Biomedical subjects
Publications and source records attributed to C A Ryan.
A child with respiratory distress was found to have been given an antibiotic which was reconstituted with methadone. A delay in standard emergency room management led to a delay in diagnosis and treatment.
Draining lymph node cells isolated from mice 48 h after topical exposure to tetrachlorosalicylanilide (TCSA) + UVA radiation (TCSA + UVA) demonstrated a two-fivefold increase in the number of dendritic cells (DC) compared with control mice treated with vehicle + UVA. The increase in number of DC was both time and dose dependent, with the peak DC accumulation occurring at 48 h post application and at a TCSA dose of 1.0%. Photospecificity was evident in that mice irradiated prior to treatment with TCSA (UVA/TCSA) demonstrated no significant increase in DC accumulation. The accumulation of DC was followed by a significant increase in total lymph node cellularity. An in situ 3H-thymidine incorporation assay showed a significant increase in proliferative activity of cells isolated from the draining lymph nodes of mice treated with TCSA + UVA as compared to naive, vehicle, or UVA/TCSA-treated mice. Dendritic cells isolated from mice treated 24 h earlier with TCSA + UVA, but not those from naive mice or mice treated with UVA/TCSA, were capable of TCSA-specific antigen presentation. Responder lymphocytes from untreated mice or mice photosensitized with musk ambrette showed a much lower response to DC isolated from TCSA + UVA-treated mice, demonstrating the specificity of the reaction. DC-depleted lymph node cells were unable to stimulate this blastogenesis response. These results suggest that application and photoactivation of TCSA induces cellular and functional changes in the lymph node DC indicative of their involvement in the induction phase of a contact photoallergic reaction.
We describe four children who died of suffocation by rubber balloons in Canada between 1983 and 1988. In the United States, at least 121 children have died in a similar manner in the 15 years between 1973 and 1988 according to a report by the US Consumer Product Safety Commission. Although the highest mortality occurred among infants, 30 (25%) of the 121 deaths occurred in children 6 years of age or older. Balloons account for 43% of the approximately 15 childhood deaths related to children's products that are documented each year by the Consumer Product Safety Commission. Toy rubber balloons are thus the leading cause of pediatric choking deaths from children's products. Preventive efforts should be directed toward a ban on this type of balloon and the development of safer alternatives. Meanwhile, public information campaigns should alert parents, physicians, and policymakers to the dangers of toy rubber balloons.
Expression of a chimeric potato Inhibitor II-CAT gene in transgenic tobacco plants was enhanced 50-fold when leaf tissue was floated on solutions containing 1% sucrose. The expression of the chimeric gene was also enhanced when leaf sections were floated on solutions of glucose, fructose, and maltose, but not when floated on solutions of mannitol. The increased expression due to sucrose was found to be correlated with an increase in CAT mRNA. Thus, the carbohydrates or their metabolic products may control Inhibitor II gene expression by regulating transcription. Levels of potato Inhibitor II proteins in leaf sections from young potato plants floated on 3% sucrose solutions increased 3-fold compared to leaf sections floated on water, supporting the possibility that sucrose may have a role in regulating or enhancing the expression of wound-inducible proteinase inhibitor genes in potato tissues. It is suggested that the Inhibitor II gene and perhaps other genes regulated by sucrose may contain a specific 'sucrose enhancer' that strongly increases transcription of genes already active at low levels.
A wound-inducible proteinase Inhibitor I gene from tomato containing 725 bp of the 5' region and 2.5 kbp of the 3' region was stably incorporated into the genome of black nightshade plants (Solanum nigrum) using an Agrobacterium Ti plasmid-derived vector. Transgenic nightshade plants were selected that expressed the tomato Inhibitor I protein in leaf tissue. The leaves of the plants contained constitutive levels of the inhibitor protein of up to 60 micrograms/g tissue. These levels increased by a factor of about two in response to severe wounding. Only leaves and petioles exhibited the presence of the inhibitor, indicating that the gene exhibited the same tissue specificity of expression found in situ in wounded tomato leaves. Inhibitor I was extracted from leaves of wounded transformed nightshade plants and was partially purified by affinity chromatography on a chymotrypsin-Sepharose column. The affinity-purified protein was identical to the native tomato Inhibitor I in its immunological reactivity and in its inhibitory activity against chymotrypsin. The protein exhibited the same Mr of 8 kDa as the native tomato Inhibitor I and its N-terminal amino acid sequence was identical to that of the native tomato inhibitor I, indicating that the protein was properly processed in nightshade plants. These experiments are the first report of the expression of a member of the wound-inducible tomato Inhibitor I gene family in transgenic plants. The results demonstrate that the gene contains elements that can be regulated in a wound-inducible, tissue-specific manner in nightshade plants.
A 6-month-old infant developed a left ventricular thrombus in association with low antithrombin-III activity following the repair of a truncus arteriosus. Conservative management was associated with spontaneous resolution of the clot. The significance of this association is discussed.
The effect of a proteinase inhibitor extracted from potatoes (POT II) which increases CCK release, on food intake was examined in 11 lean subjects. They received 1.5 g POT II in a high-protein soup vehicle (70 kcal), the soup vehicle alone, or a no-soup control five minutes before being presented with a lunchtime test meal, according to a double-blind, within-subjects design. Consuming the soup alone led to a nonsignificant 3% reduction in energy intake. The addition of 1.5 g POT II to the soup significantly reduced energy intake by a further 17.5%. Premeal ratings of motivation to eat and food preferences did not predict the reduction in energy intake by the proteinase inhibitor. These findings suggest that endogenous CCK may be important in the control of food intake and that proteinase inhibition may have therapeutic potential for reducing food intake.
The photoallergic potential of various compounds was assessed using a mouse ear-swelling model, which offers the advantage of being quantifiable and more objective than models based on subjective evaluation of erythematous skin reactions. Cyclophosphamide pretreated BALB/c mice were induced by topical treatment of the dorsal skin surface on 3 consecutive days and challenged on the ears 5 days after the last induction. For each induction and challenge treatment, mice were consecutively irradiated with ultraviolet (UV) A (10 J/cm2) and UVB (45 mJ/cm2) radiation 30 min to 1 hr after test material application. The photoallergic response to musk ambrette, a known human photoallergen, was significantly augmented when three consecutive induction exposures were used as compared with one or two inductions. The photoallergic potential of nine other known human photoallergens (tetrachlorosalicylanilide, bithionol, 6-methylcoumarin, chlorpromazine, sodium omadine, bisphenol A, sulphanilamide, fentichlor and p-aminobenzoic acid) was successfully detected using the mouse model. In each experiment, the ear thickness changes observed in the photoallergy test mice were significantly greater than the changes observed in the contact allergy, vehicle/radiation and phototoxicity control mice. Coumarin and homosalate, two agents not traditionally associated with causing photoallergy in humans or animals, did not demonstrate contact photoallergy using this model. With three of the photoallergens, musk ambrette, bithionol and tetrachlorosalicylanilide, the ear swelling response obtained was due to photoallergy alone and not due to the co-existence of both contact photoallergy and contact allergy. In addition, irradiating mice 24 hr, rather than 1 hr, following application of the test material during the induction phase resulted in a significantly reduced photoallergic response with both musk ambrette and tetrachlorosalicylanilide. These results indicate that the mouse ear-swelling model is a potentially useful model for investigative and predictive photoallergy testing.
An ELISA was developed to detect specific IgE antibody to the Bacillus subtilis-derived proteolytic detergent enzyme, subtilisin A (Alcalase), in sera from exposed detergent workers. Workers in the detergent industry are exposed via inhalation to low levels of the enzyme dust in the presence of detergent dust. Chemically inactivated Alcalase was used as the test antigen. Significant binding of IgE antibody to the immobilized enzyme was detected in the ELISA. The binding of allergic antibody to Alcalase was specifically inhibited in a dose-dependent manner by preincubating sera with 0.1 to 100 micrograms of inactivated Alcalase. Binding of IgE antibody to Alcalase could not be inhibited by two other inactivated bacterial proteases, Savinase and Esperase, derived from different Bacillus species. ELISA and skin test results demonstrated total agreement for 27 of 31 samples (87%), whereas RAST and skin test results demonstrated total agreement for only 24 of 31 samples (77%), indicating that the ELISA was more sensitive than the RAST. We conclude that the ELISA is a sensitive, fast, alternative to the RAST for detection of Alcalase-specific IgE antibody in detergent enzyme-exposed workers.
Inducible defensive responses in plants are known to be activated locally and systemically by signaling molecules that are produced at sites of pathogen or insect attacks, but only one chemical signal, ethylene, is known to travel through the atmosphere to activate plant defensive genes. Methyl jasmonate, a common plant secondary compound, when applied to surfaces of tomato plants, induces the synthesis of defensive proteinase inhibitor proteins in the treated plants and in nearby plants as well. The presence of methyl jasmonate in the atmosphere of chambers containing plants from three species of two families, Solanaceae and Fabaceae, results in the accumulation of proteinase inhibitors in leaves of all three species. When sagebrush, Artemisia tridentata, a plant shown to possess methyl jasmonate in leaf surface structures, is incubated in chambers with tomato plants, proteinase inhibitor accumulation is induced in the tomato leaves, demonstrating that interplant communication can occur from leaves of one species of plant to leaves of another species to activate the expression of defensive genes.
Deletion analysis from the 3' to the 5' end of the promoter region of the wound-inducible potato proteinase inhibitor IIK gene has identified a 421-base sequence at -136 to -557 that is necessary for expression. Utilizing DNA band-shift assays, a 10-base sequence within the 421-base region was found to bind a nuclear protein from wounded tomato leaves. This 10-base sequence is adjacent to an 8-base consensus sequence at -147 to -155 that is present in the promoter region of several elicitor-inducible genes from various other plants. The evidence suggests that a complex set of cis- and trans-acting elements within the -136 to -165 region of the potato IIK gene may be involved with the signaling mechanisms that regulate the inducibility of this gene in response to pest and pathogen attacks.
The development of a contact photoallergic response in animals or humans requires irradiation of the test material. Since consumers are exposed to both UVB and UVA radiation following the use of topically applied products, we have developed a mouse ear swelling photoallergy model for the screening of potential photoallergens. This model incorporates the use of UVB, as well as UVA, radiation for the induction and elicitation phases of the photoallergic response. In this report, we show that the use of a 10 J/cm2 UVA and 45 mJ/cm2 UVB dose regimen during both the induction and elicitation phases results in an augmented photoallergic response to 6-methylcoumarin as compared with the responses of mice treated with 6-methylcoumarin and irradiated with UVA or UVB alone or UVA plus UVB radiation for induction and then UVA or UVB radiation alone at challenge. Photoallergic responses to tetrachlorosalicylanilide and musk ambrette were neither augmented nor diminished by the use of UVB radiation at induction and challenge as compared with the use of UVA treatment alone. The non-photocontact allergic response to oxazolone was reduced approximately 25% when mice were treated with oxazolone plus UVB and UVA radiation as compared with mice treated with oxazolone alone. These results suggest that in screening a test material's photoallergic potential, UVB and UVA radiation should be included for both the induction and elicitation phases of the mouse ear swelling photoallergy protocol.
A novel member of the proteinase Inhibitor I family having a trypsin inhibitor specificity was isolated from the fruit of the wild tomato species Lycopersicon peruvianum (L.) Mill. (LA 107) and characterized. The protein is among the isoinhibitors of Inhibitor I that comprise 50% of the soluble proteins in the fruit of this wild species of tomato. A cDNA corresponding to the inhibitor protein and mRNA was isolated and characterized. The Inhibitor I mRNA represented 0.06% of the poly(A) RNA and gene copy number reconstruction experiments gave an estimate of two to four genes/haploid genome. The open reading frame of the cDNA codes for a protein of 111 amino acids having a 42-amino acid prepropolypeptide. The NH2-terminal sequence of the first 21 amino acids of the purified Inhibitor I protein confirmed that the cDNA was identical to the protein. The amino acid sequence of the L. peruvianum fruit Inhibitor I exhibits 74% identity with the wound-inducible Inhibitor I from tomato leaves. Whereas all previously identified members of the Inhibitor I family have either Met, Leu, or Asp at the P1 site and can inhibit enzymes such as chymotrypsin, subtilisin, and elastase, the fruit Inhibitor I possesses Lys at the P1 position. Thus, this is the first member of the extensive Inhibitor I family from plants and animals that exhibits trypsin inhibitory specificity. The presence of this inhibitor in wild tomato fruit may reflect a functional role to protect the tissues against herbivory.
A low molecular weight protein inhibitor of serine proteinases from Russet Burbank potato tubers, polypeptide chymotrypsin inhibitor-1 (PCI-1), has been crystallized in complex with Streptomyces griseus proteinase B (SGPB). The three-dimensional structure of the complex has been solved at 2.1 A resolution by the molecular replacement method and has been refined to a final R-factor (= sigma[[Fo[-[Fc[[/sigma[Fo[) of 0.142 (8.0 to 2.1 A resolution data). The reactive site bond of PCI-1 (Leu38I to Asn39I) is intact in the complex, and there is no significant distortion of the peptide from planarity. The distance between the active site serine O gamma of SGPB and the carbonyl carbon of the scissile bond of PCI-1 is 2.8 A (1 A = 0.1 nm). The inhibitor has little secondary structure, having a three-stranded antiparallel beta-sheet on the side opposite the reactive site and four beta-turns. PCI-1 has four disulphide bridges; these presumably take the place of extensive secondary structure in keeping the reactive site conformationally constrained. The pairing of the cystine residues, which had not been characterized chemically, is as follows: Cys3I to Cys40I, Cys6I to Cys24I, Cys7I to Cys36I, and Cys13I to Cys49I. The molecular structure of SGPB in the PCI-1 complex agrees closely with the structure of SGPB complexed with the third domain of the turkey ovomucoid inhibitor (OMTKY3). A least-squares overlap of all atoms in SGPB gives a root-mean-square difference of 0.37 A. One of the loops of SGPB (Ser35 to Gly40) differs in conformation in the two complexes by more than 2.0 A root-mean-square for the main-chain atoms. Thr39 displays the largest differences with the carbonyl carbon atom deviating by 3.6 A. This conformational alternative is a result of the differences in the molecular structures of the P'4 residues following the reactive site bonds of the two inhibitors. This displacement avoids a close contact (1.3 A) between the carbonyl oxygen of Ser38 of SGPB and Pro42I C beta of PCI-1. The solvent structure of the PCI-1-SGPB complex includes 179 waters, two sulphate or phosphate ions, and one calcium or potassium ion, which appears to play a role in crystal formation. The molecular structure of PCI-1 determined here has allowed the proposal of a model for the structure of a two-domain inhibitor from potatoes and tomatoes, inhibitor II.(ABSTRACT TRUNCATED AT 400 WORDS)
A prospective, randomized, cross-over trial was performed to compare the efficacy of nasal intermittent positive-pressure ventilation with nasal continuous positive airway pressure in infants of less than 32 weeks of gestation. Continuous positive airway pressure was delivered at end-expiratory pressures of 4 cm H2O, while peak pressures of 20 cm H2O and end-expiratory pressures of 4 cm H2O were used during nasal intermittent positive-pressure ventilation at ventilatory rates of 20 breaths per minute. The frequency and extent of apnea and bradycardia during a 6-hour period in a patient receiving nasal continuous positive airway pressure were compared with a similar crossover period of nasal intermittent positive-pressure ventilation. Although the infants had slightly less frequent episodes of apnea per hour (0.6 +/- 0.7 vs 0.5 +/- 0.7) and bradycardia per hour (1.2 +/- 1.3 vs 0.9 +/- 1.0) during nasal intermittent positive-pressure ventilation, these differences were not significant. There were no significant differences in the severity of these events as assessed by the duration and fall in transcutaneous oxygen pressure during apnea and heart rate during bradycardia. There were no significant changes in blood gases throughout the study. Nasal intermittent positive-pressure ventilation appears to have no advantages over nasal continuous positive airway pressure in preventing apnea and does not alter gas exchange in infants of less than 32 weeks of gestation.
Recent evidence indicates that the presence of serine proteinase inhibitors in plant leaves can reduce predation by insects. Plants can now be transformed with proteinase inhibitor genes with strong promoters to express the inhibitor proteins in relatively high levels at specific times. Inhibitors having variable specificities against digestive proteinases of insects and pathogens can now be assessed for their possible role(s) in natural plant defense and for their potential usefulness in protecting crop plants against herbivores.
Patients with the Beckwith-Wiedemann (B-W) syndrome have been reported to have an increased risk of congenital heart disease and of idiopathic cardiomegaly on chest x-ray. In the infant described here, reversible obstructive hypertrophic cardiomyopathy was documented and its relationship to the metabolic features of the B-W syndrome is discussed.
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