294 Stem Cell Enriched Fat Grafts Versus Autologous Fat Grafts for Facial Reconstruction: A Systematic Review and Meta-Analysis

Aim

To compare the results of stem cell-enhanced fat grafting to autologous fat grafting for face reconstruction.

Method

A systematic review and meta-analysis were carried out in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) Guidelines, and an electronic search was carried out to identify all Randomised Controlled Trials (RCTs), case control studies, and cohort studies comparing the outcomes of stem cell-enrichment fat grafting versus routine fat grafting for facial reconstruction. The primary outcome measures were volume retention and infection rate. Secondary outcome measures included post-surgery patient satisfaction, redness and swelling, fat necrosis, cysts, and operation time. For the analysis, fixed and random effects modelling were utilised.

Results

Eight studies with a total of 275 participants were assessed. In terms of mean volume retention, there was a significant difference between the stem cell-enrichment fat grafting and routine grafting groups (standardised Mean Difference [MD] = 2.49, P 0.00001). However, there was no significant difference in infection rates between the two groups (OR = 0.36, P = 0.30). Except for the operation duration, which was shorter in the latter, the intervention group had similar results to the control group for all secondary outcomes.

Conclusions

When compared to conventional fat grafting, stem cell-enriched fat grafting is a better alternative for facial reconstruction surgery since it enhances mean volume retention and does not worsen patient satisfaction or surgical complications.

Transcatheter aortic valve implantation outcomes compared between bicuspid aortic and tricuspid aortic valve stenosis: an updated systematic review and meta-analysis

Background

TAVI has emerged as an attractive treatment modality based on promising recent trial data. Patients with BAV, a commonly encountered clinical condition have largely been excluded from a majority of trials.

Purpose

Elderly patients with BAV and severe AS are increasingly encountered in clinical practice. This meta-analysis compares clinical outcomes between bicuspid and tricuspid AV patients to address the current knowledge-gap and identify optimal management strategies of these patients.

Methods

A comprehensive literature search was performed in PubMed, Embase, and Cochrane to identify the available observational studies comparing outcomes of TAVI in BAV and TAV patients. Summary effects were calculated using a DerSimonian and Laird random-effects model as odds ratio with 95% confidence intervals for all the clinical endpoints.

Results

16 Observational studies met inclusion criteria, comprising 10,053 patients with BAV and 173,307 patients with TAV that underwent TAVI. No significant differences in 30-day and long-term mortality rates were observed. Patients with BAV had an increased risk of stroke (OR 1.23; 95% CI [1.06–1.44], p=0.007), re-intervention (OR 1.90; 95% CI [1.15–3.15], p=0.01), paravalvular leak (OR 1.42; 95% CI [1.25–1.61], p<0.ehab724.22251), conversion to open surgery (OR 1.93; 95% CI [1.21–3.07], p=0.006), and new pacemaker implantation (1.57; 95% CI (1.06 - 2.33, p=0.02). Adverse event rates are lower with the use of newer generation of valves. No significant difference in major vascular complications, major bleeding, or incidence of AKI was noted.

Conclusions

Complication rates for BAV TAVI are higher, but mortality is similar to TAV TAVI indicating TAVI is an appropriate alternative for intermediate-high risk patients with BAV. A better understanding of valve anatomy, physician expertise, the use of newer-generation valves can help reduce these complications.

Funding Acknowledgement

Type of funding sources: None.

Incidence and risk predictors analysis of adverse donor reactions in whole blood donation

OBJECTIVE

Adverse donor reactions in normal healthy blood donors is not unusual. However, these unpleasant effects have a negative impact on donor retention. Adverse event due to blood donation is multifactorial in origin. Therefore, the objective of this study was to determine the frequency and type of adverse donor reactions during or after blood donation. More importantly, this study also aimed at analyzing important risk predictors of adverse donor reaction.

MATERIAL AND METHODS

This was a retrospective study conducted from May 2017 to April 2019 in the department of Transfusion Medicine at a tertiary care center in eastern India. Data were stored in Microsoft excel 2016 by using a standardized format as per ISBT criteria and analyzed with software "R, version 3.5.3" to find out the various independent precipitating factor.

RESULTS

Overall, 107 donors (0.98%) experienced adverse events with 10,814 whole blood donations. The first time, females, younger age donors (18-30 years), and donors with a mean arterial blood pressure of less than 90mm of Hg were the most important independent risk factors predicting the possibility of adverse donor reaction. Donors' weight, hemoglobin, and the type of donation had not affected the frequency of adverse events.

CONCLUSION

Analysis of adverse donor reactions helps in selecting the blood donors who are at risk of donor reactions. Our study highlights the importance of proper predonation screening especially in terms of assessment of mean blood pressure, along with identification of first time and female blood donors in order to reduce untoward donor reaction.

Deep venous thrombosis manifestation of common femoral vein leiomyoma

Deep vein thrombosis is a common clinical condition, with well-known risk factors. An unusual case of venous leiomyoma manifesting as a deep vein thrombosis in the left femoral vein of a 55-year-old man was managed successfully at our institution with anticoagulation, en-bloc excision and reconstruction of the femoral vein with spiral vein graft.

Establishing scald prevention measures in UK maternity units from takeaway drinks

AIM

To identify policies on the consumption of hot drinks by patients and visitors on all perinatal and postnatal wards in the United Kingdom, and to seek the opinions of members of the wider burns MDT as to whether standardised patient education or regulation of hot drinks around newborn babies is required.

METHODS

All maternity units with postnatal wards across the United Kingdom were surveyed to establish availability of hot drinks on site and whether these were permitted on postnatal wards around infants. An online questionnaire was distributed to members of the British Burn Association to ascertain opinions on hot drinks policies.

RESULTS

Hot takeaway drinks were permitted around newborn infants in 194 of surveyed postnatal wards and were only banned by two units. The online survey received 49 responses from different members of the British Burn Association. Thirty responders (61%) supported a takeaway hot drink ban, while those against the policy would alternatively encourage patient education, dedicated drinking areas and introduction of safety measures.

CONCLUSIONS

Almost every postnatal unit in the UK has access to hot drink retailers on site allowing parents and visitors to bring them into close contact with babies. With varying local regulations, this poses potentially serious consequences during feeding or carrying. We propose a standardised antenatal education be made available, together with standardised designated areas on wards for parents and visitors to consume hot drinks away from infants.

Temperature dissociation of liquids in reusable thermoplastic containers-An eco-friendly scald risk?

Recent global concern regarding the impact of plastic waste on the environment has resulted in efforts to utilise reusable drink containers. Research is lacking regarding temperature dissociation of drinks in reusable thermoplastic cups. This study aimed to compare the cooling time of two common hot drinks sold at a UK retailer, in the three vessels they are sold; ceramic, disposable paper (with and without lid) and reusable thermoplastic cups (with and without lid). All temperatures were collated from 250 ml volumes of black Americano coffee or café latte in the three different containers. The cooling time was measured every sixty seconds using a standardised digital thermocouple thermometer until a threshold liquid temperature of 43 °C was reached. All experiments were performed in triplicate and temperatures converted to a dimensionless logarithmic scale prior to statistical analysis. Cooling time was significantly slower for lidded cups irrespective of material. Unlidded thermoplastic cups significantly slowed cooling times for both black Americano coffee and café latte compared to ceramic and unlidded disposable paper cups. The growing trend in reusable cups does not in itself pose an increased risk of scald injury. However, we consider that the potentially increased ambulatory behaviour associated with using a lidded rather than unlidded cup may increase scald risk. We propose that further consumer guidance should be disseminated regarding the use of any lidded takeaway container to prevent scalds in both adults and children.

Acquired diaphragmatic hernia in a preterm low birth weight neonate

Iatrogenic diaphragmatic hernia is rare in children and we report a preterm low birth weight neonate with a presumably acquired diaphragmatic hernia due to trauma caused by treatment following pneumothorax.

Oral Ketamine or Midazolam or Low Dose Combination for Premedication in Children

This randomized controlled trial was designed to evaluate whether the combination of low dose oral midazolam (0.25 mg/kg) and low dose oral ketamine (3 mg/kg) provides better premedication than oral midazolam (0.5 mg/kg) or oral ketamine (6 mg/kg). Seventy-eight children of ASA physical status I or II scheduled for elective ophthalmic surgery were randomly divided into three groups and given premedication in the holding area 30 minutes before surgery. Two subjects from each group vomited the medication and were excluded, leaving 72 subjects for further analysis.

The onset of sedation was earlier in the combination group than the other two groups. At 10 minutes after premedication 12.5% in the combination group had an acceptable sedation score compared with none in the other two groups. After 20 minutes 54% in the combination group had an acceptable sedation score, 21% in the midazolam group and 16% in the ketamine group (P<0.05). There were no significant differences in the parental separation score, response to induction and emergence score. The mean time for best parental separation score was significantly less in the combination group (19±8 min) than either the midazolam (28±7) or ketamine (29±7 min) groups (P<0.05). Recovery was earlier in the combination group, as the time required to reach a modified Aldrete score of 10 was significantly less in the combination group (22±5 min) than in the oral midazolam (36±11 min) or ketamine (38±8 min) groups. The incidence of excessive salivation was significantly higher in the ketamine alone group (P<0.05). In conclusion, the combination of oral ketamine (3 mg/kg) and midazolam (0.25 mg/kg) has minimal side effects and gives a faster onset and more rapid recovery than ketamine 6 mg/kg or midazolam 0.5 mg/kg for premedication in children.

Prescription opioid use before and after kidney transplant: Implications for posttransplant outcomes

Evolving literature suggests that the epidemic of prescription opioid use affects the transplant population. We examined a novel database wherein national U.S. transplant registry records were linked to a large pharmaceutical claims warehouse (2007-2015) to characterize prescription opioid use before and after kidney transplant, and associations (adjusted hazard ratio, _95%LCL aHR_95%UCL ) with death and graft loss. Among 75 430 eligible patients, 43.1% filled opioids in the year before transplant. Use was more common among recipients who were women, white, unemployed, publicly insured, and with longer pretransplant dialysis. Of those with the highest level of pretransplant opioid use, 60% continued high-level use posttransplant. Pretransplant opioid use had graded associations with one-year posttransplant outcomes; the highest-level use predicted 46% increased risk of death (aHR _1.28 1.46_1.66 ) and 28% increased risk of all-cause graft failure (aHR _1.17 1.28_1.41 ). Effects of high-level opioid use in the first year after transplant were stronger, predicting twice the risk of death (aHR _1.93 2.24_2.60 ) and 68% higher all-cause graft failure risk (aHR _1.50 1.68_1.89 ) over the subsequent year; increased risk persisted over five years. While associations may, in part, reflect underlying conditions or behaviors, opioid use history is relevant in assessing and providing care to transplant candidates and recipients.

The impact of direct-acting antiviral agents on liver and kidney transplant costs and outcomes

Direct-acting antiviral medications (DAAs) have revolutionized care for hepatitis C positive (HCV+) liver (LT) and kidney (KT) transplant recipients. Scientific Registry of Transplant Recipients registry data were integrated with national pharmaceutical claims (2007-2016) to identify HCV treatments before January 2014 (pre-DAA) and after (post-DAA), stratified by donor (D) and recipient (R) serostatus and payer. Pre-DAA, 18% of HCV+ LT recipients were treated within 3 years and without differences by donor serostatus or payer. Post-DAA, only 6% of D-/R+ recipients, 19.8% of D+/R+ recipients with public insurance, and 11.3% with private insurance were treated within 3 years (P < .0001). LT recipients treated for HCV pre-DAA experienced higher rates of graft loss (adjusted hazard ratio [aHR] _1.34 1.85_2.10 , P < .0001) and death (aHR _1.47 1.68_1.91 , P < .0001). Post-DAA, HCV treatment was not associated with death (aHR _0.34 0.67_1.32 , P = .25) or graft failure (aHR _0.32 0.64_1.26 , P = .20) in D+R+ LT recipients. Treatment increased in D+R+ KT recipients (5.5% pre-DAA vs 12.9% post-DAA), but did not differ by payer status. DAAs reduced the risk of death after D+/R+ KT by 57% (_0.19 0.43_0.95 , P = .04) and graft loss by 46% (_0.27 0.54_1.07 , P = .08). HCV treatment with DAAs appears to improve HCV+ LT and KT outcomes; however, access to these medications appears limited in both LT and KT recipients.

Psychometric properties of the English version of the Oral Health Literacy Adults Questionnaire - OHL-AQ

Objective

To test the psychometric properties of the Oral Health Literacy Adult Questionnaire (OHL-AQ) in English. The OHL-AQ was designed to test functional oral health literacy in general populations and was initially validated in Iran.

Methods

The instrument was administered to 405 adult subjects (mean age 45 (SD 16) years and 67% female) attending the 2014 Minnesota State Fair. The OHL-AQ is composed of 17 items measuring four conceptual dimensions: reading comprehension, numeracy, listening, and decision-making. Participants selected the best answer for written or verbally administered items and entered answers on an electronic tablet. Item responses for each individual were combined into a summary score (range 0-17) with higher scores indicating better oral health literacy. Score dimensionality, reliability, and validity were investigated.

Results

For dimensionality, both exploratory factor analysis and a parallel analysis yielded evidence for scale unidimensionality. Reliability was sufficient indicated by a Cronbach's alpha ⟩0.74. Validity of scores was supported by "small" and "medium" effect sizes for construct validity. "Small" effect sizes were observed for global oral health self-report, OHIP-5 scores, treatment urgency, and having a regular dentist. "Medium" effect sizes were seen for presence of dentures, number of natural teeth present, and educational level.

Conclusions

Dimensionality, reliability and validity of the English version of the OHL-AQ in a general adult English-speaking population is supported, providing sufficient psychometric properties in an important target population of the instrument.

Under-utilization of pacemaker therapy for sinus node dysfunction - Real world data from South Asia

OBJECTIVE

Chronic symptomatic sinus node dysfunction (SND), the most common bradyarrhythmia, can be effectively managed by permanent cardiac pacing. Yet the care pathway and barriers to adoption of pacing therapy are not well understood - particularly in low volume implanting countries. The IMPROVE Brady study is a quality improvement initiative being conducted at centers in South Asia, Latin America, and Russia. We assessed the rates of SND diagnosis and pacemaker treatment for SND in the South Asia cohort.

METHODS

The prospective study enrolled patients with heart rate of  ≤50 beats per minute presenting with symptoms including syncope, dizziness, and/or dyspnea from ten centers in India and Bangladesh. Patients were followed to identify the proportion diagnosed with SND and subsequently treated with pacemaker therapy.

RESULTS

A total of 508 patients meeting criteria were enrolled and followed on average for 8.3±8.0months. Patients were on average 58 years of age, 77% were male, and 91% had completed at least primary education. An SND diagnosis was made in 368 (72%) of patients, with the majority (80%) of diagnoses occurring within 1 month of enrollment. Of the patients with an SND diagnosis, 63 (17%) were treated with a pacemaker. Reasons for not receiving treatment were: subject refusal or deferred decision (45%), unaffordability (34%), physician determined - not-indicated (20%), and other (1%). Older age, female gender, history of hypertension, lower resting heart rate, and syncopal or pre-syncopal symptoms were associated with a higher probability of implant.

CONCLUSIONS

In a care pathway assessment for the diagnosis and treatment of symptomatic SND in South Asia only 1 in 6 patients received pacemaker indicated therapy, largely due to patient refusal and physician decision. Phase II of the study will be aimed to improve this treatment rate.

Summer Temperature and Spatial Variability of all-Cause Mortality in Surat City, India

Background:

Ample information is available on extreme heat associated mortality for few Indian cities, but scant literature is available on effect of temperature on spatial variability of all-cause mortality for coastal cities.

Objective:

To assess the effect of daily maximum temperature, relative humidity and heat index on spatial variability of all-cause mortality for summer months (March to May) from 2014 to 2015 for the urban population of Surat (coastal) city.

Materials and Methods:

Retrospective analysis of the all-cause mortality data with temperature and humidity was performed on a total of 9,237 deaths for 184 summer days (2014-2015). Climatic and all-cause mortality data were obtained through Tutiempo website and Surat Municipal Corporation respectively. Bivariate analysis performed through SPSS.

Observations:

Mean daily mortality was estimated at 50.2 ± 8.5 for the study period with a rise of 20% all-cause mortality at temperature ≥ 40°C and rise of 10% deaths per day during extreme danger level (HI: > 54°C) days. Spatial (Zone wise) analysis revealed rise of 61% all-cause mortality for Southeast and 30% for East zones at temperature ≥ 40°C.

Conclusions:

All-cause mortality increased on high summer temperature days. Presence of spatial variation in all-cause mortality provided the evidence for high risk zones. Findings may be helpful in designing the interventions at micro level.

Clinical presentation, management, and outcomes in the Indian Heart Rhythm Society-Atrial Fibrillation (IHRS-AF) registry

Aim

A national atrial fibrillation (AF) registry was conducted under the aegis of the Indian Heart Rhythm Society (IHRS), to capture epidemiological data-type of AF, clinical presentation and comorbidities, current treatment practices, and 1-year follow-up outcomes.

Methods

A total of 1537 patients were enrolled from 24 sites in India in the IHRS-AF registry from July 2011 to August 2012. Their baseline characteristics and follow-up data were recorded in case report forms and subsequently analyzed.

Results

The average age of Indian AF patients was 54.7 years. There was a marginal female preponderance – 51.5% females and 48.5% males. At baseline, 20.4% had paroxysmal AF; 33% had persistent AF; 35.1% had permanent AF and 11% had first AF episode. At one-year follow-up, 45.6% patients had permanent AF.

Rheumatic valvular heart disease (RHD) was present in 47.6% of patients. Hypertension, heart failure, coronary artery disease, and diabetes were seen in 31.4%, 18.7%, 16.2%, and 16.1%, respectively.

Rate control was the strategy used in 75.2% patients, digoxin and beta-blockers being the most frequently prescribed rate-control drugs. Oral anticoagulation (OAC) drugs were used in 70% of patients. The annual mortality was 6.5%, hospitalization 8%, and incidence of stroke 1%.

Conclusions

In India, AF patients are younger and RHD is still the most frequent etiology. Almost two-third of the patients have persistent/permanent AF. At one-year follow-up, there is a significant mortality and morbidity in AF patients in India.

Underutilization of Timely Kidney Transplants in Those With Living Donors

Preemptive kidney transplant (PKTx) and kidney transplant (KTx) within 1 year of dialysis initiation have been associated with superior outcomes. Wait times should be minimal for transplants with living donors; however, there is lack of literature studying utilization of timely KTx in this population. We designed this retrospective study using data from United Network for Organ Sharing Standard Transplant Analysis and Research files from 2000 to 2012 to assess the trends in utilization of PKTx and Early KTx (combination of PKTx or transplant within 1 year of dialysis initiation) in recipients of living donor KTx. Only 32.6% transplants were PKTx, and 61.9% were Early KTx. A significant improvement in proportion of PKTx was seen from 27.5% in 2000 to 35.4% in 2006, with no change since. Similarly, the proportion of Early KTx increased from 61.4% in 2000 to 63.6% in 2006, with no increase since. Similar results were seen after adjusted analysis and were independent of living donor type. Although there was some improvement in utilization of timely transplants in the early part of the last decade, there has been no improvement since. Considering the benefits of timely kidney transplant, it is important to understand the reasons behind the same and to improve utilization.

When the living and the deceased cannot agree on organ donation: a survey of US organ procurement organizations (OPOs)

The legal concept of first person authorization (FPA) is based on the principle that a decision by a person with decision-making capacity should be respected even after he or she dies. Although the transplant community largely supports this concept, its implementation has not been universal. We conducted a web-based survey of all 58 Organ Procurement Organization (OPO)executive directors in the United States to assess OPOs' procurement policies and practices in the context of family objections. All 58 respondents(100%) responded to our survey. All OPOs except one have an online donor registration website. Most OPOs(89%) (51 of 57 respondents) estimated that the frequency of family objecting to organ donation in cases of registered donors was <10%. No OPOs reported the frequency to be higher than 25%. Only 50% (27 of 54) of the OPOs have a written policy on handling family objections. Approximately 80% of the OPOs reported honoring FPA. However, in the past 5 years, 20 OPOs (35%) have not yet participated in organ procurement from a registered deceased donor over family objection. Further research to identify the barriers and possible solutions to implementing FPA is warranted.

Lack of evidence of hepatitis E virus infection among renal transplant recipients in a disease-endemic area

Persistent hepatitis E virus (HEV) infection has been reported among solid-organ transplant recipients in nonendemic areas. Such chronic infections have all been related to genotype 3 HEV, which is prevalent in these areas. Whether persistent infection occurs with genotype 1 HEV, prevalent in areas where the infection is hyperendemic, is unclear. We therefore tested sera from renal transplant recipients receiving immunosuppressive agents in India, where genotype 1 HEV infection is endemic, for alanine aminotransferase levels, and presence of IgM and IgG anti-HEV antibodies and HEV RNA. Of the 205 subjects studied [aged 16-65 (median, 38) years, 182 male], 46 (22.4%) had abnormal ALT levels (>40 IU/mL). IgG anti-HEV was detected in 52 (20.5%) and IgM anti-HEV was detected in 14 (6.8%) subjects, including four who had IgG anti-HEV; antibody positivity had no relation with serum ALT or serum creatinine. All the sera tested were negative for HEV RNA. These findings suggest that chronic infection with genotype 1 HEV is infrequent.

Pharmaceutical care: need of the hour in India

Pharmaceutical care signifies a shift of practice in pharmacy from being drug product-oriented to the one that is patient-oriented to achieve definite outcomes that improves patients’ quality of life. In order to achieve pharmaceutical care, pharmacists have to assume the role of caregiver, communicator, decision-maker, teacher, researcher, life-long learner, leader, and manager, which will help him to provide individualized care. As the patients visit community pharmacists more often, they can play a major role in providing individual care to the patients especially in the management of chronic noncommunicable diseases (NCDs). Community pharmacists have to upgrade their expertise in drug product orientation to that of clinical orientation to provide patient oriented care. Hence pharmacists have a larger role to play in managing NCDs which are rapidly increasing in India.

Determination of site of absorption of propranolol in rat gut using in situ single-pass intestinal perfusion

Previously, permeability and site of intestinal absorption of propranolol have been reported using the Ussing chamber. In the present study, the utility of Single-Pass Intestinal Perfusion to study permeability and site of intestinal absorption of propranolol was evaluated in rats. Drug permeability in different regions of rat intestine viz. duodenum, jejunum, ileum and colon was measured. Propranolol (30 μg/ml) solution was perfused in situ in each intestinal segment of rats. Effective permeability (Peff) of propranolol in each segment was calculated and site of absorption was determined. The Peff of propranolol in rat duodenum, jejunum, ileum and colon was calculated to be 0.3316×10(-4) cm/s, 0.4035×10(-4)cm/s, 0.5092×10(-4) cm/s and 0.7167×10(-4) cm/s, respectively. The above results suggest that permeability of propranolol was highest through colon compared to other intestinal sites, which is in close agreement to that reported previously. In conclusion, in situ single pass intestinal perfusion can be used effectively to study intestinal permeability as well as site of intestinal absorption of compounds in rats.

Primary Hypothyroidism Presenting as a Sellar Mass Which Regressed with Thyroid Hormone Therapy

We describe a15-year-old girl presenting with compensatory pituitary enlargement due to primary hypothyroidism. The hyperplasia regressed following thyroxine administration. The clinical, laboratory and MRI features of the patients are described and the mechanisms of pituitary gland enlargement are discussed.

A micromechanical procedure for modelling the anisotropic mechanical properties of brain white matter

This paper proposes a micromechanics algorithm utilising the finite element method (FEM) for the analysis of heterogeneous matter. The characterisation procedure takes the material properties of the constituents, axons and extracellular matrix (ECM) as input data. The material properties of both the axons and the matrix are assumed to have linear viscoelastic behaviour with a perfect bonding between them. The results of the modelling have been validated with experimental data with material white input from brainstem by considering the morphology of brainstem in which most axons are oriented in longitudinal direction in the form of a uniaxial fibrous composite material. The method is then employed to examine the undulations of axons within different subregions of white matter and to study the impact due to axon/matrix volume fractions. For such purposes, different unit cells composed of wavy geometries and with various volume factions have been exposed to the six possible loading scenarios. The results will clearly demonstrate the undulation and axon volume fraction impacts. In this respect, undulation affects the material stiffness heavily in the axon longitudinal direction, whereas the axons' volume fraction has a much greater impact on the mechanical properties of the white matter in general. Also the results show that the created stresses and strains in the axons and matrix under loading will be impacted by undulation change. With increase in undulation the matrix suffers higher stresses when subjected to tension, whereas axons suffer higher stresses in shear. The axons always exhibit higher stresses whereas the matrix exhibits higher strains. The evaluated time-dependent local stress and strain concentrations within a repeating unit cell of the material model are indicative of the mechanical behaviour of the white tissue under different loading scenarios.

Pharmacodynamics and dermatopharmacokinetics of betamethasone 17-valerate: assessment of topical bioavailability

BACKGROUND

The bioavailability of most topically delivered drugs is difficult to quantify, but is generally believed to be very low. With the exception of the vasoconstrictor assay for corticosteroids, no methodology to quantify the rate and extent of drug delivery to the skin has been validated. Recent research has examined the dermatopharmacokinetic (DPK) technique, which is based on stratum corneum (SC) tape-stripping.

OBJECTIVE

To compare the in vivo bioavailability of different topical formulations of betamethasone 17-valerate (BMV) using the vasoconstrictor assay and the DPK method.

METHODS

BMV was formulated in different vehicles and the drug concentration was adjusted to either (i) equal thermodynamic activity, or (ii) a range of values up to that corresponding to 80% of maximum thermodynamic activity. Vasoconstriction, an accepted and widely used method to determine bioavailability and bioequivalence of topical steroids, was quantified with a chromameter over 24 h post-removal of the formulation. Drug uptake into the SC was assessed by tape-stripping.

RESULTS

BMV at the same thermodynamic activity in different vehicles provoked similar skin blanching responses, while DPK profiles distinguished between the formulations. Further, skin blanching responses and drug uptake into the SC clearly depended upon the absolute BMV concentration applied. However, while the saturable nature of the pharmacodynamic response was clear, the tape-stripping method distinguished unequivocally between the different formulations and different concentrations.

CONCLUSIONS

The DPK approach offers a reliable metric with which to quantify transfer of drug from the vehicle to the SC, and may be useful for topical bioavailability and bioequivalence determinations.

In vivo infrared spectroscopy studies of alkanol effects on human skin

Many studies investigate the permeation of actives through the skin and ignore the role of excipients. The solvents used in formulations will undoubtedly penetrate the skin where they can have a number of effects. They can extract skin lipids, they can alter the fluidity of the lipids and they can alter the polarity of the skin. The degree to which they do this and the depth into the skin where this occurs will depend on the uptake kinetics. The problem is to distinguish the different effects. Using ATR-FTIR and deuterated materials this can be achieved in vivo. The aim of the present study was to study the higher alkanols (hexanol, octanol, decanol) in vivo using a combination of ATR-FTIR spectroscopy and tape stripping. Studies conducted in vivo using deuterated vehicles confirmed the lipid extraction effects of d-hexanol and d-octanol, whereas d-decanol did not change skin lipid content. The uptake of d-decanol was higher than for the other vehicles consistent with previous observations on mouse skin for alkanols of increasing chain length. In general, solvent uptake was proportional to the induced shift in the C-H stretching frequency. Lipid disorder was induced by all vehicles studied in vivo and was proportional to the amount of vehicle present in the skin.

Transdermal Delivery of Cytochrome C—A 12.4 kDa Protein—Across Intact Skin by Constant–Current Iontophoresis

PURPOSE

To demonstrate the transdermal iontophoretic delivery of a small (12.4 kDa) protein across intact skin.

MATERIALS AND METHODS

The iontophoretic transport of Cytochrome c (Cyt c) across porcine ear skin in vitro was investigated and quantified by HPLC. The effect of protein concentration (0.35 and 0.7 mM), current density (0.15, 0.3 or 0.5 mA.cm(-2) applied for 8 h) and competing ions was evaluated. Co-iontophoresis of acetaminophen was employed to quantify the respective contributions of electromigration (EM) and electroosmosis (EO).

RESULTS

The data confirmed the transdermal iontophoretic delivery of intact Cyt c. Electromigration was the principal transport mechanism, accounting for approximately 90% of delivery; correlation between EM flux and electrophoretic mobility was consistent with earlier results using small molecules. Modest EO inhibition was observed at 0.5 mA.cm(-2). Cumulative permeation at 0.3 and 0.5 mA.cm(-2) was significantly greater than that at 0.15 mA.cm(-2); fluxes using 0.35 and 0.7 mM Cyt c in the absence of competing ions (J ( tot ) = 182.8 +/- 56.8 and 265.2 +/- 149.1 microg.cm(-2).h(-1), respectively) were statistically equivalent. Formulation in PBS (pH 8.2) confirmed the impact of competing charge carriers; inclusion of approximately 170 mM Na(+) resulted in a 3.9-fold decrease in total flux.

CONCLUSIONS

Significant amounts ( approximately 0.9 mg.cm(-2) over 8 h) of Cyt c were delivered non-invasively across intact skin by transdermal electrotransport.

Long QT syndrome revisited

Congenital Long QT Syndrome (cLQTS) is an inherited disease in children and adolescents who have structurally normal hearts but present with sudden death in a high proportion of untreated patients. More than 300 mutations have been identified in 7 LQT genes. Diagnosis still depends on ECG, clinical presentations and family history. Molecular genetic testing is useful to unravel borderline family members of LQT probands, but it continues to be a research tool at present. Beta blockers remain the mainstay of treatment. ICDs are highly effective in reducing SCD for high risk patients. Gene based therapy is still preliminary. Considerable thought is needed to address and treat the asymptomatic LQT family members. The main cause of Acquired LQTS is inhibition of Ikr current, usually by drugs. Care must be taken to avoid further exposure to QT prolonging drugs or conditions. Physicians need to be aware of the pharmacodynamic and pharmacokinetic interactions of various important drugs.

Cooling a nanomechanical resonator with quantum back-action

Quantum mechanics demands that the act of measurement must affect the measured object. When a linear amplifier is used to continuously monitor the position of an object, the Heisenberg uncertainty relationship requires that the object be driven by force impulses, called back-action. Here we measure the back-action of a superconducting single-electron transistor (SSET) on a radio-frequency nanomechanical resonator. The conductance of the SSET, which is capacitively coupled to the resonator, provides a sensitive probe of the latter's position; back-action effects manifest themselves as an effective thermal bath, the properties of which depend sensitively on SSET bias conditions. Surprisingly, when the SSET is biased near a transport resonance, we observe cooling of the nanomechanical mode from 550 mK to 300 mK--an effect that is analogous to laser cooling in atomic physics. Our measurements have implications for nanomechanical readout of quantum information devices and the limits of ultrasensitive force microscopy (such as single-nuclear-spin magnetic resonance force microscopy). Furthermore, we anticipate the use of these back-action effects to prepare ultracold and quantum states of mechanical structures, which would not be accessible with existing technology.