Epidermal aquaporin-3 is increased in the cutaneous burn wound.

INTRODUCTION: Aquaporins (AQP) are a family of transmembrane proteins that transport water and small solutes such as glycerol across cell membranes. It is a mediator of transcellular water flow and plays an important role in maintaining intra/extracellular fluid homeostasis by facilitating water transport in response to changing osmotic gradients. In the skin, AQPs permit rapid, regulated, and selective water permeability and have been demonstrated to play a role in skin hydration, cell proliferation, migration, immunity, and wound healing. However, the expression of AQP-3 in the cutaneous burn wound has never been elucidated. We sought to assess the expression of AQP-3 in patients with burn wounds. METHODS: A fresh full thickness biopsy sample was taken from the center of the burn wound, the burn wound edge, and the graft donor site in 7 patients (n=21), approximately 3-7 days post injury. Fixed, paraffin embedded sections were stained using AQP-3 specific antibody and examined by immunofluorescence. Fresh samples were processed to quantify AQP-3 protein expression with Western blot analysis. RESULTS: The central portion of the burn wound revealed destruction of the epidermis and dermis with no AQP-3 present. Along the burn wound edge where the epidermal architecture was disrupted, there was robust AQP-3 staining. Western blot analysis demonstrated deeper staining along the burn wound edge compared to unburned skin (control). Quantification of the protein shows a significant amount of AQP-3 expression along the burn wound edge (3.6±0.34) compared to unburned skin (2.1±0.28, N=7, *p<0.05). There is no AQP-3 expression in the burn wound center. CONCLUSION: AQP-3 expression is increased in the burn wound following injury. While its role in wound healing has been defined, we report for the first time the effect of cutaneous burns on AQP-3 expression. Our data provides the first step in determining its functional role in burn wounds. We hypothesize that development of AQP3 targeted therapies may improve burn wound healing.

From cholera to burns: a role for oral rehydration therapy.

According to the practice guidelines of the American Bum Association on burn shock resuscitation, intravenous (i.v.) fluid therapy is the standard of care for the replacement of fluid and electrolyte losses in burn injury of > or = 20% of the total body surface area. However, in mass burn casualties, i.v. fluid resuscitation may be delayed or unavailable. Oral rehydration therapy (ORT), which has been shown to be highly effective in the treatment of dehydration in epidemics of cholera, could be an alternate way to replace fluid losses in burns. A prospective case series of three patients was carried out as an initial step to establish whether oral Ceralyte 90 could replace fluid losses requiring i.v. fluid therapy in thermal injury. The requirement of the continuing i.v. fluid therapy was reduced by an average of 58% in the first 24 hours after the injury (range 37-78%). ORT may be a feasible alternative to i.v. fluid therapy in the resuscitation of burns. It could also potentially save many lives in mass casualty situations or in resource-poor settings where i.v. fluid therapy is not immediately available. Further studies are needed to assess the efficacy of this treatment and to determine whether the present formulations of ORT for cholera need modification.

At second glance: employers and employees with learning disabilities in the Americans with Disabilities Act era.

The impact of the Americans with Disabilities Act (ADA) of 1990 on the American workplace is examined. The findings of a previous study (Gerber, 1992) on employer knowledge about learning disabilities are compared to current findings. Important themes and employer beliefs and practices that were consistent in employer responses are described. Although employers are continuing to make efforts to comply with the regulations of the ADA, they still have relatively little knowledge or experience with it in terms of learning disabilities.

Malignant superior vena cava syndrome presenting after trauma.

A 41-year-old man was brought to the ED after a motor vehicle crash. On presentation, he demonstrated symptoms compatible with superior vena cava (SVC) syndrome, including extreme dyspnea, face and neck cyanosis and facial swelling. A chest tube was inserted and drained large amounts of sanguineous fluid. An exploratory thoracotomy revealed an extensive tumour encasing the SVC and the hilum. Biopsy confirmed the diagnosis of T-cell lymphoma. The most common cause of SVC syndrome is malignant disease, with bronchogenic carcinoma and lymphoma being most frequent. Review of the literature uncovered only a few anecdotal reports of traumatic SVC syndrome. There are no previous reported cases of malignant SVC syndrome presenting in association with trauma.

A linear hexapeptide somatostatin antagonist blocks somatostatin activity in vitro and influences growth hormone release in rats.

Somatostatin (SRIF) is the main inhibitory peptide regulating growth hormone (GH) secretion. It has been difficult to establish the role of endogenous SRIF release in the absence of pure SRIF antagonists. Although several SRIF antagonists have recently been described, none have been shown to possess in vivo activity in the absence of added SRIF. Here, an SRIF antagonist with no detectable agonist activity has been identified from a synthetic combinatorial hexapeptide library containing 6.4 x 10(7) unique peptides. Each peptide in the library is amino-terminally acetylated and carboxyl-terminally amidated and consists entirely of D-amino acids. A SRIF-responsive yeast growth assay was used as a primary screening tool, and cAMP accumulation, competitive binding, and microphysiometry also were used to confirm and further characterize SRIF antagonist activity. The hexapeptide library was screened in stepwise iterative fashion to identify AC-178,335, a pure SRIF antagonist of the sequence Ac-hfirwf-NH2. This D-hexapeptide bound SRIF receptor type 2 with an affinity constant (Ki) of 172 +/- 12 nM, blocked SRIF inhibition of adenylate cyclase in vitro (IC50 = 5.1 +/- 1.4 microM), and induced GH release when given alone (50 micrograms intravenously) to anesthetized rats with or without pretreatment with a long-acting SRIF agonist.

Investigation of growth hormone releasing hormone receptor structure and activity using yeast expression technologies.

Growth hormone releasing hormone (GHRH) is the positive regulator of growth hormone synthesis and secretion in the anterior pituitary. The peptide confers activity by binding to a seven transmembrane domain G protein-coupled receptor. Signal transduction proceeds through subsequent G alpha s stimulation of adenylyl cyclase. To investigate ligand/receptor and receptor/G protein associations, the human GHRH receptor was expressed in a modified S. cerevisiae strain which allows for facile measurement of receptor activity by cell prototrophy mediated by a reporter gene coupled to the yeast pheromone response pathway. GHRH-dependent signal activation in this system required the substitution of yeast G alpha protein with proteins containing C-terminal regions of G alpha s. A D60G variant (analogous to the little mouse mutation) of the receptor failed to respond to agonist. In parallel studies, GHRH29 and the N-terminal extracellular region of the receptor were expressed as Gal4 fusion proteins in a 2-hybrid assay. A specific interaction between these proteins was readily observed. The D60G mutation was engineered into the receptor fusion protein. This protein failed to interact with the ligand fusion, confirming the specificity of the association between unmodified proteins. These two yeast expression technologies should prove invaluable in additional structure/activity analyses of this ligand/receptor pair as well as other peptide ligands and receptors.

ORK1, a potassium-selective leak channel with two pore domains cloned from Drosophila melanogaster by expression in Saccharomyces cerevisiae.

A K+ channel gene has been cloned from Drosophila melanogaster by complementation in Saccharomyces cerevisiae cells defective for K+ uptake. Naturally expressed in the neuromuscular tissues of adult flies, this gene confers K+ transport capacity on yeast cells when heterologously expressed. In Xenopus laevis oocytes, expression yields an ungated K(+)-selective current whose attributes resemble the "leak" conductance thought to mediate the resting potential of vertebrate myelinated neurons but whose molecular nature has long remained elusive. The predicted protein has two pore (P) domains and four membrane-spanning helices and is a member of a newly recognized K+ channel family. Expression of the channel in flies and yeast cells makes feasible studies of structure and in vivo function using genetic approaches that are not possible in higher animals.

Chronic copper toxicosis presenting as liver failure in an Australian child.

A 20 month old Caucasian male child, after a five week illness, developed liver failure which was successfully treated by liver transplantation. The explanted liver had a histology identical to that seen in Indian childhood cirrhosis and its copper content was increased tenfold. Water used to prepare the child's milk feeds came from a bore via copper conduits and at times contained 120 mumol/l of copper, eight times the recommended maximum for human consumption. Because non-Indian cases of Indian childhood cirrhosis associated with excess copper ingestion are increasingly being recognised, and as early treatment can restore normal liver morphology, we support the use of the previously suggested alternative term for this condition, ie; 'copper-associated liver disease in childhood'. Measurement of hepatic copper concentrations in all children less than six years of age who develop hepatic failure of unknown cause will increase its recognition. On diagnosis sources of increased dietary copper should be investigated to ensure that younger siblings are not similarly exposed.

Identification and characterization of novel somatostatin antagonists.

The study of the five somatostatin receptor subtypes (SSTx, where x is the subtype number) has been hampered by the lack of high affinity antagonists. Potent and selective antagonists would increase our understanding of SST structure, function, and regulation. In this study, the identification of novel disulfide-linked cyclic octapeptide antagonists of somatostatin is described. The antagonists contain a core structure of a DL-cysteine pair at positions 2 and 7 of the peptides. Substitution of a D-cysteine at position 2 with an L-cysteine converts the full antagonist into a full agonist. All somatostatin receptor subtypes are coupled to inhibition of adenylate cyclase. The functional properties of these peptides have been determined in radioligand binding assays, in functional coupling of the SST2 subtype to yeast pheromone response pathway, and in cAMP accumulations. One peptide antagonist [Ac-4-NO2-Phe-c(D-Cys-Tyr-D-Trp-Lys-Thr-Cys)-D-Tyr-NH2] displays a binding affinity to SST2 comparable with that observed for the native hormone (Ki = 0.2 nM) and reverses somatostatin-mediated inhibition of cAMP accumulation in rat somatomammotroph GH4C1 cells, cells transfected with the SST2 and SST5 subtypes, as well as somatostatin-stimulated growth of yeast cells expressing the SST2 subtype. This class of somatostatin antagonists, which are the first to be described, should be useful for determination of somatostatin's diverse functions in vivo and in vitro.

Pharmacological characterization of the rat A2a adenosine receptor functionally coupled to the yeast pheromone response pathway.

The rat A2a adenosine receptor, a G protein-coupled receptor, was functionally expressed in the yeast Saccharomyces cerevisiae. High affinity binding sites for A2a adenosine agonists were detected in yeast membranes containing the endogenous Grx protein Gpa1. Agonist saturation binding isotherms using [3H]5'-N-ethylcarboxamidoadenosine indicated that the A2a adenosine receptor expressed in yeast cell membranes displays pharmacological properties equivalent to those observed when the receptor is expressed in human embryonic kidney 293 cell membranes. The rank order of potency of various agonists in [3H]5'-N-ethylcarboxamidoadenosine competition binding assays performed with yeast cell membranes was comparable to that seen for the receptor expressed in mammalian cell membranes. Adenosine agonist-dependent growth response of yeast strains expressing the A2a adenosine receptor was elicited via activation of the yeast pheromone-response pathway. Induction of a pheromone-responsive FUS1-HIS3 reporter gene in far1 his3 cells permits cell growth in medium lacking histidine. The sensitivity of the bioassay was increased by deletion of the STE2 gene, which encodes the yeast alpha-mating pheromone receptor. The growth response was dose dependent, and agonists of varying affinities displayed a rank order of potency comparable to that observed in competition binding assays. Agonist-activated growth assays performed in liquid culture gave ED50 values for various adenosine agonists consistent with reported Kd alpha values. Yeast strains expressing a single receptor/G protein complex will be useful as a model system for the study of receptor/G protein interactions in vivo.

Weak, but complex pulsed magnetic fields may reduce depression following traumatic brain injury.

Many patients who display psychological depression following a traumatic brain injury do not respond completely to antidepressant drugs. We hypothesized that this type of depression is strongly correlated with subclinical, complex partial seizure-activity within the hippocampal-amygdaloid region that continues for months to years after apparent neurological and behavioral "recovery." Four depressed patients who had sustained traumatic brain injuries and who exhibited mild to moderate brain impairment according to standardized tests received 30 min. of weak (1 microT) burst-firing magnetic fields across the temporal lobes once per week for 5 weeks. There was a significant improvement of depression and reduction of phobias while physical symptoms and other complaints were not changed.

Functional coupling of a mammalian somatostatin receptor to the yeast pheromone response pathway.

A detailed analysis of structural and functional aspects of G-protein-coupled receptors, as well as discovery of novel pharmacophores that exert their effects on members of this class of receptors, will be facilitated by development of a yeast-based bioassay. To that end, yeast strains that functionally express the rat somatostatin receptor subtype 2 (SSTR2) were constructed. High-affinity binding sites for somatostatin ([125I-Tyr-11]S-14) comparable to those in native tissues were detected in yeast membrane extracts at levels equivalent to the alpha-mating pheromone receptor (Ste2p). Somatostatin-dependent growth of strains modified by deletion of genes encoding components of the pheromone response pathway was detected through induction of a pheromone-responsive HIS3 reporter gene, enabling cells to grow on medium lacking histidine. Dose-dependent growth responses to S-14 and related SSTR2 subtype-selective agonists that were proportional to the affinity of the ligands for SSTR2 were observed. The growth response required SSTR2, G alpha proteins, and an intact signal transduction pathway. The sensitivity of the bioassay was affected by intracellular levels of the G alpha protein. A mutation in the SST2 gene, which confers supersensitivity to pheromone, was found to significantly enhance the growth response to S-14. In sst2 delta cells, SSTR2 functionally interacted with both a chimeric yeast/mammalian G alpha protein and the yeast G alpha protein, Gpa1p; to promote growth. These yeast strains should serve as a useful in vivo reconstitution system for examination of molecular interactions of the G-protein-coupled receptors and G proteins.

Paraquat and diquat interference in the analysis of creatinine by the Jaffé reaction.

Paraquat and diquat were shown to interfere significantly in the measurement of plasma creatinine by the alkaline picrate (Jaffé) reaction in a young man who ingested a massive dose of a mixture of the 2 herbicides. It is likely that these bipyridylium compounds react in a manner similar but at different rates compared with creatinine in the Jaffé reaction.

Causes of higher in-hospital mortality in women than in men after acute myocardial infarction.

Clinical, laboratory and cardiac catheterization parameters were reviewed in 355 men and 155 women hospitalized at a tertiary care referral center between February 1987 and December 1991 to analyze why women have a higher in-hospital mortality rate than do men after acute myocardial infarction. Hospital mortality was 21.4% in women and 12.1% in men (p = 0.007). In comparison with men, women were older (63.3 +/- 11.9 vs 60.5 +/- 12.6 years; p = 0.023), had more systemic hypertension (46.5 vs 34.4%; p = 0.001) and higher serum total cholesterol levels (211 +/- 51 vs 197 +/- 49 mg/dl; p = 0.0015), sought medical care later (8.9 vs 5.3 hours; p = 0.026), were referred later (47.7 vs 43.7 hours; p = 0.063) and had more shock (34.8 vs 24.2%; p = 0.013). Logistic regression analysis revealed 5 variables predictive of hospital mortality; age > 65 years, diabetes, shock, non-Q-wave infarction, and not undergoing cardiac catheterization. Gender was of borderline significance in predicting hospital mortality. Cardiac catheterization, performed in 88% of women and 87% of men, showed similar rates of 1-, 2- and 3-vessel disease, and similar characteristics of the infarction-related artery. The differences in hospital mortality between men and women are due to a combination of pre- and in-hospitalization factors in women. The excess mortality is not due to differences in disease severity as evaluated by cardiac catheterization information.

Lack of survival advantage in patients with advanced squamous cell carcinomas of the oral cavity receiving neoadjuvant chemotherapy prior to local therapy, despite achieving an initial high clinical complete remission rate.

Subset analyses have been performed on 50 patients with squamous cell carcinomas of the oral cavity from our earlier series of 208 patients with advanced, previously untreated head and neck tumors (J Clin Oncol 1986;4:1340-7). Forty patients (80%) responded to two initial courses of Schedule A chemotherapy. Side effects were minimal. After definitive local therapy the final complete remission (CR) rate was 76%. Neither chemotherapy response, nor achievement of final CR was significantly affected by stage, T or N status, sex, or histologic grade. With a median follow-up of 11.6 years, the overall 10-year survival rate was 25%. Multivariate analysis indicated that both age, i.e., < 50 years (p = .004) and achievement of a final CR (p = .002) were significant factors for improved survival. Median survival for all patients was only 21 months and for those in final CR 30 months. These survival figures were all significantly lower than those of similarly treated patients with laryngeal or nasopharyngeal tumors, illustrating that all patients with head and neck tumors achieving a final clinical CR do not automatically have improved survival. These results emphasize the need for randomized trials, with sufficient numbers to identify optimal treatment strategies for tumors at specific sites within the head and neck region.

When academic assistance is not enough: addressing the mental health issues of adolescents and adults with learning disabilities.

This article focuses on an answer to a critical question for adolescents and adults with learning disabilities: How can professionals assist students with learning disabilities who have psychosocial issues that appear to be affecting their academic progress and life adjustment? Inherent in this inquiry are other, equally important issues, such as: How do learning disabilities service providers know when to involve other service providers? What are the steps in referring a student for further assistance with different mental health issues? When are team interventions necessary? How are team interventions conducted in either secondary or postsecondary settings? How should learning disabilities service providers establish the boundaries of their professional expertise and/or responsibilities to adequately meet the needs of individuals with learning disabilities? This article illustrates answers to these questions by providing examples of interventions and case studies from two federally funded research/demonstration projects at the University of Minnesota: the Learning Disabilities Transition Project and Project Extra. The authors describe theoretical models for mental health services that address the psychosocial issues frequently encountered in academic or vocational settings. Recommendations are also included that discuss how the models can be personalized to fit the reader's home institution or agency.

Larynx preservation after initial non-cisplatin containing combination chemotherapy plus radiotherapy, as opposed to surgical intervention with or without radiotherapy in previously untreated advanced head and neck cancer: final analysis after 12 years follow-up.

After a median follow-up of 12 years, median overall survival of 73 patients with advanced squamous cell carcinoma of the larynx was 65 months. The 61 per cent of patients responding to two courses of initial schedule A combination chemotherapy, not including cisplatin, and the 81 per cent of patients achieving a final complete remission after definitive local therapy, had median overall survival figures of 95 and 97 months respectively. Overall survival and relapse-free survival in 51 patients treated with radiotherapy only with larynx preservation, were not significantly different from the 21 patients who completed their surgery with pre- or post-operative radiotherapy; median overall figures were 71 versus 65 months. These data add weight to our proposal that use of initial combination chemotherapy followed by radiotherapy may eliminate the need for radical surgery, so preserving the larynx in patients with advanced disease, and provides evidence of some long-term benefit with 32 per cent of this entire group surviving 12 years.