Tryptase haplotype in mastocytosis: relationship to disease variant and diagnostic utility of total tryptase levels

Serum mast cell tryptase levels are used as a diagnostic criterion and surrogate marker of disease severity in mastocytosis. Approximately 29% of the healthy population lacks alpha tryptase genes; however, it is not known whether lack of alpha tryptase genes leads to variability in tryptase levels or impacts on disease severity in mastocytosis. We have thus analyzed tryptase haplotype in patients with mastocytosis, computing correlations between haplotype and plasma total and mature tryptase levels; and disease category. We found: (1) the distribution of tryptase haplotype in patients with mastocytosis appeared consistent with Hardy-Weinberg equilibrium and the distribution in the general population; (2) the disease severity and plasma tryptase levels were not affected by the number of alpha or beta tryptase alleles in this study; and (3) information about the tryptase haplotype did not provide any prognostic value about the severity of disease. Total and mature tryptase levels positively correlated with disease severity, as well as prothrombin time and partial thromboplastin time, and negatively correlated with the hemoglobin concentration.     

Effect of human mast cell tryptase on human plasma proenzymes

The effect of human skin mast cell tryptase on human plasma proenzymes (prothrombin, coagulation factor XII, complement C1s, protein C and plasminogen) was investigated. Tryptase had no effect on these proenzymes, when incubated with them at 37 degrees C for up to 90 min, as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and by the ability to hydrolyze specific peptide p-nitroanilide substrates. After prolonged treatment with tryptase, proenzymes could be fully activated with their specific activators. The results indicate that tryptase neither activates these plasma proenzymes nor inactivates the corresponding active enzymes. As a positive control, the tryptase preparation was also incubated with human fibrinogen and rat thymus histones. Prolonged treatment with tryptase increased the thrombin-induced clotting time of fibrinogen. Tryptase also efficiently hydrolyzed histone H1 from rat thymus. Histones H3/H2B and H2A were hydrolyzed less efficiently than H1, and no hydrolysis of histone H4 by tryptase was detected under the experimental conditions.     

Serum immunoglobulin levels in healthy children and adults

Serum levels of IgM, IgG and IgA were determined in 270 healthy children, 4–12 years old, and in thirty healthy adults by the radial immunodiffusion method of Mancini. There were nine 1-year age groups of thirty children each (fifteen boys and fifteen girls); the adult group consisted of fifteen males and fifteen females.

The difference in values between adults and children was statistically significant. The IgG and IgA concentrations showed a gradual rise with increasing age; the IgM concentration remained constant at a distinctly lower level than that in adults. The IgA level was about the same in both sexes. Girls had significantly higher IgM and IgG levels than boys. A consistent seasonal influence on the three serum immunoglobulin concentrations could not be demonstrated. A very wide variation in serum levels of each immunoglobulin in each age group was found. Very low values were by no means exceptional. The consequence of this finding for the diagnosis of immunological incompetency is discussed.

     

Fluctuation of virus antibody levels in healthy adults

In order to determine fluctuations in virus antibody levels, blood specimens were collected weekly from 13 healthy adults during a nine-week period and tested by enzyme immunoassay for IgG antibodies against measles, rubella and cytomegalovirus. In 29 of 35 subject-titer pairs the difference between the highest and lowest titers observed was less than twofold, in five cases it was between twofold and threefold, and in one case it was 3.3-fold. These differences were higher than those caused by intra-assay variation alone. The results indicate that some physiological fluctuations seem to occur in the antibody levels of healthy individuals. Although the fluctuations are usually small, care should be taken if titer increases less than fourfold are used as a criterion to indicate recent infection.     

Tear tryptase levels and allergic conjunctivitis

We measured tryptase, a neutral protease stored in the secretory granules of mast cells, by solid-phase radioimmunoassay in tears of 12 subjects with vernal keratoconjunctivitis (VKC) during remission phases, nine subjects with seasonal or perennial allergic conjunctivitis, and eight healthy controls. Mean values of tear tryptase levels were significantly ( P < 0.02) increased in VKC patients (14.5 ± 13 μg/1) when compared to those measured in patients with seasonal or perennial allergic conjunctivitis (0.6 ±0.1 μg/1) and in controls (3.3 ± 3.2 μg/1). In subjects with allergic conjunctivitis, the levels of tryptase, almost undetectable before allergen conjunctival challenge, showed a significant increase in the challenged eye 20 min - but not 6 h - after provocation in 5/9 cases. Our results indicate that VKC, a severe ocular disease characterized by an increased number and abnormal distribution of mast cells in the conjunctiva, also shows elevated levels of tryptase in tears even during remission phases. Evidence of mast-cell activation, as revealed by a significant increase of tryptase levels in tears, is documented during the early-phase reaction, but not during the late-phase reaction, of allergic conjunctivitis patients challenged topically by specific allergen.     

Chronotype and sex effects on sleep architecture and quantitative sleep EEG in healthy young adults

STUDY OBJECTIVES: To evaluate the influence of chronotype (morning types and evening types) on sleep stages and quantitative sleep electroencephalograms when constraints on the sleep schedule are minimal and when sex difference is taken into account. DESIGN: A 48-hour session in the laboratory, including 2 nights of polysomnography, preceded by 7 days of ambulatory actigraphy. SETTING: Chronobiology laboratory. PARTICIPANTS: Twenty-four healthy young subjects: 12 morning types and 12 evening types selected by questionnaire. Each group included 6 men and 6 women. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: A polysomnography night of 8 hours in duration was recorded according to preferred sleep schedule. Sleep-stage analysis revealed that morning types and evening types did not differ in sleep architecture. However, morning-type men showed a higher percentage of stage 1 sleep and lower sleep efficiency than evening-type men. Electroencephalogram spectral analysis was conducted in non-rapid eye movement sleep for 6 frequency bands. Morning types had more spectral power in low sigma (12-14 Hz) compared with evening types. The most robust difference between women and men was found in high sigma (14-16 Hz) and was not present between chronotypes. The decay rate of slow-wave activity (1-5 Hz) tended to be faster in morning types compared with evening types (P = .06). This rate was almost identical for women and men. CONCLUSIONS: These results agree with the hypothesis that homeostatic sleep regulation differs between morning types and evening types, with morning types showing indications of a higher rate of dissipation of sleep pressure during the night. Morningness-eveningness seems to affect sleep in a sex-specific manner, with men being more affected by their chronotype.     

Biorhythmic changes of plasma histamine levels in healthy volunteers

The plasma histamine levels were reported to increase in early hours of the morning in asthmatic patients. It was supposed that this phenomenon would also be observed in normal volunteers. In this study using twelve normal healthy volunteers the plasma histamine levels were examined in a pharmacokinetic manner. It could be shown that plasma histamine levels follow biorhythmic changes with 3 maxima and 3 minima. The acrophases of the maxima are 12.77±0.61, 19.33±0.78 and 5.42±1.83 h. The most important rise in plasma histamine levels was found in the early hours of the morning representing about 55% of the total histamine available in plasma.     

Serum tryptase levels in adverse drug reactions

We evaluated the usefulness of individual tryptase levels and variations after adverse drug reactions in 64 patients. Our aim was to find a tool for the diagnosis of drug allergy. Thirty-seven subjects were confirmed to have drug allergy, 12 had nonsteroidal anti-inflammatory drug (NSAID) reactions, five had negative controlled drug challenges (NAAR), and 10 had symptoms after placebo intake (PLA). Serum tryptase levels greatly increased after anaphylactic shocks (2242%) and anaphylaxis (710.5%). Patients with allergic urticaria and those with idiosyncratic responses to acetylsalicylic acid (ASA) exhibited a small increase in serum tryptase (49.5% and 38.2%, respectively). In the other two groups (NAAR and PLA), no variation in this serum protease was observed. The time of appearance of the serum tryptase peak differed considerably among patients with similar clinical reactions (from 30 min to 6 h) and was independent of the latent period, severity of symptoms, or the amount of tryptase released. We conclude that serum tryptase determinations are helpful in the diagnosis of anaphylactic shock and anaphylaxis, but serial measurements may be needed to confirm mast-cell participation in milder reactions.     

Value of baseline levels in assessing tryptase release

Inflammation Research -     

Leptin and hunger levels in young healthy adults after one night of sleep loss

Short‐term sleep curtailment associated with activation of the stress system in healthy, young adults has been shown to be associated with decreased leptin levels, impaired insulin sensitivity, and increased hunger and appetite. To assess the effects of one night of sleep loss in a less stressful environment on hunger, leptin, adiponectin, cortisol and blood pressure/heart rate, and whether a 2‐h mid‐afternoon nap reverses the changes associated with sleep loss, 21 young healthy individuals (10 men, 11 women) participated in a 7‐day sleep deprivation experiment (four consecutive nights followed by one night of sleep loss and two recovery nights). Half of the subjects were randomly assigned to take a mid‐afternoon nap (14:00–16:00 hours) the day following the night of total sleep loss. Serial 24‐h blood sampling and hunger scales were completed on the fourth (predeprivation) and sixth day (postdeprivation). Leptin levels were significantly increased after one night of total sleep loss, whereas adiponectin, cortisol levels, blood pressure/heart rate, and hunger were not affected. Daytime napping did not influence the effects of sleep loss on leptin, adiponectin, or hunger. Acute sleep loss, in a less stressful environment, influences leptin levels in an opposite manner from that of short‐term sleep curtailment associated with activation of the stress system. It appears that sleep loss associated with activation of the stress system but not sleep loss per se may lead to increased hunger and appetite and hormonal changes, which ultimately may lead to increased consumption of ‘comfort’ food and obesity.     

Effect of sex and exercise on liver and plasma lipids of the rat

The effect of voluntary exercise on plasma and hepatic lipids was studied in 24 week old male and female Long-Evans rats who were fed a high sucrose (73% of calories) diet containing saturated fat and cholesterol for a 10 week period. Blood lipids were analyzed at week 0, 2, 5 and 10 and liver lipids at week 0 and 10. Half of the animals were housed in individual activity wheels where the females voluntarily ran 4.3 miles/day and the males voluntarily ran 2.4 miles/day. Compared to the males, the females 1. exhibited a greater lipogenic response to the diet, 2. showed a greater lowering of plasma and liver triglyceride and plasma cholesterol ester with exercise, and 3. developed with exercise a higher relative heart weight. Exercise was successful in the males in producing a 75% reduction in the level of hepatic cholesterol ester seen in the non-exercising males. The importance of this study is seen in the lipid-lowering effects of voluntary exercise which avoids food and water deprivation and thus the stress concurrent with forced exercise regimes.     

Reproductive history in relation to plasma hormone levels in healthy post-menopausal women

OBJECTIVES: We sought to examine the relationship between reproductive history and measures of selected gonadotrophins and steroid hormones among post-menopausal women. Previous studies have suggested that there is a negative correlation between parity and post-menopausal serum estrogens, which may be a mechanism by which pregnancies protect women from the development of breast cancer. METHODS: We analyzed women who experienced a natural menopause within the Healthy Women Study cohort both 1 and 8 years after menopause. Lifetime reproductive history was obtained and blood was assayed for estrone, estradiol, androstenedione, testosterone, follicle stimulating hormone (FSH), and luteinizing hormone (LH) at 1 year post-menopause and for many of these steroid hormones at 8 years post-menopause. Also at 8 years post-menopause, a hip bone mineral density measure was obtained. RESULTS: Age at menopause related to a modest increase in estrone at 1 year but a decrease in estrone and estradiol at eight years. Adjustment for body mass index (BMI), oral contraceptive use, alcohol use, cigarette smoking, and education had little impact on these findings. There were no other internally consistent relationships between reproductive variables and steroid hormones or hip-bone mineral density. CONCLUSIONS: These observations do not support the hypothesis that parity acts to diminish endogenous levels of post-menopausal estrogens.