White striping and wooden breast myopathies of broiler breast muscle is affected by time-limited feeding, genetic background, and egg storage

The effects of time-limited feeding, genetic background, and egg storage on white striping (WS) and wooden breast (WB) in broilers were studied. Male chicks (240) from 2 genetic backgrounds and 2 egg storage periods were fed on either an ad libitum (AL) or time-limited (TL) program from 7 d of age. A rapid growth strain (Growth) and an enhanced yield strain (Yield) of broiler breeder males were mated to a single female line and eggs were stored for periods of either 1 to 7 d or 8 to 14 d. Body weight (BW), feed consumption, and feed conversion ratio (FCR) were determined weekly. Carcass data including WS and WB scores were collected at 42 d of age. Breast muscle scoring was conducted either visually or by hand palpation using a 1 to 4 point ordinal scale (normal to greatest severity). Data were analyzed using the Mixed procedure of SAS. The TL fed broilers presented less WS (1.64 vs. 2.87) and WB (2.14 vs. 2.89), lower BW (2.99 vs. 3.27 kg), and improved FCR (1.55 vs. 1.58 g: g), as well as reduced dressing percentage (79.5 vs. 80.1%), breast muscle yield (33.3 vs. 34.6%), and 24 h muscle pH (5.82 vs. 5.95) relative to AL broilers (P < 0.01). Yield broilers exhibited reduced BW (2.97 vs. 3.28 kg), lower WS (2.04 vs. 2.47), and greater WB (2.65 vs. 2.38) (P < 0.05) but similar dressing percentage (80.0 vs. 79.7%) and breast muscle yield (34.3 vs. 33.6%) when compared to Growth broilers. Longer egg storage generated lower BW (3.07 vs. 3.18 kg) and when fed AL, an increased WS score (2.58 vs. 3.15) compared to the shorter egg storage period (P < 0.05). It was concluded that WS and WB could be reduced by TL feeding and that genetic background and egg storage period may influence the expression of WS and WB.

EVALUATION OF THE RHYTHMIC ARTS PROJECT, A MULTI-MODAL RHYTHM-BASED PERCEPTION AND ACTION INTERVENTION, IN A SCHOOL-BASED SETTING IN CHILDREN WITH AUTISM SPECTRUM DISORDERS

The Rhythmic Arts Project (TRAP) curriculum integrates visual, tactile, auditory and speech experiences through rhythmic drumming actions to address life skills. We evaluated life skills before and after participation in TRAP in a school-based setting in children with Autism Spectrum Disorders (ASD). Participants were 23 children in grades 6-12 in a special education program for students with ASD. We administered the Pediatric Evaluation of Disability Index Computer Adaptive Test (PEDI-CAT) before and after they participated TRAP. Children showed significant increases in participation in daily activities, mobility status, cognitive and social skills, and responsibility after participation in TRAP. We did not have a comparison or control group, however we used a repeated baseline design to support that changes were generally not observed over the summer when children were not participating in TRAP. Our results represent a first step in evaluating the effectiveness of TRAP by systematically measuring changes in life skills.

Forced Expiratory Volume in 1 Second Variability Helps Identify Patients with Cystic Fibrosis at Risk of Greater Loss of Lung Function

OBJECTIVE

To evaluate several alternative measures of forced expiratory volume in 1 second percent predicted (FEV1 %pred) variability as potential predictors of future FEV1 %pred decline in patients with cystic fibrosis.

STUDY DESIGN

We included 13,827 patients age ≥6 years from the Epidemiologic Study of Cystic Fibrosis 1994-2002 with ≥4 FEV1 %pred measurements spanning ≥366 days in both a 2-year baseline period and a 2-year follow-up period. We predicted change from best baseline FEV1 %pred to best follow-up FEV1 %pred and change from baseline to best in the second follow-up year by using multivariable regression stratified by 4 lung-disease stages. We assessed 5 measures of variability (some as deviations from the best and some as deviations from the trend line) both alone and after controlling for demographic and clinical factors and for the slope and level of FEV1 %pred.

RESULTS

All 5 measures of FEV1 %pred variability were predictive, but the strongest predictor was median deviation from the best FEV1 %pred in the baseline period. The contribution to explanatory power (R(2)) was substantial and exceeded the total contribution of all other factors excluding the FEV1 %pred rate of decline. Adding the other variability measures provided minimal additional value.

CONCLUSIONS

Median deviation from the best FEV1 %pred is a simple metric that markedly improves prediction of FEV1 %pred decline even after the inclusion of demographic and clinical characteristics and the FEV1 %pred rate of decline. The routine calculation of this variability measure could allow clinicians to better identify patients at risk and therefore in need of increased intervention.

Novel methods of ambulatory physiologic monitoring in patients with neuromuscular disease

This is a summary of the presentation on novel methods of ambulatory physiologic monitoring in patients with neuromuscular disease, presented as part of the program on pulmonary management of pediatric patients with neuromuscular disorders at the 30th annual Carrell-Krusen Neuromuscular Symposium on February 20, 2008.

Surgical management of pelvic organ prolapse in females: functional outcome of mesh sacrocolpopexy and rectopexy as a combined procedure

PURPOSE

Urogenital prolapse is relatively common compared with rectal prolapse and the combination of urogenital prolapse and rectal prolapse is still more infrequent. This study was designed to evaluate the functional outcome of a series of patients who have undergone open mesh sacrocolporectopexy surgery for combined vaginal and rectal prolapse.

METHODS

Consecutive patients from June 2000 to June 2004 with confirmed vaginal and rectal prolapse subsequently underwent open mesh sacrocolporectopexy. The Cleveland Clinic Short Form-20 Pelvic Floor Distress Inventory questionnaire with Urinary Distress Inventory, Pelvic Organ Prolapse Distress Inventory, and Colorectal-Anal Distress Inventory subscales was completed by all patients preoperatively and at six months postoperatively.

RESULTS

There were 29 patients with a median age of 66 (interquartile range, 59-73) years. Median period of follow-up was 26 (interquartile range, 15-33) months. Median global pelvic floor distress inventory scores were lower postoperatively compared with preoperatively (96.4 (interquartile range, 50.8-149.7) vs. 182.3 (interquartile range, 140.6-208.6; P = 0.001). All three median subscales scores also were significantly lower postoperatively compared with preoperatively.

CONCLUSIONS

In patients with concurrent vaginal and rectal prolapse, open mesh sacrocolporectopexy confers good symptomatic improvement for urinary-, vaginal-, and rectal-related symptoms.

Combined therapeutic use of AdGFPFasL and small molecule inhibitors of ceramide metabolism in prostate and head and neck cancers: a status report

As of January 2005, there were 1020 gene therapy clinical trials ongoing worldwide with 675 or 66.2% devoted to cancer gene therapy. The majority are occurring in the US and Europe (http://www.wiley.co.uk/genetherapy/clinical/). At the present time, to our knowledge there are no trials that employ gene delivery of Fas Ligand (FasL). As an important note, and in contrast to somatic cell therapy trials, there are no reported deaths due to therapeutic vector administration in any cancer gene therapy trial. That said, from our studies and from the published literature, the issue of gene delivery remains the major obstacle to successfully employing gene therapy for cancer treatment. Numerous laboratories are studying this with many different approaches. My co-workers and I have focused on the delivery issue by using various approaches that address tumor targeting and transgene expression. In addition, we are focusing on enhancing tumor cell killing via the bystander effect and through use of small molecules to enhance bystander activity.

Solution structures of the antifungal heliomicin and a selected variant with both antibacterial and antifungal activities

In response to an experimental infection, the lepidopteran Heliothis virescens produces an antifungal protein named heliomicin. Heliomicin displays sequence similarities with antifungal plant defensins and antibacterial or antifungal insect defensins. To gain information about the structural elements required for either antifungal or antibacterial activity, heliomicin and selected point-mutated variants were expressed in yeast as fusion proteins. The effects of mutations, defined by comparing the primary structure of heliomicin with the sequences of members of the insect defensin family, were analyzed using antibacterial and antifungal assays. One of the variants shows significant activity against Gram-positive bacteria while remaining efficient against fungi. The three-dimensional structures of this variant and of the wild-type protein were determined by two-dimensional (1)H NMR to establish a correlation between structure and antibacterial or antifungal activity. Wild-type and mutated heliomicins adopt a similar scaffold, including the so-called cysteine-stabilized alphabeta motif. A comparison of their structures with other defensin-type molecules indicates that common hydrophobic characteristics can be assigned to all the antifungal proteins. A comparative analysis of various structural features of heliomicin mutant and of antibacterial defensins enables common properties to be assessed, which will help to design new mutants with increased antibacterial activity.

Quality of hospital care of children with asthma: Medicaid versus privately insured patients

Asthma is an important condition to study in the Medicaid population because it is the most frequent reason for hospital admission of Medicaid children, with rates substantially higher than those of non-Medicaid children. This study addressed how the quality of hospital care provided to children with asthma on Medicaid compares with that provided to privately insured children. Children inpatient records were studied in California, Georgia, and Michigan, comparing the care that was provided to standards created by a national panel of physician experts. Process-of-care analysis showed that Medicaid children in each state were more likely than privately insured children to be discharged on suboptimal medication regimens. This study concluded that hospitals serving Medicaid children, at least in these three states, are providing asthma inpatient care of fairly comparable quality to that of privately insured children. However, there remain significant problems surrounding outpatient medication regimens and follow-up care.

Magnetization transfer from laser-polarized xenon to protons located in the hydrophobic cavity of the wheat nonspecific lipid transfer protein

Nonspecific lipid transfer protein from wheat is studied by liquid-state NMR in the presence of xenon. The gas-protein interaction is indicated by the dependence of the protein proton chemical shifts on the xenon pressure and formally confirmed by the first observation of magnetization transfer from laser-polarized xenon to the protein protons. Twenty-six heteronuclear nOes have allowed the characterization of four interaction sites inside the wheat ns-LTP cavity. Their locations are in agreement with the variations of the chemical shifts under xenon pressure and with solvation simulations. The richness of the information obtained by the noble gas with a nuclear polarization multiplied by approximately 12,000 makes this approach based on dipolar cross-relaxation with laser-polarized xenon promising for probing protein hydrophobic pockets at ambient pressure.

The active site of drosomycin, a small insect antifungal protein, delineated by comparison with the modeled structure of Rs-AFP2, a plant antifungal protein

Drosomycin is the first strictly antifungal protein isolated from an insect (Drosophila melanogaster). The solution structure of this 44-residue protein has been reported previously. It involves a three-stranded beta-sheet and an alpha-helix, the protein global fold being maintained by four disulfide bridges. Rs-AFP2 is a plant antifungal protein exhibiting 41% sequence similarity with drosomycin. Mutational analysis of Rs-AFP2 showed the importance of some residues in the antifungal activity of the protein against the fungus target. In order to determine the structural features responsible for antifungal activity in both drosomycin and Rs-AFP2, we modeled the three-dimensional structure of Rs-AFP2, and of other antifungal proteins, using the solution structure of drosomycin as a template. Structure analysis of drosomycin and Rs-AFP2, and comparisons with the other modeled antifungal structures, revealed that the two proteins shared a hydrophobic cluster located at the protein surface in which a lysine residue is embedded. Based on these close structural similarities and the experimental data available for Rs-AFP2 mutants, an antifungal active site of the insect protein is proposed.

Differences between child and parent reports of symptoms among Latino children with asthma

OBJECTIVES

To determine, in a population of predominantly Latino children with asthma 6 to 18 years old, whether parent and child reports of asthma symptoms with exercise differ and to evaluate the validity of child and parent reports of symptoms.

DESIGN

Data obtained from child and parent interviews; pulmonary function tests (forced vital capacity, forced expiratory volume in 1 second, forced expiratory flow25-75, peak expiratory flow), and observation of symptoms after exercise.

SETTING

Three summer camps for minority children with asthma in Los Angeles County.

PARTICIPANTS

A total of 97 children with asthma (78% Latino, 12% non-Latino White, 9% Other; 6 to 18 years of age) and their parents.

INTERVENTION(S)

None.

PRIMARY OUTCOME MEASURES

Child and parent reports of cough and wheezing with exercise and pulmonary function tests before and after exercise. While at camp, children underwent spirometry after completing the self-administered survey. The pulmonary function tests were conducted and interpreted according to the pediatric specifications for spirometry, and results >80% of predicted, adjusted for gender, age, height, and race, were considered normal. Six peak expiratory flow rates (PEFR) by peak flow meter also were recorded by trained research assistants immediately before spirometry, and values >80% of predicted based on height were considered normal. To observe child symptoms with exercise, children participated in a relay running race of 200 feet followed by a swimming race of 300 feet. Research assistants measured heart rate and 6 PEFRs using ASSESS portable peak flow meters immediately before and after each exercise. A positive exercise challenge was defined as a 15% reduction in mean PEFR and/or observed asthma symptoms (cough, wheezing, chest pain, asthma attack).

RESULTS

Of the children, 18% reported never having a cough when they exercised, 46% reported having it occasionally when they exercised, and 36% reported having it quite often or always when they exercised. For wheezing, 20% of children reported never having wheezing when they exercised, 35% having it occasionally when they exercised, and 45% having it quite often or always when they exercised. Parents reported fewer symptoms than did their children. Of the parents, 34% reported that their children did not have cough with exercise, 37% reported few to some days, and 29% reported most days or every day. Forty-seven percent of parents reported that their child did not wheeze with exercise in the last 2 months, 35% reported wheezing on a few days to some days, and 17% reported wheezing most days to every day. Parent and child reports of cough or wheezing after exercise correlated mildly with each other (parent/child cough r = 0. 23; kappa = 0.03; parent/child wheezing r = 0.21; kappa = 0.14). Children were more likely to report cough: 59 of 71 (83%) of children versus 44 of 71 (62%) of parents. The 22 children who reported cough when their parents did not account for most of the disagreement between parents and children. Children were more likely than were their parents to report wheezing; 55 of 69 (80%) children versus 36 of 69 (52%) parents reported that the child wheezed. The 24 children who reported wheezing when their parents did not account for most of the disagreement between parents and children. Forty-seven percent of the children had a value <80% of predicted for at least one of the four spirometry tests; 29% of mean baseline PEFRs were <80% of predicted. Overall, 86% of the children met one or more of the following: any percent of predicted pulmonary function tests <80% or any symptom or PEFR reduction of 15% after exercise, or other occurrence of nonexercise symptoms during camp. Almost all child reports of cough and wheezing correlated significantly with the criterion validity criteria. For example, child reports of wheezing were, as expected, correlated negatively with the percent of predicted FEV1 (r = -0.28) and correlated positive

[Scorpion toxins and defensins]

The scorpion venoms possess many neurotoxic peptides which constitute a group of molecular families with a common architecture and a high degree of polymorphism. This architecture is found also in circulating antimicrobial peptides belonging to the defensins family, which are especially structurally related to the blocking potassium channels neurotoxins. The diversification in functions with a unique architectural scheme is discussed taking in account the biophysiological characteristics of the scorpion order.

A novel composite 90 degrees pulse sequence which provides distortionless NMR spectra and suppresses without destroying the water magnetization

A novel 90 degrees composite pulse sequence which allows one to record 1D and 2D NMR spectra without disturbing the water magnetization is described. A home-written program was used to optimize the pulse angles for which the pulse sequence response fitted best the desired excitation profile, producing a neat and distortionless spectrum with a broad null excitation at the carrier frequency. The resulting pulse sequence was first evaluated using the simulation program "PENCIL" and then tested on two protein samples. A 3.5 degrees phase shift of the last pulse was required to cancel correctly the water signal. The pulse scheme was appended to a NOESY pulse sequence. Inspection of the water cross section revealed interactions between water and some protons of drosomycine, a small insect antifungal protein.

Early presentation of type 2 diabetes in Mexican-American youth

OBJECTIVE

To describe features of pediatric-onset type 2 diabetes in the Hispanic population.

RESEARCH DESIGN AND METHODS

The medical records of 55 Hispanic subjects with diabetes who were treated from 1990 to 1994 in a pediatric clinic serving lower income Mexican-Americans were reviewed to assess the frequency and clinical features of type 2 diabetes. Additionally, nondiabetic siblings of several patients underwent oral glucose tolerance testing, and a survey of six high schools in the same county was performed.

RESULTS

Seventeen of 55 (31%) of the diabetic children and adolescents had type 2 diabetes. An additional 4 Hispanic children with type 2 diabetes treated in other clinics were also identified, yielding a total of 21 subjects who were used to describe the characteristics of childhood type 2 diabetes. At presentation, all were obese (mean BMI 32.9 +/- 6.2 kg/m2), 62% had no ketonuria, and fasting C-peptide levels were elevated (4.28 +/- 3.43 ng/ml). Diabetes was easily controlled with diet, sulfonylureas, or low-dose insulin. No autoantibodies were present in those tested, and family histories were positive for type 2 diabetes. Compliance was poor, and 3 subjects developed diabetic complications. Of the tested siblings, 2 of 8 had impaired glucose tolerance and 5 of 8 had stimulated hyperinsulinemia, correlated with BMI (r = 0.80, P < 0.05). The school survey identified 28 diabetic adolescents, 75% more than expected (P < 0.01). The Hispanic enrollment at each school was highly correlated with the number of diabetic students (r = 0.87, P = 0.011).

CONCLUSIONS

Genetic susceptibility to type 2 diabetes, when coupled with obesity, can produce type 2 diabetes in Mexican-American children. This diagnosis should be considered in young Hispanic patients, who might otherwise be assumed to have type 1 diabetes, and also when caring for overweight Hispanic youth with a family history of type 2 diabetes, in whom intervention may prevent or delay diabetes onset.

Solution structure of drosomycin, the first inducible antifungal protein from insects

Drosomycin is the first antifungal protein characterized recently among the broad family of inducible peptides and proteins produced by insects to respond to bacterial or septic injuries. It is a small protein of 44 amino acid residues extracted from Drosophila melanogaster that exhibits a potent activity against filamentous fungi. Its three-dimensional structure in aqueous solution was determined using 1H 2D NMR. This structure, involving an alpha-helix and a twisted three-stranded beta-sheet, is stabilized by three disulfide bridges. The corresponding Cysteine Stabilized alpha beta (CS alpha beta) motif, which was found in other defense proteins such as the antibacterial insect defensin A, short- and long-chain scorpion toxins, as well as in plant thionins and potent antifungal plant defensins, appears as remarkably persistent along evolution.

Refined solution structure of the anti-mammal and anti-insect LqqIII scorpion toxin: comparison with other scorpion toxins

The solution structure of the anti-mammal and anti-insect LqqIII toxin from the scorpion Leiurus quinquestriatus quinquestriatus was refined and compared with other long-chain scorpion toxins. This structure, determined by 1H-NMR and molecular modeling, involves an alpha-helix (18-29) linked to a three-stranded beta-sheet (2-6, 33-39, and 43-51) by two disulfide bridges. The average RMSD between the 15 best structures and the mean structure is 0.71 A for C alpha atoms. Comparison between LqqIII, the potent anti-mammal AaHII, and the weakly active variant-3 toxins revealed that the LqqIII three-dimensional structure is closer to that of AaHII than to the variant-3 structure. Moreover, striking analogies were observed between the electrostatic and hydrophobic potentials of LqqIII and AaHII. Several residues are well conserved in long-chain scorpion toxin sequences and seem to be important in protein structure stability and function. Some of them are involved in the CS alpha beta (Cysteine Stabilized alpha-helix beta-sheet) motif. A comparison between the sequences of the RII rat brain and the Drosophila extracellular loops forming scorpion toxin binding-sites of Na+ channels displays differences in the subsites interacting with anti-mammal or anti-insect toxins. This suggests that hydrophobic as well as electrostatic interactions are essential for the binding and specificity of long-chain scorpion toxins.

1H-NMR-derived secondary structure and the overall fold of the potent anti-mammal and anti-insect toxin III from the scorpion Leiurus quinquestriatus quinquestriatus

We describe the secondary structure and the overall fold of toxin III from the venom of the scorpion Leiurus quinquestriatus quinquestriatus determined using two-dimensional-1H-NMR spectroscopy. This protein, which contains 64 amino acids and 4 disulfide bridges, belongs to the long-chain toxin category and is highly toxic to both mammals and insects. The overall fold was determined on the basis of 1208 inter-proton-distance restraints derived from NOE measurements and 90 psi, phi dihedral-angle restraints derived from NOE connectivities and 3JNH-alphaH coupling constants using the HABAS program. This fold, which mainly consists of an alpha-helix packed against a small antiparallel three-stranded beta-sheet, and of several turns and loops, is similar to that of other long-chain scorpion toxins. Aromatic and non-polar residues form several patches on the surface of the protein which alternate with patches of charged and polar residues. Such a topology should be important in the interactions of toxin III with sodium channels in membranes. Two weakly constrained loops introduce some flexibility to the structure which could be related to the activity of this toxin. The central core of toxin III is compared with the cysteine-stabilized alpha beta motif (an alpha-helix connected to a beta-sheet through two disulfide bridges) found in insect defensins and plant thionins. Defensins and thionins are small proteins (approximately 40--50 amino acid residues) containing three or four disulfide bridges, respectively. This comparison confirms that the cysteine-stabilized alpha beta motif is a common core to a number of small proteins from different origins and having different activities.

Comparison of the T cell receptors on insulin-specific hybridomas from insulin transgenic and nontransgenic mice. Loss of a subpopulation of self-reactive clones

Transgenic mice expressing the human insulin gene do not produce insulin-specific antibody after injection of human insulin. Nevertheless, they have some peripheral T cells that proliferate to human insulin in vitro. To investigate the nature of these T cells, human insulin-specific T cell hybridomas were produced from transgenic and nontransgenic mice. Transgenic hybridomas required more insulin to achieve maximum responses and they produced lower levels of lymphokines than nontransgenic hybridomas. The majority of nontransgenic hybridomas recognized only human and pork insulin whereas transgenic hybridomas recognized beef, sheep, and/or horse insulin in addition to human and pork insulin. The TCR expressed by transgenic and nontransgenic hybridomas were determined by Northern analysis. Both types of hybridomas used several different V alpha and V beta gene families and no favored association between V alpha and V beta gene usage was detected in either type. V beta 1 was used by 7 of 16 nontransgenic hybridomas but only by 1 of 16 transgenic hybridomas. V beta 6 receptors were predominantly expressed by the transgenic hybridomas and all V beta 6-bearing hybridomas recognized beef as well as human insulin. The differences in Ag reactivity and TCR gene usage suggest that V beta 1-bearing human insulin-reactive T cells were clonally deleted or inactivated in the transgenic animal. Other clones, representing a minor subpopulation in nontransgenic mice, were recovered from transgenic mice.

Comparison of the T cell receptors on insulin-specific hybridomas from insulin transgenic and nontransgenic mice. Loss of a subpopulation of self-reactive clones

Transgenic mice expressing the human insulin gene do not produce insulin-specific antibody after injection of human insulin. Nevertheless, they have some peripheral T cells that proliferate to human insulin in vitro. To investigate the nature of these T cells, human insulin-specific T cell hybridomas were produced from transgenic and nontransgenic mice. Transgenic hybridomas required more insulin to achieve maximum responses and they produced lower levels of lymphokines than nontransgenic hybridomas. The majority of nontransgenic hybridomas recognized only human and pork insulin whereas transgenic hybridomas recognized beef, sheep, and/or horse insulin in addition to human and pork insulin. The TCR expressed by transgenic and nontransgenic hybridomas were determined by Northern analysis. Both types of hybridomas used several different V alpha and V beta gene families and no favored association between V alpha and V beta gene usage was detected in either type. V beta 1 was used by 7 of 16 nontransgenic hybridomas but only by 1 of 16 transgenic hybridomas. V beta 6 receptors were predominantly expressed by the transgenic hybridomas and all V beta 6-bearing hybridomas recognized beef as well as human insulin. The differences in Ag reactivity and TCR gene usage suggest that V beta 1-bearing human insulin-reactive T cells were clonally deleted or inactivated in the transgenic animal. Other clones, representing a minor subpopulation in nontransgenic mice, were recovered from transgenic mice.

Nicotinamide and 3-aminobenzamide interfere with receptor-mediated transmembrane signaling in murine cytotoxic T cells: independence of Golgi reorientation from calcium mobilization and inositol phosphate generation

The two competitive inhibitors of ADP-ribosylation, nicotinamide and 3-aminobenzamide, have been reported to interfere with TNF-induced cell apoptosis, and there is evidence that they inhibit killer-induced target cell lysis as well. There are very few drugs known to specifically interfere with target apoptosis induced by killer cells. We therefore sought to explore the effects these inhibitors have on CTL-mediated cell lysis. Here we show that TcR-mediated transmembrane signaling in CTL, measured by Ca2+ mobilization and generation of inositol phosphates, is inhibited by nicotinamide. The possibility that all cell functions are suppressed by the drug is excluded by the finding that constitutive secretion of BLT serine esterase is not inhibited, whereas stimulated secretion of this enzyme is suppressed. We also show that nicotinamide does not interfere with CTL target cell binding or reorientation of the Golgi apparatus toward the target binding site. It is concluded that nicotinamide inhibits transmembrane signaling in CTL and thereby interferes with delivery of the lethal hit to targets.

A peripheral mechanism preserves self-tolerance to a secreted protein in transgenic mice

We have examined mechanisms of tolerance to circulating self-proteins in mice that are transgenic for human insulin. Normal, nontransgenic mice develop serum antibody responses when injected with human insulin in CFA; syngeneic transgenic mice do not. B cell responsiveness was assessed by immunizing with human insulin coupled to a T-independent Ag, Brucella abortus. No differences were found in the numbers of insulin-specific splenic plaque-forming cells between transgenic and nontransgenic mice suggesting that insulin-specific B cells are not tolerant in transgenic mice. Similarly, APC from transgenic and nontransgenic mice display no differences in their ability to process and present human insulin to human insulin-specific T cells in vitro. However, marked differences were detected between transgenic and nontransgenic T cells. Lymph node T cells from transgenic mice primed with human insulin provided no detectable helper activity for secondary antibody responses to human insulin whereas, lymph node T cells from nontransgenic mice did. Nevertheless, lymph node T cells from transgenic mice developed significant proliferative responses to human insulin. Lymph node T cells obtained from transgenic and nontransgenic mice were fused to BW5147 and human insulin-specific T cell hybridomas were generated. The fact that human insulin-specific T cell hybridomas were obtained from the transgenic mice suggests that these T cells were not clonally deleted. In addition, APC from transgenic mice did not stimulate human insulin-specific hybridomas from normal mice in the absence of exogenous insulin. We suggest that T cells specific for human insulin are not deleted in the thymus of transgenic mice because APC in the thymus do not bear the requisite levels of endogenous human insulin/Ia complexes. Therefore, we conclude that tolerance in the transgenic mice is preserved by peripheral mechanisms.

A peripheral mechanism preserves self-tolerance to a secreted protein in transgenic mice

We have examined mechanisms of tolerance to circulating self-proteins in mice that are transgenic for human insulin. Normal, nontransgenic mice develop serum antibody responses when injected with human insulin in CFA; syngeneic transgenic mice do not. B cell responsiveness was assessed by immunizing with human insulin coupled to a T-independent Ag, Brucella abortus. No differences were found in the numbers of insulin-specific splenic plaque-forming cells between transgenic and nontransgenic mice suggesting that insulin-specific B cells are not tolerant in transgenic mice. Similarly, APC from transgenic and nontransgenic mice display no differences in their ability to process and present human insulin to human insulin-specific T cells in vitro. However, marked differences were detected between transgenic and nontransgenic T cells. Lymph node T cells from transgenic mice primed with human insulin provided no detectable helper activity for secondary antibody responses to human insulin whereas, lymph node T cells from nontransgenic mice did. Nevertheless, lymph node T cells from transgenic mice developed significant proliferative responses to human insulin. Lymph node T cells obtained from transgenic and nontransgenic mice were fused to BW5147 and human insulin-specific T cell hybridomas were generated. The fact that human insulin-specific T cell hybridomas were obtained from the transgenic mice suggests that these T cells were not clonally deleted. In addition, APC from transgenic mice did not stimulate human insulin-specific hybridomas from normal mice in the absence of exogenous insulin. We suggest that T cells specific for human insulin are not deleted in the thymus of transgenic mice because APC in the thymus do not bear the requisite levels of endogenous human insulin/Ia complexes. Therefore, we conclude that tolerance in the transgenic mice is preserved by peripheral mechanisms.

Differential effects of protein synthesis inhibition on CTL and targets in cell-mediated cytotoxicity

The reactions that lead to target cell lysis by cytotoxic T cells (CTL) are despite intensive investigations poorly understood. To examine the relative roles effectors and targets play in the lytic reaction, protein synthesis in either CTL or targets was inhibited before assay of lysis. We show, in agreement with previous results, that de novo protein synthesis is not necessary in either effectors or targets during the cytolytic reaction. However, activation of CTL requires protein synthesis. Activated CTL respond to protein synthesis inhibitors with a cycling of activity, a result that is interpreted to be consistent with a stimulus secretion mechanism. Treatment of targets with protein synthesis inhibitors prior to incubation with CTL leads to a very rapid and irreversible loss of lytic susceptibility. It is shown that the decrease in lysability is not due to lack of proper CTL target interaction: MHC class I antigens are expressed on drug-treated targets and these cells serve as cold targets in competitive inhibition experiments. Moreover, drug-treated targets trigger transient Ca2+ mobilization and generation of inositol phosphates in CTL. It is therefore concluded that drug-treated targets are able to trigger CTL function but lack a component that is required for their successful lysis.

Transmembrane chloride flux is required for target cell lysis but not for Golgi reorientation in cloned cytolytic effector cells. Golgi reorientation, N alpha-benzyloxycarbonyl-L-lysine thiobenzyl ester serine esterase release, and delivery of the lethal hit are separable events in target cell lysis

Cell-mediated cytotoxicity can be inhibited by the replacement of chloride with ions that are incapable of passing through chloride channels or by the presence of stilbene disulfonate derivatives known to interfere with chloride flux. We show that the stilbene disulfonate (4,4-diisothiocyano-2,2'-disulfonic acid stilbene (DIDS) inhibits lysis of YAC-1 targets by the cloned cell line NKB61A2. Inhibition of lysis occurs on the level of the effector cell inasmuch as preincubation of effectors but not of targets interferes with subsequent lysis. Moreover, inhibition of chloride flux in the target does not interfere with target cell lysis by cytotoxic granules isolated from killer cells. Target cell binding takes place in the presence of DIDS or absence of external chloride, suggesting that events that follow target cell binding require chloride flux. We show that reorientation of the Golgi apparatus, which occurs subsequent to target cell binding in the effector cell, occurs under conditions that interfere with chloride flux. It is therefore suggested that events in the effector cell taking place subsequent to the Golgi apparatus reorientation reaction are inhibited and that delivery of the lethal hit is a stimulus-induced secretory event that requires transmembrane chloride flux. Delivery of the lethal hit is shown to be independent of the release of N alpha-benzyloxycarbonyl-L-lysine thiobenzyl ester (BLT) serine esterase, suggesting that cytolytic components and BLT serine esterase are likely packaged in different vesicles.

Transmembrane chloride flux is required for target cell lysis but not for Golgi reorientation in cloned cytolytic effector cells. Golgi reorientation, N alpha-benzyloxycarbonyl-L-lysine thiobenzyl ester serine esterase release, and delivery of the lethal hit are separable events in target cell lysis

Cell-mediated cytotoxicity can be inhibited by the replacement of chloride with ions that are incapable of passing through chloride channels or by the presence of stilbene disulfonate derivatives known to interfere with chloride flux. We show that the stilbene disulfonate (4,4-diisothiocyano-2,2'-disulfonic acid stilbene (DIDS) inhibits lysis of YAC-1 targets by the cloned cell line NKB61A2. Inhibition of lysis occurs on the level of the effector cell inasmuch as preincubation of effectors but not of targets interferes with subsequent lysis. Moreover, inhibition of chloride flux in the target does not interfere with target cell lysis by cytotoxic granules isolated from killer cells. Target cell binding takes place in the presence of DIDS or absence of external chloride, suggesting that events that follow target cell binding require chloride flux. We show that reorientation of the Golgi apparatus, which occurs subsequent to target cell binding in the effector cell, occurs under conditions that interfere with chloride flux. It is therefore suggested that events in the effector cell taking place subsequent to the Golgi apparatus reorientation reaction are inhibited and that delivery of the lethal hit is a stimulus-induced secretory event that requires transmembrane chloride flux. Delivery of the lethal hit is shown to be independent of the release of N alpha-benzyloxycarbonyl-L-lysine thiobenzyl ester (BLT) serine esterase, suggesting that cytolytic components and BLT serine esterase are likely packaged in different vesicles.

Cell-mediated and glucocorticoid-mediated target cell lysis do not appear to share common pathways

Target cell lysis by cytolyic lymphocytes follows a sequence of events that culminate in osmotic destruction of the target. Although it is clear that killer cell derived components play a crucial role in target cell lysis it is not clear to what extent the target itself is involved in its destruction. Recent observations have pointed to the possibility that glucocorticoid mediated and cell mediated lysis may utilize common pathways of cell lysis. In analyzing this question we found that cell lines that have nonfunctional glucocorticoid receptors like S49-78 and S49-88 are good targets for both NK and thymus-derived killer (TK) cells. Cell lines that are glucocorticoid sensitive such as Q1(4)6 are sensitive to NK-mediated lysis as its derivative HL4-6-3 which contains glucocorticoid receptors but is glucocorticoid resistant. An intriguing exception to this is the glucocorticoid-resistant mutant S49-4RD which is relatively resistant to both NK and TK lysis compared with parent S49. The resistance of S49-4RD to cell-mediated lysis we show here is most likely due to a defect in the target which results in its failure to trigger the cytolytic machinery in the killer cell rather than in its resistance to lysis per se. In support of this we demonstrate that lysis of S49-4RD by cytolytic granules from TK cells is normal. Moreover TK cells lyse S49-4RD as efficiently as its parent in the presence of the lectin Con A. The conclusion that S49-4RD has a defect in its ability to induce killer cells to initiate the cytolytic reaction is also in agreement with the finding that TK-S49-4RD conjugates show inefficient reorientation of the Golgi apparatus in the effector.

Cell-mediated and glucocorticoid-mediated target cell lysis do not appear to share common pathways

Target cell lysis by cytolyic lymphocytes follows a sequence of events that culminate in osmotic destruction of the target. Although it is clear that killer cell derived components play a crucial role in target cell lysis it is not clear to what extent the target itself is involved in its destruction. Recent observations have pointed to the possibility that glucocorticoid mediated and cell mediated lysis may utilize common pathways of cell lysis. In analyzing this question we found that cell lines that have nonfunctional glucocorticoid receptors like S49-78 and S49-88 are good targets for both NK and thymus-derived killer (TK) cells. Cell lines that are glucocorticoid sensitive such as Q1(4)6 are sensitive to NK-mediated lysis as its derivative HL4-6-3 which contains glucocorticoid receptors but is glucocorticoid resistant. An intriguing exception to this is the glucocorticoid-resistant mutant S49-4RD which is relatively resistant to both NK and TK lysis compared with parent S49. The resistance of S49-4RD to cell-mediated lysis we show here is most likely due to a defect in the target which results in its failure to trigger the cytolytic machinery in the killer cell rather than in its resistance to lysis per se. In support of this we demonstrate that lysis of S49-4RD by cytolytic granules from TK cells is normal. Moreover TK cells lyse S49-4RD as efficiently as its parent in the presence of the lectin Con A. The conclusion that S49-4RD has a defect in its ability to induce killer cells to initiate the cytolytic reaction is also in agreement with the finding that TK-S49-4RD conjugates show inefficient reorientation of the Golgi apparatus in the effector.

Lysis of a lung carcinoma by poly I:C-induced natural killer cells is independent of the expression of class I histocompatibility antigens

Cells from the line 1 murine carcinoma express little if any H-2d when grown in normal medium. These cells are susceptible to splenic cell populations with NK activity, stimulated by prior injection of poly I:C, but are not lysed by NK-deficient splenocytes from homozygous beige mice treated with anti-asialo GM1. Incubation of line 1 cells in medium containing DMSO leads to a dramatic stimulation of H-2d expression but no change in lytic susceptibility to splenic NK cells. Transfection of H-2Dp into line 1 leads to a constitutive and DMSO-inducible expression of H-2Dp at functionally significant levels, but this expression appears to have no influence on NK cytolytic susceptibility.

Lysis of a lung carcinoma by poly I:C-induced natural killer cells is independent of the expression of class I histocompatibility antigens

Cells from the line 1 murine carcinoma express little if any H-2d when grown in normal medium. These cells are susceptible to splenic cell populations with NK activity, stimulated by prior injection of poly I:C, but are not lysed by NK-deficient splenocytes from homozygous beige mice treated with anti-asialo GM1. Incubation of line 1 cells in medium containing DMSO leads to a dramatic stimulation of H-2d expression but no change in lytic susceptibility to splenic NK cells. Transfection of H-2Dp into line 1 leads to a constitutive and DMSO-inducible expression of H-2Dp at functionally significant levels, but this expression appears to have no influence on NK cytolytic susceptibility.

Functional analysis of the HLA-A2/Aw68 recombinant molecule HLA-Aw69: Epstein-Barr virus specific cytotoxic T cells restricted through Aw69 can utilise restricting determinants on Aw68 but not on A2

Epstein-Barr virus-specific cytotoxic T cell lines, expanded in interleukin 2-conditioned medium, have been generated in vitro from virus-immune individuals bearing either the common HLA-A2 antigen (A2.1), a variant A2 antigen (A2.2) or a novel antigen Aw69 which is a recombinant molecule having identity with HLA-Aw68 in the alpha 1 domain and with HLA-A2 in the alpha 2 and alpha 3 domains. Virus-specific cytotoxic T cells restricted through A2.1 or A2.2 only recognised targets bearing the identical sub-type of A2 molecules and showed no cross-recognition of other A2 sub-types, of Aw68 or of Aw69. In contrast, virus-specific cytotoxic T cells restricted through the Aw69 antigen showed a significant cross-recognition of restricting determinants on Aw68 but not on A2 molecules. The results suggest that the alpha 1 extracellular domain of the HLA-Aw69 molecule plays a predominant role in the formation of T cell restricting determinants.

Short stature and pubertal delay in male adolescents with cystic fibrosis. Androgen treatment

We evaluated the growth rate and pubertal status of 54 adolescent and young adult men with cystic fibrosis and assessed the efficacy of short-term androgen therapy in promoting growth and pubertal development. Thirty-nine percent were below the fifth percentile in height and 8/28 (28%) between the ages of 14 and 18 had delays in pubertal development. Five male adolescents aged 13 years 8 months to 18 years 3 months were treated with testosterone and their conditions were prospectively evaluated. Growth rate increased from an entry mean of 2.2 cm/yr (range 0 to 4 cm/yr) to 7.2 cm/yr (3 to 10 cm/yr). We conclude that a brief course of testosterone appears to be a safe, effective means of improving growth rate in male adolescents with cystic fibrosis with delay of puberty.

Oral correction of essential fatty acid deficiency in cystic fibrosis

A combination of pancreatic insufficiency and inadequate caloric intake may produce essential fatty acids (EFA) deficiency in patients with cystic fibrosis. Seventy-five percent of the adolescents and young adults with poor weight gain in our clinic were EFA-deficient by total plasma linoleic acid criteria. Twenty of these patients were placed on an oral hyperalimentation regimen containing 230% of calories required for basal energy expenditure, 40% as fat. Forty percent of these (8/20) achieved normal EFA levels on this diet. Eight of the nonresponding patients were given an additional 5% of their caloric intake as linoleic acid monoglyceride. All who maintained caloric intake achieved normal EFA levels. Normalization of EFA levels was associated with a number of clinical benefits including increase in weight and activity and, in five teenage girls, regulation of menses. The 16 control patients who received standard pancrelipase therapy and nutritional supplements remained fatty acid deficient. We conclude that oral hyperalimentation can restore EFA levels in cystic fibrosis patients if adequate calories are available to provide energy needs.