Enhanced disease resistance conferred by expression of an antimicrobial magainin analog in transgenic tobacco.

Magainins are a group of short peptides originally isolated from frog skin and thought to function as a natural defense mechanism against infection due to their antimicrobial properties. The engineered magainin analog peptide Myp30 was found to inhibit spore germination of the oomycete, Peronospora tabacina (Adam) in vitro, and the growth of a bacterial pathogen Erwinia carotovora subsp. carotovora (Jones). Transgenic tobacco (Nicotiana tabacum L.) plants expressing Myp30 were evaluated for resistance to these pathogens. The expression of the peptide only to an extracellular location resulted in significant reduction in sporulation and lesion size due to P. tabacina infection. A significant increase in resistance to the bacterial pathogen was also observed regardless of the targeting location of the peptide.

A mutant deubiquitinating enzyme (Ubp-M) associates with mitotic chromosomes and blocks cell division.

A new ubiquitin-processing protease (Ubp-M) has been identified in mammalian cells that is phosphorylated at the onset of mitosis and dephosphorylated during the metaphase/anaphase transition. The carboxyl-terminal domain of this 823-aa protein can be phosphorylated in vitro with either extracts of mitotic cells or purified cdc-2/cyclin B complexes. Recombinant Ubp-M is able to deubiquitinate histone H2A in vitro, and the phosphorylated form is also enzymatically active. Wild-type Ubp-M, transiently expressed as green fluorescent protein-fusion proteins, localizes in the cytoplasm of cultured cells, but mutant forms, lacking an active-site cysteine, associate closely with mitotic chromosomes during all stages of cell division and remain within the nucleus during the postmitotic period. Cells transfected with plasmids containing mutant Ubp-M genes stop dividing and eventually undergo apoptosis. Ubp-M may deubiquitinate one or more critical proteins that are involved in the condensation of mitotic chromosomes, possibly acting selectively on histones H2A and H2B, the major ubiquitinated proteins of chromatin.

Use of texture fading in the treatment of food selectivity.

Children with feeding disorders often display severe food selectivity. For many of these children, consuming highly textured foods may be aversive or potentially dangerous because of frequent gagging. The purpose of this study was to demonstrate the efficacy of texture fading in the treatment of food selectivity displayed by 4 children. Treatment involved the gradual addition of higher textures based on the results of periodic probes. In addition, food acceptance and swallowing were reinforced, while food refusal and food expulsion were placed on extinction. Results showed that all participants successfully advanced to consumption of age-appropriate texture and volume. The results suggest that texture fading with intermittent probes at higher textures may be an effective method for the treatment of food selectivity by texture.

Use of extinction and reinforcement to increase food consumption and reduce expulsion.

Extinction and reinforcement contingencies were used to treat 2 children with feeding disorders. Positive reinforcement and avoidance extinction effectively increased food acceptance but also increased food expulsion. Reduced expulsion and increased swallowing were achieved by repeated presentation of expelled food, a second extinction component

Decreased resting metabolic rate among persons with Down Syndrome.

OBJECTIVE: To compare the resting metabolic rates (RMRs) of adults with and without DS while controlling for potential confounds. DESIGN: Observational, cross-sectional study. SETTING: Outpatient core of the New York Obesity Research Center. SUBJECTS: Thirteen adults (nine males and four females) with DS were compared to 77 adults without DS. MEASUREMENTS: RMR was measured by indirect calorimetry. Fat mass (FM) and fat free mass (FFM) were determined using dual energy X-ray absorptiometry (DXA). Thyroid function (thyroxin, T3 uptake, and free T4) were determined from fasting blood samples for all DS subjects and a subset of the controls. RESULTS: An analysis of covariance was conducted in which DS status was the independent variable. Covariates were sex, FFM, FM, age, and T4. After controlling for sex, FFM, FM, age, and height, persons with DS had lower RMRs than persons without DS (F(1,83) = 7.697, P = 0.007; eta = 0.29). In terms of kcalories, the adjusted means were 1333.5 for DS subjects and 1670.1 for non-DS subjects, a difference of 20.8% relative to the grand mean. When thyroxine was added to the regression the effect of DS on RMR was of questionable significance. CONCLUSION: This research demonstrates that persons with DS have lower RMRs than do persons without DS. This difference persists after controlling for obvious confounds and was of a moderate magnitude.

Age-related changes in albumin-excluded volume fraction.

The space available to large macromolecules, such as albumin and globulin, is less than the total interstitial fluid volume due to the dense matrix formed by the interstitial ground substance. Changes in excluded volume are likely to indicate changes in the composition of the matrix. Sprague-Dawley rats were anesthetized with sodium pentobarbital. Serum, mesenteric tissue, and peritoneal fluid samples were obtained. Albumin contents were determined by microrod electrophoresis. Serum and mesenteric tissue chloride concentrations were measured by the coulometric-amperometric method. Serum and mesenteric tissue sample chloride concentrations were not significantly different, suggesting that this loose connective tissue is composed almost entirely of extracellular matrix. Matrix hydration decreased with a regression slope of -0.014 (microgram tissue water/microgram tissue dry wt)/10 days. Serum and tissue albumin concentrations decreased between 210 and 630 days of age. Mesenteric loose connective tissue albumin-excluded volume fraction increased by 80% over this age range. The increase could not be accounted for by dehydration alone, suggesting that the increase in excluded volume fraction for albumin is also due to changes in tissue glycosaminoglycans or collagen.

Age-related changes in perimicrovascular protein distribution.

The diffusion hypothesis for physiological aging proposes that an increase in interstitial matrix fiber-to-gel ratio causes a decrease in nutrient diffusion to the cells. This hypothesis predicts a decrease in interstitial matrix protein with age. The objective was to test this hypothesis by determining age-related changes in plasma protein distribution in perimicrovascular and distal regions of rat mesentery interstitial matrix. Rats that were 77, 140, 210, 315, 455, and 630 days old were anesthetized with pentobarbital sodium, and a mesenteric loop was exteriorized. Intravital video microspectrophotometry was performed using wavelengths of 280, 320, and 700 nm. Perimicrovascular protein concentrations from the protein absorbance images were used to obtain the histogram, mean, and skewness of the proximal and distal protein concentration distributions. An exponential gradient model was also used to obtain the proximal and distal protein concentrations and gradient decay constants. Proximal protein concentration increased from 77- to 140-day-old rat and then decreased gradually through 210-, 315-, 455-, and 630-day-old rats. Distal concentration decreased gradually from 140- to 630-day-old rats. There was an increase in positive skewness of the proximal protein distributions from 140- through 630-day-old rats. We found an age-related decrease in perimicrovascular protein and propose that this is due to a decrease in protein permeability with age. The results support the diffusion theory of aging.

Age-related changes in rat interstitial matrix hydration and serum proteins.

Measurements of effects of age-related changes on loose connective tissue protein concentrations and water are lacking. Tissue hydration is an important determinant of tissue protein diffusion coefficients and hydraulic conductivity. Sprague-Dawley rats (ages 11, 30, 57, and 89 wk) were anesthetized. Blood and mesenteric tissue samples were taken. Tissue water content was determined by microgravimetric technique. Protein content was determined by electrophoresis. Tissue hydration decreased 18% between 11 and 89 wk with one-half the fall occurring between 57 and 89 wk. Tissue albumin concentration decreased 37% between 11 and 89 wk. Serum albumin increased 22% between 11 and 30 wk and then decreased by 37% to 1.4 g/dl in 89-wk rats. Serum total protein concentration increased by 13% between 11 and 89 wk, whereas tissue total protein concentration decreased 30% with age to 1.9 g/dl at 89 wk. The results suggest that age-related tissue dehydration is due, in part, to a shift in the colloid osmotic pressure components of Starling equilibrium favoring fluid reabsorption.

Simulation and counterconditioning as adjuncts to pharmacotherapy for invasive pediatric procedures.

Behavioral counterconditioning was conducted during simulated medical routines to supplement medical management of five children's distress during invasive procedures (bone marrow aspiration, lumbar puncture, tracheostomy care, venipuncture, and finger pricks). Preferred activities were paired in vivo with medical stimuli, and differential positive reinforcement was provided contingent on engagement with the preferred activities and on compliance with adult instructions, first during simulations and later during actual procedures. Data on cooperation, escape/avoidance, and negative vocalizations were evaluated using both single-subject experimental methods and a baseline-treatment group statistical comparison. Results support the benefits of this approach as an adjunctive intervention to decrease behavioral distress in some children requiring repeated invasive procedures. Discussion emphasizes the potential for training medical personnel to implement these techniques preventively, for decreasing or discontinuing sedation for some children treated under local anesthesia, and for preparing children with developmental disabilities for invasive procedures.

A swallow induction avoidance procedure to establish eating.

Swallow induction has been used to shape swallowing behavior in dysphagic children and to accelerate swallowing in nondysphagic children with profound mental retardation who display primitive swallows. Swallow induction may be considered a type of prompt. This project coupled swallow induction with a modified delayed prompting paradigm to establish eating in a 3.5-year-old girl. Coupling these procedures produced prompt swallowing and established oral consumption. Follow-ups at 1, 2, 6 and 12 months demonstrated maintenance and further improvement of the newly acquired feeding skills. Implications for treatment and further research are discussed.

Fire in the Brazilian Amazon: 1. Biomass, nutrient pools, and losses in slashed primary forests.

Deforestation in the Brazilian Amazon has resulted in the conversion of >230,000 km2 of tropical forest, yet little is known on the quantities of biomass consumed or the losses of nutrients from the ecosystem. We quantified the above-ground biomass, nutrient pools and the effects of biomass burning in four slashed primary tropical moist forests in the Brazilian Amazon. Total above-ground biomass (TAGB) ranged from 292 Mg ha-1 to 436 Mg ha-1. Coarse wood debris (>20.5 cm diameter) was the dominant fuel component. However, structure of the four sites were variable. Coarse wood debris comprised from 44% to 69% of the TAGB, while the forest floor (litter and rootmat) comprised from 3.7 to 8.0% of the TAGB. Total biomass consumption ranged from 42% to 57%. Fires resulted in the consumption of >99% of the litter and rootmat, yet <50% of the coarse wood debirs. Dramatic losses in C, N, and S were quantified. Lesser quantities of P, K, and Ca were lost by combustion processes. Carbon losses from the ecosystem were 58-112 Mg ha-1. Nitrogen losses ranged from 817 to 1605 kg ha-1 and S losses ranged from 92 to 122 kg ha-1. This represents losses that are as high as 56%, 68%, and 49% of the total above-ground pools of these nutrients, respectively. Losses of P were as high as 20 kg ha-1 or 32% of the above-ground pool. Losses to the atmosphere arising from primary slash fires were variable among sites due to site differences in concentration, fuel biomass, and fuel structure, climatic fluctuations, and anthropogenic influences. Compared to fires in other forest ecosystems, fires in slashed primary tropical evergreen forests result in among the highest total losses of nutrients ever measured. In addition, the proportion of the total nutrient pool lost from slash fires is higher in this ecosystem compared to other ecosystems due to a higher percentage of nutrients stored in above-ground biomass.

Behavioral assessment and treatment of pediatric feeding disorders.

Pediatric feeding disorders are estimated to occur in as many as one in every four infants and children, and when serious can require numerous, costly and sustained interventions. For over a decade research has cumulated evidence on the contributions of Behavior Analysis in understanding and remediating some types of pediatric feeding disorders. The systematic use of this body of evidence in conjunction with other approaches (medical, nutrition, occupational therapy, physical therapy, and so forth) is being carried out on an inpatient treatment unit at the Kennedy Krieger Institute. Key aspects are described here, including direct observation behavior assessment, approaches for increasing and decreasing feeding behavior, skill acquisition, transfer of treatment gains, and parent training. The results based on case studies and overall program evaluation indicate that medically complicated, severe feeding disorders can be treated successfully in a few months with a multidisciplinary approach which incorporates behavioral procedures.

Changes in perimicrovascular protein spatial distribution due to superfusate.

OBJECTIVE: To determine superfusate-induced changes in the distribution of plasma proteins in the perimicrovascular interstitial matrix. METHODS: Rats were anesthetized with sodium pentobarbital and a mesenteric loop was exteriorized. Intravital video microspectrophotometry was performed using wavelengths of 280, 320, and 700 nm. The images were analyzed to give protein and collagen spatial distributions in vascular regions of rat mesenteric tissue. Perimicrovascular protein concentrations were fitted to an exponential decay model ci + cr exp (-x/k), where ci is distal protein concentration, ci + cr is the protein concentration proximal to the vessel, x is the distance from the vessel wall, and k is the decay constant indicating protein gradient slope. RESULTS: Before superfusion with 0.5-ml normal saline, ci = 1.45 +/- 0.13 g/dl, ci + cr = 4.56 +/- 0.23 g/dl. After the first superfusion, ci decreased (p < 0.01) to 0.53 +/- 0.06 g/dl; following a second superfusion, cr decreased to 0.4 +/- 0.03 g/dl; an additional final superfusion caused a further decrease to 0.33 +/- 0.02 g/dl. ci + cr also decreased significantly during repeated superfusions to 2.92 +/- 0.15, 2.35 +/- 0.25, and 2.1 +/- 0.12 g/dl, respectively. CONCLUSIONS: Superfusion produced changes in perivascular and distal interstitial matrix protein distribution. Protein concentration proximal to the microvessel remained higher than distal concentrations. This could be due to increased gel concentrations inhibiting protein mobility.

Contingency contacting. Combining positive reinforcement and escape extinction procedures to treat persistent food refusal.

Chronic food refusal has traditionally been treated with forced feeding and other physical prompting-based procedures when positive reinforcement procedures prove inadequate. Potential problems with such procedures, however, include exacerbation of feeding difficulties and health risks, as well as low parental approval and probability of implementation. Contingency contacting maximizes contact between oral acceptance and positive reinforcement, prevents escape functions of inappropriate behaviors, and requires minimal physical contact between feeder and child. Performances of two children exhibiting chronic food refusal were observed under baseline, positive reinforcement, and contingency contacting conditions. Positive reinforcement increased acceptance only slightly and did not change negative vocalization or interruption for one child. Contingency contacting rapidly increased acceptance and grams of food consumed, and decreased negative vocalization and interruption for both children. Withdrawal to positive reinforcement decreased acceptance for both children and grams consumed for one. Reinstituting contingency contacting rapidly increased acceptance and recovery of grams consumed for one child. Parental approval ratings and treatment and research implications are discussed.

Antecedent manipulation in the treatment of primary solid food refusal.

A 4-year-old with primary solid food refusal was treated with systematic fading of utensil type and food texture, using a multiple probe design across food groups. The subject was a multi-handicapped boy hospitalized for feeding problems, self-injurious behaviors, and sleep cycle reversal. At admission, the subject received all nutrition in the form of a liquid nutritional supplement through regular bottle feedings every half hour. Craniofacial anomalies and past multiple facial surgeries precluded the use of a physical prompting procedure. During the first treatment phase, pureed foods were presented with a preexisting stimulus (a regular baby bottle). Accepted presentations were reinforced with music delivered through headphones. All other behaviors received neutral consequences. In the second treatment phase, undiluted pureed foods were presented in bottles, which allowed experimenter control of the size of the bolus entering the mouth. Consequences were identical to those in Treatment 1. Next, spoon-feedings were introduced with the same consequences in place. Reinforcement with a newly acquired preferred food was initiated and faded to a variable ratio three (VR3) schedule. This fading procedure was effective in teaching this young multihandicapped child to consume a nutritionally balanced diet of pureed foods with an average acceptance of 94% and a concomitant decrease in inappropriate mealtime behaviors.

Changes in rat mesentery interstitial matrix due to superfusate.

Animal preparations for microscopy often require a superfusate solution to cover surgically exposed tissue. There are few, if any, data concerning the effects of this solution on extravascular protein concentration and hydration. The effect of superfusion on mesenteric tissue in anesthetized male Sprague-Dawley rats was studied. Tissue samples were taken from nonsuperfused and superfused tissue and analyzed for hydration, albumin, and transferrin content. The mesenteric tissue interstitial matrix was rapidly altered by normal saline superfusate. After superfusion, there was a decrease (P < 0.01) in tissue albumin concentration from 1.17 +/- 0.27 to 0.10 +/- 0.08 g/dl (n = 9). Tissue hydration increased from 4.98 +/- 0.8 micrograms water/microgram dry wt in controls to 7.38 +/- 1.2 micrograms water/micrograms dry wt after superfusion. When a range of superfusate albumin concentrations was used (0, 1, 2, and 3 g/dl), tissue albumin concentration changed 0.59 +/- 0.09 g/dl for each gram per deciliter change in superfusate concentration (P < 0.0001). The large changes in interstitial matrix protein content and hydration suggest that superfusate solution effects need to be considered in microvascular protein transport experiments.

Behavior analysis and intervention during hospitalization for brain trauma rehabilitation.

Continued problematic behavior in children and adolescents after brain trauma is a major barrier to medical care, rehabilitation, and eventual independent living. The present study demonstrates the application of already well-developed behavior analysis techniques to the early posttrauma expression of behavior problems during hospital recovery. To satisfy concerns regarding both cost and individualized treatment, interventions were carried out primarily by regular hospital staff (nurses and therapists), medical record data were used to document gains, and time series, within subject designs were used to show experimental control. Four patients (three male and one female) ranging in age from 10 to 16 years, received intervention based on behavior analysis techniques, which reduced disruption and increased cooperation with therapy and medical care. Behavior analysis techniques will be relevant to future rehabilitation research to the extent that the posttrauma patient's behavior is effected by environmental consequences as demonstrated here.

Adiposity in children: is mental retardation a critical variable?

Several authors have suggested that obesity is more prevalent amongst children with mental retardation than non-mentally retarded children. However, studies on which this suggestion is based typically lack adequate control groups. The current research compared adiposity amongst mentally retarded versus non-mentally retarded children. Study 1 compared 110 mentally retarded children with 107 non-mentally retarded children (162 males, 61 females; age range 11 months-20 years). The independent (predictor) variables included IQ and mental retardation. Dependent (criteria) variables were BMI and age-corrected BMI. Study 2, using the National Health and Nutrition Examination Survey-II data bank compared 20 children with reported mental retardation with 4015 control children on three variables: BMI, age-corrected BMI, and subscapular to triceps skinfold ratio. Results of both studies found no significant difference in adiposity or body fat distribution between mentally retarded and non-mentally retarded children. Moreover, no significant difference emerged when either age or gender were controlled and no curvilinear or interaction effects were observed.

Teaching developmentally disabled children with chronic illness to swallow prescribed capsules.

Child noncompliance with prescribed medical regimens, including nonacceptance of oral medication, frequently impedes medical treatment and achievement of clinical aims. During this study, we used a single-subject experimental design to evaluate the effectiveness of a capsule-swallowing training curriculum specifically developed to promote acceptance of oral medication by multihandicapped children. Four such children participated, each diagnosed with a chronic pediatric illness requiring daily intake of oral medication. Training consisted of verbal instruction, demonstration, reinforcement for swallowing candies/capsules progressively larger in size, ignoring mild inappropriate behavior, and gradually providing less guidance and structure. In each case, the curriculum produced routine independent swallowing of prescribed capsules/tablets. Follow-up assessments, coupled with parent satisfaction ratings, suggest that skill acquisition was both enduring and clinically significant. This study validates a brief, readily exportable, and effective approach to teaching handicapped children to swallow capsules.

Phone phobia, phact or phantasy? An operant approach to a child's disruptive behavior induced by telephone usage.

The clinical efficacy of a contingency management program for treating a developmentally disabled girl referred for telephone phobia was evaluated using both a multiple baseline across settings design and a reversal design. A descriptive analysis indicated that the 'phobia' was in all probability an operant, rather than a respondent. The treatment, consisting of differential reinforcement, extinction and time-out, was effective in reducing the frequency and intensity of disruptive behaviors in response to telephone usage. Follow-up assessments at 1, 3, and 6 months revealed that treatment gains were maintained.