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H D Hochstein

Publications and source records attributed to H D Hochstein.

36 records · Page 2Linked to original sources
PubMed1979

Statistical procedure for evaluating the sensitivity of Limulus amoebocyte lysate by using a reference lysate.

A study was designed to estimate variability of the Limulus amoebocyte lysate test by comparing a reference lysate against itself. Three technicians performed parallel tests, i.e., titrated side by side, the contents of two vials of reference lysate on 4 different days using 24 vials of the United States reference lysate and 12 vials of the United States reference endotoxin. Each parallel test was replicated three times. From the sensitivity endpoints, ratios were calculated for each parallel test. These ratios were converted to the logarithm for estimating variability among technicians and among vials of endotoxin. By using the overall variability of log ratios, a statistical procedure was developed to evaluate the sensitivity of each lot of licensed lysate submitted to the Bureau of Biologics for release.

Endotoxins↗
PubMed1979

Limulus amebocyte lysate testing of nomral serum albumin (human) in the United States since 1975.

In order to determine the reactivity of Limulus Amebocyte Lysate to albumin products, over 1500 lots of 25% Normal Serum (Human) produced by 12 U.S. licensed manufacturers were tested over the past 4 years. Representative samples of 5% Normal Serum Albumin (Human) and Purified Protein Fraction (human) were also tested with Limulus Amebocyte Lysate. Problems associated with apparent false negative reactions are discussed. Model test protocols are presented that might be useful in determining the degree of false positivity of albumin products. These models could be adopted by blood fractionators to gather validation data to support substitution of the Limulus Amebocyte Lysate test for the rabbit pyrogen test.

Animals↗
PubMed1977

Statistical determination of endotoxin content in influenza virus vaccine by the limulus amoebocyte lysate test.

To determine laboratory-to-laboratory variability of the limulus amoebocyte lysate (LAL) test for evaluating endotoxin content in influenza virus vaccine, a collaborative study was designed. Participants were six influenza virus vaccine manufacturers and the Bureau of Biologics (BoB). Lysate lot 116, Reference Influenza Virus Vaccine for Endotoxin Assay E-1, and four test vaccines having different ratios of LAL activity relative to reference E-1 were supplied by the BoB. Each laboratory used its normal test procedure. All vaccines were coded. One pair (reference and test) of vaccines per day was tested for 4 days a week over a 4-week period. All data were analyzed at the BoB. The degree of variability experienced by testing laboratories was estimated by the study. This estimate did not conflict with experience gained from previous routine testing in any of the participating laboratories. A statistical approach to the evaluation of LAL data from testing influenza virus vaccine for endotoxin content was developed based upon the overall variation obtained from the collaborative study.

Drug Contamination↗
PubMed1976

Comparative trial of influenza vaccines. II. Adverse reactions in children and adults.

Commercially prepared zonally and chromatographically purified bivalent (A/England-B/Mass) and monovalent (B/Hong Kong) inactivated influenza vaccines were given to 438 individuals 6-33 years old. The vaccines had been examined for antigen content by chick cell agglutination (CCA) tests and electron microscopic particle count determinations. Endotoxin and pyrogen content were determined by limulus amebocyte lysate (LAL) and rabbit pyrogenicity assays; and egg-associated protein contamination was estimated by total protein and single radial immunodiffusion assays. Although great differences (10-200-fold) were found in the amount of endotoxin or pyrogen in the vaccines, no significant differences were found in the febrile responses they induced. Both bivalent and monovalent vaccines induced fever of greater than or equal to 38 C at a rate of approximately 3 1/2-4% above background. The febrile responses were most frequent at 24 hours after inoculation and a higher rate was observed in children than adults. Local reactions consisting of tenderness, erythema or induration were seen in from 20-57% of the recipients and also were unrelated to the pyrogenic or host-derived materials in the vaccines. Adults had higher local reaction rates than children and some vaccines containing larger amounts of viral antigen induced significantly higher rates of reactivity than did vaccines containing smaller amounts of antigen. Although 37-51% of all recipients experienced either a local and/or febrile reaction to influenza immunization, the reactions were in general mild and would not consitute a significant disadvantage in the immunization of children over 6 years and adults to prevent influenza infection and its sequelae.

Adolescent↗
PubMed1976

Preparation and properties of a national reference endotoxin.

A large pool of refined endotoxin was prepared from Escherichia coli O113 by extraction with hot acqueous phenol. It was characterized chemically and biologically and will be available for a reference standard designated as reference endotoxin EC.

Animals↗
PubMed1972

Parathyroid necrosis and hypocalcemic tetany induced in rabbits by L-asparaginase.

Fifty percent of New Zealand white rabbits became profoundly weak, had generalized seizures and died between 22 and 47 hours after an intravenous injection of 1000 IU/kg of L-asparaginase. The biochemical correlate of this syndrome is severe hypocalcemia associated with marked, single cell, oxyphilic necrosis in the parathyroid glands. Although survivors remained clinically well, they also developed hypocalcemia and parathyroid necrosis but to a lesser degree. Rabbits given an equivolumetric amount of saline did not develop alterations in any of these parameters. L-Asparaginase, therefore, exerts a direct toxic effect on the parathyroid glands of rabbits. The implications of this finding for man are briefly discussed.

Animals↗
PubMed1970

Titration of cholera antitoxin in human sera by microhemagglutination with formalinized erythrocytes.

Microtiter hemagglutination tests employing formalinized sheep erythrocytes sensitized with either crude or purified cholera toxin were used to assay the cholera antitoxin content of human sera. Comparable results were obtained with either crude or purified toxin-sensitized cells with the exception of two sera that gave unusually high hemagglutination titers with the crude toxin. Sera from 13 convalescent cholera patients showed a high degree of correlation between antitoxin levels as determined in vitro by the hemagglutination test and in vivo by the skin permeability factor neutralization test. Fourfold or greater rises in antitoxin levels between acute and convalescent sera were detected in 9 of 15 patients with bacteriologically proven cholera. No significant increases in titer were observed in 14 cases of noncholera diarrhea. Cholera antitoxin was detected by hemagglutination in only 1 of 33 sera, obtained from eight countries, containing vibriocidal antibodies. Formalinized sheep erythrocytes sensitized with toxin and stored at 4 C in the presence of 1:10,000 thimerosal were stable and sensitive for at least 6 months (the longest time tested).

Animals↗
PubMedDate not supplied

Bacteriological activity in unfiltered calf sera collected for tissue culture use.

Bacteriological tests were made on 24 lots of unfiltered calf serum collected for subsequent use as a component of tissue culture media. The examination included the isolation and identification of bacteria, assay of phages, and demonstration of endotoxin material. Only Gram-positive bacteria were isolated and 96% of the sera were contaminated with bacteria. The prevalent strains of bacteria found were Bacillus species and streptococci and 63% of the sera coagulated Limulus amebocyte lysate. More than 90% of the lots contained phages demonstrable with the C-3000 strain of Escherichia coli. Only one lot of the serum was found to be free from bacteria, phages, and endotoxin by the tests used.

Bacillus↗
PubMedDate not supplied

Pyrogen reactions associated with the infusion of normal serum albumin (human).

In November, 1974, eight patients in three hospitals had pyrogen reactions associated with the infusion of 25% Normal Serum Albumin from the same lot. The reactions were recognized because the same physician or nurse observed several patients having recurrent reactions or because a single patient receiving several vials had consecutive reactions. The remaining albumin in three vials associated with reactions had apparent endotoxin concentrations of 4, 16, and 32 ng/ml and that 22 vials from recalled supplies had a median concentration of 4 ng/ml (range: 2 to 64) as determined by the Limulus amebocyte lysate test, but the lot again passed the rabbit pyrogen test. In a prospective study to determine the efficacy of the Limulus test in quality control, patients had their temperatures taken hourly during albumin infusions and the remaining fluid was tested by the Limulus assay. The albumin in 443 of the 662 vials infused (65%) gave a positive test and 311 of these vials (45%) had apparent endotoxin concentrations of 4 to 64 ng/ml, but no patient had a reaction. Because of the limitations of both the rabbit pyrogen and Limulus test, the detection of some pyrogenic lots continues to depend on hospital surveillance and reporting os suspect reactions.

Adult↗