Childhood exposure to ambient polycyclic aromatic hydrocarbons is linked to epigenetic modifications and impaired systemic immunity in T cells.

BACKGROUND: Evidence suggests that exposure to polycyclic aromatic hydrocarbons (PAHs) increases atopy; it is unclear how PAH exposure is linked to increased severity of atopic diseases. OBJECTIVE: We hypothesized that ambient PAH exposure is linked to impairment of immunity in atopic children (defined as children with asthma and/or allergic rhinitis) from Fresno, California, an area with elevated ambient PAHs. METHODS: We recruited 256 subjects from Fresno, CA. Ambient PAH concentrations (ng/m(3) ) were measured using a spatial-temporal regression model over multiple time periods. Asthma diagnosis was determined by current NHLBI criteria. Phenotyping and functional immune measurements were performed from isolated cells. For epigenetic measurements, DNA was isolated and pyrosequenced. RESULTS: We show that higher average PAH exposure was significantly associated with impaired Treg function and increased methylation in the forkhead box protein 3 (FOXP3) locus (P < 0.05), conditional on atopic status. These epigenetic modifications were significantly linked to differential protein expression of FOXP3 (P < 0.001). Methylation was associated with cellular functional changes, specifically Treg dysfunction, and an increase in total plasma IgE levels. Protein expression of IL-10 decreased and IFN-γ increased as the extent of PAH exposure increased. The strength of the associations generally increased as the time window for average PAH exposure increased from 24 hr to 1 year, suggesting more of a chronic response. Significant associations with chronic PAH exposure and immune outcomes were also observed in subjects with allergic rhinitis. CONCLUSIONS AND CLINICAL RELEVANCE: Collectively, these results demonstrate that increased ambient PAH exposure is associated with impaired systemic immunity and epigenetic modifications in a key locus involved in atopy: FOXP3, with a higher impact on atopic children. The results suggest that increased atopic clinical symptoms in children could be linked to increased PAH exposure in air pollution.

Intracellular regulators of neuronal sprouting: calmodulin-binding proteins of nerve growth cones.

The focus of this study is a quantitative biochemical analysis of the calcium-dependent interactions of calmodulin with a nerve growth cone preparation from fetal rat brain (Pfenninger, K. H., L. Ellis, M. P. Johnson, L. B. Freidman, and S. Somlo, 1983, Cell 35:573-584). The presence of calmodulin as an integral component of this preparation is demonstrated, and quantitative binding studies are presented. The binding of 125I-calmodulin to nerve growth cone material is shown to be highly specific, calcium dependent, and saturable at nanomolar calmodulin concentrations. Additionally, the growth cones' binding components appear to be membrane proteins. The individual molecular mass species of growth cone proteins displaying calcium-dependent calmodulin binding are also detailed and presented in comparison with those of synaptosomes. This analysis reveals differences between the calmodulin binding proteins of the growth cone preparation and the synaptosome fraction, suggesting the presence in growth cones of a specialized set of components which may be involved in regulatory mechanisms controlling neuritic sprouting.

Degradation of acetylcholine receptors in muscle cells: effect of leupeptin on turnover rate, intracellular pool sizes, and receptor properties.

The cellular mechanisms of degradation of a transmembrane protein, the acetylcholine receptor (AChR), have been examined in a mouse muscle cell line, BC3H-1. The halftime of degradation of cell surface receptors labeled with [125I] alpha-Bungarotoxin ([125I] alpha-BuTx) is 11-16 h. Leupeptin, a lysosomal protease inhibitor, slows the degradation rate two- to sixfold, depending on the concentration of inhibitor used. The inhibition is reversible since the normal degradation rate is regained within 20 h after removal of the inhibitor. Cells incubated with leupeptin accumulate AChR. Little change in the number of surface AChR occurs but the amount of intracellular AChR increases two- to threefold. Accumulated AChR are unable to bind [125I] alpha-BuTx if excess, unlabeled alpha-BuTx is present in the culture medium during leupeptin treatment. Thus, leupeptin causes the accumulation of a surface-derived receptor population not previously described in these cells. Subcellular fractionation studies utilizing Percoll and metrizamide gradient centrifugation in addition to molecular exclusion chromatography suggest that the accumulated AChR reside in a compartment with lysosomal characteristics. In contrast, the subcellular component containing another intracellular pool of AChR not derived from the surface is clearly separated from lysosomes on Percoll gradients. The sedimentation properties of AChR solubilized from the plasma membrane and the lysosomal fraction have been compared. The plasma membrane AChR exhibits a sedimentation coefficient of 9S in sucrose gradients containing Triton, whereas the AChR derived from the lysosomal fraction exists in part in a high molecular weight form. The large aggregate and the organelle in which it resides may represent important intermediates in the degradative pathway of this membrane protein.

Pain location and widespread pain in youth with orthopaedic conditions: Exploration of the reliability and validity of a body map.

BACKGROUND: Pain location and widespread pain are important but underexamined dimensions of paediatric pain. Body map tools to assess pain location in youth have been used for several decades, but few studies have established reliability and validity of these measures. The purpose of this study was to explore the reliability and validity of a pain body map among youth with orthopaedic conditions before surgery. METHOD: Youth ages 10-17 years completed the body map and other self-reported outcomes at their preoperative clinic visit and at their day of surgery. RESULTS: Most (91.7%) youth had small discrepancy between body map scores at preoperative clinic visit (baseline) and day of surgery (second assessment), and site-to-site agreement ranged from 78% to 98%. Those with back and lower extremity diagnoses had high correspondence between body map sites and diagnostic sites. Body map scores and widespread pain were associated with other dimensions of pain, as well as other patient-reported outcomes. Higher pain intensity and widespread pain predicted greater discrepancy between body map scores. CONCLUSIONS: These results support the use of body map tools in further research examining widespread pain among youth by demonstrating adequate reliability, descriptive validity and associative validity. SIGNIFICANCE: These results contribute to the limited information regarding psychometric properties of paediatric pain body maps, provide novel information about widespread pain among youth undergoing orthopaedic surgeries, and pave the way for improved assessment and treatment of paediatric pain.

An unusual hemoglobin anomaly and its relation to alpha-thalassemia and hemoglobin-H disease.

A Chinese family with hemoglobin H in the propositus has been reinvestigated. Although the original propositus is now deceased, a sister has the same hematological manifestations. Her hemoglobin, like that of the deceased sister, contains hemoglobins A, H, and Bart's. In addition, however, two minor components have been detected. These minor components appear to have abnormal alpha-chains and are also present in the maternal grandmother, the mother, a maternal aunt, and three other siblings but only in about one-tenth the amount. One of the minor components may be the same as Hb-Thai (25). The father has the characteristics of classical alpha-thalassemia. These results are discussed in relation to current concepts of alpha-thalassemia as they relate to "silent" and "classical" alpha-thalassemia and to possible multiple alpha-chain loci.

Carbohydrate metabolism and pancreatic islet-cell function in thalassemia major.

To investigate the development of diabetes mellitus in patients with thalassemia major, plasma glucose and immunoreactive insulin (IRI) levels following oral glucose and intravenous tolbutamide and glucose disappearance rates following intravenous insulin were measured in 10 patients before and during five years on a high transfusion program (HTP). Plasma immunoreactive glucagon (IRG) levels following oral glucose, intravenous insulin, and arginine were measured during the sixth year. Serial percutaneous liver biopsies were performed on seven patients. The oral glucose tolerance tests (OGAT) and mean peak IRI levels were normal in nine of 10 patients before HTP. After HTP was begun a progressive deterioration of OGTT occurred despite normal IRI levels. Following tolbutamide, the mean per cent fall in plasma glucose in the patients before HTP was significantly less than in controls (p less than 0.01) and similar to that of controls during five years of HTP in spite of higher than normal peak IRI levels. Of seven survivors after six years of HTP, three had normal OGTT and four had chemical diabetes; mean peak IRI levels were normal, but fasting IRG levels were significantly higher than in controls (p less than 0.05). In all seven patients, plasma IRG failed to increase following insulin-induced hypoglycemia and was significantly higher than in controls after arginine (p less than 0.01); after oral glucose, plasma IRG fell significantly below that of fasting only in the patients with chemical diabetes (p less than 0.03). Following intravenous insulin, the mean per cent fall in glucose before and during HTP was significantly less than in controls (p less than 0.01). Hemosiderosis and cirrhosis were present in all biopsied patients. Four patients died; two had chemical and two had nonketotic insulin-dependent diabetes. These data suggest that diabetes mellitus occurs frequently in patients with thalassemia on HTP and that insulin resistance and hyperglucagonemia, possibly due to cirrhosis, are important etiologic factors.

Inhibitors of dihydropteroate synthase: substituent effects in the side-chain aromatic ring of 6-[[3-(aryloxy)propyl]amino]-5-nitrosoisocytosines and synthesis and inhibitory potency of bridged 5-nitrosoisocytosine-p-aminobenzoic acid analogues.

We previously reported that 6-(methylamino)-5-nitrosoisocytosine (5) is a potent inhibitor (I50 = 1.6 microM) of Escherichia coli dihydropteroate synthase. It was noted that 6-amino substituents larger than methyl were detrimental to binding, although the adverse steric effect could be overcome by a positive ancillary binding contribution of a phenyl ring attached at the terminus of certain 6-alkylamino substituents. We selected the 6-[[3-(aryloxy)propyl]amino]-5-nitrosoisocytosine structure as a parent system and explored the effects of aromatic substituents on synthase inhibition. The nature of the aryl substitution influences binding, as shown by a 30-fold range of inhibitory potencies observed for the 15 aryl analogues (I50 values = 0.6-18 microM), although there is no apparent correlation between synthase inhibition and the electronic or hydrophobic characteristics of the aryl substituents. To explore the possibility that the aryl ring of these inhibitors might interact with the synthase binding site for the substrate p-aminobenzoic acid (PABA), three compounds were synthesized in which a PABA analogue is bridged to the nitrosoisocytosine moiety by linkage to an amino group at C-6 of the isocytosine. The bridged analogues significantly inhibited the synthase (I50 values = 2.5-8.9 microM) but were of unexceptional potency compared with other members of the (aryloxy)propyl series. Structure-activity considerations and inhibition kinetics did not support the PABA binding site as the synthase region that interacts with the aryl ring of these inhibitors. Despite the potent synthase inhibition exhibited by many of the nitrosoisocytosines studied, none of the 18 new analogues showed significant antibacterial activity.

Pulmonary function abnormalities in thalassemia patients on a hypertransfusion program.

Pulmonary function tests were performed in 12 thalassemia patients on a hypertransfusion program (age 18.4 +/- 2.6 SEM years) to determine the presence of any abnormalities of lung function. These included spirometry, expiratory flow rates, body plethysmography, single-breath nitrogen washout, single breath carbon monoxide diffusing capacity, and arterial blood gases. Only one patient had normal pulmonary function. Arterial hypoxemia was present in ten of 12 patients at rest. The total lung capacity (TLC) was normal. The residual volume was abnormally increased in five of 12 patients. The slope of phase III of single breath nitrogen washout curve was abnormal in five of 12 patients, but the closing volume was normal. The maximal expiratory flow rate at 60% total lung capacity was decreased in four of 12 patients, suggesting the presence of small airway disease. The single breath carbon monoxide diffusing capacity was normal in all patients. These pulmonary function abnormalities did not correlate with age or the cumulative amount of iron via blood transfused. The small airway obstruction, hyperinflation; and hypoxemia observed in thalassemia patients on a hypertransfusion program may result from the basic disease, iron deposition in the lungs, or other factors.

Medical-resource use for suspected tuberculosis in a New York City hospital.

OBJECTIVE: To compare resource use by diagnostic outcome among hospital admissions during which tuberculosis (TB) was suspected. DESIGN: Retrospective study based on chart review and microbiology laboratory data. SETTING: The department of medicine in a municipal hospital serving central Brooklyn, New York. PARTICIPANTS: We identified all adult admissions in 1993 during which TB was suspected. We assigned each admission to one of four mutually exclusive groups defined by the results of microbiological tests (acid-fast bacilli [AFB] smear and culture): culture-positive and smear-positive (C+S+); culture-positive and smear-negative (C+S-); culture-negative and smear-positive (C-S+); or culture-negative and smear-negative (C-S-). Each admission was divided into two separate periods to which the utilization of medical resources was assigned: the diagnostic and the postdiagnostic periods, which were separated by the date of receipt of the first definitive culture report. RESULTS: Data on 519 admissions (93 C+S+; 57 C+S-; 30 C-S+; and 339 C-S-) were analyzed. Although C+S+ were more likely than other groups to have an admitting diagnosis of TB, approximately one quarter of the admissions without TB (C-S+, C-S-) were admitted with the principal diagnosis of TB. For the four groups, C+S+, C+S-, C-S+, and C-S-, the respective rates of TB isolation and anti-TB treatment, and median lengths of isolation were 98%, 87%, and 34 days; 74%, 74%, and 7 days; 83%, 83%, and 15 days; and 44%, 29%, and 0 days. During the diagnostic period, the rate and length of isolation were similar in the AFB-smear-positive groups (C+S+ and C-S+). We estimated that admissions without culture-proven TB (C-S+ and C-S-) accounted for 3,174 (36%) of the 8,712 days of TB isolation expended and for 65% of the 16,671 days of anti-TB treatment. The vast majority of this resource consumption (2,737 [86%] of 3,174 days of isolation) occurred during the diagnostic period before a definitive culture result was known. CONCLUSIONS: Our results suggest that prolonged diagnostic uncertainty and misclassification of cases due to false-positive and false-negative smears are associated with substantial medical-resource consumption. New diagnostic modalities that reduce the period of diagnostic uncertainty could reduce the utilization of resources later found to be unnecessary.

The neurotrophin family of NGF-related neurotrophic factors.

The recent molecular cloning of brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3) has established the existence of an NGF-related family of neurotrophic factors - the neurotrophins. Purification and recombinant production of BDNF and NT-3 has allowed the initiation or extension of in vitro studies of the neuronal specificity of each of these factors. We have found that NT-3, like NGF and BDNF, promotes survival and neurite outgrowth from certain populations of sensory neurons. There appear to be both distinct and overlapping specificities of the 3 neurotrophins towards peripheral neurons - sympathetic neurons and subpopulations of neural crest and neural placode-derived sensory neurons. Using cultures of central nervous system neurons, we have recently established that BDNF: (i) promotes the survival and phenotypic differentiation of rat septal cholinergic neurons, a property consistent with the discovery of high levels of BDNF mRNA expression within the hippocampus; (ii) promotes the survival of rat nigral dopaminergic neurons and furthermore protects these neurons from two dopaminergic neurotoxins, 6-hydroxydopamine (6-OHDA) and MPTP. Thus the neurotrophic effects of these factors towards peripheral neurons and neuronal populations known to degenerate in two of the major human neurodegenerative diseases - Alzheimer's and Parkinson's disease - provokes the question of whether neurotrophic factors may have therapeutic potential in halting the progression and ameliorating the symptoms of devastating neurological disorders of the CNS or PNS, or improving regeneration of neurons of CNS or PNS after traumatic injury.

Combined subcutaneous and high-dose intravenous deferoxamine therapy of thalassemia.

Although the preliminary findings are encouraging, to assess the effectiveness of the SHYD program on the long-term course of thalassemia, a larger patient population and longer treatment and follow-up period are needed. The presence of cardiac abnormalities in patients in Group I suggests that to prevent heart damage in thalassemia, it may be necessary to start the HTP and effective chelation therapy at a very young age, realizing that the amount of iron removed will be small. The finding that two of the four patients who survived to receive the largest amount of Fe/kg have intact spleens and another had splenectomy at age 24 suggests that, in these patients, the spleen may have had a protective role for the heart. If this observation is confirmed, it would provide evidence that removal of the spleen may adversely affect the long-term course of patients with thalassemia. Six years' experience with the SHYD program has not provided evidence for significant acute or chronic toxicity. This suggests that it might be safe to administer the i.v. treatments at home, a program that is anticipated for the future, as it would significantly reduce cost and possibly be more convenient.

The clinical significance of magnesium depletion in thalassemia.

(1) Mg depletion in a population of 14 patients with thalassemia was documented by low serum Mg levels, abnormal Mg tolerance tests, and/or symptoms responsive to Mg therapy. (2) The observation that some degree of Mg depletion was present even in younger asymptomatic patients needs further investigation and suggests that monitoring of Mg status should be included in the routine care of patients with thalassemia. (3) Careful consideration should be given to the possibility that in patients with thalassemia early continuous supplementation with Mg is needed and may have a beneficial influence on the heart's response to chronic Fe overload and chronic hypoxemia.

A continuous striatal infusion of 6-hydroxydopamine produces a terminal axotomy and delayed behavioral effects.

Rat models of Parkinson's disease typically employ a rapid nigral injection of 6-hydroxydopamine (6-OHDA) to produce a near-complete loss of nigrostriatal dopamine neurons, and thus, model end stage disease. The present report describes the use of a continuous, low dose infusion of 6-OHDA into the striatum which produces a terminal axotomy of nigrostriatal dopamine neurons and protracted behavioral response. A solution of 6-OHDA in 0.4% ascorbate, delivered at 37 degrees C from osmotic minipumps, was stable for 8 days as determined by its retained toxicity to a dopaminergic neuroblastoma cell line. The continuous infusion of 0.2 mu g 6-OHDA per h did not affect the striatal uptake of [3H]%GABA, [3H]choline, or [3H]glutamate but reduced [3H]dopamine uptake by 55% within 1.5 days after the start of the infusion. The striatal infusion of 6-OHDA produced a dose-dependent reduction of striatal dopamine and DOPAC levels but did not alter HVA, 5-HT, or 5-HIAA. An increase in amphetamine-induced ipsiversive rotations occurred within 1.5 days after the acute striatal injection of 20 mu g or 30 mu g of 6-OHDA but required 4 days to develop with the continuous 6-OHDA infusion. The topography of the lesion mapped by [3H]mazindol binding showed that, beginning by 1.5 days, a diffuse depletion of terminals encompassed much of the striatum in the 30 mu g acute injection group, whereas in the continuously infused rats, the lesion was apparent only by 4 days and was restricted to a smaller and more completely lesioned area. Unlike acutely lesioned animals, continuously infused rats revealed no obvious loss of dopamine neurons in the pars compacta by 5 weeks after 6-OHDA. The continuous striatal infusion of 6-OHDA can produce a topographically limited terminal axotomy of dopamine neurons and a protracted behavioral impairment.

Predicting early adolescent disorder from childhood aggression and peer rejection.

Two large cohorts of Black 3rd-grade children from low-income families were followed into early adolescence. Adjustment at the end of the 1st year of middle school was assessed by teacher and parent ratings and by adolescent self-reports. Childhood peer social status predicted parent-reported externalized and internalized disorder and self-reported internalized disorder. Childhood aggression predicted self-reported externalized and internalized disorder and parent-reported externalized disorder. Teacher ratings of school adjustment were predicted by aggression, rejection, and sex of the child. Consensus judgments of poor adjustment were predicted by both aggression and peer rejection, with sex moderating the effect of peer rejection. Both childhood aggression and peer rejection appear to be significant predictors of adolescent disorder, with each making a predictive contribution uniquely its own.

Nutritional impact of acquired immune deficiency syndrome: a unique counseling opportunity.

The acquired immune deficiency syndrome (AIDS) presents a challenge for dietitians. Changes in the immune system have a potentially detrimental effect on nutritional status as a result of conditions such as anorexia, infection, diarrhea, and drug side effects. Conversely, poor nutrition status may adversely alter the immune systems. Dietary guidelines for the management of these conditions and additional obstacles are discussed. When counseling patients with AIDS, the dietitian needs to be aware of and sensitive to alternative therapies, to evaluate their effectiveness, and to assist in determining their place in the patient's treatment. Psychosocial factors that could influence nutritional status, such as dementia, unemployment, and isolation, must also be taken into consideration. A nutrition program has been established to address the needs of AIDS patients at AIDS Project Los Angeles-Necessities of Life Program (APLA-NOLP), a food distribution center. The goal of the program is to maintain or improve the client's nutritional status by providing education and counseling. The nutrition program has been enthusiastically received, and the outcome of the program on the nutritional status of the participants is currently under study. The dietitian is in a unique position to intervene by providing resource information, food preparation tips, and individualized nutrition plans. It is imperative that the dietitian become familiar with the AIDS disease process and its implications for nutritional status to be considered an expert in the nutrition management of such patients.