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Biomedical subjects

M J Schumacher

Publications and source records attributed to M J Schumacher.

At least 19 recordsLinked to original sources
PubMed2000

Stability of fresh and preserved fetal and adult lymphocyte cell surface markers.

Delay between blood collection and immunophenotyping of peripheral blood (PB) and umbilical cord blood (UCB) lymphocytes occurs frequently. Holding media address this problem, but there are few reports of their limitations. We tested the ability of Cyto-Chex (CC) to preserve the ability of lymphocyte subpopulations to be immunophenotyped after time delays. Ten UCB and 10 PB specimens were kept up to 48 hr and then placed in CC for 1 week, with removal of aliquots for staining with CD3, CD4, CD8, CD19, and CD45 at intervals. There were no significant changes in the number of nonpreserved PB or UCB cells stained with any of the reagents after 48 hr. Aside from a small decrease in UCB B-cell numbers, there were no changes in UCB or PB lymphocyte numbers after placing them in CC for 1 week. However, PB and UCB CD19+ cells and CD8+ T cells lost capacity for bright staining after 1 week in CC. The results suggest that UCB and PB can be held for up to 48 hr before being placed in CC and then kept for up to 1 week in CC with no decrease in T-cell numbers and only a minor reduction of B-cell numbers, albeit with a marked reduction in staining intensity.

Adult↗
PubMed1996

Neutralization of bee venom lethality by immune serum antibodies.

The lethal effects of Africanized honey bee venom depend on the absorption of venom delivered during simultaneous sting attacks by large numbers of bees. The hypothesis that antibodies to whole bee venom and bee venom components could neutralize the lethal effect of bee venom was tested. Antibodies from beekeepers and immunized rabbits were incubated with bee venom and neutralization was studied by survival of intravenously injected mice. Beekeeper serum antibodies were found effective in protecting mice challenged with whole venom, and serum from rabbits immunized with phospholipase A2 (PLA2) was effective in protection against lethal effects of PLA2. Serum antibodies from rabbits immunized with whole venom or melittin were ineffective in neutralizing whole venom in vivo and had low titers in a venom enzyme-linked immunosorbent assay. The results suggest the need for development of more effective methods for raising antitoxic antibodies to bee venom components in other animals as a means of developing an antiserum that would be effective for treatment of human victims of multiple bee stings.

Animals↗
PubMed1995

Significance of Africanized bees for public health. A review.

Although massive sting attacks by Africanized bees are currently rare, this type of bee is now endemic in parts of Arizona and Texas, and will probably spread to other warm climate areas in the United States. Treatment of severe toxic reactions to multiple stings usually includes management of shock, hypoxia, and other effects of organ damage. New approaches to reduce blood levels of venom including production of a bee antivenom and hemodialysis require further study. Patients with a trivial allergy to single stings could be at risk from systemic anaphylaxis to multiple bee sting. Those who wish to remain in endemic areas in spite of histories of systemic anaphylaxis to bee stings should be treated with venom immunotherapy, possibly administered more intensively and for longer periods than currently recommended. Continued public education is needed to limit contact with aggressive Africanized bee colonies.

Anaphylaxis↗
PubMed1995

Heterogeneity of pollen proteins within individual Betula pendula trees.

To determine the variation of antigenic water soluble proteins in white birch (Betula pendula) pollen, extracts of pollen from different sides of individual trees were analyzed by isoelectric focusing (IEF), crossed immunoelectrophoresis, and crossed radioimmunoelectrophoresis. IgE-antibody-binding patterns were also studied in samples analyzed by IEF by probing with serum pooled from patients with birch pollen allergy, followed by radiolabelled anti-IgE. Antigenic proteins and allergens per unit weight of extracted protein were greatest in pollen extracts from the south side of the trees. Allergens decreased progressively in pollen from west-through east- to north- facing branches. Proteins with high isoelectric points (pI > 8.5) and proteins between pI 4.5 and 5.6 were infrequent in extracts from the north side. Extracts from branches facing north were poor in allergens: in general, only one or two precipitin lines were found, and in some cases they did not bind to IgE antibodies. Differences between numbers of proteins and allergens found in extracts from south, west and north branches were statistically significant for all methods used. The results indicate the need to collect birch pollen for allergen extract manufacture from south-facing branches.

Allergens↗
PubMed1994

Rate and quantity of delivery of venom from honeybee stings.

To determine the rate and completeness of delivery of venom from honeybee stings, European bees were collected at the entrance of a hive and studied with the use of two laboratory models. In one model bees were induced to sting the shaved skin of anesthetized rabbits. The stings were removed from the skin at various time intervals after autotomization, and residual venom was assayed with a hemolytic method. In the other model the bees were induced to sting preweighed filter paper disks, which were weighed again after removal of the sting at various intervals. Results of both experiments were in agreement, showing that at least 90% of the venom sac contents were delivered within 20 seconds and that venom delivery was complete within 1 minute. The data suggest that a bee sting must be removed within a few seconds after autotomization to prevent anaphylaxis in an allergic person. The extensive variation found in the amount of venom delivered at each time point may explain inconsistencies in relationships among reactions to field stings, sting challenge testing, venom skin tests and RAST.

Anaphylaxis↗
PubMed1994

Immunoreactivity of umbilical cord blood and post-partum maternal peripheral blood with regard to HLA-haploidentical transplantation.

Recent clinical reports have demonstrated that umbilical cord blood (CB) may be utilized as a source of transplantable hematopoietic stem cells when bone marrow is not available. However, it is not apparent that CB can be used to transplant partially HLA-matched siblings or matched, non-familial recipients. In this study the immunoreactivity of CB has been investigated within familial confines; 14 families were analyzed at the time of birth of their child and six of these families were reassessed at 6 months post-partum. In mixed lymphocyte reactions, CB was unable to significantly respond to stimulation with cells from either the mother or father. Furthermore, unlike adult peripheral blood, CB displayed depressed immune responses to alloantigen and T cell mitogen. At 6 months, the immune responses of the infant demonstrated normal development in terms of alloantigen and mitogen responses. However, at 6 months both the mother and the infant demonstrated a continued immune tolerance to one another. The data suggest that CB could be used in familial transplant situations when siblings are HLA-haploidentical if the donor/recipients are chosen based on the paternal haplotype. Furthermore, maternal bone marrow harvested during the 6 months immediately following delivery of a child also should be suitable as a stem cell graft in haploidentical situations.

Cytotoxicity, Immunologic↗
PubMed1994

Collection, separation and cryopreservation of umbilical cord blood for use in transplantation.

Bone marrow transplantation (BMT) is limited by the paucity of HLA-matched donors and the frequent occurrence of graft-versus-host disease (GVHD). Recent clinical reports have implied that the use of umbilical cord blood (UCB) may alleviate some of the problems associated with BMT. Banks of frozen UCB could make the problem of finding suitable stem cell donors easier and stem cell grafts would be more readily available. However, definitive experiments are needed to develop optimal methods for collection, separation and storage of cryopreserved UCB for extended periods of time. We have found that several simple techniques may be utilized to collect large volumes of UCB (up to 220 ml). Also, modification of a common density gradient separation method permits recovery of large quantities of UCB mononuclear cells. Finally, we have examined the effects of prolonged frozen storage on the ability to recover viable and functional UCB, particularly stem/progenitor cells. It was observed that storage of UCB in liquid nitrogen for as long as 7 years had minimal effects on cell viability, cellular composition of UCB and progenitor/stem cell capacity. Thus, the establishment of UCB banks for use in transplantation appears to be a feasible approach.

Blood Banks↗
PubMed1992

Phenotypic and functional immaturity of human umbilical cord blood T lymphocytes.

Successful implementation of bone marrow transplantation for hematopoietic reconstitution is limited by the lack of suitably HLA-matched donors and by the occurrence of graft-versus-host disease that frequently accompanies this procedure. Recent clinical reports have implied that the use of umbilical cord blood as a source of transplantable stem cells may solve these problems. To date, definitive experiments have not been performed to assess the immunological potential of T cells found in umbilical cord blood, which could mediate graft-versus-host disease. In the present study we have observed that umbilical cord blood contains T lymphocytes that appear to be phenotypically immature. In addition, umbilical cord blood lymphocytes appeared to be functionally immature as shown by minimal responses to stimulation with interleukin 2, phytohemagglutinin, or alloantigens. Thus, umbilical cord blood may be more suitable for allogeneic transplantation than bone marrow in that these cord blood cells may not be as capable of mediating graft-versus-host disease.

Animals↗
PubMed1992

Biochemical variability of venoms from individual European and Africanized honeybees (Apis mellifera).

To study biochemical differences between venom from individual honeybees, venom sacs from 103 European (EU) bees and 92 Africanized bees representing 12 different colonies were dissected, and the dry weight (DW) of venom from each bee was determined. Venom from each of these bees was studied with isoelectric focusing and functional assays for phospholipase A2 and melittin. Phospholipase concentrations in individual EU bee venoms varied between 1.8% and 27.4% (wt/wt). The melittin concentration in EU bee venom varied less and, on the average, was found to be much lower than previously reported. There was an eightfold to ninefold difference between lowest and highest venom sac DW contents, suggesting the possibility of highly variable venom delivery from bee stings. One EU bee contained greater than 300 micrograms of venom, three times the recommended maintenance dose for venom immunotherapy. Isoelectric focusing also demonstrated large differences between individual bees, with respect to major and minor components of their venoms. Africanized bees contained significantly less venom but more phospholipase than did EU bees. Bee venoms from different colonies differed in their DW content and in their concentrations of phospholipase and melittin. The results are relevant to the uncertainty of responses from sting challenges and field stings in allergic patients and massive stinging attacks on normal subjects.

Africa↗
PubMed1991

Characterization of the major allergen of Cynodon dactylon (Bermuda grass) pollen, Cyn d I.

An allergen from Cynodon dactylon (Bermuda grass) pollen, Cyn d I, has been purified by a combination of concanavalin A-Sepharose affinity chromatography, and carboxymethyl-Sepharose chromatography. The allergen constitutes the major allergenic component of the pollen extract as observed by immunoelectrophoretic techniques, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, an IgE-inhibition experiment, and skin testing. In sodium dodecyl sulfate-polyacrylamide gel electrophoresis, Cyn d I is presented as a dominant 32 kd band and a minor 29 kd band, both binding IgE. Both bands are identified by monospecific rabbit antibodies (Abs) raised against Cyn d I. These Abs only weakly precipitate allergens from other grass species, indicating that Cyn d I possesses some unique immunochemical properties. Two of four purified murine monoclonal Abs raised against Cyn d I also bind to both bands of Cyn d I, indicating that the bands represent isoallergens with slightly different immunochemical properties. All four monoclonal Abs cross-react with pollen components from other grass species, especially Poa pratensis and Dactylis glomerata. The NH2-terminal sequence corresponding to approximately 10% of the complete sequence was determined, and it revealed high homology to the corresponding sequence of the major allergen of Lolium perenne, Lol p I. From the amino acid composition determination and immunoelectrophoretic comparison, the amount of Cyn d I in the source whole-pollen extract was estimated to be 15% wt/wt.

Allergens↗
PubMed1990

Quantity, analysis, and lethality of European and Africanized honey bee venoms.

Venom from Africanized honey bees (derived mainly from Apis mellifera scutellata) was compared with venom from domestic, European bees by study of lethality, immunological cross-reactivity, venom yield, isoelectric focusing (IEF) patterns, and melittin titers. The LD50s of European and Africanized bee venom by iv injection in mice were similar. In venom neutralization experiments, Africanized bee venom was mixed with antibodies from a beekeeper exposed only to European bees and used to challenge mice. Survival times of mice given these mixtures were significantly prolonged, indicating that human serum antibodies to European bee venom neutralized the lethal effects of Africanized bee venom. Reservoirs from Africanized bees contained less venom than European bees (94 and 147 micrograms venom/bee, respectively) and Africanized bee venom had a lower melittin content. The IEF patterns of venom from individual European bees varied considerably, as did IEF patterns of individual Africanized bees. Pools of venom from 1,000 bees of each population of A. mellifera showed noticeable but less obvious electrophoretic differences. The findings suggest that multiple stinging, and not increased venom potency or delivery, is the cause of serious reactions from Africanized bee attacks.

Africa↗
PubMed1989

Rhinomanometry.

Explore the source record for details and available documents.

Airway Obstruction↗
PubMed1989

An immunoelectrophoretic analysis of the allergens of Cynodon dactylon (Bermuda grass) pollen.

A crude extract of Cynodon dactylon (Bermuda grass) pollen was obtained by extraction, centrifugation, dialysis, and lyophilization. The corresponding polyspecific rabbit antibodies were obtained by immunization, bleeding, and purification and were used for a cross immunoelectrophoretic analysis of the crude extract. At least 52 antigens (Ags), of which 47 migrated toward the anode, and five, toward the cathode, were revealed. Crossed radioimmunoelectrophoretic analysis performed with sera from 32 patients allergic to Bermuda grass and a pool from 1000 normal individuals revealed specific IgE binding to 13 of these Ags. The approximate molecular weights (MWs) for 10 of these IgE-binding Ags were determined by a combination of gel filtration and immunochemical analysis. These Ags had apparent MWs greater than 14 kd. A combination of preparative sucrose gradient isoelectric focusing and immunochemical analysis was used to determine the approximate isoelectric point values of five of the IgE-binding Ags. Most precipitating Ags had isoelectric points between 4.5 and 5.5. Four of the Ags (Ag 24, MW, less than 65 kd; Ag 31, MW, 33 kd; Ag 33, MW, 20 kd; and Ag 34/35, MW, 32 kd) were classified as major allergens.

Adolescent↗
PubMed1988

Fiberoptic nasopharyngolaryngoscopy: a procedure for allergists?

Fiberoptic endoscopy of the nose is not essential for routine evaluation of allergic rhinitis when the allergist is skilled in performing a thorough speculum examination. However, it is useful in the diagnosis of nasal polyps, malformations, tumors, and foreign bodies; when severe septal deviation or small nasal valves preclude good visualization; and in assessment of adenoid size in small children when lateral neck radiographs are inconclusive and digital examination is unacceptable.

Airway Obstruction↗