bronchial dilatation, bronchial wall thickening, and crazy-paving patterns.

CONCLUSIONS

Peripheral subpleural GGO without zonal predominance in the absence of centrilobular nodule, pleural effusion, and lymph node enlargement were consistent findings in patients with confirmed COVID-19. The observed radiological patterns on CT scans can help identify COVID-19 and assess affected patients in the context of the ongoing outbreak.

Abstract 1667: A robust human immune profiling assay using CyTOF technology and automated data analysis software

Immune monitoring is an essential method for quantifying changes in immune cell population numbers and states over time in health and disease. A cornerstone in translational and clinical research, it is frequently used in the investigation of chronic inflammation, infectious disease, autoimmune diseases, and cancer. The diversity of immune cell populations demands a highparameter approach to more fully and efficiently quantify these changes. Mass cytometry, which utilizes CyTOF® technology, is a single-cell analysis platform that uses metal-tagged antibodies to resolve over 40 markers in a single tube of sample without the need for compensation. It is an ideal solution for routine enumeration of immune cell populations. However, development of a robust, highly multiplexed assay requires panel optimization as well as standardization of instrument setup and an analysis pipeline.

We have developed a sample-to-answer solution for human immune profiling using mass cytometry. It includes an optimized 30-marker immune profiling panel provided in a lyophilized, single-tube format, validated SOPs for human whole blood and PBMC staining, an instrument data acquisition template, instructions for data acquisition on a Helios™ system, and automated software for data analysis. The software analyzes FCS 3.0 files generated with the kit; automatically reports cell counts, percentage calculations, and staining intensity; and produces graphical elements such as histograms, dot plots, and a Cen-se′™ (t-SNE variant) graph for 36 immune cell populations.

Here we present assay analytical validation data on repeatability, reproducibility, software precision, and software accuracy. We also present a performance comparison of the lyophilized material and a liquid formulation of the same antibodies and clones used in the lyophilized format. This assay provides a robust, complete solution for broad immune profiling using mass cytometry that reduces sources of variability and subjectivity in sample preparation and data analysis.

Citation Format: Stephen K. Li, Daniel Majonis, C. Bruce Bagwell, Benjamin C. Hunsberger, Vladimir I. Baranov, Olga I. Ornatsky. A robust human immune profiling assay using CyTOF technology and automated data analysis software [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1667.

In vitro skin penetration of petrolatum and soybean oil and effects of glyceryl monooleate

OBJECTIVES

Petrolatum and soybean oil are common ingredients incorporated in topical skin formulations for skin protection and moisturization. However, the stratum corneum (SC) penetration kinetics of these two cosmetic ingredients has not been systematically studied. Glyceryl monooleate (GlyMOle) has been shown to enhance skin penetration of various compounds. It was hypothesized that GlyMOle could enhance skin penetration of petrolatum and soybean oil. This study aimed to examine the in vitro skin penetration of petrolatum and soybean oil in the presence or absence of GlyMOle.

METHODS

Skin permeation experiments were conducted using the in vitro Franz diffusion cell model with split-thickness human skin and human epidermal membrane (HEM). The effect of permeant dose and the kinetics of permeant penetration were examined with and without GlyMOle in vitro.

RESULTS

Petrolatum and soybean oil were found to permeate across HEM, and no effect of GlyMOle on skin permeation into the receptor chamber was observed. GlyMOle enhanced the penetration of petrolatum into the split-thickness skin at 50 μg dose (petrolatum:GlyMOle, 49 : 1, w/w). However, no effect of GlyMOle on petrolatum penetration was observed at 200 μg dose (of the same petrolatum:GlyMOle ratio), indicating a dose-dependent effect. GlyMOle at the level used in the study did not enhance the penetration of soybean oil with 50 and 200 μg doses at any timepoints.

CONCLUSION

GlyMOle was a skin penetration enhancer for petrolatum under the in vitro conditions identified in this study.

Magnetization reversal and magnetic interactions in anisotropic Nd-Dy-Fe-Co-B/MgO/α-Fe disks and multilayers

We report on a field induced domain evolutionary procedure in the anisotropic Nd-Dy-Fe-Co-B/MgO/Fe multilayers by using first-order-reversal-curves and magnetic force microscopy. Different reversal behaviors and domain sizes are found in well coupled and decoupled multilayers by changing the thickness of the spacer layer. The competition between dipolar magnetostatic energy and Zeeman energy is evaluated by in-field observation throughout nucleation and annihilation processes. In addition, lithography-patterned arrays of soft Fe disks onto a continuous Nd-Dy-Fe-Co-B hard-magnetic layer are designed. By decreasing the applied field, it is found that magnetization orientations of the Fe disk and Nd-Dy-Fe-Co-B layer are aligned parallel. In the decoupled disk, although the out-of-plane magnetization orientations are observed, the orientation of the domains in the Fe disk is random. Furthermore, it is found that a stronger anisotropy of the Nd-Dy-Fe-Co-B layer decreases the interaction length. Our results provide a new understanding of anisotropic nanocomposite magnets with long-ranged magnetic interactions.

Characterization of novel nitrate reductase-deficient mutants for transgenic Dunaliella salina systems

The aim of the present study was to isolate and characterize novel nitrate reductase (NR)-deficient mutants, which may be useful for the transgenic manipulation of Dunaliella salina. Three NR-deficient mutants of D. salina, J-1, J-2, and J-3, were successfully isolated by screening for chlorate resistance after chemical mutagenesis with ethylnitrosourea. NR activity was not detected in the mutants and the expression of NR mRNA was significantly decreased. Growth analysis of D. salina strains grown in media containing different nitrogen sources revealed that these mutants were capable of utilizing nitrite and urea, but not nitrate as a nitrogen source, indicating that these mutants are indeed NR-deficient. Mutation analysis of NR cDNA sequences revealed that there were 11 point mutations shared by the J-1, J-2, and J-3 mutants. Furthermore, the results of the functional complementation experiment showed that NR activity of transformant T-1 derived from J-1 was recovered to 48.1 % of that of the wild-type D. salina. The findings of the present study indicate that nitrate may be used as a selective agent rather than antibiotics or herbicides for the isolated NR-deficient mutants in future transgenic D. salina systems.

Passive and iontophoretic transport through the skin polar pathway

The purpose of the present article is to briefly recount the contributions of Prof. William I. Higuchi to the area of skin transport. These contributions include developing fundamental knowledge of the barrier properties of the stratum corneum, mechanisms of skin transport, concentration gradient across skin in topical drug applications that target the viable epidermal layer, and permeation enhancement by chemical and electrical means. The complex and changeable nature of the skin barrier makes it difficult to assess and characterize the critical parameters that influence skin permeation. The systematic and mechanistic approaches taken by Dr. Higuchi in studying these parameters provided fundamental knowledge in this area and had a measured and lasting influence upon this field of study. This article specifically reviews the validation and characterization of the polar permeation pathway, the mechanistic model of skin transport, the influence of the dermis on the target skin concentration concept, and iontophoretic transport across the polar pathway of skin including the effects of electroosmosis and electropermeabilization.

Aspirin desensitisation for Chinese patients with coronary artery disease

OBJECTIVE. To assess the efficacy and safety of aspirin desensitisation in Chinese patients with coronary artery disease. DESIGN. Case series. SETTING. A regional hospital in Hong Kong. PATIENTS. Chinese patients with coronary artery disease and a history of a hypersensitivity reaction to aspirin or non-steroidal anti-inflammatory drug, who underwent aspirin desensitisation between February 2008 and July 2012. RESULTS. There were 24 Chinese patients with coronary artery disease who were admitted to our unit for aspirin desensitisation during this period. The majority (79%) were clinical admissions for desensitisation; eight (33%) of them developed a hypersensitivity reaction during desensitisation. Half of the latter had only limited cutaneous reactions and were able to complete the desensitisation protocol and developed aspirin tolerance. Overall, 20 (83%) of the patients were successfully desensitised at the initial attempt. No serious adverse reactions occurred in the cohort. Twelve of the patients had significant coronary artery disease revealed by coronary angiography and received a percutaneous coronary intervention, nine of whom received drug-eluting stents while three received bare metal stents due to financial constraints. All 11 successfully desensitised patients received aspirin and clopidogrel as double antiplatelet therapy after percutaneous coronary intervention. The remaining patient had a bare metal stent implant due to failed aspirin desensitisation. CONCLUSION. Given the potentially different genetic basis of aspirin hypersensitivity in different ethnicities, recourse to desensitisation in the Chinese population has not previously been addressed. This study demonstrated that aspirin desensitisation using a rapid protocol can be performed effectively and safely in Chinese patients. Our results were comparable to those in other reported studies involving other ethnicities. Successful aspirin desensitisation permits patients to pursue long-term double antiplatelet therapy that includes aspirin after percutaneous coronary intervention, and thus allows the use of drug-eluting stents as a feasible option.

Role of fatty acid transport protein 4 in oleic acid-induced glucagon-like peptide-1 secretion from murine intestinal L cells

The antidiabetic intestinal L cell hormone glucagon-like peptide-1 (GLP-1) enhances glucose-dependent insulin secretion and inhibits gastric emptying. GLP-1 secretion is stimulated by luminal oleic acid (OA), which crosses the cell membrane by an unknown mechanism. We hypothesized that L cell fatty acid transport proteins (FATPs) are essential for OA-induced GLP-1 release. Therefore, the murine GLUTag L cell model was used for immunoblotting, [(3)H]OA uptake assay, and GLP-1 secretion assay as determined by radioimmunoassay following treatment with OA ± phloretin, sulfo-N-succinimidyl oleate, or siRNA against FATP4. FATP4(-/-) and cluster-of-differentiation 36 (CD36)(-/-) mice received intraileal OA, and plasma GLP-1 was measured by sandwich immunoassay. GLUTag cells were found to express CD36, FATP1, FATP3, and FATP4. The cells demonstrated specific (3)H[OA] uptake that was dose-dependently inhibited by 500 and 1,000 μM unlabeled OA (P < 0.001). Cell viability was not altered by treatment with OA. Phloretin and sulfo-N-succinimidyl oleate, inhibitors of protein-mediated transport and CD36, respectively, also decreased [(3)H]OA uptake, as did knockdown of FATP4 by siRNA transfection (P < 0.05-0.001). OA dose-dependently increased GLP-1 secretion at 500 and 1,000 μM (P < 0.001), whereas phloretin, sulfo-N-succinimidyl oleate, and FATP4 knockdown decreased this response (P < 0.05-0.01). FATP4(-/-) mice displayed lower plasma GLP-1 at 60 min in response to intraileal OA (P < 0.05), whereas, unexpectedly, CD36(-/-) mice displayed higher basal GLP-1 levels (P < 0.01) but a normal response to intraileal OA. Together, these findings demonstrate a key role for FATP4 in OA-induced GLP-1 secretion from the murine L cell in vitro and in vivo, whereas the precise role of CD36 remains unclear.

Reperfusion strategy for ST-segment elevation myocardial infarction: trend over a 10-year period

OBJECTIVES. To review the 10-year trend of reperfusion strategies in patients with ST-segment elevation myocardial infarction, and the adoption rate of percutaneous coronary interventions as opposed to thrombolytic therapy. Also to explore why some patients did not receive reperfusion therapy, and document changes in reperfusion strategies after the introduction of primary percutaneous coronary intervention programmes. DESIGN. Case series. SETTING. A regional hospital, Hong Kong. PATIENTS. All patients with ST-segment elevation myocardial infarction from January 2000 to December 2009. RESULTS. There were 1835 patients with ST-segment elevation myocardial infarction in that period, of which 1179 (64.3%) received reperfusion therapy (thrombolytic therapy, 46.0%; primary percutaneous coronary intervention, 17.5%; emergency coronary artery bypass graft, 0.7%). After introduction of the primary percutaneous coronary intervention programme, significantly more ST-segment elevation myocardial infarction cases underwent that particular intervention (1.6% in 2000 increasing to 30.6% in 2009), while the proportion receiving thrombolytic therapy declined (57.4% in 2000 decreasing to 35.0% in 2009). Seven reasons for no reperfusion therapy were identified. The commonest ones were delayed presentation (45.1%), succumbed before reperfusion (16.0%), multiple medical co-morbidities (15.2%), and contra-indication to thrombolytic therapy (14.8%). The proportion without reperfusion therapy due to a contra-indication to thrombolytic therapy declined (22.7% in 2000 decreasing to 4.9% to 2009), whilst an increasing proportion received primary percutaneous coronary interventions. CONCLUSIONS. Primary percutaneous coronary intervention is increasingly used as the reperfusion therapy in ST-segment elevation myocardial infarction and is replacing thrombolytic therapy, though the latter still remains a mainstay of therapy. A significant proportion of ST-segment elevation myocardial infarction cases received no reperfusion due to various reasons.

Ethnic differentiation of copy number variation on chromosome 16p12.3 for association with obesity phenotypes in European and Chinese populations

OBJECTIVE

Genomic copy number variations (CNVs) have been strongly implicated as important genetic factors for obesity. A recent genome-wide association study identified a novel variant, rs12444979, which is in high linkage disequilibrium with CNV 16p12.3, for association with obesity in Europeans. The aim of this study was to directly examine the relationship between the CNV 16p12.3 and obesity phenotypes, including body mass index (BMI) and body fat mass.

SUBJECTS

Subjects were a multi-ethnic sample, including 2286 unrelated subjects from a European population and 1627 unrelated Han subjects from a Chinese population. Body fat mass was measured using dual energy X-ray absorptiometry.

RESULTS

Using Affymetrix Genome-Wide Human SNP Array 6.0, we directly detected CNV 16p12.3, with the deletion frequency of 27.26 and 0.8% in the European and Chinese populations, respectively. We confirmed the significant association between this CNV and obesity (BMI: P=1.38 × 10(-2); body fat mass: P=2.13 × 10(-3)) in the European population. Less copy numbers were associated with lower BMI and body fat mass, and the effect size was estimated to be 0.62 (BMI) and 1.41 (body fat mass), respectively. However, for the Chinese population, we did not observe significant association signal, and the frequencies of this deletion CNV are quite different between the European and Chinese populations (P<0.001).

CONCLUSION

Our findings first suggest that CNV 16p12.3 might be ethnic specific and cause ethnic phenotypic diversity, which may provide some new clues into the understanding of the genetic architecture of obesity.

Primary percutaneous coronary intervention for ST elevation myocardial infarction: performance with focus on timeliness of treatment

OBJECTIVE

To review primary percutaneous coronary interventions performed for patients with ST elevation myocardial infarction with a focus on door-to-treatment time, especially after introduction of a new management programme in November 2003.

DESIGN

Retrospective study.

SETTING

Regional hospital, Hong Kong.

PATIENTS

All patients with ST elevation myocardial infarction who underwent primary percutaneous coronary intervention in our hospital from January 2002 to December 2007.

RESULTS

In all, 209 patients with ST elevation myocardial infarction had primary percutaneous coronary interventions between January 2002 and December 2007; 140 of them were admitted within office hours, 125 of whom came directly from Accident and Emergency Department. The mean door-to-balloon time of these patients was 115 minutes, and in 41% the time was less than 90 minutes (as recommended by the American College of Cardiology/American Heart Association guidelines). Since introduction of the new programme, the mean door-to-balloon time has diminished significantly, from 146 to 116 minutes (P=0.047). Delay in diagnosis (28%) and Cardiac Catheterization Laboratory being occupied (20%) were the two most common reasons for prolonged door-to-balloon times.

CONCLUSION

We achieved satisfactory performance in our primary percutaneous coronary intervention programme, providing timely reperfusion therapy for patients with ST elevation myocardial infarction. A well-organised and systematic clinical pathway is a prerequisite for a centre that provides a timely and effective primary percutaneous coronary intervention service for patients with ST elevation myocardial infarction. Better public education and greater awareness on the part of medical service providers are needed, so as to facilitate urgent revascularisation and improve outcomes in patients with ST elevation myocardial infarction.

A report on a randomly sampled questionnaire survey about renal stone disease in Hong Kong

OBJECTIVES

To investigate the prevalence and characteristics of patients with renal stone in Hong Kong, and awareness of corresponding prevention strategies.

DESIGN

Telephone public survey.

SETTING

Hong Kong community. PARTICIPANTS. A public telephone survey concerning the occurrence of renal stone disease and the public awareness of the condition was performed. Respondents whose telephone numbers were randomly selected by computer and the family member of the household who had the closest birthday to that date was chosen for interview. Data collected were further adjusted for the gender and age distribution of the Hong Kong population in mid-2007.

RESULTS

A total of 1010 Hong Kong citizens aged 18 years or above were successfully interviewed in November 2007. Among them, 25 respondents themselves had a history of renal stones, yielding a point prevalence of 2.5%. In addition, 70 respondents had family members with a history of renal stones, yielding an estimated household point prevalence of 6.9%. Stone patients were mainly older, male, and imbibed less fluids than the average for all respondents. The public's concepts with regard to the diet necessary and the importance of taking more fluid to prevent stone formation was poor.

CONCLUSION

Hong Kong has a relatively low prevalence of renal stone disease, compared to neighbouring areas. However, the local public and affected patients had little knowledge and awareness about this important health problem.

Investigation of the frequency and force of chest vibration performed by physiotherapists

PURPOSE

To investigate the frequency and force of chest vibration as applied by 18 physiotherapists working in a teaching hospital.

METHOD

CHEST VIBRATION WAS APPLIED TO A HEALTHY ADULT MALE LYING SUPINE ON A PLINTH WITH SEVEN MOUNTED SENSORS MEASURING FREQUENCY AND FORCE, DURING THREE TEST CONDITIONS: (1) directly on the chest, (2) on the chest through a layer of sheet, and (3) on the chest through a layer of towelling. The influence of gender and current practice area (physiotherapists working in cardiopulmonary areas [cardiopulmonary physiotherapists] and physiotherapists who presently did not work in the cardiopulmonary area, but had treated cardiopulmonary patients within the last year [general practice physiotherapists]) on the frequency and force of chest vibrations was examined.

RESULTS

Physiotherapists demonstrated a mean frequency of 5.7, 5.3, and 5 Hz and a mean maximum force of 272.78, 273.47, and 271.13 N for conditions 1, 2, and 3 respectively. There were no significant differences in the frequency or forces generated by vibration between cardiopulmonary and general practice physiotherapists, between genders, or among the three test conditions.

CONCLUSIONS

Vibration frequency was lower and force higher than previously recorded. Force may vary depending on the patient. The addition of a sheet or towel did not affect the force or frequency of vibration compared to vibration performed directly on the chest.

Complete recovery from acute encephalopathy of late-onset ornithine transcarbamylase deficiency in a 3-year-old boy

Ornithine transcarbamylase deficiency is the commonest urea cycle disorder which is transmitted in X-linked inheritance. It is mainly characterized in males by acute encephalopathy and hyperammonaemia with fatal outcomes in both classical neonatal and late-onset types. We report a 3-year-old healthy Hong Kong Chinese boy who presented with acute encephalopathy and coma after three days of gastroenteritis. He had no focal neurological deficit and brain CT imaging was normal. His plasma ammonia (54 micromol/L) and glutamine (747 micromol/L) concentrations were normal. The only biochemical abnormalities detected were marked orotic aciduria (700 micromol/mmol creatinine) and elevated urinary uracil. He regained consciousness spontaneously after three days under intensive care with parenteral fluid therapy. He recovered completely without any neurological deficits. Five months after discharge, urinary uracil concentration remained elevated despite normalized orotic acid concentration. Finally, ornithine transcarbamylase deficiency was diagnosed by DNA analysis. A missense mutation of arginine-to-glutamine substitution on amino acid 277 (p.R277Q) was revealed to be a late-onset mutant. Our case strengthens the argument that in any child with coma or acute encephalopathy of undetermined cause, genetic analysis of the OTC gene and the measurement of urinary uracil concentration remain the most reliable indicators of late-onset OTCD during acute and even quiescent phases. Existing neonatal screening programmes for inheritable metabolic disorders fail to detect late-onset variants. Therefore, a high clinical suspicion is a key to correct and timely diagnosis, especially in those patients with atypical presentations.

Noninvasive measurement of phenylalanine by iontophoretic extraction in patients with phenylketonuria

Phenylketonuria is an autosomal recessive disorder characterized by elevated concentrations of phenylalanine. Elevated phenylalanine concentrations can impair intellectual functions and the disease is treated with a lifelong diet and frequent monitoring of plasma phenylalanine concentrations. Previous in vitro studies have demonstrated the feasibility of iontophoretically enhanced transdermal transport of phenylalanine. Here we evaluate the feasibility of transdermal iontophoretic extraction of phenylalanine in vivo. Phenylalanine was iontophoretically extracted from the skin of healthy volunteers and of patients with phenylketonuria for up to 6 h and concentrations were compared with those measured in plasma. The amount of phenylalanine iontophoretically extracted from the skin declined over time, suggesting contribution of phenylalanine from the skin in the initial extraction. Phenylalanine iontophoretically extracted from skin correlated with plasma phenylalanine levels at plasma levels above 300 micromol/L. This correlation supports the feasibility of iontophoretic phenylalanine extraction for monitoring phenylketonuria.

A free scapular skin flap for penile reconstruction

INTRODUCTION

There are many possible methods for penis reconstruction, among them, pedicled flaps, myocutaneous flaps, combined osseocutaneous flaps, and free skin flaps. This study evaluated the free scapular skin flap method for penile reconstruction.

METHODS

Fifteen men aged 20 to 48 underwent the procedure between March 2000 and February 2006, with follow-up examinations from 6 months to 5 years.

RESULTS

Fourteen of the reconstructions were successful, with patients enjoying good cosmetic results as well as functionality.

CONCLUSION

The free scapular skin flap technique is a good method for penile reconstruction.

Difference in expression level and localization of DNA polymerase beta among human esophageal cancer focus, adjacent and corresponding normal tissues

The aim of this paper was to study the expression level and localization of DNA polymerase beta (polbeta) and the difference in those among the human esophageal cancer focus, cancer adjacent and corresponding normal esophageal tissues. These three kinds of tissues were collected from surgically resected tissues in 17 patients with esophageal carcinoma in Linzhou, China. Each of a total of 51 tissue pieces was divided into two aliquots: one aliquot for detection of polbeta expression by in situ hybridization and by immunohistochemistry; another for detection of polbeta expression by RNA dot blot and immunoblotting. In the tissue specimens detected by in situ hybridization and immunohistochemistry, the cancer focus tissue had much stronger polbeta expression signals localized in the scattered heteromorphologic cancer cells. The cancer adjacent tissue exhibited slightly stronger polbeta signals mainly localized in the epithelial proliferating cells and the corresponding normal tissue displayed weak polbeta signals basically located in the epithelial basal cells. The difference in expression level of polbeta among the three kinds of tissues detected by RNA dot blot and immunoblotting was similar to the above results. Further, the truncated POLB could be demonstrated in both cancer focus and cancer adjacent tissues, but could not be found in the corresponding normal tissue in immunoblotting. The results suggest that the overexpression of polbeta with truncated form may be a potential biomarker for early diagnosis of human esophageal carcinoma.

Feasibility of transradial coronary angiography and angioplasty in Chinese patients

OBJECTIVE

To assess the clinical applicability, efficacy, and safety of coronary angiography and angioplasty via a transradial approach in local Chinese patients.

DESIGN

Prospective case series.

SETTING

Regional hospital, Hong Kong.

PATIENTS

All patients undergoing coronary angiography and coronary angioplasty between 1 January and 30 June 2004.

INTERVENTIONS

Transradial coronary angiography and coronary angioplasty.

MAIN OUTCOME MEASURES

Feasibility, success rate, and complications.

RESULTS

A total of 268 coronary angiographies (62% of all coronary angiographies) and 118 coronary angioplasties (48% of all coronary angioplasties) were performed via a transradial approach. The procedural success rate for coronary angiography was 93.7% with a mean duration of 21.8 (standard deviation, 13.5) minutes compared with 17.9 (10.0) minutes for angiography via a femoral approach. Most (99%) patients were free from any complications. Of those patients who underwent elective transradial coronary angiography in the morning, 64% were discharged on the same day. Comparison of data in the first half of the study period with those in the second half revealed a significant increase in the percentage of coronary angiographies performed via a transradial approach (from 52% to 73%, P<0.0001), and an improved procedural success rate (from 91.5% to 95.3%, P=0.1). For transradial coronary angioplasty, the procedural success rate was 98%. A total of 246 lesions (2.08 lesions per patient) were treated with no procedure-related complications.

CONCLUSIONS

Transradial coronary angiography and angioplasty are feasible in a significant proportion of local Chinese patients and achieve a high success rate and low complication rate. It tends to prolong procedural duration, but improves patients' comfort and permits earlier ambulation and discharge. The procedural success rate improves with accumulating experience.

Necrotic cardiac haemangioma masquerading as sepsis with disseminated intravascular coagulation

Cardiac haemangiomas are exceptionally rare benign vascular tumours. We report a case of cardiac haemangioma presenting with pyrexia of unknown origin and clinical features simulating sepsis with disseminated intravascular coagulation. The clinical course was complicated by systemic embolism.

Long-term pharmacotherapy for overweight and obesity: a systematic review and meta-analysis of randomized controlled trials

CONTEXT

Safe and effective strategies to curb rising obesity prevalence rates are urgently needed and medications may play a more prominent role in future therapeutic regimens.

OBJECTIVE

To review systematically the long-term efficacy and safety of approved antiobesity medications.

DATA SOURCES

MEDLINE, EMBASE, the Cochrane Controlled Trials Register, Current Science Meta-register of Controlled Trials, and reference lists of original studies and reviews were searched. Drug manufacturers and two obesity experts were contacted. No language restrictions were imposed.

STUDY SELECTION

Double-blind, randomized controlled studies of approved antiobesity medications with follow-up periods of 1 y or greater were eligible for inclusion.

DATA EXTRACTION

Two reviewers independently assessed all potentially relevant studies for inclusion and methodological quality using standardized abstraction forms.

RESULTS

A total of 11orlistat (n=6021) and three sibutramine (n=929) studies met inclusion criteria. Attrition rates averaged 33% in orlistat studies and 48% in sibutramine studies. A random effects model was used for meta-analysis. Compared to placebo, orlistat-treated patients displayed a 2.7 kg (95% CI: 2.3-3.1 kg) or 2.9% (95% CI: 2.3-3.4%) greater reduction in weight and patients on sibutramine displayed a 4.3 kg (95% CI: 3.6-4.9 kg) or 4.6% (95% CI: 3.8-5.4%) greater weight reduction after 1 y of follow-up. The number of patients achieving 10% or greater weight loss was 12% (95% CI: 8-16%) higher with orlistat and 15% (95% CI: 4-27%) higher with sibutramine compared to placebo. Orlistat caused gastrointestinal side effects and sibutramine increased blood pressure and pulse rate.

CONCLUSION

There is a relative paucity of long-term studies of antiobesity agents. In weight loss trials of 1-y duration, orlistat and sibutramine appear modestly effective in promoting weight loss. Longer, more methodologically rigorous studies that are powered to examine end points such as mortality and cardiovascular morbidity are required.

Isolated ventricular non-compaction presenting with ventricular tachycardia

Isolated ventricular non-compaction is a rare congenital cardiomyopathy, manifested morphologically as prominent myocardial trabeculations and deep inter-trabecular recesses that communicate with the ventricular cavity. Heart failure is the most common presenting condition. Other manifestations include arrhythmia and cardioembolic events. This report is illustrative of isolated ventricular non-compaction in a 78-year-old woman. The diagnosis was made when she presented with ventricular tachycardia many years after a stroke. She subsequently underwent implantation of a cardioverter-defibrillator. This report documents an uncommon presentation of this disease entity in the oldest patient at presentation as yet reported in the literature.

Mechanistic studies of the effect of hydroxypropyl-beta-cyclodextrin on in vitro transdermal permeation of corticosterone through hairless mouse skin

Literature reports reveal that the issue of whether cyclodextrins may act as skin permeation enhancers has not been resolved. Accordingly, in vitro skin transport studies were conducted to address this question. Corticosterone (3H-CS and/or non-radiolabeled CS) was chosen as the model permeant for transport experiments with hairless mouse skin (HMS) and with a synthetic cellulose membrane of 500 molecular weight cut off (MWCO), the latter to help establish baseline behavior. Hydroxypropyl-beta-cyclodextrin (HPbetaCD) was selected as the representative cyclodextrin. The CS/HPbetaCD complexation constant was determined both from solubility data (saturation conditions) in phosphate buffered saline (PBS), pH 7.4 and with data obtained from PBS/silicone polymer partitioning experiments, the latter experiments permitting the determination of the complexation constant at low CS concentrations. These results were used in the calculations of the free CS concentrations in the donor chamber of the transport experiments. The CS transport experiments were conducted at CS solubility saturation and under supersaturation (resulting from autoclaving at 121 degrees C) conditions as well at very low (tracer level) concentrations. The effect of polyvinylpyrrolidone as a solution additive was also evaluated. The following were the key outcomes of this study. Contrary to literature reports, there was no evidence that HPbetaCD is an enhancer for CS transport through HMS. The CS permeability coefficient values obtained with HMS in all of the experiments were found to be the same within experimental error when calculated on the basis of the free CS concentration as the driving force for permeation. The constancy of the permeability coefficient in the presence and absence of HPbetaCD is interpreted to mean that, in these experiments, HPbetaCD did not alter the barrier properties of HMS stratum corneum to any significant extent nor did it enhance CS transport in any other manner such as by a carrier mechanism involving the aqueous boundary layer or by a carrier mechanism within the stratum corneum.

Long-term pharmacotherapy for obesity and overweight

BACKGROUND

Worldwide prevalence rates of obesity and overweight are rising and safe and effective treatment strategies are urgently needed. A number of anti-obesity agents have been studied in short-term clinical trials, but long-term efficacy and safety need to be established.

OBJECTIVES

To assess/compare the effects and safety of approved anti-obesity medications in clinical trials of at least one-year duration.

SEARCH STRATEGY

MEDLINE, EMBASE, the Cochrane Controlled Trials Register, the Current Science Meta-register of Controlled Trials, and reference lists of original studies and reviews were searched. Date of last search was December 2002. Drug manufacturers and two obesity experts were contacted in to detect unpublished trials. No language restrictions were imposed.

SELECTION CRITERIA

Double-blind, randomised controlled weight loss and weight maintenance trials of approved anti-obesity agents that 1) enrolled adult overweight or obese patients, 2) included a placebo control group or compared two or more anti-obesity drugs 3) used an intention-to-treat analysis, and 4) had a minimum follow-up period of one year. Abstracts and pseudo-randomised trials were not included.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed all potentially relevant citations for inclusion and methodological quality. The primary outcome measure was weight loss.

MAIN RESULTS

Of the eight anti-obesity agents investigated, only orlistat and sibutramine trials met inclusion criteria. Eleven orlistat weight loss studies (four of which reported a second year weight maintenance phase) and five sibutramine studies (three weight loss and two weight maintenance trials) were included. Attrition rates averaged 33% during the weight loss phase of orlistat trials and 43% in sibutramine studies. All patients received lifestyle modification as a co-intervention. Compared to placebo, orlistat-treated patients lost 2.7 kg (95% CI: 2.3 kg to 3.1 kg) or 2.9% (95% CI: 2.3 % to 3.4%) more weight and patients on sibutramine experienced 4.3 kg (95% CI: 3.6 kg to 4.9 kg) or 4.6% (95% CI: 3.8% to 5.4%) greater weight loss. The number of patients achieving ten percent or greater weight loss was 12% (95% CI: 8% to 16%) higher with orlistat and 15% (95% CI: 4% to 27%) higher with sibutramine therapy. Weight loss maintenance results were similar. Orlistat caused gastrointestinal side effects and sibutramine was associated with small increases in blood pressure and pulse rate.

REVIEWER'S CONCLUSIONS

Studies evaluating the long-term efficacy of anti-obesity agents are limited to orlistat and sibutramine. Both drugs appear modestly effective in promoting weight loss; however, interpretation is limited by high attrition rates. Longer and more methodologically rigorous studies of anti-obesity drugs that are powered to examine endpoints such as mortality and cardiovascular morbidity are required to fully evaluate any potential benefit of such agents.

[Repair of facial soft tissue defect using temporal flap pedicled with orbicularis oculi muscle]

OBJECTIVE

To probe into the methods and effects of small soft tissue defect of facial area, nose and eyelid repaired by temporal island flap pedicled with orbicularis oculi muscle.

METHODS

From 1994 to 1999, 12 cases with cicatricial ectropion of eyelid, scar in nose and facial area or facial mole were repaired by temporal flap pedicled with orbicularis oculi muscle. The maximal area of skin flap was 3 cm x 5 cm.

RESULTS

All the skin flaps were survived after operation. Six cases were followed up from 6 months to 4 years, the results were satisfied. There were no secondary deformity or scar formation in the donor site.

CONCLUSION

The blood supply of orbicularis oculi muscle is plentiful. It is a reliable method to repair of small facial tissue defect using temporal island flap pedicled with orbicularis oculi muscle. But in bigger facial soft tissue defect, it should be cautious.

Influences of alkyl group chain length and polar head group on chemical skin permeation enhancement

Previous investigations in our laboratory on the influence of the n-alkanols and the 1-alkyl-2-pyrrolidones as skin permeation enhancers for steroid molecules as permeants demonstrated that the enhancer potencies (based on aqueous concentration values) of these two homologous series were the same when compared at the same alkyl chain length; that is, the contribution of the hydroxyl group and that of the pyrrolidone group to enhancer potency were the same. The purpose of the present study was to further investigate what was believed to be a somewhat surprising finding, and two additional homologous series, the 1,2-alkanediols and N,N-dimethylalkanamides, were selected for study as enhancers. Corticosterone (CS) flux enhancement along the lipoidal pathway of hairless mouse skin stratum corneum was determined with 1,2-hexane-, 1,2-octane-, and 1,2-decanediol and with N,N-dimethylhexanamide, N,N- dimethylheptanamide, N,N-dimethyloctanamide, and N,N-dimethylnonanamide as enhancers. The enhancement factor (E) for the lipoidal pathway was calculated from the CS permeability coefficient and the CS solubility data over a 4 to 100 range of E values. Comparisons of the enhancer potencies of all four homologous series revealed that the enhancer potencies of all were very nearly the same when compared at equal alkyl group chain length. Moreover, the contribution of each of the polar head groups toward the enhancer potency was essentially constant, independent of the alkyl group chain length. It was reasoned that this outcome was either the result of the random selection of four polar head groups making the same contribution to enhancer potency or the result of these particular polar head groups not contributing to enhancer potency. To test the hypothesis that the former was more likely than the latter and that a suitable semipolar organic phase may mimic the microenvironment of the polar head group at the site of enhancer action, n-octanol-phosphate buffered saline (PBS) and n-hexane-PBS partition coefficients were determined for all the enhancers. The n-octanol-PBS partition coefficients for the enhancers, but not the n-hexane-PBS partition coefficients, were very nearly the same when compared at equal alkyl group chain lengths; this result supports the hypothesis that each of the four polar head groups likely contributes the same toward the enhancer potency and locates in the semipolar region of the hairless mouse skin stratum corneum lipid bilayers, which is well-approximated by water-saturated n-octanol.

On-off transport through a thermoresponsive hydrogel composite membrane

A novel thermoresponsive composite membrane is described through which the permeation of molecules is dependent on the temperature of the milieu. The thermoresponsive composite membranes utilise a thermosensitive crosslinked polymeric hydrogel, which possesses a volume phase transition temperature (VPTT). The hydrogel was polymerised in situ within the pores of a sintered glass filter, through which significant permeation of molecules only occurred at temperatures above the VPTT of the hydrogel. It was found that the permeation of molecules through the thermoresponsive composite membranes could be modulated by changing the environmental temperature.

Iontophoretic transport of oligonucleotides across human epidermal membrane: a study of the Nernst-Planck model

The objective of this study was to investigate the transport behavior of a series of oligonucleotides with human epidermal membrane (HEM) and to examine the applicability of the modified NERNST-PLANCK model to transdermal iontophoresis of these macromolecules. Iontophoretic transport experiments were first carried out in a synthetic model membrane system (Nuclepore membranes) with a four-electrode potentiostat to examine the baseline modified NERNST-PLANCK model. The modified NERNST-PLANCK model derived from the Einstein relation and the Stokes-Einstein equation taken from previous work did not hold for the oligonucleotides. Results obtained in the Nuclepore studies were, however, consistent with predictions of the modified NERNST-PLANCK model using the experimentally determined electromobilities and diffusion coefficients. The electromobilities of the oligonucleotides (determined by capillary electrophoresis) were found to be more than a factor of two smaller than expected from the Einstein relation between electromobilities and diffusion coefficients (the latter determined in diffusion cell experiments). A correlation between these electromobilities and the theoretical electromobilities estimated by considering the effects of counterion binding and the effects of mobility reduction according to colloid theory was also observed. These results suggest that the modified NERNST-PLANCK model predictions are satisfactory only when the electromobilities and the effective molecular size of the oligonucleotides are known and are used directly to predict the iontophoretically enhanced transport. Results with the HEM experiments generally agreed with model predictions based on the experimental electromobilities. The oligonucleotide HEM flux data also suggest the existence of pores with effective pore radii greater than the effective radii estimated in previous studies with small molecular weight model permeants.

Quantification of pore induction in human epidermal membrane during iontophoresis: the importance of background electrolyte selection

It has been shown that significant pore induction (electroporation) occurs in human epidermal membrane (HEM) during iontophoresis even at moderate applied voltages (1-10 V). Recent efforts in our laboratory have been aimed at quantifying HEM electroporation by examining the proportionality between flux enhancement due to electroporation and electrical conductance changes during iontophoresis. The specific purpose of the present study was to test the hypothesis that by matching the background electrolyte ion sizes with the permeant ion sizes, the flux enhancement due to electroporation can be quantified by the change in HEM electrical conductance. In this study, radiolabeled tetraethylammonium (TEA(+)), methylammonium (MA(+)), and mannitol were the permeants. Potassium chloride (KCl), tetraethylammonium bromide (TEAB), tetraethylammonium pivalate (TEAP), and sodium fluoride (NaF) were the background electrolytes. Iontophoresis experiments were carried out over an applied voltage range of 1 to 3 V. The experimental flux enhancement results were compared with the theoretical predictions from the Nernst-Planck model after corrections were made: (a) for HEM pore induction during iontophoresis based on electrical conductance changes and (b) for electroosmosis employing mannitol as the neutral probe permeant. In experiments where the ion sizes of the background electrolyte and permeant were closely matched (e.g., TEA(+) as the permeant and TEAP as the background electrolyte), there was excellent agreement between experimental results and theoretical predictions of the modified Nernst-Planck model, with only modest data scatter. When the electrolyte and permeant sizes were quite different (e.g., TEA(+)/KCl and MA(+)/TEAP), the experimental flux data were inconsistent with model predictions and there were large variations in the experimental results. The results of the present study illustrate that permeant flux enhancement can be predicted by the modified Nernst-Planck model even during moderate voltage iontophoresis when electroporation is operative.

Retroperitoneoscopic nephrectomy (RN): using the gravity technique to facilitate specimen entrapment

BACKGROUND

Kidney entrapment is generally considered to be a difficult step in retroperitoneoscopic nephrectomy (RN). Normally, a large device is needed to accommodate the specimen, which may measure </=14 x 10 cm. There is just too little space to maneuver either the entrapment device or the specimen. Herein we describe a technique that can overcome this difficulty and even turn the space limitation to advantage.

METHODS

After the nephrectomy, the specimen is pushed caudally. A 15-mm Endocatch is inserted via the posterior cranial port. It is positioned strategically underneath the specimen so that when the entrapment bag is released, the specimen will have no room to move (because of the limited space) and will simply fall into the bag (because of gravity).

RESULTS

We have used this technique for our last four cases of retroperitoneoscopic nephrectomy and found that it remarkably shortened the operative time for this step.

CONCLUSION

One of the criticisms leveled against retroperitoneoscopic surgery concerns the problems posed by the space limitation. This technique turns the space limitation into an advantage and guarantees successful specimen entrapment.

Isolation of thecal cells: an assessment of purity and steroidogenic potential

In the present investigation, the responsiveness of rat thecal cells, prepared by means of an optimised discontinuous Percoll density gradient centrifugation procedure and cultured under serum-free cell culture conditions, to different concentrations of follitropin (FSH), basic fibroblast growth factor (FGF-2 or bFGF), and lutropin (LH) has been examined. The estradiol (E(2)) and progesterone (P(4)) contents of the cell culture medium were simultaneously determined with aliquots collected after different times of exposure to these regulatory proteins, either individually or in combination. The results confirm that no E(2) could be detected in the cell culture medium of the rat thecal cells prepared and cultured in this manner following all of these different treatments, and hence no contamination of the thecal cell preparations by granulosa cells was evident. The effects of FGF-2 and LH on the steroidogenic and cytodifferentiational properties of these rat thecal cells under serum-free cell culture procedures were also examined. The production of P(4) in the Percoll-purified rat thecal cell cultures receiving different treatments of FSH, and/or FGF-2 did not differ from the basal cell cultures, and no E(2) was detected from the same culture media. In contrast, LH (20 or 50 ng/ml) was found to enhance the production of P(4) (P<0.05) in the serum-free cell culture media. The stimulation of P(4) production was greater at higher LH concentration (50 ng/ml) (P<0.05). Concurrent treatment of LH (20 or 50 ng/ml) and FGF-2 (1-100 ng/ml) showed that FGF-2 inhibited the production of P(4) by LH-stimulated thecal cell cultures (P<0.05). The inhibition by FGF-2 was greater when LH was at a lower concentration (EC(50)<1 ng/ml at LH-20 ng/ml vs. EC(50)>1 ng/ml at LH-50 ng/ml). The results of the present study thus indicate that rat thecal cells isolated by this optimised Percoll density centrifugation procedure maintain a very high steroidogenic potential and specificity. Consistent with the absence of contaminating granulosa cells, these rat theca cell preparations do not respond to FSH treatment in terms of E(2) production. However, these rat theca cell preparations can be stimulated by LH to express their differentiated status in serum-free medium and respond to growth factors such as FGF-2.

[Transplantation of free scapular flap to repairing injury of faciocervical region]

OBJECTIVE

To sum up transplantation of free scapular flap to repairing injury of faciocervical region, 103 cases in past 16 years were reviewed.

METHODS

The scapular flap contained the ascending, descending, and transverse branches of the circumflex scapular artery. The range of the flap was as following: across the scapular spine to the acromion in upper edge, to the level of anterior iliac spine in lower edge, to the bilateral middle axillary line in both sides.

RESULTS

The clinical result was good. Fifty eight cases were followed up for 3 months to 10 years, the function of the faciocervical region was recovered with satisfied contour. In part of the patients, a second-stage operation was performed to make the flap thinner.

CONCLUSION

The maximal range of the flap can be 45 cm x 16 cm. For its sufficient blood supply, it should be of no influence on survival of the flap if the window is open in suitable site. Because of its large range of donating region and sufficient blood supply, it is fit for children.

Mechanistic aspects of iontophoresis in human epidermal membrane

A large number of factors are involved in the movement of ions and molecules across human epidermal membrane (HEM) under the influence of an electric field. These factors and their interplay need to be understood if our knowledge of iontophoretic transport of drugs across HEM is to reach a point where physical models and strategies may be employed for useful quantitative predictions. In a typical in vitro experiment, the fully hydrated HEM is positioned between aqueous compartments of a two-chamber diffusion cell. When a low electric field is applied across the HEM under these conditions, the transport enhancement of ions in the pre-existing pores of the stratum corneum is the result of, (a) the direct interaction of the electric field with the charge of the ion in question, and (b) convective solvent flow (electroosmosis); in the case where the permeant is non-ionic under these circumstances, transport enhancement is by convective solvent flow only. At moderate-to-high voltage iontophoresis (> or = around 1.0 V applied across a single HEM), in addition to the direct field effect and convective solvent flow in the pre-existing pores, there can generally be a significant (e.g. 10- to 100-fold enhancement) contribution to transport enhancement arising from new pore induction (electroporation). Much of the recent work in our laboratory has been devoted to defining and quantifying HEM electroporation, and an especially difficult aspect has been that of dealing with the large HEM membrane-to-membrane variabilities with regard to, (a) the extent of new pore induction, and (b) the characteristics of the newly induced pores. Recently we discovered that the extent of relevant (i.e. permeant accessible) pore induction may be correlated to the change in HEM electrical conductance (and quantifiable) if an appropriate matching background electrolyte can be selected having ion sizes comparable to that of the permeant. For example, employing tetraethylammonium (TEA) pivalate (PIV) for which the ion sizes are approximately 3.5 A, but not KCl (ion sizes approximately 1.9 A), as the background electrolyte for TEA (as the permeant) gave very good results; in this example, the sizable contribution of pore induction to iontophoresis was quantitatively factored out from the total iontophoretic enhancement. Experiments with a large number of HEM samples gave good agreement with the Nernst-Planck (N-P) predictions of the direct field effect when TEA-PIV was used as the background electrolyte for TEA transport, but large variations (up to 300%) between N-P predictions and experimental results were observed with KCl as the background electrolyte. Another area of recent effort has been HEM pore size determinations, both at low voltages (i.e. for pre-existing pores) and at voltages where the newly induced pores dominate HEM permeability. The sizes of pre-existing pores of HEM have been determined with the hindered diffusion theory (using experimental fluxes of several probe permeants of different known molecular sizes) to be generally in the range, 10-20 A, by a number of investigators in our laboratory for a large number HEM samples. Deducing pore sizes of electric field induced pores under steady electroporation conditions has been a more challenging task. We succeeded recently in developing a novel method for 'passively' determining pore sizes (i.e. by passive diffusion with hindered diffusion theory) under steady electroporation conditions: by using low frequency (12.5 Hz) a.c. at 2-5 V. We have been able to sustain electroporation at a nearly constant state of electroporation long enough to carry out a set of 'passive' diffusion experiments with relatively good precision to obtain the sizes of the newly induced pores. Studies to date have revealed that the sizes of pores induced with 2-5 V are of the same order of magnitude as those of the pre-existing pores (i.e. 10-20 A). Finally, another research question of interest has been that of pore charge

Pore charge distribution considerations in human epidermal membrane electroosmosis

The aim of this study was to assess the extent to which a model with pores having only net negative charges would adequately describe transdermal electroosmosis in human epidermal membrane (HEM) at neutral pH. Such information would enhance the predictive value of the modified Nernst-Planck model for transdermal iontophoresis, in addition to providing insights regarding the likelihood of significant pore charge distribution in HEM. Baseline results (the control) obtained from 0.1 to 0.4 V anodal and cathodal electroosmosis experiments with synthetic polycarbonate membranes (Nuclepore membranes), using radiolabeled urea and mannitol as the model permeants, demonstrated that such a membrane system can be modeled by the electrokinetic (electroosmosis) theory with the assumption of the pores possessing only negative charges. The studies with HEM were carried out at low voltage (</=0.5 V) where alterations in the barrier properties of HEM were minimal and at higher voltages (>/approximately = 1.0 V) where significant field-induced pore formation in HEM occurred. In both the low and high voltage studies, radiolabeled urea, mannitol, and water were employed as permeants in cathodal and anodal iontophoresis experiments. The results of the low voltage iontophoresis experiments suggest significant pore charge distribution in HEM (a significant deviation between the predictions from the single pore charge type assumption and the experimental data). Under the higher applied voltage conditions (>/approximately = 1.0 V), results from anodal and cathodal electroosmosis studies were consistent with the model in which the HEM has only pores that are net negatively charged.

Pore induction in human epidermal membrane during low to moderate voltage iontophoresis: A study using AC iontophoresis

The present study aimed to investigate new pore induction as a flux-enhancing mechanism in human epidermal membrane (HEM) with low to moderate voltage electric fields. The extent of pore induction and the effective pore sizes of these induced pores were to be assessed using a low frequency (12.5 Hz) low to moderate voltage (2. 0 to 4.0 V) square-wave alternating current (ac) "passive" permeation method (ac iontophoresis). This ac approach was to allow for inducing and sustaining a state of pore induction in HEM while permitting no significant transport enhancement via electroosmosis; thus, transport enhancement entirely due to new pore induction (enhanced passive permeation) was to be assessed without any contributions from electroosmosis. Good proportionality between the increase in HEM permeability and its electrical conductance was found with the "passive" transport data obtained during square-wave ac iontophoresis using urea as the model permeant. Typically, at 3.0 to 4.0 V, HEM conductance increases (and permeability increases) ranged from around 3- to 30-fold. These results appear to be the first direct evidence that new pore induction in HEM is a significant flux enhancing mechanism under moderate voltage conditions. The extents of pore induction in HEM under low frequency moderate voltage (2.0 to 3.0 V) ac, pulsed direct current (dc), and continuous dc were also compared. The extents of pore induction from square-wave ac and pulsed dc were generally of the same order of magnitude but somewhat less than that observed during continuous dc iontophoresis at the same applied voltage and duration, suggesting less extent of pore induction with reversing polarity or when a brief delay is provided between pulses to allow for membrane depolarization. The average effective pore sizes calculated for the induced pores from the experimental data with urea and mannitol as probe permeants and the hindered transport theory were 12 +/- 2 A, which are of the same order of magnitude as those of preexisting pores determined from conventional passive diffusion experiments.

Flux enhancement effects of ionic surfactants upon passive and electroosmotic transdermal transport

This study focused upon the enhancement effects of ionic surfactants upon passive and electroosmotic transdermal flux. The first phase of the study involved validating theories relating surface properties of a membrane to electroosmotic solvent flow under appropriate experimental conditions using a synthetic model membrane (stack of 50 Nuclepore membranes). Numerical solutions to the Poisson-Boltzmann equation and the equations of fluid motion served as the theoretical basis for the experimental studies. Important outcomes of the model membrane studies were that electroosmotic solvent flow velocity was enhanced by the addition of an anionic surfactant, sodium dodecyl sulfate, and reversed by the addition of a cationic surfactant, dodecyltrimethylammonium bromide. The effective membrane pore wall surface charge densities were determined under a variety of experimental conditions. Adsorption of dodecyl sulfate to the pore wall increased the net negative charge on the pore wall. A reversal of the net pore wall surface charge density resulted from the adsorption of dodecyltrimethylammonium. The interrelationship between electroosmosis, surfactant adsorption, and ionic strength was also evaluated. The second phase of the study was an investigation of the effects of sodium dodecyl sulfate upon the transport of neutral polar permeants through human epidermal membrane (HEM). Fluxes of [14C]urea and [3H]sucrose were simultaneously measured across HEM samples under passive and 250 mV conditions; flux measurements were made before, during, and after HEM exposure to sodium dodecyl sulfate. A systematic analysis of the experimental data made it possible to elucidate the specific contributions of sodium dodecyl sulfate and the applied electric potential to the overall flux enhancement. Sodium dodecyl sulfate enhanced the intrinsic passive permeability of the HEM, and it also enhanced the contribution of electroosmosis to the flux during iontophoresis.

Influence of the permeation enhancers 1-alkyl-2-pyrrolidones on permeant partitioning into the stratum corneum

In a previous study, the enhancing effects of a series of 1-alkyl-2-pyrrolidones (APs; 1-ethyl, 1-butyl, 1-hexyl, and 1-octyl-2-pyrrolidone) on the transport of steroidal permeants across hairless mouse skin were investigated via a parallel pathway skin model. Isoenhancement concentration conditions were deduced under which different APs induce essentially the same transport enhancement for the lipoidal pathway of the stratum corneum (s.c.). As a continuing effort to understand the mechanism of action of permeation enhancers, the influence of the APs on permeant partitioning into hairless mouse s.c. was investigated under the isoenhancement concentration conditions using beta-estradiol (E2 beta) as the model permeant. The amount of E2 beta uptake into s.c. was found to be essentially the same for all the APs under these isoenhancement conditions. This result suggests that inducing a higher partitioning tendency for E2 beta into the lipoidal pathway of hairless mouse s.c. is a principal mechanism of action of the APs in enhancing transdermal transport. The uptake of the APs into s.c. lipoidal domains was also determined, and the results show only a modest (approximately 2-fold) increase in the uptake of the APs in going from 1-ethyl-to 1-octyl-2-pyrrolidone under isoenhancement conditions. This indicates the potency of the APs as permeation enhancers is only very modestly dependent upon the alkyl chain length in this chain length region when compared at concentrations in the microenvironment where the action occurs in the lipid domains.

Characterization of the transport pathways induced during low to moderate voltage iontophoresis in human epidermal membrane

This report describes the results of iontophoresis experiments involving the transport of polar nonelectrolytes across human epidermal membrane (HEM) at a moderate applied voltage of 2.0 V and where the data are interpreted via a convective transport model and hindered transport theory. A principal finding is that although HEM iontophoresis at 2.0 V resulted in a large increase in HEM porosity, the pore radii of the newly induced pores in HEM as calculated from the iontophoresis data using the hindered transport theory were found to be in the range of 6-12 A. This supports the view that electroporation at these modest applied voltages results in pores with sizes the same order of magnitude but somewhat smaller than those estimated for the preexisting pores in HEM prior to electroporation. This outcome is also important from a practical standpoint, as flux enhancement for large molecules (such as oligonucleotides and polypeptides) arising from electroporation under these conditions would be expected to be significantly less than if the resulting pore sizes were much greater. Providing a "prepulse" of 4.0, 8.0, and 15 V prior to the 2.0 V iontophoresis generally gave greater increases in HEM conductance (and, therefore, in porosity) but did not significantly change the deduced effective pore radii (around 5-9 A). The alteration during and the recovery of HEM after iontophoresis was also investigated. The recovery behavior was found to be dependent upon both the duration of the applied voltage and the magnitude of its effects: the recovery for a HEM sample that experienced a large increase in electrical conductance during iontophoresis was generally poorer than that for a sample that was more resistant to the electric field. Incomplete recovery was generally observed in experiments with long iontophoresis duration (50 min) and with the higher voltages (4.0, 8.0 V, and 15 V). In these cases, the barrier properties of HEM were more greatly altered as indicated by larger increases in the electrical conductance and passive permeability of HEM after iontophoresis.

Iontophoretic transport across a synthetic membrane and human epidermal membrane: a study of the effects of permeant charge

The effects of permeant charge (z) on iontophoretic-enhanced transport were investigated with synthetic Nucleopore membranes and with human epidermal membranes using a four-electrode potentiostat with side-by-side diffusion cells. The modified Nernst-Planck model (Nernst-Planck theory with an additional transport term to correct for the effect of the convective solvent flow due to electroosmosis) was first examined in a Nuclepore membrane system with model permeants calcein (z = -4), salicylate (z = -1), and a series of polystyrene sulfonates (from monomer to molecular weight of approximately 8000 with a z range of -1 to approximately -40). The flux enhancement (E) for each permeant was determined at 470 mV. Mannitol (a neutral molecule) was used as a probe to determine a correction for convective solvent flow under the same applied voltage conditions. Good agreement between the experimental results and the predictions from the modified Nernst-Planck model was found for calcein, salicylate, and polystyrene sulfonates up to molecular weight of approximately 1800 (z approximately -8). The flux enhancements for the higher molecular weight polystyrene sulfonates with greater z values were more than a factor of three lower than theoretical predictions; the electrophoretic effect and counterion binding to the permeants are proposed as possible explanations for these discrepancies between experiment and the modified Nernst-Planck theory. In the studies with human epidermal membranes, iontophoretic flux enhancements for calcein, salicylate, and taurocholate were determined at 250 and/or 470 mV. The flux enhancements were generally consistent with the results calculated from the modified Nernst-Planck model.

Quantitative description of the effect of molecular size upon electroosmotic flux enhancement during iontophoresis for a synthetic membrane and human epidermal membrane

This study focused upon quantitatively determining the influence of permeant molecular size upon flux enhancement which results from electroosmosis. The first phase of the study involved validation of a fundamental model describing the molecular size dependence of flux enhancement which results from convective solvent flow. This was accomplished using a model synthetic membrane (stack of 50 Nuclepore membranes) and four model permeants with a molecular weight range of 60-504 (urea, mannitol, sucrose, and raffinose). The steady-state flux of each permeant was determined under passive conditions and applied voltages of 125, 250, 500, and 1000 mV using side-by-side diffusion cells and a four-electrode potentiostat system. On the basis of the permeability enhancement for each permeant at each applied voltage (relative to the passive permeability) it was possible to calculate the effective solvent flow velocity from each permeant at each field strength. An important finding was that the flux enhancement due to electroosmosis was strongly molecular weight dependent (i.e., the flux enhancement ratio was around 4 times greater for raffinose than for urea, with mannitol and sucrose yielding intermediate values), while the calculated effective flow velocity at each voltage was independent of the molecular weight of the permeant. This coupled with a linear correlation between flow velocity and applied voltage served to establish the validity of the method and model. The second phase of the study was an extension of the model to human epidermal membrane (HEM). These experiments involved simultaneously measuring the fluxes of [14C]urea and [3H]sucrose across HEM samples under passive, 250 mV, and 500 mV conditions. Similar to the Nuclepore system, the observed flux enhancement ratios with HEM were approximately 3 times greater for sucrose than for urea. A detailed analysis of the HEM data showed semiquantitative agreement between predictions of the model and experimental results.

Sensori-motor function, gait patterns and falls in community-dwelling women

Tests of vision, vestibular function, peripheral sensation, strength, reaction time, balance and gait were administered to 183 community-dwelling women aged 22-99 years. Walking speed, stride length and cadence declined with age with corresponding increases in stance duration and percentage of the stride in the stance phase. Visual acuity and contrast sensitivity, tactile and vibration sense in the lower limb, vestibular function (as assessed by the vestibular X Writing Test), quadriceps and ankle dorsiflexion strength and reaction time were significantly associated with all five gait parameters. Postural sway measures were associated with walking speed, stride length and percentage of the stride in the stance phase. Multiple regression analyses revealed seven sensori-motor measures as significant predictors for one or more of the gait parameters: low contrast visual acuity, tactile sensitivity, vibration sense, vestibular X-test writing performance, quadriceps strength, reaction time and sway. Quadriceps strength was included as a predictor variable for every gait parameter and in each case had the strongest beta weight. Women who fell on two or more occasions in a one-year prospective period had significantly reduced and more variable cadence and significantly increased stance duration (measured in absolute terms and as a percentage of stride) than those who did not fall or fell on one occasion only. The study findings elucidate the relative importance of specific physiological systems in the maintenance of normal gait and identify temporal gait measures that are associated with falling in older people.

Fluorescent probe studies of the interactions of 1-alkyl-2-pyrrolidones with stratum corneum lipid liposomes

Previously, the effects of a series of 1-alkyl-2-pyrrolidones (APs; C2-C8) on the lipoidal pathway of hairless mouse skin (HMS) were studied with a parallel pathway skin model. At their isoenhancement concentrations, these 1-alkyl-2-pyrrolidones induce the same transport enhancement (isoenhancement factor, EHMS) on the lipoidal pathway of the stratum comeum for the probe permeants studied. In the present study, the fluidizing effects of APs upon the stratum comeum lipid liposome (SCLL) bilayer were investigated under these isoenhancement conditions using steady state anisotropy and fluorescence lifetime studies with fluorescent probes 2-, 6-, and 9-(9-anthroyloxy)stearic acids, 16-(9-anthroyloxy)palmitic acid, and 1,6-diphenyl-1,3,5-hexatriene to examine a possible correlation between the fluidizing properties of APs and their enhancement effects on transdermal drug transport. Time-resolved fluorescence decay studies were also conducted to further investigate the fluidizing properties of APs and add support to the steady-state fluorescence results. Under an isoenhancement condition of EHMS = 10, these APs fluidized the alkyl chains of the lipids at intermediate depths (C6-C9) in the SCLL bilayer (a 40-50% decrease in the rotational correlation times) but did not significantly change the fluidity in the deep hydrophobic region of the bilayer. Three rotational correlation times were deduced from the global simultaneous analysis in time-resolved fluorescence decay measurements. The slowest of these (greater than 1000 ns) was attributed to the global motion of SCLLs and is probably related to the static component of steady-state anisotropy. The other two rotational correlation times (on the order of nanoseconds) were in the range expected for the local motion of the fluorophores and may correspond to their vibrational and rotational motions. When the concentrations of APs were increased (increasing the EHMS value), the static component (alpha) decreased. This suggests that APs might induce a general fluidizing effect upon the lipid bilayer (i.e., a decrease in the order of the lipid bilayer). The decrease in the longer rotational correlation time (on the order of nanoseconds) with increasing EHMS value, on the other hand, indicates a possible increase in the "cavity volume" for the hindered motions of the fluorophores (i.e., an increase in the free volume at intermediate depths in the bilayer).

A mechanistic study of the effects of the 1-alkyl-2-pyrrolidones on bilayer permeability of stratum corneum lipid liposomes: a comparison with hairless mouse skin studies

The influence of a series of 1-alkyl-2-pyrrolidones (C2-C8) on the transport behavior of lipophilic and polar/ionic permeants across hairless mouse skin was recently investigated by employing a physical model approach that treats the stratum corneum barrier as a diffusional system of parallel lipoidal and pore pathways. In this previous study, the transport enhancement effects (enhancement factor, EHMS) on the lipoidal pathway of the stratum corneum were found to be essentially the same for all steroidal probe permeants investigated at various concentrations of these 1-alkyl-2-pyrrolidones. In the present research, the relationship between solute transport enhancement in the lipoidal pathway of hairless mouse skin and the transport enhancement in the stratum corneum lipid liposome bilayer was studied by comparing the enhancement factor for the lipoidal pathway in the hairless mouse skin, EHMS, with that for the stratum corneum lipid liposome, ESCLL, at equal solution concentrations of the 1-alkyl-2-pyrrolidones. The release rates of D-mannitol, D-glucose, 3-O-methyl-D-glucose, sucrose, and raffinose from stratum corneum lipid liposomes were determined, and the ESCLL values for these permeants were compared with the EHMS values obtained with hairless mouse skin using the steroidal permeants. An important finding in this study was a semiquantitative correlation between the enhancement effects induced by the 1-alkyl-2-pyrrolidones, except 1-ethyl-2-pyrrolidone, with the liposome bilayer using sugar molecules as permeants and those found with the lipoidal pathway in hairless mouse skin using steroid molecules as permeants.(ABSTRACT TRUNCATED AT 250 WORDS)