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Biomedical subjects

H Baer

Publications and source records attributed to H Baer.

At least 127 records · Page 7Linked to original sources
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

Factors influencing adherence of group B streptococci to human vaginal epithelial cells.

Factors affecting the adherence of group B streptococci to human vaginal epithelial cells in vitro were examined. Maximal adherence was achieved within 15 min of incubation of bacteria with epithelial cells. Adherence was temperature and pH dependent; maximal adherence occurred at 37 degrees C and pH 5.5. Killing of streptococci with ultraviolet light or penicillin did not affect adherence. Similarly, adherence was not altered by preincubating epithelial cells at 65 degrees C for 30 min. Thus neither bacterial nor epithelial cell viability appears to be a prerequisite for adherence. Preincubation of streptococci at 65 degrees C for 30 min resulted in a marked decrease in adherence, whereas preincubation of group B streptococci with neuraminidase was associated with a significant increase in adherence. The adherence of strains belonging to five different group B streptococcal serotypes was not altered by group-specific or type-specific rabbit antisera. These findings suggest that the site for adherence on the bacterial cell wall is heat sensitive and is marked by sialic acid, but is not related to either group-specific or type-specific antigens.

Adhesiveness↗
PubMed1979

In vitro studies of poison oak immunity. I. In vitro reaction of human lymphocytes to urushiol.

Poison oak, ivy, and sumac dermatitis is a T-cell-mediated reaction against urushiol, the oil found in the leaf of the plants. This hapten is extremely lipophilic and concentrates in cell membranes. A blastogenesis assay employing peripheral blood lymphocytes obtained from humans sensitized to urushiol is described. The reactivity appears 1--3 wk after exposure and persists from 6 wk to 2 mon. The dose-response range is narrow, with inhibition occurring at higher antigen concentrations. Urushiol introduced into the in vitro culture on autologous lymphocytes, erythrocytes and heterologous erythrocytes produces equal results as measured by the optimal urushiol dose, the intensity of reaction, and the frequency of positive reactors. This suggests that the urushiol is passed from introducer to some other presenter cell. Although the blastogenically reactive cell is a T cell, there is also a requirement for an accessory cell, found in the non-T-cell population, for reactivity. Evidence is presented that this cell is a macrophage.

Adolescent↗
PubMed1978

Susceptibility of the anaerobic bacteria, group D streptococci, Enterobacteriaceae, and Pseudomonas to semisynthetic penicillins: carbenicillin, piperacillin, and ticarcillin.

Sodium piperacillin T-1220, a new semisynthetic penicillin, was tested in vitro against 297 clinical isolates of anaerobic bacteria and 669 aerobic bacteria by the conventional agar dilution method and compared with carbenicillin and ticarcillin. At a 100-mug/ml concentration the three drugs showed comparable effectiveness against the anaerobes tested. However, at 20 mug/ml, piperacillin was the most effective drug against Bacteroides fragilis, peptostreptococci, and group D streptococci. At this drug concentration only 48% of the B. fragilis strains exhibited susceptibility to carbenicillin only, 64% exhibited susceptibility to ticarcillin but 90% exhibited susceptibility to piperacillin. Similar findings were observed with peptostreptococci and group D streptococci. On a weight basis piperacillin was statistically shown to be the most effective antibiotic of the three tested against these anaerobes. At 20 mug/ml, piperacillin exhibited a statistically significant difference (P < 0.01) over carbenicillin and ticarcillin for Serratia marcescens, Escherichia coli, Klebsiella species, Klebsiella pneumoniae, Pseudomonas isolates, and Citrobacter diversus. At both 20- and 100-mug/ml concentrations, piperacillin appeared to be the most effective (calculated P < 0.01) upon Klebsiella species, K. pneumoniae, S. marcescens, and C. freundii in activity over ticarcillin and carbenicillin.

Aerobiosis↗
PubMed1977

Clinical response of patients with gonococcal endocervicitis and endometritis-salpingitis-peritonitis to doxycycline.

The clinical response to single-drug therapy with doxycycline was evaluated in 25 patients with gonococcal endoceruicitis and was correlated with the bacterial isolates present within the cul-de-sac. The 10 patients with gonococcal salpingitis salpingitis and the three patients with gonococcal peritonitis exhibited excellent clinical responses. When polymicrobial infection coexisted with gonococcal peritonitis or functioned without the concomitant presence of Neisseria gonorrhoeae, a significantly altered therapeutic response was observed in four of the 12 patients. Four patients in this grouping exhibited either secondary temperature elevations or lack of a significant alteration of the white blood cell count, two features which were not characteristic of the patients with either gonococcal salpingitis or peritonitis. In the cases of polymicrobial peritonitis, there was a poor correlation between ensuing clinical response and in vitro resistance of one or more cul-de-sac isolated to doxycycline. The presence of a resistant organism did not preclude a good or satisfactory clinical response. The absence of a resistant organism correlated well with a good clinical response.

Adolescent↗
PubMed1977

A high molecular weight allergenic fraction of honeybee venom.

Chromatography of honeybee venom on Sephadex G-150 super fine revealed a high molecular weight (HMW) fraction that elutes prior to hyaluronidase (HYAL) and comprises 2% to 4% of the venom weight. HMW appears to exist in polymeric form, and the polymer which is present in greatest concentration has an estimated molecular weight of 105,000 D. The 12% nitrogen content of HMW suggests it may not be all protein. HMW is antigenically and enzymatically distinct from HYAL and phospholipase A2 (PHOS A). The acid phosphatase activity known to be present in honeybee venom was found in the HMW fraction. Since it reacts by RAST with the sera of most individuals known to be sensitive to honeybee venom, and releases histamine from the peripheral leukocytes of such individuals, its role as an allergen is confirmed. Since individuals react to different degrees to HMW, HYAL, and PHOS A, there does not appear to be a single principal allergen in honeybee venom.

Allergens↗
PubMed1977

Rectal colonization with group B streptococcus: relation to vaginal colonization of pregnant women.

Anorectal carriage as a possible primary source of vaginal colonization by group B Streptococcus was investigated. The study was performed during two separate periods and included 789 pregnant women and 422 neonates. Specimens from multiple sites were obtained for culture from all women and infants and were streaked onto blood agar plates containing 8 mug of gentamicin sulfate/ml and 15 mug of nalidixic acid/ml, which allow selective growth of streptococci. Cultures positive for group B streptococci were obtained from 162 (20.5%) of the pregnant women and from 50 (11.8%) of the neonates. Rectal cultures were positive for streptococci in 142 (17.9%) of the women, and vaginal cultures gave positive results in 81 (10.2%). The higher incidence of positive results in rectal as opposed to vaginal cultures (ratio of 2:1) was encountered during all phases of the study. This finding suggests that the gastrointestinal tract may be the primary site of colonization by group B Streptococcus and that vaginal colonization may represent contamination from this source.

Culture Media↗
PubMed1977

The induction of immune tolerance in delayed contact sensitivity by the use of chemically related substances of low immunogenicity.

Immune tolerance in delayed contact sensitivity to pentadecylcatechol can be induced by a series of derivatives substituted in the 6 position of the ring. Some of these derivatives have the property of being very poor sensitizers and having very low dermal toxicity. Thus, sensitization and tolerance have different biologic mechanisms and are associated with different properties of these chemicals.

Animals↗
PubMed1976

Cul-de-sac isolates from patients with endometritis-salpingitis-peritonitis and gonococcal endocervicitis.

Neisseria gonorrhoeae was cultured from the cul-de-sac in 11 of 17 patients with bacteriologically documented gonococcal endometritis-salpingitis and identified by Gram stain in one other instance. In five, N. gonorrhoeae was the only isolate. In six other patients, the presence of other aerobic (two) and anaerobic bacteria (three), as well as N. gonorrhoeae, was documented. In the remaining six patients, only aerobic and anaerobic organisms were isolated. The data are interpreted as supporting the concept of anaerobic superinfections following initial infection with N. gonorrhoeae late in the course of this disease entity.

Aerobiosis↗
PubMed1976

Allergy to insect stings. II. Phospholipase A: the major allergen in honeybee venom.

In order to determine the proteins of major allergenic importance in honeybee venom (Apis mellifera) it was chromatographed on G-50 Sephadex. The four major protein peaks eluted were identified as hyaluronidase, phospholipase, melittin, and apamin. Testing these preparations on the leukocytes of 6 honeybee-sensitive patients, with the in vitro method of histamine release, revealed that all individuals were most sensitive to phospholipase A. IgE antibodies against phospholipase A (RAST) were found in the sera of honeybee-sensitive patients and IgG antibodies to this venom component were found in the sera from beekeepers and venom-treated patients. Melittin appeared to be allergenic in several patients, but the results were variable and were possibly due to contamination with phospholipase. All patients were insensitive to the hyaluronidase and apamin preparations. We conclude that phospholipase A is the major allergen of honeybee venom and, since this protein is readily available, it should be useful for diagnostic and therapeutic studies as well as for the standardization of materials used in the management of honeybee-sensitive patients.

Allergens↗
PubMed1976

Analysis of the potency of extracts of June grass pollen by their inhibitory capacities in the radioallergosorbent test.

The potencies of 11 commercial extracts of June grass pollen were analyzed by skin test end point titrations and compared to potencies as determined in vitro (1) by the radioallergosorbent test (RAST), (2) by Group I antigen content, and (3) by protein nitrogen units (PNU). RAST potencies were determined by the capacity of the extract to inhibit the binding of IgE antibody to solid-phase allergen, and they were expressed as the quantity of extract required for 50% inhibition of binding. Potencies determined by skin testing in 8 patients were significantly related among the various patients in 19 of 27 comparisons and showed differences of up to 95,000-fold in the strengths of the extracts. Estimation of potencies by RAST inhibition showed approximately a 100-fold difference among the extracts and in 5 of 8 cases these were significantly related to potencies measured by skin tests. Similarly, PNU determinations and Group I determinations were also significantly related to potencies by skin test titration in 5 of 8 and in 4 of 8 comparisons, respectively. Comparison of the geometric mean skin test potencies with RAST, PNU, and Group I potencies revealed that all were significantly related to skin test potencies although the correlation of RAST and skin potency was the highest. The results indicate that measurement of potency by RAST inhibition compares favorably with other in vitro measurements of potency. These results are compared with those of a prior study with extracts of short ragweed, and the reasons for the differences between the results in the two studies are discussed.

Absorption↗
PubMed1976

The stability of short ragweed pollen extract as measured by skin test and antigen E.

A short ragweed pollen extract stored at 4 degrees C was shown to retain its skin reactivity for 18 mo, although 60% of the antigen E was lost. When stored at higher temperatures, the extracts had a markedly reduced skin reactivity for some individuals, but retained full reactivity in others even though the antigen E was markedly diminished. Thus, some ragweed-sensitive individuals are very sensitive to antigen E, which is heat-labile, but some have a major sensitivity to other allergens, which are heat-stable. During the 18-mo course of this study, skin test reactions to a similar extract did not show significant variability.

Adolescent↗
PubMed1976

Ethchlorvynol (Placidyl)-induced pulmonary edema.

Two patients experienced severe nonhemodynamic pulmonary edema following the intravenous injection of 25 and 40 mg/kg of body weight of ethchlorvynol (Placidyl). The pulmonary edema cleared rapidly. Injection of Placidyl (12 to 80 mg/kg of body weight) intravenously into dogs caused acute, severe, nonhemodynamic pulmonary edema (as evidenced by markedly elevated lung weights and microscopic evidence of intra-alveolar edema), hypotension with a relative bradycardia, and a decreased cardiac output. Injection of polyethylene glycol, the vehicle in which ethchlorvynol is diluted, did not reproduce the syndrome.

Adult↗