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D R Hoffman

Publications and source records attributed to D R Hoffman.

At least 37 records · Page 2Linked to original sources
PubMed1997

Purification of a major allergen, Asp f 2 binding to IgE in allergic bronchopulmonary aspergillosis, from culture filtrate of Aspergillus fumigatus.

BACKGROUND: Most cases of allergic bronchopulmonary aspergillosis (ABPA) are caused by the fungus Aspergillus fumigatus. Successful treatment of this disease depends on early diagnosis with the use of well-characterized and relevant antigens/allergens of the organism. OBJECTIVE: The aim of this study was to purify and characterize relevant proteins from A. fumigatus that could be used in the reliable diagnosis of ABPA. METHODS: Monoclonal antibodies were raised against A. fumigatus culture filtrate antigens. A Concanavalin A nonbinding protein fraction was purified with use of one of the monoclonal antibody immunoaffinity columns. The purified protein was analyzed on sodium dodecylsulfate-polyacrylamide gel electrophoresis gel and Western blots. The sensitivity and specificity of the purified protein were evaluated by RAST and ELISA with sera from 25 patients with ABPA, from 10 with allergic asthma, and from 10 normal control subjects. RESULTS: The 37 kD Concanavalin A nonbinding protein reacted specifically with IgE antibodies in patients with ABPA. Among the 25 patients with ABPA studied, 96% had IgE antibody against the allergen, whereas none of the subjects with allergic asthma who had positive results on the skin prick test or normal control subjects had a reaction. Both RAST and ELISA results exhibited strong correlation with IgE binding. This allergen exhibited N-terminal sequence identity to a recombinant allergen Asp f 2. CONCLUSIONS: A 37 kD protein with complete N-terminal homology to Asp f 2 is a major allergen of A. fumigatus that significantly reacts with IgE antibody in patients with ABPA, but does not elicit reaction in Aspergillus-sensitive subjects with asthma and normal control subjects.

Allergens↗
PubMed1997

Spectrum of mutations in the RPGR gene that are identified in 20% of families with X-linked retinitis pigmentosa.

The RPGR (retinitis pigmentosa GTPase regulator) gene for RP3, the most frequent genetic subtype of X-linked retinitis pigmentosa (XLRP), has been shown to be mutated in 10%-15% of European XLRP patients. We have examined the RPGR gene for mutations in a cohort of 80 affected males from apparently unrelated XLRP families, by direct sequencing of the PCR-amplified products from the genomic DNA. Fifteen different putative disease-causing mutations were identified in 17 of the 80 families; these include four nonsense mutations, one missense mutation, six microdeletions, and four intronic-sequence substitutions resulting in splice defects. Most of the mutations were detected in the conserved N-terminal region of the RPGR protein, containing tandem repeats homologous to those present in the RCC-1 protein (a guanine nucleotide-exchange factor for Ran-GTPase). Our results indicate that mutations either in as yet uncharacterized sequences of the RPGR gene or in another gene located in its vicinity may be a more frequent cause of XLRP. The reported studies will be beneficial in establishing genotype-phenotype correlations and should lead to further investigations seeking to understand the mechanism of disease pathogenesis.

Carrier Proteins↗
PubMed1997

The federal effort to eliminate fraud and ensure quality care.

In 1996, the United States filed a lawsuit against a nursing home that it alleged was providing inadequate nutrition and wound care to residents, despite the fact that the facility had submitted claims to Medicare and Medicaid for payment for nutrition services. The lawsuit alleged that these submissions for payment violated the False Claims Act. This was the first time the False Claims Act was used to enforce quality-of-care standards set by Congress in the Nursing Home Reform Act. A federal prosecutor involved in the case discusses the steps leading up to the lawsuit and the details of the settlement.

Financing, Government↗
PubMed1996

Cloning and characterization of Ancylostoma-secreted protein. A novel protein associated with the transition to parasitism by infective hookworm larvae.

The developmentally arrested third stage infective larva of hookworms resumes development upon entry into the definitive host. This transition to parasitism can be modeled in vitro by stimulating infective larvae with a low molecular weight ultrafiltrate of host serum together with methylated glutathione analogues. When stimulated to resume development in vitro, activated larvae of the hookworm Ancylostoma caninum released a 42-kDa protein, termed Ancylostoma-secreted protein (ASP). ASP was the major protein released by activated hookworm larvae. Degenerate oligonucleotide primers, based on a partial internal amino acid sequence of the protein, were used together with flanking vector sequence primers to amplify a fragment from a third stage larval cDNA library by polymerase chain reaction. The fragment was used as a probe to isolate a longer clone from the larval cDNA library. The full-length ASP cDNA was found to encode a 424-amino acid protein with homology to the antigen 5/antigen 3 family of proteins from hymenopteran venoms and a family of cysteine-rich secretory proteins. ASP was expressed in bacterial cells, and a polyclonal antiserum against purified recombinant ASP was produced. The antiserum, which was demonstrated to be specific for ASP, was used as a probe to measure the kinetics of ASP release by hookworm larvae. ASP is released within 30 min of stimulation, with the majority released by 4 h. Low levels of ASP were released continuously following activation, but only if the stimuli were present in the incubation medium. The compound 4,7-phenanthroline, previously shown to inhibit larval activation, also inhibited release of ASP. The specific, rapid release of ASP by activated infective larvae suggests that this molecule occupies a critical and central role in the transition from the external environment to parasitism.

Amino Acid Sequence↗
PubMed1996

Production of a recombinant imported fire ant venom allergen, Sol i 2, in native and immunoreactive form.

BACKGROUND: The complementary DNA encoding for the important imported fire ant venom allergen, Sol i 2, has previously been cloned. The binding of human IgE antibodies to Sol i 2 has been demonstrated to be conformation-dependent. METHODS: A couple cDNA clone encoding the Sol i 2 protein sequence and its natural signal sequence has been produced by polymerase chain reaction. The clone was ligated into a pBluebac III transfer vector (Invitrogen Corp., San Diego, Calif.), and the recombinant baculovirus was isolated by plaque purification. The recombinant baculovirus was grown in Sf9 and High-Five cells (Invitrogen Corp.) in serum-free media. The recombinant Sol i 2 was isolated and characterized. RESULTS: Recombinant (r) Sol i 2 was produced in microgram/per milliliter amounts in Sf9 cells and at 30 micrograms/ml in High-Five cells. It was isolated by ultrafiltration and reverse-phase chromatography. The rSol i 2 demonstrated similar binding to natural-Sol i 2 in both a conformation-dependent ELISA assay and in RAST with sera from patients allergic to Sol i 2. The N-terminal sequence of the rSol i 2 was identical to that of the natural molecule. No significant increase in binding activity was found after treatment of rSol i 2 with protein disulfide isomerase. The binding of rSol i 2 to a conformation-dependent monoclonal antibody was lost by heating in sodium dodecylsulfate and reduction. CONCLUSION: A recombinant Sol i 2 protein was produced at high yield in a baculovirus expression system by using serum-free medium with a sequence identical to that of the natural molecule. Conformation-dependent immunologic assays indicate that the recombinant protein is produced with the native conformation.

Allergens↗
PubMed1996

Allergens in Hymenoptera venom. XXVII: bumblebee venom allergy and allergens.

BACKGROUND: Allergic reactions to bumblebee stings are much less common than allergic reactions to honeybee stings. Preliminary studies suggest that there may be a high degree of cross-reactivity between honeybee and bumblebee venoms. OBJECTIVE: This study was done to determine the immunochemical and structural relationships between bumblebee and honeybee venom allergens. METHODS: Allergens were purified from bumblebee venom and compared immunochemically with sera from patients with allergy and hyperimmunized rabbits. The purified proteins were characterized, enzyme activities were measured, and the complete amino acid sequences of two proteins were determined. RESULTS: The venoms wer highly cross-reactive, consistent with the degree of structural similarity in the phospholipases. Hyaluronidases and acid phosphatases were also similar. Bumblebee venom contained several proteins not found in honeybee venom, including an interesting tryptic amidase related to clotting enzymes and acrosin. CONCLUSION: Skin testing with honeybee venom will detect almost all cases of bumblebee venom allergy, however; RAST with bumblebee venom can detect some additional cases.

Allergens↗
PubMed1996

Radiocephalometric evaluation of a family with mandibulofacial dysostosis.

Persons from four generations of a family with mandibulofacial dysostosis (MFD), known as Treacher Collins (TC) Syndrome, were examined for the presence of clinical signs traditionally associated with this syndrome. In this family, 14 adults, who had been judged trait bearers by an earlier family study were included in this study. Maxillary and mandibular study models were taken of affected and unaffected family members. Panoramic cephalograms and lateral radiographs were taken. The lateral cephalograms were traced and digitized on a computer system and compared. The 117 cephalometric values of the trait bearers were compared with known standard values and nontrait bearing family members. In the trait bearing group, 81 of the 117 values and, in the nontrait bearing group, 72 of the 117 values were significantly different (p < 0.05) when comparing mean values to the accepted normal range. The interfamily comparison between trait-bearing and nontrait members revealed nine values to be significantly different. This indicates that cephalometric analysis of these patients, some of whom have minimal clinical expression of the gene, may have potential value for screening and further characterization of this condition. The results also suggest that intrafamily comparisons may be of greater value for diagnostic confirmation of TC than comparison with literature norms.

Adult↗
PubMed1995

Characterization of a major latex allergen associated with hypersensitivity in spina bifida patients.

Hypersensitivity to latex proteins present in health care products, particularly in latex gloves, has emerged as an important public health problem in recent years. Most of these latex allergens have not been purified or characterized. Here we report the purification and characterization of a 23-kDa latex polypeptide from nonammoniated natural rubber latex. This purified 23-kDa polypeptide reacted with IgE from 13 of 17 (76%) latex-allergic spina bifida patients, but from only 1 of 5 health care workers with latex allergy. Furthermore, all the sera of patients with anaphylaxis to latex showed reactivity with the 23-kDa polypeptide. This allergen also induced significant lymphocyte proliferation by PBMC from spina bifida patients, but not from health care workers. The 90 amino acid residues sequenced from the 23-kDa polypeptide showed a 45.6% homology with a previously reported latex protein, rubber elongation factor. By using a mAb LAM-1, produced against the 23-kDa allergen, we could also detect this allergen or its epitope in ammoniated latex and natural rubber latex products used in health care management, but not in non-latex extracts studied.

Allergens↗
PubMed1995

Metabolism of omega-3 fatty acids in patients with autosomal dominant retinitis pigmentosa.

Abnormalities in lipid metabolism have been reported in numerous patients with retinitis pigmentosa. As an initial step in evaluating these anomalies, two trials of fatty acid intervention were conducted with autosomal dominant retinitis pigmentosa (adRP) patients and controls. The first trial addressed absorption and incorporation of omega 3 long-chain fatty acids from a fish-oil concentrate into red blood cell (RBC) lipids. The utilization of omega 3 long-chain fatty acids by adRP patients was found to be equivalent to that of controls. The second trial addressed the conversion of precursor, eicosapentaenoic acid (EPA, 20:5 omega 3), to end-product, docosahexaenoic acid (DHA, 22:6 omega 3), following oral supplementation of EPA ethyl ester. Although the levels of EPA and the intermediate, docosapentaenoic acid (22:5 omega 3), were both elevated by EPA supplementation in RBCs of adRP patients with rhodopsin gene mutations and controls, DHA production was elevated only in controls. Based on these results, we suggest the presence of a metabolic defect in the final stages of DHA biosynthesis.

Adult↗
PubMed1995

Laboratory evaluation of a commercial immunoassay for fire ant allergen-specific IgE antibodies.

BACKGROUND: In vitro testing for fire ant sensitization would be useful for research purposes and in special clinical situations. METHODS: Laboratory performance of a commercial assay (Pharmacia CAP System, [PCS]), for specific IgE to Solenopsis invicta whole body extract was studied in 46 persons. Assay results were compared with those of venom skin testing, RAST, and ELISA. The manufacturer's global cutoffs were compared with cutoffs set by using methods derived from analytical detection limit theory. RESULTS: Thirty-two study subjects had positive skin test results, and 14 had negative results. Raw PCS data demonstrated a high level of correlation with RAST (rho = 0.941) and ELISA (rho = 0.931), and showed good correlation with skin testing (rho = -0.769). Analysis of binormal receiver operating characteristic curves, using skin test results as the reference standard, demonstrated no difference in performance among the three assays. The fixed global quantitative cutoff of 0.35 kUa/L was relatively insensitive. Use of the manufacturer's qualitative alternate scoring method cutoff substantially increased sensitivity without loss of specificity, as did lower limit of detection set by use of diluent. CONCLUSIONS: In situations in which skin testing for fire ant sensitization is not feasible, PCS appears to be an acceptable in vitro alternative method for determination of fire ant allergen-specific IgE.

Allergens↗
PubMed1995

Lol p XI, a new major grass pollen allergen, is a member of a family of soybean trypsin inhibitor-related proteins.

BACKGROUND: Monoclonal antibodies were obtained against an unknown allergen from Lolium perenne grass pollen. The allergen had an apparent molecular mass of 18 kd on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Earlier immunoblotting studies had shown that carbohydrate-specific IgG antibodies recognize an antigen of similar size. OBJECTIVE: We sought to characterize the allergen biochemically and immunologically. METHODS: The amino acid sequence of the allergen was determined by automated Edman degradation, and its monosaccharide composition was determined by gas chromatographic analysis. A panel of 270 grass pollen-positive sera was assessed in a RAST with the purified allergen. Protease digestion (proteinase K) and chemical deglycosylation (trifluoromethane sulfonic acid) were used to distinguish between carbohydrate and peptide epitopes for IgE antibodies. RESULTS: The allergen was shown to be a glycoprotein with a molecular mass of 16 kd, of which 8% is carbohydrate. Its amino acid sequence shares 32% homology with soybean trypsin inhibitor (Kunitz) but lacks its active site. No homology was found with known grass pollen allergens, hence it was designated Lol p XI. A high degree of homology (44%) was found with a tree pollen allergen, Ole e I, the major allergen of olive pollen. More than 65% of grass pollen-positive sera had IgE against Lol p XI. IgE reactivity was demonstrated both with the carbohydrate moiety and the peptide backbone. CONCLUSIONS: Lol p XI is a new major grass pollen allergen carrying an IgE-binding carbohydrate determinant. Lol p XI is structurally related to the major allergen from olive pollen.

Allergens↗
PubMed1995

The natural history of exposure to the imported fire ant (Solenopsis invicta).

BACKGROUND: Imported fire ants (IFA) are a common cause of insect venom hypersensitivity in the southeastern United States. The purpose of this study was to determine the sting attack rate and development of specific IgE in an unsensitized population. METHODS: Study participants consisted of 137 medical students with limited exposure to IFA-endemic areas who were temporarily training in San Antonio, Tex. Subjects were surveyed for prior IFA exposure with a questionnaire, and IFA-specific IgE was evaluated with RAST and intradermal skin testing. Evaluations were performed on arrival and reported at departure from the endemic area 3 weeks later. RESULTS: One hundred seven subjects completed the study. Field stings were reported in 55 subjects, resulting in a sting attack rate of 51%. In these 55 subjects 53 (96%) reported a pustule or a small local reaction at the sting site, one (2%) reported an isolated large local reaction, and none reported a systemic reaction. At the 3-week follow-up skin test and RAST conversions occurred in seven subjects (13%) and in one subject (1.8%), respectively. CONCLUSIONS: Even brief exposures to IFA-endemic areas result in significant sting rates and concurrent rapid development of IFA-specific IgE in 16% of stung subjects.

Adult↗
PubMed1995

A new device for absolute anchorage for orthodontics.

A new device has been designed to provide anchorage for orthodontic tooth movement. It is a disk, textured and hydroxylapatite coated on one side, with an internal thread on the other side. It is placed on palatal bone and, after integration, can be connected to teeth for anchorage. This article reviews a dog study demonstrating unilateral tooth movement towards the "onplant" and a monkey study mimicking its use to anchor the molars for anterior retraction.

Alloys↗