Serological, genomic and structural analyses of the major mite allergen Der p 23

BACKGROUND

Der p 23 was recently identified in a European population as a major allergen and potentially a chitin binding protein.

OBJECTIVE

This study sought to assess the importance of Der p 23 among other Dermatophagoides allergens in a North American population and to determine the structure for functional characterization.

METHODS

IgE binding to Der p 23, Der p 1, Der p 2, Der p 5, Der p 7 and Der p 8 was measured by ELISA. RNA-seq data from D. pteronyssinus were compared as estimates of allergen expression levels. The structure was analysed by X-ray crystallography and NMR.

RESULTS

Despite a high prevalence of Der p 23, (75% vs. 87% and 79% for Der p 1 and Der p 2, respectively), the anti-Der p 23 IgE levels were relatively low. The patient response to the 6 allergens tested was variable (n = 47), but on average anti-Der p 1 and anti-Der p 2 together accounted for 85% of the specific IgE. In terms of abundance, the RNA expression level of Der p 23 is the lowest of the major allergens, thirty fold less than Der p 1 and sevenfold less than Der p 2. The structure of Der p 23 is a small, globular protein stabilized by two disulphide bonds, which is structurally related to allergens such as Blo t 12 that contain carbohydrate binding domains that bind chitin. Functional assays failed to confirm chitin binding by Der p 23.

CONCLUSIONS AND CLINICAL RELEVANCE

Der p 23 accounts for a small percentage of the IgE response to mite allergens, which is dominated by Der p 1 and Der p 2. The prevalence and amount of specific IgE to Der p 23 and Der p 2 are disproportionately high compared to the expression of other Dermatophagoides allergens.

Identification of Maillard reaction products on peanut allergens that influence binding to the receptor for advanced glycation end products

BACKGROUND

Recent immunological data demonstrated that dendritic cells preferentially recognize advanced glycation end product (AGE)-modified proteins, upregulate expression of the receptor for AGE (RAGE), and consequently bias the immune response toward allergy.

METHODS

Peanut extract was characterized by mass spectrometry (MS) to elucidate the specific residues and specific AGE modifications found in raw and roasted peanuts and on rAra h 1 that was artificially glycated by incubation with glucose or xylose. The binding of the RAGE-V1C1 domain to peanut allergens was assessed by PAGE and Western analysis with anti-Ara h 1, 2, and 3 antibodies. IgE binding to rAra h 1 was also assessed using the same methods.

RESULTS

AGE modifications were found on Ara h 1 and Ara h 3 in both raw and roasted peanut extract. No AGE modifications were found on Ara h 2. Mass spectrometry and Western blot analysis demonstrated that RAGE binds selectively to Ara h 1 and Ara h 3 derived from peanut extract, whereas the analysis failed to demonstrate Ara h 2 binding to RAGE. rAra h 1 with no AGE modifications did not bind RAGE; however, after AGE modification with xylose, rAra h 1 bound to RAGE.

CONCLUSIONS

AGE modifications to Ara h 1 and Ara h 3 can be found in both raw and roasted peanuts. Receptor for AGE was demonstrated to selectively interact with AGE-modified rAra h 1. If sensitization to peanut allergens occurs in dendritic cells via RAGE interactions, these cells are likely interacting with modified Ara h 1 and Ara h 3, but not Ara h 2.

Neurophysiologic evaluation of cyclosporine toxicity associated with bone marrow transplantation

INTRODUCTION

Cortical blindness, a rare form of cyclosporine (CSA) neurotoxicity, has previously been described in only nine bone marrow transplant (BMT) recipients.

METHODS

Our institution averages 35 allogeneic BMT's per year. In the past year we have seen two women with reversible cortical blindness secondary to CSA toxicity.

RESULTS

Age (years) (Case 1; Case 2): 32; 22. Day post-BMT: 41; 50. Peak CSA level (ng/ml): 1159; 632. Both had a history of renal toxicity requiring adjustment of CSA dosage. MRI - both with diffuse while matter changes. EEG - both with moderate to severe generalized slowing. Visual evoked potentials were markedly prolonged in both. Auditory evoked potentials: minimally abnormal; normal. Somatosensory evoked potentials - both normal. Prompt improvement occurred with discontinuation of CSA. Followup neurophysiologic evaluations were normal, however structural changes remained on MRI.

CONCLUSION

As neurophysiologic studies closely follow the clinical status they should be included in the evaluation and followup of CSA neurotoxicity.

Neurophysiologic evaluation of cyclosporine toxicity associated with bone marrow transplantation

INTRODUCTION

Cortical blindness, a rare form of cyclosporine (CSA) neurotoxicity, has previously been described in only nine bone marrow transplant (BMT) recipients.

METHODS

Our institutions averages 35 allogeneic BMT's per year. In the past year we have seen two women with reversible cortical blindness secondary to CSA toxicity.

RESULTS

Age (years) (Case 1; Case 2): 32; 22. Day post-BMT: 41: 50. Peak CSA level (ng/ml): 1159; 632. Both had a history of renal toxicity requiring adjustment of CSA dosage. MRI - both with diffuse white matter changes. EEG-both with moderate to severe generalized slowing. Visual evoked potentials were markedly prolonged in both. Auditory evoked potentials: minimally abnormal; normal. Somatosensory evoked potential - both normal. Prompt improvement occurred with discontinuation of CSA. Followup neurophysiologic evaluations were normal, however structural changes remain on MRI.

CONCLUSION

As neurophysiologic studies closely follow the clinical status they should be included in the evaluation and followup of CSA neurotoxicity.

Anorectal function in fluctuating (on-off) Parkinson's disease: evaluation by combined anorectal manometry and electromyography

Anorectal dysfunction and constipation are well recognized in Parkinson's disease and may reflect the direct involvement of the gastrointestinal tract by the primary Parkinson's disease process. We hypothesized, therefore, that anorectal function would alter in parallel with fluctuations in motor function related to on- and off-periods in Parkinson's disease, and employed combined anorectal manometry and electromyography to investigate anorectal function during both on- and off-periods in patients with Parkinson's disease. Manometric recordings revealed a deterioration in voluntary sphincter squeeze during off-periods (squeeze index, on versus off, mean +/- SEM: 46.4 +/- 11.1 versus 29.6 +/- 7.9 mm Hg, p < 0.05); correspondingly, simultaneous electromyographic (EMG) recordings showed poor recruitment of external anal sphincter and puborectalis muscles during off-periods. A hypercontractile ("paradoxical") rectosphincteric reflex response occurred during both on- and off-periods, and was associated with an increase in EMG activity in the external sphincter and/or the puborectalis muscle. These changes in manometric and EMG parameters paralleled changes in overall motor function. These findings provide further support for the involvement of the pelvic floor musculature in the Parkinson's disease process and also provide EMG correlates for some of the manometric abnormalities described in Parkinson's disease.

Cervical dystonia: a review the role of botulinum toxin

Cervical dystonia, although rare in the general population, can severely affect the lives of those afflicted with the disease. Throughout history several theories have been proposed regarding its etiology and pathophysiology, from underlying mental disorders to post-infectious to altered basal ganglia and brainstem function. However, CD remains poorly understood. Because of its similarity to Idiopathic Torsion Dystonia a genetic basic is suspected, but is not proven. Without a true understanding of the disease treatment remains symptomatic, and begins with physical therapy and medications and progresses to consideration of surgery. These treatment strategies have provided some relief, which is usually less than satisfactory within a short period of time. Recently, the use of botulinum toxin has provided significant symptomatic relief of pain in CD and has been associated with subjective and objective improvement in head posture. This newest therapy, although symptomatic, restores a more normal head posture and pain relief enabling the individuals with CD to continue to be active and productive participants in life, providing a ray of hope to these people as we continue to search for a better understanding of the disease process and the development of more effective treatment strategies.

Characterization of swallowing and defecation in Parkinson's disease

Despite the high prevalence of Parkinson's disease, the pathophysiology of its gastrointestinal symptoms remains poorly understood.

OBJECTIVES

to evaluate swallowing and defecatory function in patients with Parkinson's disease and age- and sex-matched controls and to correlate objective findings with subjective symptoms.

METHODS

The following studies were performed on 13 patients with Parkinson's disease and seven controls: extrapyramidal function assessment, gastrointestinal symptom survey, videoesophagram, colon transit study, defecography, and anorectal manometry.

RESULTS

Abnormal salivation (frequency, %, control vs. Parkinson's disease: 14 vs. 77, p < 0.05), dysphagia (14 vs. 77, p < 0.05), constipation (14 vs. 31, p < 0.05), and defecatory dysfunction (29 vs. 77, p < 0.05) were more common among Parkinsonian patients. However, videoesophagographic abnormalities were equally common in both groups. Colon transit time was significantly prolonged in the Parkinson's disease group. Altered puborectalis function was noted on defecography in 31% of Parkinson's disease subjects, but in none of the controls (p < 0.05). Anorectal manometry identified several abnormalities in the Parkinson's disease group, which included decreased basal anal sphincter pressures, prominent phasic fluctuations on squeeze, and a hyper-contractile external sphincter response to the rectosphincteric reflex. Many patients exhibited both slow transit and manometric abnormalities, and symptoms were poor predictors of test results.

CONCLUSION

In this group of patients with mild to moderate Parkinson's disease, videoesophagographic abnormalities were not confined to the patients with Parkinson's disease. Studies of colonic and anorectal function, in contrast, identified a number of abnormalities. Therefore, colonic and anorectal dysfunction appears to be an early gastrointestinal manifestation of Parkinson's disease, and may represent the direct involvement of the gut by this disease process.

Defecatory function in Parkinson's disease: response to apomorphine

We evaluated the effects of the dopaminergic agent apomorphine on defecation and anorectal function in patients with Parkinson's disease (PD). A gastrointestinal symptom survey, extrapyramidal assessment, defecating proctogram, and anorectal manometric study were performed in 8 subjects with PD. Basal studies showing abnormalities were repeated following apomorphine administration. Prior defecographic abnormalities were normalized following apomorphine injection in 1 of 3 subjects and significant improvements in manometric parameters were observed in all 5 subjects who underwent repeat anorectal manometry. We conclude that apomorphine can correct anorectal dysfunction in PD, and that these abnormalities may be a consequence of dopamine deficiency secondary to the PD process. These findings may also have therapeutic implications.

Gastrointestinal dysfunction in Parkinson's disease: frequency and pathophysiology

Although more extensive research is required to fully characterize the pathophysiology of the gastrointestinal symptoms in PD, much of the presently available data suggest that the primary PD process is the major factor in the etiology of gut dysfunction in this patient population. This may be mediated by both central and peripheral mechanisms. Involvement of the dorsal motor nucleus of the vagus might produce dysfunction of muscles controlling deglutition and esophageal motility, thereby leading to drooling, dysphagia, and gastroesophageal reflux. The presence of Lewy bodies, the primary neuropathologic finding in the CNS in PD, in the myenteric plexus of both the esophagus and colon suggests that the PD process may also affect the enteric nervous system and contribute to the development of esophageal dysmotility and constipation through this peripheral mechanism. Dopamine receptors have been identified in the lower esophageal sphincter and the esophageal body of animals. If similarly present in humans, involvement of this dopaminergic system could contribute to the development of dysphagia and nausea of PD. Constipation may reflect both peripheral involvement, indicated by Lewy bodies in the colonic myenteric plexus, leading to colonic inertia, and central mechanisms, leading to pelvic floor dysfunction.

Gastrointestinal symptoms in Parkinson's disease

We have investigated the prevalence of gastrointestinal (GI) symptoms in 98 individuals with Parkinson's disease (PD) and in a control group of 50. Seventy-nine of those with PD were being treated with dopaminergic medications and 19 were untreated. Those symptoms occurring more frequently in PD patients than in controls included abnormal salivation, dysphagia, nausea, constipation, and defecatory dysfunction. Except for defecatory dysfunction, symptoms did not correlate with treatment but instead correlated with disease severity. This suggests that the GI symptoms of PD reflect direct involvement in the GI tract by the primary disease process.

Amino acid uptake in isolated, perfused liver: effect of trauma and sepsis

To examine alterations in amino acid metabolism after trauma and sepsis, male Sprague-Dawley rats underwent no operation (control, CON), celiotomy (trauma, TRA), or cecal ligation and puncture (sepsis, CLP). After 16 hr, plasma amino acid concentrations were determined. A second group of similarly prepared animals underwent isolated liver perfusion, and net amino acid uptake or release was determined over 30 min. Sepsis significantly decreased total amino acid concentration in portal plasma (CON, 3486 +/- 156 nmole/ml; TRA, 3407 +/- 150 nmole/ml; CLP, 2738 +/- 148 nmole/ml). Glutamine concentrations were uniformly lower in portal plasma than in arterial plasma in all states. There were depressed concentrations of the branched chain amino acids (BCAA) in portal plasma after trauma but not sepsis. In the isolated liver perfusion model, a marked increase in amino acid uptake was induced by sepsis (CON, 39.9 +/- 7.9 mumol/g liver protein; TRA, 49.5 +/- 17.3 mumol/g liver protein; CLP, 124 +/- 11 mumol/g liver protein). In addition, there was significantly greater uptake of threonine, asparagine, proline, methionine, tyrosine, and arginine. Although the BCAA isoleucine and valine were taken up to a greater extent in sepsis, the overall BCAA uptake was not significantly greater in sepsis than in control (CON 6.92 +/- 2.15 mumol/g liver protein vs CLP 15.8 +/- 1.9 mumol/g liver protein). The greatest increase in uptake following sepsis was among the gluconeogenic precursor amino acids alanine, glycine, threonine, and serine (CON, 27.0 +/- 4.2 mumol/g liver protein, TRA, 38.8 +/- 8.9 mumol/g liver protein; CLP, 62.8 +/- 6.0 mumol/g liver protein).(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of different intravenous nutritional regimens on renal function during acute renal failure in the rat

Acute renal failure in the surgical patient is accompanied by a state of hypermetabolism and increased catabolism. Nutritional therapy is therefore directed at the preservation of body cell mass and protein synthesis for repair of wounds and damaged renal tubuli and for maintenance of host defense mechanisms. We examined the effect of two levels of protein intake (18.4 +/- 1.4 and 30.8 +/- 2.4 mg N/100 g BW/day) and three different amino acid formulations (Freamine III, Nephramine, and a made-up mixture of Nephramine + Freamine HBC) on renal function following mercury chloride-induced acute renal failure in the rat. All animals suffered severe renal failure manifested by increased plasma urea and creatinine levels, decreased creatinine clearance, and increased fractional excretion of sodium. On day 4 of acute renal failure, rats receiving low dose amino acids had better-preserved renal function than those receiving high dose amino acids. However, the type of solution infused did not affect recovery of renal function.

The effect of indomethacin on muscle and liver protein synthesis and on whole-body protein degradation during abdominal sepsis in the rat

It has been recently suggested that increased muscle protein degradation during injury or infection is at least partially mediated by the increased production of prostaglandin E2 in muscle, and some have suggested that cyclooxygenase inhibitors might decrease protein loss in injured or septic patients. In these experiments, fractional synthesis rates of mixed muscle and liver protein and whole-body tyrosine flux were measured by constant intravenous infusion of tyrosine labeled with carbon 14 in 17 rats with sham operations and 15 severely septic rats with or without indomethacin treatment (20 mg/kg/d). Fractional synthesis rates in muscle and liver were decreased in late sepsis and were lowest in the septic group receiving indomethacin. Unlike the fractional synthesis rate, which was affected by indomethacin in septic rats only, tyrosine flux was significantly lower in indomethacin-treated rats with sham operations and those with sepsis. Although indomethacin reduced total-body protein breakdown during sepsis, it was also associated with lower plasma albumin levels and with decreased protein synthesis in muscle and liver at a time when the survival of the septic host may be dependent on its ability to produce new protein for a variety of vital functions. These results do not support the use of indomethacin in sepsis.

Efficacy of two elemental diets: a pair feeding study

The efficacy and side effects of two elemental diets were studied. Twenty young Sprague-Dawley rats were fed one of three different diets. Group I (n = 7) was fed Vivonex-HN (VIV) ad lib; group II (n = 7) was given Criticare-HN (CRI), pair-fed to group I (the two elemental diets were given in glass bottles); group III was fed regular rat chow and served as control (CON). Body weight (WT), food intake, and nitrogen balance (NB) were measured daily. After 21 days, change in body weight was similar in the three groups (VIV = 64.9 +/- 3.2%; CRI = 59.6 +/- 3.3%; CON = 63.9 +/- 4.8%). Cumulative nitrogen balance was also similar in the two groups fed elemental diets (VIV = 4788 +/- 277 mg N; CRI = 4690 +/- 118 mg N), but in both these groups it was less than the control group fed chow (8060 +/- 85 mg N). Blood urea nitrogen (BUN) on the last day was higher in the VIV group (12.9 +/- 1.22 mg/dl) than in the CRI group (9.43 +/- 0.43 mg/dl), but in both study groups it was lower than in the CON group (17.2 +/- 1.08 mg/dl), although nitrogen intake was higher in the control (ad lib) group. SGPT was similar in the two elemental diets but higher than in CON. Liver weights were higher in the CRI group, probably abnormally so and likely due to increased fat content. Both diets had similar efficacy in nutritional support.

Infusion of branched-chain amino acids and ammonium salts in rats with portacaval shunts

During infusion into rats with a portacaval shunt of either ammonium (NH4+) salts alone or NH4+ salts combined with the three branched-chain amino acids (BCAAs) in equimolar quantities, we assessed neurologic function and measured plasma and brain ammonia and amino acid levels and the brain content of amine neurotransmitters and their metabolites. Survival was lengthened and neurologic function was preserved longer in rats receiving BCAAs. Infusion of BCAAs resulted in lower plasma and brain ammonia concentrations compared with rats receiving NH4+ salts alone. Plasma glutamine and alanine levels were higher in rats receiving BCAAs, suggesting increased ammonia detoxification. Loss of neurologic function, regardless of which solution was infused, eventually occurred and corresponded with decreased brain norepinephrine and increased brain alanine levels. These results suggest that BCAAs can protect against hyperammonemia by stimulating the peripheral detoxification of ammonia.

Behavioral depression after intraventricular infusion of octopamine in rats

The behavioral and neurochemical effects of four intraventricular infusions of octopamine (3,200 micrograms), tryptophan (800 micrograms), and octopamine plus tryptophan delivered over 6 hours was studied in rats after performing a portacaval anastomosis or a sham operation. After each infusion, each animal was rated for neurologic depression with a 17 point test battery. Although overt coma was not induced, octopamine infusions severely depressed neurologic function. Concentrations of norepinephrine, dopamine, and serotonin in the brain were significantly decreased after the infusion of octopamine. Levels of norepinephrine in the brain were significantly correlated with neurologic status and greater depletion of norepinephrine was associated with greater neurologic depression. These studies demonstrate that infusing large amounts of the trace amine octopamine depresses behavior in the rat and this depression is most closely associated with depletion of stores of norepinephrine in the brain.

Relationship of brain glutamine and brain neutral amino acid concentrations after portacaval anastomosis in rats

Evidence from several sources suggest that blood-brain transport of the large neutral amino acids (NAA) is abnormal in animals with a portacaval anastomosis (PCA) and in patients with liver cirrhosis and portal-systemic shunting and encephalopathy, but the underlying mechanisms are unknown. After PCA, the concentration of glutamine (Gln) in brain is markedly increased as a by-product of cerebral ammonia detoxification, and the rate of efflux of Gln from brain is also increased. The following studies were undertaken to clarify the relationships among plasma and brain concentrations of NAA after PCA in rats and to examine the relationship of brain Gln concentration to plasma and brain NAA concentrations. After PCA plasma phenylalanine, tyrosine and histidine were elevated and leucine, isoleucine and valine were lowered. In brain, phenylalanine, tyrosine, histidine and methionine were markedly elevated after PCA and their concentrations in brain far exceeded the concentrations in plasma. Analyses of single, partial and multiple correlations of plasma NAA ratios expressed as plasma competitor function (PCF), brain NAA and brain Gln showed significant correlations between PCF nd brain NAA in shunted rats. A better correlation was found between brain NAA and brain Gln. Correlation coefficients obtained from multiple correlation analysis equalled or exceeded those obtained in the partial correlation or in the single correlation, suggesting that the effects of PCF and brain Gln on brain NAA were separate and additive. Gln was shown to compete with other NAA for blood brain transport by inhibiting brain 14C phenylalanine uptake.(ABSTRACT TRUNCATED AT 250 WORDS)

Infusion of branched chain-enriched amino acid solutions in sepsis

The goal of nutritional support in sepsis is, as in other conditions, to prevent the use of endogenous protein as an energy substrate and, ideally, to promote the synthesis of proteins specifically required in responding to the particular insult or stress at hand. This entails provision of an utilizable fuel, in sufficient quantity, that does not inhibit the use of endogenous nonprotein sources; preservation of the existing protein mass by minimizing skeletal muscle and visceral proteolysis; provision of amino acids in sufficient quantity and in the appropriate proportions such that protein synthesis is optimized. Specifically, this includes the synthesis of those proteins required to maintain hyperdynamic function of the essential organs as well as the hepatic and leukocytic synthesis of proteins required in immunologic defense. This study has assessed one aspect of this goal during the administration of nutrient solutions differing primarily in branched chain amino acid content. We conclude that leucine is fundamental among the branched chain amino acids for reducing skeletal muscle proteolysis. Solutions designed for sepsis or stress should, therefore, contain adequate amounts of this amino acid.

Optimizing the continuous production of Candida utilis and Saccharomycopsis fibuliger on potato processing wastewater

The yeasts Candida utilis and Saccharomycopsis fibuliger were propagated as a source of single-cell protein in a continuous, mixed, aerobic, single-stage cultivation on blancher water generated during potato processing. A series of steady-state experiments based on a two-level factorial design, half-replicate modified with an intermediate experiment, was performed to determine the effect of pH, 3.8 to 4.8; dissolved oxygen, 42 to 80% saturation; dilution rate, 0.17 to 0.31 h(-1); and temperature, 27 to 32 degrees C on the amount of carbon consumed, the rate of carbon consumption (R(c)), the amount of reducing sugar consumed, the rate of sugar consumption (R(g)), the amount of protein produced, the rate of protein production (R(p)), the yield from carbon, and the yield from reducing sugar. The results were analyzed by stepwise multiple regression and Fisher's least significant difference test. Analyses showed that high dilution rates resulted in increased R(c), R(g), and R(p) and indicated that a rate of 0.31 h(-1) was below the critical dilution rate. A temperature of 32 degrees C increased the amount of carbon consumed by 34%. A pH of 4.3 to 4.8 increased the amount of protein produced. The yield from carbon was constant, and the relatively high yield from reducing sugar indicated that other substrates were consumed. Dissolved oxygen was in excess at 42% saturation and above. Since C. utilis predominated the mixed cultures and amylase production appeared to be limited, a single-stage fermentation lacked efficiency. The experimental design allowed preliminary optimization of major environmental variables with relatively few experiments and provided a basis for future kinetic studies.