Acetyl Zingerone: A Photostable Multifunctional Skincare Ingredient That Combats Features of Intrinsic and Extrinsic Skin Aging

The cumulative damage skin sustains from exposure to environmental stressors throughout life exerts significant effects on skin aging and cancer development. One of the main ways by which environmental stressors mediate their effects within skin is through induction of reactive oxygen species (ROS). In this review, we chronicle the multiple properties by which acetyl zingerone (AZ) as a skincare ingredient can benefit skin (1) by helping manage overproduction of ROS through multiple routes as an antioxidant, physical quencher and selective chelator, (2) by fortifying protection after UV exposure ends to prevent the type of epidermal DNA damage that correlates with development of skin cancer, (3) by modulating matrisome activity and nurturing the integrity of the extracellular matrix (ECM) within the dermis and (4) through its proficient ability to neutralize singlet oxygen, by stabilizing the ascorbic acid precursor tetrahexyldecyl ascorbate (THDC) in the dermal microenvironment. This activity improves THDC bioavailability and may blunt pro-inflammatory effects of THDC, such as activation of type I interferon signaling. Moreover, AZ is photostable and can sustain its properties during UV exposure, in contrast to α-tocopherol. All these properties of AZ translate into measurable clinical benefits to improve the visual appearance of photoaged facial skin and to strengthen the skin's own defenses against sun damage.

The Role of Acetyl Zingerone and Its Derivatives in Inhibiting UV-Induced, Incident, and Delayed Cyclobutane Pyrimidine Dimers

Cyclobutane pyrimidine dimers (CPDs) are ultraviolet radiation (UV)-induced carcinogenic DNA photoproducts that lead to UV signature mutations in melanoma. Previously, we discovered that, in addition to their incident formation (iCPDs), UV exposure induces melanin chemiexcitation (MeCh), where UV generates peroxynitrite (ONOO^-), which oxidizes melanin into melanin-carbonyls (MCs) in their excited triplet state. Chronic MeCh and energy transfer by MCs to DNA generates CPDs for several hours after UV exposure ends (dark CPD, dCPDs). We hypothesized that MeCh and the resulting dCPDs can be inhibited using MeCh inhibitors, and MC and ONOO^- scavengers. Here, we investigated the efficacy of Acetyl Zingerone (AZ), a plant-based phenolic alkanone, and its chemical analogs in inhibiting iCPDs and dCPDs in skin fibroblasts, keratinocytes, and isogenic pigmented and albino melanocytes. While AZ and its methoxy analog, 3-(4-Methoxy-benzyl)-Pentane-2,4-dione (MBPD) completely inhibited the dCPDs, MBPD also inhibited ~50% of iCPDs. This suggests the inhibition of ~80% of total CPDs at any time point post UV exposure by MBPD, which is markedly significant. MBPD downregulated melanin synthesis, which is indispensable for dCPD generation, but this did not occur with AZ. Meanwhile, AZ and MBPD both upregulated the expression of nucleotide excision repair (NER) pathways genes including Xpa, Xpc, and Mitf. AZ and its analogs were non-toxic to the skin cells and did not act as photosensitizers. We propose that AZ and MBPD represent "next-generation skin care additives" that are safe and effective for use not only in sunscreens but also in other specialized clinical applications owing to their extremely high efficacy in blocking both iCPDs and dCPDs.

Quantitation of the Nitrosamine 2-EthylhexyI-4-(N-Methyl-N-Nitrosoamino) Benzoate (NPABAO) in Sunscreen Products

We have devised a method to quantitate the nitrosamine, 2- ethylhexyM-(N-methyl-N-nitrosoamino) benzoate (NPABAO), In commercial products containing the sunscreen ingredient, Padimate 0. The method involves a minimum of cleanup steps to afford a nonaqueous extract from product emulsions suitable for analysis by a liquid chromatograph Interfaced to a thermal energy analyzer (LC/TEA). The method Is applicable to lotions, creams, and gels. Oils are normally soluble In the mobile phase and can be analyzed directly on the LC/TEA without additional cleanup procedures. The method has a minimum detectable limit of about 30 ppb and yields > 80% recovery. It is highly reproducible and generates no NPABAO artifactually prior to quantitation on the LC/TEA Application of the method to 22 different commercial product formulas disclosed that the level of NPABAO in each of the products Is below 250 ppb, with 18 of the products containing less than 100 ppb. Of interest was the observation that musk ketone, a common fragrance constituent, produces a false-positive TEA response that can Interfere with accurate analysis of NPABAO content In typical commercial products

Lipomyelomeningocele for the urologist: Should we view it the same as myelomeningocele?

INTRODUCTION

The primary urologic objectives for lipomyelomeningocele (LMM) and myelomeningocele (MM) are preserving renal integrity and achieving continence. Due to this common ground, LMM and MM are urologically treated the same. However, unlike MM, LMM may present with no evident functional concerns. Indications for and timing of tethered cord release (TCR) in LMM are therefore controversial. Long-term urologic outcomes are not well defined.

OBJECTIVE

Expectations for continence and potential for intermittent catheterization (CIC) following TCR in LMM are important for realistically counseling families regarding future needs. The present study aimed to identify prognostic factors for continence and need for CIC in LMM.

STUDY DESIGN

The present study retrospectively identified 143 patients from the multidisciplinary clinic who underwent TCR for LMM between 1995 and 2010. Concomitant anorectal/genitourinary anomalies, filar lipoma, fatty filum, previous TCR, and follow-up <1 year were excluded. Analysis was limited to those toilet trained or aged ≥6 years at latest follow-up. Lipomyelomeningocele was classified as dorsal, distal, transitional or chaotic. Pre- and post-TCR urologic status was assessed. Ability to achieve urinary continence, with or without CIC, was the primary outcome, and need for CIC was the secondary outcome of interest.

RESULTS

A total of 56 patients met inclusion criteria. Median age at TCR was 4.4 months (range 1.0-224.0) with a median follow-up of 10.7 years (range 1.3-19.1); 68% were asymptomatic at presentation. Clinical symptoms were urologic in 7%. At the latest follow-up, 86% of patients were continent spontaneously or with CIC (Summary Fig.). Of the four patients who presented with urologic symptoms, all were continent, but three required CIC. Overall, 23% of patients required CIC. Median age at CIC initiation was 7.6 years (range 1.6-17.4). Long-term continence was not associated with any demographic, anatomic, surgical or functional variable. Need for CIC at latest follow-up was associated with symptomatic presentation, partial TCR, transitional lipoma, and high-risk pre-operative urodynamics.

DISCUSSION

In this series of primary TCR for LMM, where 93% of patients were urologically asymptomatic before TCR, prospects for continence were excellent. No studied parameter clearly impacted continence; however, need for CIC was associated with multiple variables.

CONCLUSIONS

Clear predictors for continence after TCR will require additional long-term patient outcomes. Families can anticipate 23% likelihood of CIC, which is considerably less than in MM, but long-term urologic follow-up is still strongly recommended.

Effects of solar radiation on the skin

No one would underestimate the importance of sunlight to the evolution of life on the earth and its role in human development. However, all humans - especially individuals who are lightly pigmented or whose occupation or lifestyle exposes them to excessive amounts of sunlight - are potentially susceptible to its deleterious effects. These effects can range from acute biological responses, such as sunburn and skin tanning, to conditions resulting from chronic exposure such as photoaged skin and potentially life-threatening conditions such as skin cancer. The objective of this review is to present a concise and up-to-date perspective on the effects of UVB, UVA, visible, and infrared radiation on cutaneous biochemistry and physiology.

Characterization of the UVA protection provided by avobenzone, zinc oxide, and titanium dioxide in broad-spectrum sunscreen products

BACKGROUND

Solar UV radiation (UVR) is composed of UVB (290-320 nm) and UVA (320-400 nm) wavelengths. Only two sunscreen active ingredients approved in the US, avobenzone (butylmethoxydibenzoylmethane) and zinc oxide (ZnO), provide true broad-spectrum protection against UVA wavelengths >360 nm. Although effective against shorter UVR wavelengths <360 nm, titanium dioxide (TiO(2)) is also often believed to confer broad-spectrum protection and is substituted for ZnO or avobenzone. To sustain its absorption capacity within a sunscreen film during UVR exposure, avobenzone needs to be formulated into sunscreen products using sound formulation strategies.

OBJECTIVES

To characterize the efficacy of avobenzone, ZnO, and TiO(2) in terms of their abilities to provide broad UVA protection and to demonstrate the effectiveness of the different formulation strategies used today to maintain the efficacy of avobenzone even during prolonged exposures to UVR.

METHODS

UVA efficacy was assessed by measuring absorbance profiles in vitro using Vitro Skin® (IMS Inc., Orange, CT, USA) as an inert substrate and by determining UVA protection factors (PFA) on human skin. The impact of avobenzone loss on sun protection factor (SPF) and PFA values was evaluated by serially reducing avobenzone concentrations in an otherwise photostable product. The photostabilizing influence of specific formulation ingredients was monitored by measuring the extent to which they prevented UVR-induced degradation of avobenzone, whereas photostability of commercial sunscreen products was quantified by measuring the percentage change in absorbance within the UVB and UVA spectral regions following irradiation of thin product films on inert substrates.

RESULTS

Model formulations containing 3% avobenzone or 5% ZnO provided superior attenuation of UVA wavelengths >360 nm compared with formulas containing 5% TiO(2). Additionally, sunscreen products of similar SPF containing avobenzone or ZnO exhibited significantly higher PFA values than those containing TiO(2). The addition of photostabilized avobenzone or ZnO increased PFA values nearly 3-fold, whereas the addition of TiO(2) increased PFA values only modestly. Judicious selection of sunscreen actives alone or in combination with extra stabilizing agents maintained the photostability of avobenzone in formulations to deliver sustained broad-spectrum absorbance during 4 hours of exposure to UVR. Small losses (<20%) of avobenzone did not significantly reduce a product's protective effects as measured by SPF and PFA values on human skin.

CONCLUSIONS

TiO(2) provided neither the same level of UVA attenuation nor the same degree of UVA protection on human skin as did products containing photostabilized avobenzone or ZnO. Hence, TiO(2) cannot be considered a substitute for avobenzone or ZnO in providing high levels of UVA protection to human skin. Use of proper formulation strategies can ensure that avobenzone losses are minimized to the extent that they have no impact on a product's ability to deliver sustained protection, even over periods of prolonged exposure to UVR.

Temperature dependence of the energy gap of semiconductors in the low-temperature limit

The temperature dependence of the electronic states and energy gaps of semiconductors is an old but still important experimental and theoretical topic. Remarkably, extant results do not clarify the asymptotic T-->0 behavior. Recent breakthroughs in the spectroscopy of enriched 28Si allow us to measure changes in the band gap over the liquid 4He temperature range with an astounding precision of one part in 10(8), revealing a T4.0+/-0.2 decrease with increasing T. This is in excellent agreement with a theoretical argument predicting an exponent of 4. This power law should apply, in the low temperature limit, to the temperature dependence of the energies of all electronic states in semiconductors and insulators.

Usefulness of surveillance cultures in neonatal extracorporeal membrane oxygenation

Sepsis is difficult to identify in patients treated with extracorporeal membrane oxygenation (ECMO). This study evaluates the usefulness of surveillance cultures obtained during ECMO. We retrospectively reviewed the records of 187 patients from four ECMO centers with birth weights 1,574 to 4,900 gm and gestational ages 33-43 weeks, over a 4 year interval. Most patients had surveillance blood cultures daily, and tracheal aspirates and urine culture every other day. Charts were reviewed for culture results before, during, and for the 7 days after ECMO, and clinical response to the culture results. A total of 2,423 cultures were obtained during 1,487 days of ECMO, of which 155 were positive (6.4%): 13 of 1,370 blood cultures (0.9%), 137 of 850 tracheal aspirate cultures (16%), and 5 of 203 urine cultures (2.3%). After 72 hours, tracheal aspirate cultures became positive with nosocomial organisms in 33 of 131 patients. None of 153 bacterial urine cultures were positive, and only one of 34 viral urine cultures were positive (CMV). We conclude that routine daily blood cultures are not useful in neonatal ECMO. Tracheal aspirate cultures may be helpful in the management of antibiotic therapy in patients on ECMO for more than 5 days. Routine bacterial urine cultures did not provide useful information.

Perceptual "vowel spaces" of cochlear implant users: implications for the study of auditory adaptation to spectral shift

Cochlear implant (CI) users differ in their ability to perceive and recognize speech sounds. Two possible reasons for such individual differences may lie in their ability to discriminate formant frequencies or to adapt to the spectrally shifted information presented by cochlear implants, a basalward shift related to the implant's depth of insertion in the cochlea. In the present study, we examined these two alternatives using a method-of-adjustment (MOA) procedure with 330 synthetic vowel stimuli varying in F1 and F2 that were arranged in a two-dimensional grid. Subjects were asked to label the synthetic stimuli that matched ten monophthongal vowels in visually presented words. Subjects then provided goodness ratings for the stimuli they had chosen. The subjects' responses to all ten vowels were used to construct individual perceptual "vowel spaces." If CI users fail to adapt completely to the basalward spectral shift, then the formant frequencies of their vowel categories should be shifted lower in both F1 and F2. However, with one exception, no systematic shifts were observed in the vowel spaces of CI users. Instead, the vowel spaces differed from one another in the relative size of their vowel categories. The results suggest that differences in formant frequency discrimination may account for the individual differences in vowel perception observed in cochlear implant users.

Improving the quality of the order-writing process for inpatient orders and outpatient prescriptions

Because many preventable medication errors occur at the ordering stage, a program for improving the quality of writing inpatient orders and outpatient prescriptions at one institution was developed. To determine whether potential problems existed in the order-writing process for inpatients, all physician orders for a seven-day period in 1997 were reviewed (n = 3740). More than 10% of all orders had illegible handwriting or were written with a felt-tip pen, which makes NCR copies difficult to read. Other potential errors were also identified. Following educational programs for physicians and residents focusing on the importance of writing orders clearly, physician orders were reviewed for a 24-hour period (n = 654). The use of felt-tip pens decreased to 1.37% of all orders, and no orders had illegible handwriting. A similar quality improvement approach was used to evaluate the outpatient prescription-writing process. A review of all new prescriptions for a consecutive seven-day period at a local hospital-owned community pharmacy (n = 1425) revealed that about 15% of the prescriptions had illegible handwriting and roughly 10% were incomplete. Additional data were gathered through a survey sent to 71 outside provider pharmacies requesting information on problems related to prescriptions written by physicians from the institution; 66% responded. Failure to print prescriber name (96%), illegible signature (94%), failure to include DEA number (89%), and illegible handwriting other than signature (69%) were reported as the main problems. Each physician was given a self-inking name stamp to use when writing prescriptions. In addition, educational programs covering examples of poorly written prescriptions and the legal requirements of a prescription were held for physicians and residents. A follow-up survey showed that 72% of pharmacies saw stamps being used; when stamps were not used, however, illegible signatures continued to be a problem. Follow-up reviews of outpatient prescriptions indicate improvements in handwriting and completeness, but continuing educational efforts are needed. The quality of order writing for inpatients and outpatients continues to be monitored on a regular basis. Ongoing educational programs, follow-up reminders, and feedback to physicians have greatly improved the prescription-writing habits of physicians.

Modeling phoneme and open-set word recognition by cochlear implant users: a preliminary report

On the basis of the good predictions for phonemes correct, we conclude that closed-set feature identification may successfully predict phoneme identification in an open-set word recognition task. For word recognition, however, the PCM model underpredicted observed performance, and the addition of a mental lexicon (ie, the SPAMR model) was needed for a good match to data averaged across 7 adults with CIs. The predictions for words correct improved with the addition of a lexicon, providing support for the hypothesis that lexical information is used in open-set spoken word recognition by CI users. The perception of words more complex than CNCs is also likely to require lexical knowledge (Frisch et al, this supplement, pp 60-62) In the future, we will use the performance off individual CI users on psychophysical tasks to generate predicted vowel and consonant confusion matrices to be used to predict open-set spoken word recognition.

Formation and persistence of O(6)-methylguanine in the mouse colon following treatment with 1,2-dimethylhydrazine as measured by an O(6)-alkylguanine-DNA alkyltransferase inactivation assay

Female SWR mice were treated with 1,2-dimethylhydrazine (DMH: 6.8 mg/kg i.p. injection) once weekly for up to 10 weeks, a dosing regime that produced tumours principally within the distal colon (Jackson et al., 1999. Carcinogenesis 20, 509-513). O(6)-Methylguanine (O(6)-MeG) levels, measured using a simple [3H]-based O(6)-alkylguanine-DNA alkyltransferase (ATase) inactivation assay, ranged from 0.6 to 16.7 fmol/microg DNA with: (i) highest levels in the distal colon; and (ii) higher levels after 68 mg/kg total DMH than 6.8 mg/kg DMH. Basal ATase activity varied between 0.97 and 1.22 fmol/microg DNA within the colon but was not associated with adduct levels or tumour induction. After 6.8 mg/kg DMH, the half life of O(6)-MeG in colonic tissue was 36-42 h whereas after 68 mg/kg DMH, t1/2 was approximately 25, 57 and 96 h in the proximal, mid and distal colon, respectively. Tumour induction was thus associated with the levels and persistence of O(6)-MeG in the distal colon.

Some computational analyses of the PBK test: effects of frequency and lexical density on spoken word recognition

OBJECTIVE

The Phonetically Balanced Kindergarten (PBK) Test (Haskins, Reference Note 2) has been used for almost 50 yr to assess spoken word recognition performance in children with hearing impairments. The test originally consisted of four lists of 50 words, but only three of the lists (lists 1, 3, and 4) were considered "equivalent" enough to be used clinically with children. Our goal was to determine if the lexical properties of the different PBK lists could explain any differences between the three "equivalent" lists and the fourth PBK list (List 2) that has not been used in clinical testing.

DESIGN

Word frequency and lexical neighborhood frequency and density measures were obtained from a computerized database for all of the words on the four lists from the PBK Test as well as the words from a single PB-50 (Egan, 1948) word list.

RESULTS

The words in the "easy" PBK list (List 2) were of higher frequency than the words in the three "equivalent" lists. Moreover, the lexical neighborhoods of the words on the "easy" list contained fewer phonetically similar words than the neighborhoods of the words on the other three "equivalent" lists.

CONCLUSIONS

It is important for researchers to consider word frequency and lexical neighborhood frequency and density when constructing word lists for testing speech perception. The results of this computational analysis of the PBK Test provide additional support for the proposal that spoken words are recognized "relationally" in the context of other phonetically similar words in the lexicon. Implications of using open-set word recognition tests with children with hearing impairments are discussed with regard to the specific vocabulary and information processing demands of the PBK Test.

Comparison of speech perception in pediatric CLARION cochlear implant and hearing aid users

Multichannel cochlear implants (CIs) allow many profoundly deaf children to achieve high levels of speech perception. In order to develop optimal criteria for implantation, it is crucial to test representative samples (or, if possible, full populations) of CI users and compare their results to those of hearing aid (HA) users of the same age and communication mode (oral or total communication) to determine which subgroups of HA users may obtain more perceptual benefit from a CI than from an HA. Word and phoneme identification skills of deaf children who use either HAs or CIs were evaluated and compared. The CI group included all of the prelingually deaf children in the United States who were implanted with the CLARION Multi-Strategy Cochlear Implant during the clinical trial (as of January 1998). Before implantation, the mean scores on the PB-K test (scored phonemically) were lower for prospective CI users than for HA users. However, by 12 to 18 months postimplantation, the average scores for the CI users were higher than those of HA users with residual hearing in the 101- to 110-dB hearing level (HL) range. The CI scores were similar to those of HA users with residual hearing in the 90- to 100-dB HL range.

Endotoxemia in mice stimulates production of complement C3 and serum amyloid A in mucosa of small intestine

We examined the effect of endotoxemia in mice on protein and mRNA levels for the acute phase proteins complement C3 and serum amyloid A (SAA) in jejunal mucosa. Endotoxemia was induced in mice by the subcutaneous injection of 250 microg lipopolysaccharide per mouse. Control mice were injected with saline. C3 and SAA were measured by ELISA. Messenger RNA levels were determined by Northern blot analysis or competitive PCR. Immunohistochemistry was performed to determine in which cell type(s) C3 and SAA were present. Mucosal C3 and SAA protein and mRNA levels were increased in endotoxemic mice. Immunohistochemistry showed that C3 was present in both enterocytes and cells of the lamina propria, whereas SAA was seen mainly in lamina propria cells. Results suggest that endotoxemia stimulates production of C3 and SAA in small intestinal mucosa. The response may be regulated at the transcriptional level and probably reflects increased synthesis of the acute phase proteins in both enterocytes and cells of the lamina propria.

Utility of daily head ultrasonography for infants on extracorporeal membrane oxygenation

BACKGROUND/PURPOSE

Intracranial hemorrhage (ICH) is a major concern during extracorporeal membrane oxygenation (ECMO). Daily cranial ultrasonography has been used by many ECMO centers as a diagnostic tool for both detecting and following ICH while infants are on bypass. The purpose of this patient review was to look at the usefulness of performing daily cranial ultrasonography (HUS) in infants on ECMO in detecting intraventricular hemorrhage of a magnitude sufficient to alter patient treatment.

METHODS

The authors reviewed retrospectively all of the records of all neonates treated with ECMO at the Hermann Children's Hospital, Wilford Hall USAF Medical Center, Cincinnati Children's Hospital, The University of Texas Medical Branch at Galveston, and Texas Children's Hospital between February 1986 to March 1995. Two hundred ninety-eight patients were placed on ECMO during this period. All patients had HUS before, and daily while on ECMO, and all were reviewed by the staff radiologists. A total of 2,518 HUS examinations were performed.

RESULTS

Fifty-two of 298 patients (17.5%) had an intraventricular hemorrhage seen on ultrasound scan. Nine of 52 patients (17.3%) had an ICH seen on the initial HUS examination before ECMO, all of which were grade I, and 43 of 52 patients (82.7%) had ICH while on ECMO. Of these ICH, 15 were grade I, 10 were grade II, 10 were grade III, and eight were grade IV. Forty of these ICH (93%) were diagnosed by HUS during the first 5 days of the ECMO course. Seven hundred eighty-six HUS were performed after day 5, at an estimated cost of $300,000 to $450,000 (charges), demonstrating three new intraventricular hemorrhages, one grade I, and one grade IV on day 7 and one grade I on day 8. Eight patients were taken off ECMO because of ICH diagnosed within the first 5 days. One patient was taken off ECMO because of ICH diagnosed after 5 days. This patient had clinical symptoms suggestive of ICH.

CONCLUSIONS

Almost all ICH occur during the first 5 days of an ECMO course. Unless there is a clinical suspicion, it is not cost effective to perform HUS after the fifth day on ECMO, because subsequent HUS examinations are unlikely to yield information significant enough to alter management.

Improvements in speech perception by children with profound prelingual hearing loss: effects of device, communication mode, and chronological age

The present investigation expanded on an earlier study by Miyamoto, Osberger, Todd, Robbins, Karasek, et al. (1994) who compared the speech perception skills of two groups of children with profound prelingual hearing loss. The first group had received the Nucleus multichannel cochlear implant and was tested longitudinally. The second group, who were not implanted and used conventional hearing aids, was tested at a single point in time. In the present study, speech perception scores were examined over time for both groups of children as a function of communication mode of the child. Separate linear regressions of speech perception scores as a function of age were computed to estimate the rate of improvement in speech perception abilities that might be expected due to maturation for the hearing aid users (n=58) within each communication mode. The resulting regression lines were used to compare the estimated rate of speech perception growth for each hearing aid group to the observed gains in speech perception made by the children with multichannel cochlear implants. A large number of children using cochlear implants (n=74) were tested over a long period of implant use (m=3.5 years) that ranged from zero to 8.5 years. In general, speech perception scores for the children using cochlear implants were higher than those predicted for a group of children with 101-110 dB HL of hearing loss using hearing aids, and they approached the scores predicted for a group of children with 90-100 dB HL of hearing loss using hearing aids.

Psychometric equivalence of recorded spondaic words as test items

In the determination of the speech-reception threshold (SRT), spondaic words are assumed to be homogeneous with respect to intelligibility; and the assumption of equal intelligibility requires that the words be comparable for all signal levels. Previous attempts to assess the equal intelligibility assumption using word thresholds as the sole criterion are not an adequate basis for specifying the equality of intelligibility. In the present study, the recorded spondaic words (Tillman recording) were analyzed in an attempt to create a more homogeneous set of spondaic words for future laboratory work. To achieve this goal, the data reported by Young, Dudley, and Gunter (1982) and data collected in our laboratory were fitted to a logistic function (psychometric function) from which a 50% point (threshold) and slope were obtained. To specify their acoustical parameters, the recorded spondaic words were digitized and the RMS level and duration of each syllable and word were calculated. None of the RMS or duration measures were correlated with word thresholds, so no attempt was made to equate level or duration. On the other hand, when the threshold of each word was adjusted to equal the mean threshold of the set (n = 36), the dispersion among word thresholds and slopes was greatly reduced. Further, we recommend that small sets of "equally intelligible" spondaic words not be used for clinical testing because set size is a strong factor in determining threshold for spondees (Meyer & Bilger, 1997; Punch & Howard, 1985).

Effect of set size and method on speech reception thresholds in noise

OBJECTIVE

The threshold for speech is known to improve as signal (Miller, Heise, & Lichten, 1951) or response (Pollack, 1959) uncertainty is decreased. The definition of threshold as the signal level or signal to noise ratio (S/N) at which a fixed percent-correct score is obtained, therefore, becomes problematic when set size, M, is varied through the range for which threshold varies systematically (M = 2 to M = 16) because the meaning of that fixed percent changes as M is increased or decreased. The goal of the present study is to examine the effect of set size, M, on speech reception thresholds (SRTs) under two testing strategies.

DESIGN

SRTs were obtained in the presence of 80 dB SPL white noise for sets containing 2, 4, 8, and 16 words using two different procedures, one in which threshold was based on a fixed percent correct (American Speech-Language-Hearing Association, 1988) and one in which threshold was defined in terms of d' = 1.00. The subjects were 12 young women with normal hearing and little or no experience with audiologic testing procedures.

RESULTS

When threshold was based on a fixed percent correct, S/N at threshold was found to be dependent on set size (F = 3.333; df = 3, 33; p = 0.031). When threshold was defined in terms of d' = 1.00, S/N at threshold was found to be independent of set size.

CONCLUSIONS

If a smaller set size than that recommended by the American Speech-Language-Hearing Association (1988) guidelines is to be used for obtaining SRTs in a clinical setting, thresholds should be based on a criterion-free measure that is independent of the size of the set of words being tested, if possible.

Sepsis and endotoxaemia in mice stimulate the expression of interleukin-I and interleukin-6 in the central nervous system

1. In previous studies, experimental endotoxaemia was found to stimulate cytokine production in the central nervous system. The effect of sepsis on brain cytokines is not fully known. We compared the effect of endotoxaemia and sepsis on brain interleukin-1 and interleukin-6 expression. 2. Male A/J mice were injected subcutaneously with lipopolysaccharide (10 mg/kg) or an equal volume of saline as control. Sepsis was induced by caecal ligation and puncture (CLP); control mice underwent sham-operation. Brain tissue was assayed for interleukin-1 and interleukin-6 by ELISA. Northern blotting or the polymerase chain reaction was used to determine cytokine mRNA levels. 3. Administration of endotoxin induced a greater than fourfold increase in brain interleukin-1, a greater than threefold increase in interleukin-6 and an increase in mRNA for both cytokines. Caecal ligation and puncture resulted in increased brain interleukin-1 and interleukin-6 levels, but the changes were less pronounced and occurred later than after injection of endotoxin. There was no detectable difference in brain interleukin-1 mRNA between septic and sham-operated mice, whereas interleukin-6 mRNA was increased in brains of septic animals. 4. Sepsis and endotoxaemia resulted in similar, although not identical, changes in brain interleukin-1 and interleukin-6 concentrations and mRNA levels, suggesting that increased cytokine production in the central nervous system is part of the systemic response to sepsis and may be mediated by endotoxin.

Extracorporeal life support for the treatment of viral pneumonia: collective experience from the ELSO registry. Extracorporeal Life Support Organization

Viral pneumonia is the most common indication for pediatric extracorporeal life support (ECLS). Despite this fact, no previous studies have directly stratified patient outcome according to viral etiology.

METHODS

Using the Extracorporeal Life Support Organization (ELSO) registry database, the authors reviewed the national experience of patients undergoing ECLS with culture or serologically demonstrated viral pneumonia and compared outcome parameters according to viral etiology.

RESULTS

Patients differed with respect to age and weight according to the viral type. Patients with respiratory syncytial virus (RSV, median age 3 months), herpes simplex virus (HSV, 0.13 months), cytomegalovirus (CMV, 2.5 months), and adenovirus (0.6 months) were younger than those with other viruses (5.5 months). The patient groups did not significantly differ with respect to pre-ECLS Pao2 mean airway pressure (MAP), oxygenation index (OI), mode, or duration of ECLS. The overall survival of patients with viral pneumonia was 57%, although patients with RSV or CMV were found to have a 67% survival. Patients infected with HSV and adenovirus had a significantly lower survival rate (31% and 25%, respectively) when compared with those with RSV. In addition RSV pneumonia was associated with fewer cardiovascular complications than several of the other viral types. When comparison was made between survivors and nonsurvivors, a higher last pre-ECLS MAP and increased incidence of elevated creatinine and renal failure requiring dialysis were noted among nonsurvivors.

CONCLUSION

ECLS remains an important modality in the treatment of neonatal and pediatric patients with respiratory failure secondary to viral pneumonia. The survival rate of these patients varies according to the type of viral infection.

Sepsis is associated with increased mRNAs of the ubiquitin-proteasome proteolytic pathway in human skeletal muscle

Previous studies provided evidence that sepsis-induced muscle proteolysis in experimental animals is caused by increased ubiquitin-proteasome-dependent protein breakdown. It is not known if a similar mechanism accounts for muscle proteolysis in patients with sepsis. We determined mRNA levels for ubiquitin and the 20 S proteasome subunit HC3 by Northern blot analysis in muscle tissue from septic (n = 7) and non-septic (n = 11) patients. Plasma and muscle amino acid concentrations and concentrations in urine of 3-methylhistidine (3-MH), creatinine, and cortisol were measured at the time of surgery to assess the catabolic state of the patients. A three- to fourfold increase in mRNA levels for ubiquitin and HC3 was noted in muscle tissue from the septic patients concomitant with increased muscle levels of phenylalanine and 3-MH and reduced levels of glutamine. Total plasma amino acids were decreased by approximately 30% in the septic patients. The 3-MH/creatinine ratio in urine was almost doubled in septic patients. The cortisol levels in urine were higher in septic than in control patients but this difference did not reach statistical significance. The results suggest that sepsis is associated with increased mRNAs of the ubiquitin-proteasome pathway in human skeletal muscle.

Laparoscopic splenectomy by the lateral approach: a safe and effective alternative to open splenectomy for hematologic diseases

BACKGROUND

The purpose of this study was to compare the clinical outcomes and expense of laparoscopic splenectomy by the lateral approach with open splenectomy for the treatment of hematologic diseases.

METHODS

Medical records of 20 matched patients undergoing open splenectomy and lateral approach laparoscopic splenectomy were retrospectively reviewed detailing perioperative course, clinical outcome, and hospital charges.

RESULTS

Patients undergoing laparoscopic splenectomy (n = 10) experienced longer anesthesia (324 versus 176 minutes; p < 0.05) and operative times (261 versus 131 minutes; p < 0.05) than those undergoing open splenectomy (n = 10). No difference was noted in both intraoperative and postoperative packed red blood cells transfused. Laparoscopic splenectomy resulted in a shorter duration of nasogastric decompression (1.2 versus 2.6 days), more rapid resumption of normal oral intake (1.9 versus 4.4 days), and earlier hospital dismissal (3.0 versus 5.8 days). Although hospital charges were not significantly higher in the laparoscopic group ($17,071.00 versus $13,196.00; p > 0.05), operative charges were always significantly higher.

CONCLUSIONS

When compared with open splenectomy, lateral approach laparoscopic splenectomy allows a more rapid return of normal gastrointestinal function and shorter hospital stay. The operative expense of laparoscopic splenectomy is significantly higher; however, the overall hospital expense is not. If costs can be decreased, the lateral approach laparoscopic splenectomy will be the preferred operative approach.

Influence of sepsis and endotoxemia on polyamine metabolism in mucosa of small intestine in rats

We examined the influence of sepsis and endotoxemia in rats on the biosynthesis of polyamines in small-intestinal mucosa. Sepsis was induced by cecal ligation and puncture (CLP); control rats were sham-operated. In other experiments, rats were treated with two subcutaneous injections of endotoxin (1 mg/kg) or corresponding injections of sterile saline. Ornithine decarboxylase (ODC) and S-adenosylmethionine decarboxylase (SAMDC) activities and concentrations of putrescine, spermidine, and spermine were measured in jejunal mucosa at intervals during 16 hours. Sepsis stimulated ODC and SAMDC activities and increased putrescine and spermidine concentrations in jejunal mucosa. Injection of endotoxin resulted in metabolic changes similar to those observed following CLP. The results suggest that sepsis and endotoxemia stimulate polyamine biosynthesis in mucosa of small intestine. The role of polyamines in the regulation of cell proliferation and metabolic changes in the intestinal mucosa during sepsis remains to be determined.

Sepsis and endotoxemia stimulate intestinal interleukin-6 production

BACKGROUND

Endotoxemia stimulates tumor necrosis factor (TNF) and interleukin-1 (IL-1) production in mucosa of the small intestine, but the effect on IL-6 production is not known. Intestinal IL-6 may be especially important, considering its role in the acute phase response. We tested the influence of endotoxemia and sepsis in mice on intestinal IL-6 and IL-6 messenger RNA (mRNA) levels.

METHODS

Mice were injected with lipopolysaccharide (LPS 10 mg/kg) or saline solution. In some experiments animals were pretreated with indomethacin (5 mg/kg) or N-nitro-L-arginine (NNA, 100 mg/kg) before LPS injection. In other experiments, sepsis was induced by cecal ligation and puncture (CLP); controls were sham operated. Serum and jejunal mucosa were harvested at intervals during 16 hours, and IL-6 levels were determined by enzyme-linked immunosorbent assay. IL-6 mRNA was detected by polymerase chain reaction.

RESULTS

Endotoxemia and sepsis increased serum and mucosal IL-6 and IL-6 mRNA, with maximum levels noted at 1 and 4 hours after LPS and at 8 hours after CLP. Pretreatment of endotoxemic mice with indomethacin or NNA blunted the increase in mucosal IL-6.

CONCLUSIONS

Results suggest that sepsis and endotoxemia stimulate IL-6 production in small intestinal mucosa and that this response may be transcriptionally regulated. The effect of endotoxemia may be partly mediated by prostaglandins and nitric oxide. The results also suggest that the intestinal mucosa may be a participant in the cytokine response, rather than just a passive bystander.

Nitric oxide inhibits LPS-induced IL-6 production in enterocytes

In recent studies, production of interleukin-6 (IL-6) in cultured enterocytes was stimulated by lipolysaccharide (LPS). In other cell types, IL-6 production was inhibited by nitric oxide (NO). We tested the hypothesis that LPS-induced IL-6 production in the enterocyte is regulated, at least in part, by NO. IEC-6 cells (a rat intestinal epithelial cell line) were cultured for 3 days with different combinations of LPS (1-10 micrograms/ml), the NO synthase inhibitor N-omega-nitro-L-arginine (NNA, 3-300 microM), L-arginine (10 mM), the NO donor sodium nitroprusside (SNP, 0.5-1 microM), or medium alone as control. IL-6 levels in the culture medium were determined by the B9 murine hybridoma bioassay. Nitrite, a stable end product of NO metabolism, was measured by HPLC. PCR was performed to determine inducible NO synthase (iNOS) mRNA expression in the IEC-6 cells. Treatment of IEC-6 cells with LPS stimulated IL-6 production. LPS-induced IL-6 production was further increased by NNA in a dose-dependent fashion. This effect of NNA was abolished by the addition of L-arginine. SNP caused a dose-dependent decrease in IL-6 production. Nitrite production was increased in a dose-dependent fashion after LPS treatment. PCR revealed an increase in iNOS mRNA expression in IEC-6 cells after administration of 1 microgram/ml LPS. The results suggest that NO inhibits LPS-induced IL-6 production in the enterocyte. NO may be an important regulator of intestinal cytokine response during sepsis and endotoxemia.

Endotoxin stimulates interleukin-6 production in intestinal epithelial cells. A synergistic effect with prostaglandin E2

OBJECTIVE

To test the hypothesis that endotoxin stimulates the release of interleukin-6 (IL-6) from intestinal epithelial cells and that this effect of endotoxin is regulated by prostaglandin E2 (PGE2).

DESIGN

A rat intestinal crypt cell line, IEC-6, was cultured in the presence of lipopolysaccharide (LPS), 0.1 to 1.0 microgram/mL, and/or PGE2, 1 mumol/L. In other experiments, indomethacin, 20 mumol/L, was added to LPS-treated cells to block the effects of prostaglandins. Control wells contained medium alone. Levels of IL-6 were determined by the B9 murine hybridoma bioassay. Polymerase chain reaction was performed on RNA from control and LPS-treated cells to examine IL-6 message.

RESULTS

Lipopolysaccharide and PGE2 induced IL-6 release from IEC-6 cells in a dose- and time-dependent fashion, and the substances interacted synergistically. Addition of indomethacin blunted the effect of endotoxin on IL-6 production, consistent with a stimulatory role of PGE2. Polymerase chain reaction demonstrated increased IL-6 messenger RNA in endotoxin-treated cells.

CONCLUSIONS

Endotoxin and PGE2 stimulate IL-6 production in IEC-6 cells and interact synergistically. The endotoxin-stimulated IL-6 release may be regulated at the transcriptional level.

Reliability of threshold estimation in hearing-impaired adults using the AMFR

The amplitude modulation-following response (AMFR), an auditory evoked potential elicited by continuous amplitude-modulated tones, can be recorded for carrier frequencies across the audiometric range. AMFR thresholds (based on the amplitude spectra of the responses) have been found to closely follow behavioral thresholds in six normal-hearing and four hearing-impaired adults. In the current work, we studied the reliability of the AMFR as an index of behavioral low-frequency (500 and 1000 Hz) thresholds in a larger sample (n = 16) of hearing-impaired adults with mild to moderate hearing loss. The AMFR amplitudes and detection thresholds were strongly correlated across the two recording sessions, and AMFR thresholds obtained in both sessions were strongly correlated to behavioral thresholds. The average absolute difference between the AMFR and behavioral thresholds was 7.3 dB and 6.4 dB for 500 Hz and 1000 Hz, respectively.

Quantitation of the nitrosamine 2-ethylhexyl-4-(N-methyl-N-nitrosoamino) benzoate (NPABAO) in sunscreen products

We have devised a method to quantitate the nitrosamine, 2-ethylhexyl-4-(N-methyl-N-nitrosoamino) benzoate (NPABAO), in commercial products containing the sunscreen ingredient, Padimate O. The method involves a minimum of cleanup steps to afford a nonaqueous extract from product emulsions suitable for analysis by a liquid chromatograph interfaced to a thermal energy analyzer (LC/TEA). The method is applicable to lotions, creams, and gels. Oils are normally soluble in the mobile phase and can be analyzed directly on the LC/TEA without additional cleanup procedures. The method has a minimum detectable limit of about 30 ppb and yields greater than 80% recovery. It is highly reproducible and generates no NPABAO artifactually prior to quantitation on the LC/TEA. Application of the method to 22 different commercial product formulas disclosed that the level of NPABAO in each of the products is below 250 ppb, with 18 of the products containing less than 100 ppb. Of interest was the observation that musk ketone, a common fragrance constituent, produces a false-positive TEA response that can interfere with accurate analysis of NPABAO content in typical commercial products.

Reactions of nitrosamines with nucleophiles in acid solution

The kinetics of denitrosation of N-alkyl (and aryl) N-nitrosoaniline derivatives in ethanolic HCl have been studied. In contrast with the results for the corresponding reactions in water, there is no catalysis by added nucleophiles and the solvent isotope effect is 3.8. Similar results were obtained for reactions in water at high nucleophile concentrations and also for N-methyl-N-nitrosourea in water in the absence of added nucleophiles. All the results are consistent with a change in rate-determining step which can be brought about in three independent ways. This also explains the absence of nucleophilic catalysis for N-nitrosation of amides. Results are presented for the nitrosation of N-methyl urea.

Cyclic AMP-stimulated phosphorylation of bovine tracheal smooth muscle contractile and non-contractile proteins

1. Various proteins isolated from bovine tracheal smooth muscle were examined as phosphate acceptor substrates for a cyclic AMP-dependent protein kinase isolated from the same tissue. A fraction prepared in a manner similar to that of skeletal muscle troponin was the best substrate of the presumptive contractile proteins isolate. Actomyosin and tropomyosin were relatively poor substrates. 2. An assay was developed for the rapid detection in a large number of samples of the muscle specific substrate for the protein kinase on which we reported previously. 3. Using this assay, the muscle specific substrate found in bovine tracheal smooth muscle was partially purified resulting in a preparation which when resolved by polyacrylamide gel electrophoresis showed a single peak of 32P incorporated, and which could be further characterized. 4. Our findings suggest that the substrate contains a protein subunit of molecular weight 19 000, which can be phosphorylated at serine and threonine residues, in the presence of cyclic AMP and protein kinase. The phosphate is in a covalent ester linkage with these residues. 5. A phosphoprotein phosphatase was isolated from the bovine tracheal smooth muscle. 6. Bovine tracheal smooth muscle contains cyclic AMP dependent protein kinase and phosphoprotein phospahatase activity as well as the muscle specific substrate, suggesting that these elements may be part of a mechanism which regulates smooth muscle tone.