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Biomedical subjects

D Barber

Publications and source records attributed to D Barber.

At least 19 recordsLinked to original sources
PubMed1999

Lipid-transfer proteins are relevant allergens in fruit allergy.

BACKGROUND: Allergy to apple and Prunus fruits is frequently associated with birch pollinosis, with the principal cross-reacting allergens involved being members of the Bet v 1 family. However, a major 13-kd component, nonimmunologically related to Bet v 1, has been implicated as allergen in patients allergic to Prunoideae fruit but not to birch pollen. OBJECTIVE: We sought to isolate and characterize the 13-kd allergen present in apple and peach. METHODS: Sera from patients allergic to both fruits were selected on the basis of clinical symptoms, skin prick tests responses, and specific IgE levels. Allergens were purified by reverse-phase HPLC and characterized by N-terminal amino acid sequencing, MALDI analysis, specific IgE immunodetection, and immunoblot inhibition assays. RESULTS: A 13-kd protein band was recognized in crude apple and peach extracts by 9 of 10 and 10 of 10 sera from patients allergic to fruit, respectively. The isolation and characterization of the corresponding allergens allowed their identification as lipid-transfer proteins, with a molecular mass of 9058 d for the apple protein and 9138 d for the peach protein. Both purified allergens were recognized by sera from patients allergic to fruit and fully inhibited the IgE binding by the 13-kd component present in the 2 crude fruit extracts. CONCLUSION: Lipid-transfer proteins are relevant apple and peach allergens and, considering their ubiquitous distribution in tissues of many plant species, could be a novel type of panallergen of fruits and vegetables.

Adult↗
PubMed1999

Comparison of two in vitro activation systems for protoxicant organophosphorous esterase inhibitors.

In order to perform in vitro testing of esterase inhibition caused by organophosphorous (OP) protoxicants, simple, reliable methods are needed to convert protoxicants to their esterase-inhibiting forms. Incubation of parathion or chlorpyrifos with 0.05% bromine solution or uninduced rat liver microsomes (RLM) resulted in production of the corresponding oxygen analogs of these OP compounds and markedly increased esterase inhibition in SH-SY5Y human neuroblastoma cells. Neither activation system affected cell viability or the activity of AChE or NTE in the absence of OP compounds. Although parathion and chlorpyrifos were activated by RLM, bromine activation required fewer steps and produced more esterase inhibition for a given concentration of chlorpyrifos. However, RLM activation of OP protoxicants produced metabolites other than oxygen analogs and may, therefore, be more relevant as a surrogate for OP biotransformation in vivo. This methodology makes the use of intact cells for in vitro testing of esterase inhibition caused by protoxicant organophosphate compounds a viable alternative to in vivo tests.

Animals↗
PubMed1998

Online learning from finite training sets and robustness to input bias.

We analyze online gradient descent learning from finite training sets at noninfinitesimal learning rates eta. Exact results are obtained for the time-dependent generalization error of a simple model system: a linear network with a large number of weights N, trained on p = alphaN examples. This allows us to study in detail the effects of finite training set size alpha on, for example, the optimal choice of learning rate eta. We also compare online and offline learning, for respective optimal settings of eta at given final learning time. Online learning turns out to be much more robust to input bias and actually outperforms offline learning when such bias is present; for unbiased inputs, online and offline learning perform almost equally well.

Learning↗
PubMed1998

Use of a live attenuated varicella vaccine to boost varicella-specific immune responses in seropositive people 55 years of age and older: duration of booster effect.

Varicella-zoster virus (VZV)-specific T cell immunity was measured in 130 persons > or = 55 years of age 6 years after they received a live attenuated VZV vaccine. Circulating T cells, which proliferated in vitro in response to VZV antigen, were enumerated (VZV responder cell frequency assay). Six years after the booster vaccination, the VZV-responding cell frequency (1/61,000 circulating cells) was still significantly (P < .05) improved over the baseline measurements (1/70,000) and appears to have diminished the expected decline in frequency as these vaccinees aged (to 1/86,000). Ten herpes-zoster--like clinical events were recorded. Although the frequency of these events, approximately 1/100 patient-years, is within the expected range of such events for this age cohort, the number of lesions was small, there was very little pain, and there was no postherpetic neuralgia. These results support the development of a vaccine to prevent or attenuate herpes zoster.

Aged↗
PubMed1998

A logical stepwise approach to laser diffraction particle size distribution analysis methods development and validation.

In this study, a logical, stepwise, efficient approach was used to develop and validate particle size distribution analysis methods for 58 different pharmaceutical bulk powders in a timely fashion. Image analysis was used to determine particle morphology and laser diffraction particle size distribution analysis was used to evaluate the dispersion medium, dispersion concentration, sonication time, and dispersion stability. Ruggedness validation was performed, by two different analysis, on different days, with different instruments on two preparations each of two different lots of material. It was determined that if the relative standard deviation (RSD) of the median volume diameters (d50) of the four preparations for each lot was below 20%, the method was suitably rugged for use in a quality control setting. Data for methyldopa, metoprolol tartrate, and metronidazole are presented as typical method validation results for three different modes of analysis. Data at three points (d10, d50, and d90) on the distributions were tabulated and evaluated for all 58 methods validated. The median volume diameter (d50) was found to be adequate for method validation. The approach rapidly generated valid, reproducible particle size distribution analysis methodology.

Chemistry, Pharmaceutical↗
PubMed1998

Detection of microscopic neuroblastoma in marrow by histology, immunocytology, and reverse transcription-PCR of multiple molecular markers.

We explored the use of multiple molecular markers to overcome tumor heterogeneity. Sixty-seven neuroblastoma (NB) tumors were tested for the expression of GAGE, MAGE-1, MAGE-2, MAGE-3, and MAGE-4 by reverse transcription-PCR. Eighty-two percent of 67 NB tumors had detectable GAGE, and 88% expressed at least one of the four MAGE genes. By combining GAGE and MAGE, we found that 64 of 67 (95%) of tumors became detectable and 17 of 67 coexpressed all five molecular markers. Neither GAGE nor MAGE expression correlated with stage. GAGE was found to have the broadest (18 of 18) expression among stage 4 tumors. A total of 259 bone marrows from 99 patients were then studied for NB positivity by four detection methods: histology (aspirate by Wright-Giemsa and biopsy by H&E staining), immunocytology (by a panel of anti-GD2 monoclonal antibodies), and molecular detection by GAGE and tyrosine hydroxylase mRNA. Two hundred seven samples were NB positive by one or more detection methods. All four techniques were comparable in detecting tumor cells at diagnosis. GAGE and immunocytology were more sensitive than histology or tyrosine hydroxylase reverse transcription-PCR when marrows were obtained from patients on therapy or off therapy during clinical remission. Agreement among tests was highest at the time of gross disease. We conclude that, by combining multiple molecular markers and independent screening techniques, we may be able to overcome tumor heterogeneity and expedite the detection of microscopic disease in the clinical management of NB.

Antigens, Neoplasm↗
PubMed1997

Anaphylaxis after ingestion of wheat flour contaminated with mites.

BACKGROUND: Anaphylaxis after ingestion of flours contaminated with mites has been recently reported. OBJECTIVE: The study was designed to determine whether four-induced reactions in the absence of food sensitivity may result from mite contamination. METHODS: Patients with systemic reactions after ingestion of foods containing wheat flour and without food sensitivities were included in a prospective study. The flours were examined microscopically, and major Dermatophagoides allergens were quantified by monoclonal antibody techniques. Skin prick tests and IgE determinations to mites and flours were performed. Single-blind, placebo-controlled oral challenges were also performed. RESULTS: Sixteen patients were included in our protocol. They showed respiratory allergies to dust mites (100%) and intolerance to acetylsalicylic acid (87%). Microscopic examination of four flours implicated in allergic reactions revealed a high degree of mite contamination: Dermatophagoides farinae in one case and Thyreophagus entomophagus in three cases. Our patients' skin test and specific IgE responses to the flours implicated in the reactions were positive. A high level of Der 2 was found in the flour infested by D. farinae. Three of six food challenges with contaminated flours resulted in systemic reactions. Good tolerance to control flours was shown in our patients. CONCLUSION: Ingestion of foods contaminated with mites may induce systemic anaphylactic reactions in patients with respiratory allergy to mites.

Adolescent↗
PubMed1997

The physiology and pharmacology of pain: a review of opioids.

Patients in the postoperative period are often inadequately medicated for pain. Appropriate nursing assessment and intervention is critical for controlling a patient's pain and preventing associated complications. Nurses must understand the physiology of pain and the pharmacology of the drugs used. This article reviews the physiology of pain and the pharmacology of opioids. The three classes of opioids-opioid agonists, opioid agonist-antagonists, and opioid antagonists-are examined in detail. Included in the discussion are opioid receptor interaction with the various agents, dosages administration, and side effects.

Analgesics, Opioid↗
PubMed1997

Group 5 determination in Pooideae grass pollen extracts by monoclonal antibody-based ELISA. Correlation with biologic activity.

A solid-phase, monoclonal antibody-based ELISA was set up to quantitate group 5 allergens in pollen extracts of wild and cultivated Pooideae grasses. The method was able to evaluate group 5 concentration in mass units with a sensitivity in the ng/ml range and a practical working range of 1-100 ng/ml. The group 5 ELISA was compared with rocket immunoelectrophoresis for determination of allergen levels in several Phleum pratense extracts, and a very good quantitative correlation was found (r = 0.98; P < 0.0001). A highly significant correlation (r > 0.8) was also obtained in comparing allergenic potency determined by RAST inhibition to group 5 content in several wild and cultivated grass species. The results proved the usefulness of the method in the standardization of Pooideae pollen extracts employed in diagnosis and treatment.

Allergens↗
PubMed1997

Pollinosis due to Australian pine (Casuarina): an aerobiologic and clinical study in southern Spain.

An aerobiologic and clinical survey was conducted in Málaga, southern Spain, in order to determine fluctuations of Australian pine (Casuarina) pollen in the atmosphere of the city, and the prevalence of sensitivity in a nonatopic population. The aerobiologic survey, using a Burkard spore trap, was conducted from January 1991 to December 1994, and sensitization was ascertained by the skin prick test. The pollen season is relatively short and the pollen dispersion period occurs during October and November, mainly during the last 3 weeks of October. Diurnal patterns showed that the highest concentrations of pollen occur between 12 a.m. and 2 p.m., the most influential variables in its dispersion being temperature, sunshine, and rainfall. The prevalence of sensitization to Casuarina pollen was determined by skin prick test (SPT) in a nonatopic population of 210 patients with a previous history of autumn rhinitis, asthma, or rhinitis asthma. Six subjects showed a positive reaction to the pollen extracts, and the presence of specific IgE was demonstrated by the conventional radioallergosorbent test (RAST > or = 2) in five of these patients with positive SPT.

Adolescent↗
PubMed1997

Mutation in the Jak kinase JH2 domain hyperactivates Drosophila and mammalian Jak-Stat pathways.

The Jak (Janus) family of nonreceptor tyrosine kinases plays a critical role in cytokine signal transduction pathways. In Drosophila melanogaster, the dominant hop(Tum-l) mutation in the Hop Jak kinase causes leukemia-like and other developmental defects. Previous studies have suggested that the Hop(Tum-l) protein might be a hyperactive kinase. Here, we report on the new dominant mutation hop(T42), which causes abnormalities that are similar to but more extreme than those caused by hop(Tum-l). We determined that Hop(T42) contains a glutamic acid-to-lysine substitution at amino acid residue 695 (E695K). This residue occurs in the JH2 (kinase-like) domain and is conserved among all Jak family members. We determined that Hop(Tum-1) and Hop(T42) both hyperphosphorylated and hyperactivated D-Stat when overexpressed in Drosophila cells. Moreover, we found that the hop(T42) phenotype was partially rescued by a reduction of wild-type D-stat activity. Finally, generation of the corresponding E695K mutation in murine Jak2 resulted in increased autophosphorylation and increased activation of Stat5 in COS cells. These results demonstrate that the mutant Hop proteins do indeed have increased tyrosine kinase activity, that the mutations hyperactivate the Hop-D-Stat pathway, and that Drosophila is a relevant system for the functional dissection of mammalian Jak-Stat pathways. Finally, we propose a model for the role of the Hop-D-Stat pathway in Drosophila hematopoiesis.

Amino Acid Sequence↗
PubMed1997

Research into the role of fertility nurses for the development of guidelines for clinical practice.

The Fertility Nurses Group (FNG) celebrates its 10th anniversary this year after a decade of many exciting developments. The pioneers of the FNG believed that professional advice and support were needed for nurses developing their roles within a dynamic and rapidly advancing field with new clinical and scientific techniques which also brought challenging moral dilemmas. A specialist membership group was therefore established with the Royal College of Nursing (RCN). One of the first tasks was to investigate the educational requirements of infertility nurses and assess the professional and ethical issues raised by nurses caring for infertile patients. The results of this were published in the first 'professional survey'. A decade later the FNG undertook further research into the scope of clinical practice and the working conditions of its membership. Members of the group directly involved with the provision of fertility treatment, from ovulation induction to in-vitro fertilization, were surveyed. A questionnaire was circulated which aimed to: (i) assess the roles, skill and working patterns of nurses working in infertility units; (ii) identify the training needs of nurses and the management and educational provision required to support this. Further research will also be undertaken to explore issues related to the extended role of fertility nurses and its relevance to the UK Central Council guidelines on clinical nurse specialists and advance nurse practitioners. The results of the forthcoming research studies will provide data to assist with: (i) the development of guidelines for clinical practice; and (ii) continued development of appropriate educational programmes for fertility nurses.

Infertility↗
PubMed1996

Specific depletion of the house dust mite allergen Der p 1 cereal flour prolamins.

BACKGROUND: Quantitation of Der 1 and Der 2 in dust samples by specific monoclonal antibodies is a method used increasingly to evaluate mite allergen exposure. The level of Der 1 has been proposed as a risk factor for sensitization. AIM: We report a drastic decrease in the Der 1/Der 2 ratio when dust samples are collected in bakeries. METHODS: Wheat flour and purified mites were extracted simultaneously; levels of Der p 1 and Der p 2 and cysteine protease activity were determined by ELISA and inhibition experiments. RESULTS: High titers of Der 2, but only trace amounts of Der p 1, were detected in dust collected from bakeries. Both the level and proteolytic activity of Der p 1 appeared greatly decreased when mites and wheat flour were coextracted. CONCLUSION: Group 1 protein was found to be masked by flour components, resulting in an underestimation of the mite content in bakery dust. This problem was not found for group 2 allergen.

Allergens↗
PubMed1996

Nurses performing embryo transfer: successful outcome of in-vitro fertilization.

This prospective study demonstrates the feasibility and outcome of embryo transfer performed by nursing staff with medical cover available. Of 771 patients who had embryo transfer, 679 (88%) had their embryo transfer performed by a nurse. In 92 cases (12%) a doctor performed the embryo transfer, either as the first operator, or having been brought in to assist the nurse who experienced difficulty. The pregnancies per transfer for nurse transfer was 246/679 (36%) and where a doctor performed the transfer 20/68 (29%). These data show a high comparable success rate when a nurse performed the embryo transfer, and a low incidence of direct medical involvement.

Embryo Transfer↗
PubMed1996

Interaction of allergens from house-dust mite and from cereal flours: Dermatophagoides pteronyssinus alpha-amylase (Der p 4) and wheat and rye alpha-amylase inhibitors.

Major wheat and rye allergens associated with baker's asthma have been identified as specific inhibitors of Dermatophagoides pteronyssinus alpha-amylase (Der p 4). the most active inhibitors were the wheat tetrameric one and the rye dimeric RDAI-1. these data suggest that interaction between mite and cereal allergens (alpha-amylase/inhibitor complexes) might occur in house-dust-mite-infected flours. In contrast to the strong inhibition of the d. pteronyssinus enzyme by the wheat and rye inhibitors, the amylases from D. farinae, Lepidoglyphus destructor, and Tyrophagus putrescentiae were much less affected. Moreover, the D. pteronyssinus amylase showed higher pH optimum (6.5 versus 5.0) and activity level (2-6 times/mg of protein in whole-mite extracts) than those from the three other mite species.

Allergens↗