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H D Hochstein

Publications and source records attributed to H D Hochstein.

At least 19 recordsLinked to original sources
PubMed1992

Experimental evaluation of antitoxic protective effect of new cholera vaccines in mice.

Intraperitoneal immunization of mice and subsequent challenge with purified cholera toxin (CT) were employed to evaluate the anti-cholera toxin protective effect of two new oral cholera vaccines, live CVD 103-HgR and killed B subunit-whole cell (BS-WC). CVD 103-HgR vaccine demonstrated 100% protection of mice against 2.25 LD50 and 70% against 3 LD50 of CT. Mice immunized with BS-WC vaccine were protected against 2.25 and 3 LD50 of CT in 88 and 62% of cases, respectively. All three killed parenteral vaccines failed to protect against CT. We suggest this mouse system for preliminary evaluation of the antitoxic protective activity of cholera vaccines.

Animals↗
PubMed1991

The HIV-1 gp120 envelope protein has the intrinsic capacity to stimulate monokine secretion.

Results and conclusions concerning the ability of HIV glycoprotein (gp) 120 to stimulate monokine secretion have been equivocal, based on observations using natural gp120 derived from infected human cells and a Chinese hamster ovary (CHO) cell-derived recombinant fusion protein. Current studies were designed to determine whether differences in recombinant gp120 proteins could result in failure to trigger monokine production. We found that natural gp120 could stimulate monocytes to release TNF-alpha, IL-1 beta, IL-6, and granulocyte-macrophage-CSF, and this effect could be blocked with soluble CD4. Full-length rgp120 either expressed from an adenovirus vector and purified from infected human cells, or derived from CHO cells, could function similarly. In contrast, full-length recombinant envelope protein expressed in a baculovirus system and a CHO cell-derived recombinant fusion protein tested previously, consistently failed to stimulate monokine production. The stimulatory capacity of both natural and full-length CHO cell-derived gp120 was eliminated by heating at 100 degrees C, and could be blocked with excess CHO cell-derived gp120 fusion protein. Inasmuch as the baculovirus-expressed gp120 and the CHO cell-derived recombinant fusion protein can bind to CD4, these results suggest that HIV gp120 binding to CD4 on the monocyte surface may of itself be insufficient for stimulation of monokine secretion. Therefore, primary protein structure, as well as posttranslational protein modifications, may determine this activity.

Animals↗
PubMed1991

Bacterial lipopolysaccharide acts synergistically with selected macromolecular polyanions to induce MHC-nonrestricted cytotoxic cells.

We examined whether bacterial lipopolysaccharide, at a dose range extending to less than 1.0 ng/ml, would work with cofactors to induce MHC-nonrestricted cytotoxic cells. To this end, normal mouse splenocytes were cultured for 5 days with LPS and potential cofactors, after which the cells were tested for cytotoxic activity in short-term 51Cr-release assays. We found that LPS can act synergistically with the macromolecular polyanions, dextran sulfate and polyinosinic acid. The effector cells induced by LPS and polyanions showed characteristics of activated NK cells in that they were (1) cytotoxic for widely differing sources of tumor cells, (2) not inhibited by an anti-T cell receptor antibody, and (3) not removed by depletion of CD4+ or CD8+ cells. LPS was active at picogram concentrations when dextran sulfate was included. Exposure of splenocytes to LPS was necessary during the early phase of the 5-day culture, but as little as 1 h of exposure was required, whereas exposure to the macromolecular polyanions during either the first or the last 2 days of a 5-day culture with LPS was effective. As expected with LPS activity, the cytotoxic cell response was prevented by polymyxin B or by the use of splenocytes from LPS non-responder C3H/HeJ mice. Screening of the S. minnesota R mutants and other partial LPS structures revealed that lipid A was closely associated with LPS activity in this assay system and that at least one partially detoxified structure, a deacylated LPS, could substitute for native LPS.

Animals↗
PubMed1990

In vitro characterization of Salmonella typhi mutant strains for live oral vaccines.

Several Salmonella typhi attenuated mutant strains, suggested as candidates for live oral vaccine, were examined for their characteristics in vitro in comparison with parental strains Ty2 and CDC10-80. Three methods were used: interaction of bacteria with the human monocyte-macrophage U937 cell line evaluated by microscopic examination, bacterial growth in the cell culture medium estimated by absorbance and bacterial resistance to human plasma assessed by the viable count technique. The most informative data were obtained in the test with U937 cells. Ty2 penetrated almost 100% of the cells, multiplied rapidly and caused death of the cells. CDC10-80 infected about 30% of the cells, multiplied slightly and did not kill the cells. The Ty2 mutant galE via EX462 behaved like CDC10-80. Bacteria of the galE Ty21a, Vi + Ty21a, 541 Ty and 543 Ty, found in only 3-4% of the cells, did not multiply within the cells and decreased in number with time. These findings correlate with the reported virulence of these strains for humans. With the second method, the rate of bacterial growth in cell culture medium did not differentiate Ty2, CDC10-80 and EX462. They grew at the same rate and faster than the remaining mutants. The plasma resistance test did not discriminate between EX462 and other mutants. These tests did not reveal any difference between Vi + Ty21a and Vi-Ty21a.

Administration, Oral↗
PubMed1989

Measurements of lipopolysaccharide (endotoxin) in meningococcal protein and polysaccharide preparations for vaccine usage.

Lipopolysaccharide (LPS, i.e. endotoxin) present in meningococcal outer-membrane protein and polysaccharide preparations made for vaccine use was quantitated by a silver-stain method following SDS-PAGE. The reactivities of LPS in the preparations were also measured by rabbit pyrogenicity and Limulus amoebocyte lysate (LAL) assay. Although rabbit pyrogenicity and LAL assay are more sensitive than the silver stain method, the latter provided an actual amount of LPS present in the protein or in the polysaccharide. For a meningococcal protein preparation, rabbit pyrogenicity showed about one-tenth, and even less by LAL assay, of the actual amount of LPS. This is because protein-bound LPS in meningococcal protein preparations is about 10-fold less active in causing fever in rabbits, and 20- to 40-fold less active in the gelation of LAL than the same amount of a purified free LPS which is generally used as a reference in quantitating LPS in these two assays. As for the small amount of LPS present in a meningococcal polysaccharide preparation, similar LPS content was obtained when measured by the three methods suggesting that the LPS is not bound to the polysaccharide in contrast to that in the proteins mentioned above. The purified meningococcal LPS was pyrogenic in rabbits at 1 ng/kg.

Animals↗
PubMed1986

Uridine-induced hyperthermia in the rabbit.

Uridine injection in 0.6% saline elevated rabbit temperatures (mean = 0.9 degree C) in the USP XX pyrogen test. Hyperthermia was delayed in onset and peaking 3-4 h post injection, but the injection was negative in the limulus amoebocyte lysate (LAL) assay. Uridine from five lots of different sources exceeded USP XX limits in the rabbit pyrogen test and proved negative in the LAL assay. Because the dose of uridine was high, several procedures were used to determine if an impurity was the cause of temperature elevation. Uridine remained pyrogenic in spite of ultrafiltration (10 000 nominal mol. wt), recrystallization and preparative scale HPLC. Sterile filtration and autoclaving also did not affect the response. Hyperthermia, therefore, appears to be an inherent property of uridine. Uridine was also found to release endogenous pyrogen in-vitro from human mononuclear cells. Uridine has been reported to induce fever in man, thus the USP rabbit pyrogen test predicted for the clinical response.

Animals↗
PubMed1979

Allergenic and biologic activity of commercial preparations of house dust extract.

The endotoxin, protein nitrogen unit (PNU) content, and allergenic activity of seven different extracts of house dust were determined. The PNU content varied from 1,600 to 44,000 PNU/ml. The endotoxin content as measured by the limulus assay varied from 450 to 500,000 ng/ml. Pyrogenic activity was present by rabbit fever assay and correlated well with the limulus assay. There was no correlation between endotoxin and PNU content of the different dust preparations. Leukocytes from 15 patients with a clinical history of allergy to dust were used for histamine release studies. The allergenic activity did not correlate with the PNU or endotoxin content of the different house dust preparations. The dust extracts could be divided into three groups according to their activities: three extracts which were the most reactive (30% histamine release with 0.12 to 0.39 PNU/ml), two which were about 20 times less active (4.75 to 6.43 PNU/ml for 30% histamine release), and a final group of two which were about 600 times less active. The leukocytes of three out of 15 patients failed to release histamine with one of these least reactive extracts. The reactivity pattern of five of the dust preparations appeared to correlate, suggesting that the different preparations contained the same allergens. Reactivities of two of the other extracts correlated poorly, and the reactivity of the least reactive sample did not correlate with six out of the seven preparations. Therefore, some dust preparations contain significant endotoxin-like material. Wide variations in the endotoxin, PNU content, allergenic activity, and reactivity patterns of different dust preparations were observed.

Adult↗
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↗
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↗