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Biomedical subjects

D R Hoffman

Publications and source records attributed to D R Hoffman.

At least 145 records · Page 8Linked to original sources
PubMed1980

Hymenoptera venom allergy: a geographic study.

RAST results for the five common venoms from 1,024 positive sera obtained from patients who experienced recent severe allergic reactions to insect stings were analyzed for nine different geographic areas of the United States. Substantial differences were found as a function of geography and insect distribution. The results suggest that multiple reactivity is most common in areas with the most variety of insects, that cross reactivity is not the only important cause of multiple reactivity and that sensitization by multiple stings is more common than suggested by patient histories.

Bee Venoms↗
PubMed1980

Comparison of methods of performing the radioallergosorbent test: Phadebas, Fadal-Nalebuff and Hoffman protocols.

A series of control, IgE myeloma containing and atopic sera were tested by the radioallergosorbent test using identical lots of commercially available reagents following three different RAST protocols: Phadebas, Fadal-Nalebuff and that used in our own laboratories. In addition, a new RAST tracer was evaluated in the Phadebas and Fadal-Nalebuff methods. The Phadebas technique, using the standard 0.35 PRU cut-off, was the least sensitive at 68% but its sensitivity was raised to 84% using an 0.14 PRU cut-off. The specificity was 100% at 0.35 and 95% at 0.14 PRU. Our laboratory's technique gave a sensitivity of 84% and a specificity of 100%. The Fadal-Nalebuff method had the highest sensitivity at 92% but the lowest specificity at 92%. The Fadal-Nalebuff technique leads to a significant number of false positive scores, particularly in sera with IgE > 500 U/ml or with RAST discs that have significant non-specific binding. The Fadal-Nalebuff method can be used reliably if modified to include suitable negative controls for each antigen tested.

Allergens↗
PubMed1980

Venom immunotherapy: comparison of "rush" vs "conventional" schedules.

Twenty-three patients aged five to 52 years with good clinical histories of severe systemic reactions to hymenoptera stings confirmed by skin tests and RAST levels were treated with specific insect venoms. A more conventional, slow, bi-weekly schedule was used to determine whether they could be as successfully treated as those in earlier studies employing the "Rush desensitization" approach. It was also hoped these subjects would experience fewer untoward reactions. Comparisons of IgG (anti-hyaluronidase and phospholipase) levels pretreatment and after top dose (100 mcg) in all cases showed greater than three-fold rise, indicating protection. RAST IgE rose in most cases and plateaued by six months. Nineteen patients were restung to verify protection. Untoward reactions to injections were low (13%) and easily controlled. The authors conclude that the use of specific freeze dried insect venoms in a slow dose schedule is safe and effective in protecting severely sensitized individuals.

Adolescent↗
PubMed1979

Relationship between tissue levels of S-adenosylmethionine, S-adenylhomocysteine, and transmethylation reactions.

The concentrations of S-adenosylmethionine (AdoMet), S-adenosylhomocysteine (AdoHcy), and various methyltransferases were determined in the cerebrum, cerebellum, and liver of rats during development and aging. The liver contained from 3 to 7 and from 10 to 15 nmol AdoHcy per gram in young and adult rats, respectively. The AdoMet concentration was 60 to 90 nmol/g liver from rats of the same age and sex. It did not vary significantly with age. In the brain the AdoMet concentration was 45 to 50 nmol/g at birth and decreased to 20 nmol/ g tissue with maturity of the organ. The level of AdoHcy in this organ was less than 1 nmol/g tissue throughout the life-span of the rat. Since the ratio of AdoMet to AdoHcy is relatively high, the rate of methylation of histones, DNA, or phosphatidylethanolamine in the liver or brain was not significantly influenced by AdoHcy. Under normal nutritional conditions, the tissue concentration of AdoMet is far above the Km values of histone and phosphatidylethanolamine methyltransferases. The levels of activity of these enzymes in liver and brain did not correlated with the cellular concentration of AdoHcy. Thi histone methyltransferase activity was elevated in rapidly proliferating tissues and declined markedly in the absence of histone biosynthesis. Phosphatidylethanolamine methyltransferase activity was elevated during development of the liver. The specific activity of the AdoHcy hydrolase remained relatively constant in the rat brain and liver. The activity of this enzyme was 10 times higher in liver than in brain, yet the concentration of AdoHcy was much lower in the latter organ. The tissue levels of this compound are evidently dependent on the rates of removal of homocysteine and adenosine. Adenosine deaminase was present in the liver and brain at relatively high concentrations, particularly during development.

Aging↗
PubMed1979

The use and interpretation of RAST to stinging insect venoms.

Quality controlled, standardized RAST systems for five stinging insect venoms are described. These systems were evaluated using 375 sera from insect reactive patients from six diverse geographic regions. Ninety-four percent of patients with recent histories of systemic allergic reactions to stings were positive to at least one venom while 4 percent of normal local reactors were positive. The cross reactions between honey bee and vespid venoms were studied by RAST inhibition. A quantitative method for interpretation of venom RAST is presented to account for cross-reactivities and the approach to diagnosis is discussed.

Animals↗
PubMed1979

Comparison of the radioallergosorbent test to intradermal skin testing in the diagnosis of stinging insect venom allergy.

RAST and skin tests were compared for five venoms in a group of 60 patients with histories of stinging insect allergy. Twelve patients were skin test negative to all venoms and also RAST negative. The 48 skin test positive patients gave an 88% correlation of RAST and skin test with 92% of the skin test positive patients RAST positive and 82% of the RAST positive patients skin test positive. If patients strongly positive to honey bee showing positive RAST to vespids with negative skin test were not counted, then 91% of the RAST positive patients were skin positive. The term "false" should not be used in relating RAST to skin test results without supporting challenge evidence.

Bee Venoms↗
PubMed1978

Allergens in hymenoptera venom. V. Identification of some of the enzymes and demonstration of multiple allergens in yellow jacket venom.

Yellow jacket venom (YJV) contains acid phosphatase, hyaluronidase and phospholipase but neither allergen C nor melittin as bee venom (BV). YJV enzymes did not cross react with antisera to BV enzymes. YJV was separated into seven fractions, all of which had some activity in RAST. Sera were found specific for the fractions containing phospholipase and acid phosphatase. The other three protein fractions also exhibited substantial RAST activity, suggesting there are at least five allergens in YJV.

Acid Phosphatase↗
PubMed1978

Diagnosis of honey bee venom allergy.

Studies using both an optimized RAST assay and intradermal skin testing with whole bee venom indicate that both methods should be used for diagnosis. RAST and skin test are of similar sensitivity but each misses some patients found positive by the other. Correlation between the tests was 91% with an additional 5% only RAST positive and 4% only skin test positive.

Adolescent↗
PubMed1978

Honey bee venom allergy immunological studies of systemic and large local reactions.

The IgE and IgG antibody responses to four allergen fractions of honey bee venom were studied in 13 sera from patients who experienced systemic reactions from bee stings and eight from those who experienced large locals. Both groups were similar in allergen response. IgE and IgG levels and ratios. A significant number of patients were found to have experienced both types of reactions from bee stings. It is proposed that IgE antibody positive systemic and large local reactions are both IgE mediated allergic reactions. The determining factors for reaction type include venom dose and sting site.

Adolescent↗
PubMed1977

Allergens in bee venom. III. Identification of allergen B of bee venom as an acid phosphatase.

Allergen B previously isolated from honeybee venom and shown to be a mildly acidic protein consisting of polymers of a chain of 49,000 d is shown to have acid phosphatase activity. Allergen B is homogeneous by several criteria. No acid phosphatase, alkaline phosphatase, or esterase activity was found in any other allergen or fraction of bee venom. Acid phosphatase activity was also found in yellow jacket venom and extracts of venom sacs from bumblebees and paper wasps.

Acid Phosphatase↗
PubMed1977

Allergens in Hymenoptera venoms. IV. Comparison of venom and venom sac extracts.

Honeybee venom sac extract is compared with pure venom. All five known allergens of venom are present in venom sac extract. Enzyme analyses indicate that the sac extracts contain 11% to 16% venom. At least 10 additional components, several of which are proteins, are present in venom sac extract. Radioallergosorbent test (RAST) studies of yellow jacket venom and venom sac extract yielded a correlation of r = 0.94, with only some weakly reactive sera positive to only one preparation. A few sera were substantially more reactive with venom sac extract. Venom sac extracts appear to be suitable for in vitro diagnostic use, but the extraneous proteins and peptides may make them less suitable than pure venoms for use in immunotherapy.

Acid Phosphatase↗
PubMed1977

Allergens in bee venom II. Two new high molecular weight allergenic specificities.

Two new allergenic specificites were detected in honeybee venom and the two corresponding protein substances isolated by gel filtration, immunoadsorption, and ion exchange chromatography. The first of these, allergen B, has a molecular weight ranging from 49,000 to more than 200,00 d and can be recognized by rabbit and guinea pig antisera as well as by human reaginic sera using the radioallergosorbent test (RAST). Allergen B gives a single line in immunodiffusion distinct from hyaluronidase, phospholipase A, melittin, and the other high molecular weight substances described and gives a single band at 49,000 d in sodium dodecyl sulfate (SDS) polyacrylamide gel. The second substance, allergen C, has a molecular weight of 105,000 d and was separated from allergen B by immunoadsorption with insoluble antibody. Allergen C was shown to be distinct from the other sustances in bee venom by immunodiffusion with animal antisera. One human reaginic serum was monospecific for allergen C. Two other minor components of 86,000 and 71,000 d are present in bee venom; their allergenic activities are unknown. The two specifities, B and C, comprise most of the reactivity of the previously described Sephadex G-75 fraction 1 and clearly are important allergens, reacting with 98% of sera from bee venom-allergic individuals.

Allergens↗
PubMed1976

Allergens in bee venom. I. Separation and identification of the major allergens.

Honeybee venom was separated into seven fractions by gel filtration on Sephadex G-75. Allergenic activities of these fractions were assessed by the paper disc radioallergosorbent test (RAST) with a panel of sera from 24 individuals who had systemic reactions to bee stings, 7 who had large local reactions, and 10 control subjects who had reactions of 5 cm or less following bee stings. Three fractions were identified by enzyme or direct hemolytic activity. Twenty-nine of 31 sera from patients having either systemic or large local reactions to bee stings were positive when radioallergosorbent tested with whole bee venom; 22 were positive to phospholipase A, and 28 were positive to both fractions 1 and 2. Thirteen sera combined most strongly with fraction 1, 12 sera most strongly with fraction 2, hyaluronidase, and three sera about equally with fractions 1, 2, and 3. Reactions with other fractions were much weaker. Fractions 1 and 2 were potent inhibitors of RAST with whole venom in the sera reacting most strongly with fractions 1 or 2, respectively. Fraction 3, phospholipase A, and commercial bee venom phospholipase A were significantly less potent inhibitors with the sera tested. In the cases in which IgE antibody bindings to fractions 1, 2, and 3 were of similar magnitude, inhibitions of RAST using the various fractions both on the discs and as inhibitors demonstrated substantial cross-reactivity between the fractions. These results strongly indicate that by using RAST with human sera from bee sting-sensitive individuals, fraction 1, the high molecular materials, and fraction 2, hyaluronidase, are the major allergens in honeybee venom. Phospholipase A appears to be of secondary importance.

Allergens↗
PubMed1975

Viral stimulation of choline phosphotransferase in spleen microsomes.

Choline phosphotransferase and phosphatidyl ethanolamine methyltransferase enzymatic activities (nmoles phosphatidyl choline/min/mg protein) have been determined in spleen microsomes of Rauscher virus infected balb/c male mice at 5, 10, 14, and 21 days following inoculation of the virus. There is a significant stimulation of the choline phosphotransferase activity in the virus infected spleens with the peak of activity at about 10 days of viral infection. The specific activity of choline phosphotransferase is 10 times that of the phosphatidyl ethanolamine methyltransferase at 10 days of viral infection. There is a 51-fold increase over controls for the total microsomal choline phosphotransferase at 14 days of viral infection and only an 18-fold increase over controls for the phosphatidyl ethanolamine methyltransferase activity. There is a significant (P less than 0.001) increase over controls in the concentration of total phospholipid-P, phosphatidyl choline-P, and phosphatidyl choline-P fractions as separated by argentation chromatography of microsomes from spleens of mice infected with Friend virus of Rauscher virus for 14 days. The choline phosphotransferase and phosphatidyl ethanolamine methyltransferase specific activities in liver microsomes of 14 day Friend and/or Rauscher virus are unaltered during viral infection.

Animals↗