Structural characterization of modified hemoglobins.
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Amino Acid Sequence↗
Biomedical subjects
R T Jones
Publications and source records attributed to R T Jones.
Extractable latex allergens and proteins in disposable medical gloves and other rubber products.
BACKGROUND: IgE-mediated sensitization to rubber proteins is being reported with increasing frequency in health care workers. To explore the relative importance of various sources of allergen exposure, we measured the total rubber allergen and protein levels in extracts of disposable rubber gloves and compared the allergen levels with those in extracts of other medical and consumer rubber products. METHODS: Rubber allergens were measured by inhibition immunoassay with a rubber glove extract as the solid-phase allergen and pooled plasma from five rubber-sensitized health care workers as the IgE antibody source. Proteins were measured by Ninhydrin assay. RESULTS: Among 71 lots of gloves tested, the extractable allergen and protein levels were significantly correlated and were appreciably higher in powdered gloves than in powder-free gloves. Allergen levels varied 3000-fold among gloves from different manufacturers and were higher in examination gloves than in surgical or chemotherapy gloves. Measurable allergen was found in 11 of 24 lots of "hypoallergenic" gloves tested. Allergen levels in toy balloons were comparable to those in powdered gloves; much lower allergen levels were measured in condoms and anesthesia rebreathing bags. CONCLUSIONS: The allergen content of disposable rubber gloves varies widely and is higher in powdered gloves than in powder-free gloves and higher in examination gloves than in surgical gloves. Hypoallergenic gloves may contain substantial amounts of IgE-binding proteins. Gloves and toy balloons appear to be more important sources of rubber allergens than the other rubber products tested.
Allergens↗
Hemoglobin Denver [alpha 2 beta 2(41) (C7) Phe-->Ser]: a low-O2-affinity variant associated with chronic cyanosis and anemia.
OBJECTIVE: To report a previously undescribed low-O2-affinity hemoglobin variant that is associated with chronic cyanosis. DESIGN: Pertinent laboratory and historical data for the index case (from Denver, Colorado) and certain family members were recorded, and the hemoglobin variant was characterized. MATERIAL AND METHODS: Electrophoresis, high-performance liquid chromatography (HPLC), and isoelectric focusing were used to examine blood specimens for the presence of hemoglobin variants, and the O2 affinity of whole blood was determined. The abnormal peptide detected on reverse-phase HPLC of separated globin chains was analyzed for its amino acid composition and sequence. RESULTS: Although no abnormal hemoglobin band separated from hemoglobin A on electrophoresis, HPLC, and isoelectric focusing, a heat test showed hemoglobin instability, and O2 affinity studies disclosed an appreciably right-shifted dissociation curve. On chromatography, the new variant--hemoglobin Denver--was found to be due to a substitution of serine for phenylalanine at position 41 (C7) in the beta chain. In addition to substantial reduction in O2 affinity, hemoglobin Denver is accompanied by moderate reticulocytosis and mild anemia. CONCLUSION: Hemoglobin Denver causes no clinical symptoms other than cyanosis, which is attributable to the low O2 affinity.
Adolescent↗
Nonoperative management of blunt hepatic injuries: safe at any grade?
Nonoperative management of blunt hepatic injury (BHI) has become more widely accepted. A prospective trial was undertaken to test the belief that clinical state could identify the patients with BHI confirmed by computed tomography (CT) who could be safely managed without a surgical operation. Patients were excluded from nonoperative management only if they manifested hemodynamic instability, the presence or suspicion of any other injury requiring laparotomy, or would be unavailable for controlled monitoring. Of 60 patients treated for BHI, 30 were managed nonoperatively. The 30 who had laparotomies served as a comparative group. The groups were statistically similar in age, sex, and Injury Severity Score (ISS). The group managed nonoperatively had significantly more severe BHI. There were no deaths or delayed laparotomies in the nonoperative management group. The groups had similar ICU and total hospital stays when analyzed as independent variables or with control for BHI grade and ISS. Transfusion requirements were significantly lower for the nonoperative management group when analyzed independently or when controlled for BHI grade, ISS, and the number of non-abdominal injuries. Nineteen (63%) patients managed nonoperatively were followed until their CT scans showed complete resolution. None had complications. We conclude that nonoperative management of BHI is a safe and effective technique applicable to hemodynamically stable patients who lack other indications for laparotomy and who can be adequately monitored.
Adolescent↗
Hb Washtenaw [ beta 11(A8)Val-->Phe]: an electrophorectically silent, unstable, low oxygen affinity variant associated with anemia and chronic cyanosis.
Hb Washtenaw [beta 11(A8)Val-->Phe] is a new, low oxygen affinity variant with a previously undescribed substitution, identified in seven members over three generations of a Hungarian-American family. The hemoglobin is mildly unstable and the family members studied are clinically asymptomatic but mildly cyanotic, and some exhibit mild anemia. The index case had severe pulmonary hypertension and some of the family members had increased pulmonary vascular resistance on echocardiography. An association between the inheritance of this abnormal hemoglobin and the pathogenesis of primary pulmonary hypertension is suggested but the mechanism is unclear.
Adolescent↗
Cross-linking hemoglobin by design: lessons from using molecular clamps.
The development of a red cell substitute by chemical modification of hemoglobin has been approached as a systematic, iterative process. Acyl phosphate methyl esters were designed as anionic electrophiles to permit selective acylation of amino groups in the cationic site of hemoglobin which binds polyanions. Kinetic studies with systematically substituted acyl phosphates and amines show that the reaction is controlled by a reversible addition step followed by an irreversible elimination step. Acyl phosphate methyl esters which are derivatives of rigid dicarboxylic acids introduce cross-links in human hemoglobin between amino groups in the beta subunits (epsilon-NH2-Lys-82, alpha-NH2-Val-1) and permit correlation of oxygen binding properties with cross-link structure. The data suggest that the cross-link maintains cooperativity while reducing overall oxygen affinity by lowering the affinity of the R form for oxygen rather than by perturbing the R,T equilibrium of native hemoglobin. Materials produced from deoxyhemoglobin with a cross-link between positions 1 and 82 of the two beta units have appropriate oxygen affinity for red cell substitutes. The use of a trifunctional cross-linker, trimesyl tris(methyl phosphate) selectively produces hemoglobin with the desired 1-82 connection in good yield. The reagent is readily prepared and the properties of this chemically modified hemoglobin are suitable for trial as a red cell substitute, closely resembling those of optimized materials produced by recombinant technology. Further work is producing new chemicals and providing structural information.
Binding Sites↗
Prospective study of extractable latex allergen contents of disposable medical gloves.
BACKGROUND: Exposure to natural rubber latex medical gloves poses risks to latex-sensitive patients and medical workers. Preliminary studies have shown that the latex allergen contents of these gloves vary widely. OBJECTIVE: To study long-term trends in latex allergen levels of disposable medical gloves prospectively, and to identify lower allergen gloves for purchase by our medical center. METHODS: Extractable total latex allergen was measured by solid-phase inhibition immunoassay. Allergen contents of gloves were expressed in allergy units (AU)/mL relative to a raw latex standard assigned an arbitrary potency of 100,000 AU/mL. RESULTS: For gloves in use during July, 1993, extractable allergen levels ranged from < 10 to 5,500 AU/mL among nine lots of examination gloves, from < 10 to 2,300 AU/mL among 13 lots of surgical gloves, and from < 10 to 1,000 AU/mL among five lots of chemotherapy, autopsy, or utility gloves. Among ten lots of examination gloves purchased on two occasions between July, 1993 and January, 1994, the allergen levels in two of the three private label brands were more variable (6- to 40-fold) than in the other eight brands tested (0- to 2-fold). CONCLUSIONS: Extractable allergen levels in latex medical gloves remain highly variable, particularly among some private label brands. Use of synthetic gloves or lower allergen latex gloves should lessen exposure of latex-sensitized patients and health care workers to latex aeroallergens.
Allergens↗
Left ventricular function immediately after intravenous cocaine: a quantitative two-dimensional echocardiographic study.
OBJECTIVES: We tested the hypothesis that intravenous cocaine, in doses commonly self-administered in nonmedical settings, causes acute myocardial ischemia and left ventricular dysfunction. BACKGROUND: Cocaine-induced cardiac complications are responsible for a growing number of deaths in young people, but the mechanism by which cocaine induces these complications is unclear. METHODS: We performed 12-lead electrocardiography and quantitative two-dimensional echocardiography in 20 subjects before and after single intravenous doses of high dose cocaine (1.2 mg/kg body weight), low dose cocaine (0.6 mg/kg) and placebo. RESULTS: At 2 to 7 min after cocaine administration, the rate-pressure product was increased significantly from baseline (high dose 73%, low dose 63%, placebo 8%, p < 0.001 for either dose vs. placebo). During this time, electrocardiography demonstrated dose-related nonspecific changes (high dose in 14 of 20 subjects, low dose in 9 of 20 subjects, placebo in 2 of 20 subjects, p < 0.002 for either dose vs. placebo). In contrast, echocardiography showed that the frequency of hyperdynamic left ventricular wall segments doubled after high dose cocaine compared with placebo (34% [108 of 318] vs. 16% [51 of 319], respectively, p = 0.0001) but that there was no change in either left ventricular ejection fraction (high dose 66 +/- 9%, placebo 67 +/- 6%, p = NS) or wall motion score index (high dose 0.67 +/- 0.44, placebo 0.85 +/- 0.30, p = NS). CONCLUSIONS: We conclude that intravenous cocaine, in doses commonly self-administered in nonmedical settings, does not cause acute myocardial ischemia or left ventricular dysfunction. We speculate that cocaine-induced cardiac complications are caused by idiosyncratic coronary artery vasospasm, by exceptionally high dosages or by cocaine-induced coronary artery thrombosis.
Adult↗
p53 protein accumulates frequently in early bronchial neoplasia.
p53 mutations are common in human lung cancer and frequently generate levels of p53 protein that are detectable by immunohistochemistry. For this reason, p53 protein accumulation is a candidate biomarker, but little is known about its timing or frequency in multistage bronchial carcinogenesis. We studied human lung tissues containing preinvasive squamous neoplasms from 34 donors with and without lung cancer. Nuclear p53 protein was present in 0% of normal mucosas, 6.7% of squamous metaplasias, 29.5% of mild dysplasias, 26.9% of moderate dysplasias, 59.7% of severe dysplasias, 58.5% of carcinomas in situ, 67.5% of microinvasive carcinomas, and 79.5% of invasive tumors. These data indicate that (a) p53 protein accumulates in about 30% of the earliest recognized neoplastic lesions (i.e., mild dysplasia), (b) there is an increasing frequency of p53 protein accumulation starting with mild dysplasia, and (c) p53 protein accumulates infrequently in normal or metaplastic mucosa. In a subset of six patients whose most advanced lesion was carcinoma in situ without evidence of invasive cancer, p53 protein was detected in 0% of normal mucosas, 8.3% of squamous metaplasias, 37.5% of mild dysplasias, 12.5% of moderate dysplasias, 93.8% of severe dysplasias, and 55% of carcinoma in situ lesions. These data show clearly that p53 alterations can occur before invasion and suggest that the frequency is similar to that observed in the full series. Since two-thirds or more of lung cancers have p53 alterations, the timing and frequency of p53 protein accumulation make the p53 tumor suppressor gene an attractive marker for early diagnosis and evaluation of chemoprevention agents.
Biomarkers, Tumor↗
Modification of human hemoglobin with methyl acyl phosphates derived from dicarboxylic acids. Systematic relationships between cross-linked structure and oxygen-binding properties.
Human hemoglobin was reacted with five dicarboxylic acid bis(methyl phosphate) reagents under different ligand conditions. The bis(methyl phosphate) reagents tested were derived from fumaric, isophthalic, terephthalic, trans-stilbene-3,3'-dicarboxylic, and trans-stilbene-4,4'-dicarboxylic acids. These acyl phosphate mixed anhydrides are anionic electrophiles and will react with N-terminal amino and lysyl epsilon-amino groups to form amides. The major and many of the minor reaction products that result have been isolated and structurally characterized by globin chain and peptide analysis. Products which are not cross-linked, intrachain linked, and interchain singly and doubly cross-linked occur in proportions which depend upon the reaction conditions and reagent. Modifications of the beta chains were limited to the amino groups of beta 1Val, beta 82Lys, and, to a minor extent, beta 144Lys. In the case of the smaller reagents, the amino groups of alpha 1Val, alpha 99Lys, and, to a minor extent, alpha 139Lys were modified. The oxygen binding affinities of most of the major modified hemoglobins have been measured and are characterized by P50 values from about 1/2 to over 5 times that of unmodified human hemoglobin. Most show strong cooperativity with Hill coefficients (n) of 2.0 or greater. Several of the products that are cross-linked between the beta 1Val of one chain and the beta 82Lys of the other chain have oxygen affinities in a physiologically useful range for oxygen transport and delivery. An inverse linear correlation has been found between the log of P50 and bridging distances for the hemoglobins cross-linked between beta 1Val of one chain and the beta 82Lys of the other chain.(ABSTRACT TRUNCATED AT 250 WORDS)
Amino Acid Sequence↗
Improved performance 4 hours after cocaine.
Cocaine (2 mg/kg) was given orally to 13 healthy volunteers and physiologic, subjective, attentional and performance effects were measured over a period of 4 h. Posner's reaction time paradigm measured the effects of cocaine on performance and on attention to visual cues. Cocaine increased heart rate, systolic blood pressure and pupil diameter and reduced skin temperature. Physiologic effects, subjective rating of intoxication, and cocaine levels in saliva peaked at approximately 75 min and returned to precocaine levels within 3 h. In contrast, a reaction time measure of performance speed on the visual attention task showed improvement for 4 h after cocaine. A measure of covert attention in the cocaine condition failed to show the improvement which occurred in the placebo condition. Less fatigue was reported 4 h after cocaine than after placebo. Cocaine users may experience the drug's stimulant effects considerably longer than the euphoriant effects.
Adult↗
Anaphylaxis to measles, mumps, and rubella vaccine mediated by IgE to gelatin.
BACKGROUND: Allergic reactions to measles, mumps, and rubella (MMR) vaccine are rare; some have been attributed to allergy to trace quantities of egg proteins. We report a 17-year-old female who had an anaphylactic reaction to MMR vaccine. A primary vaccination with MMR at age 15 months had been uneventful. She is not allergic to eggs; however, ear and throat pruritus and tongue swelling develop after she eats gelatin. MMR vaccine contains gelatin as a stabilizer. METHODS AND RESULTS: Prick skin tests were positive to 1:10 wt/vol dilutions of MMR vaccine and gelatin but negative to egg. By immunoassay, her serum IgE antibodies were elevated to both MMR vaccine and gelatin, but not to isolated MMR antigens. IgE binding to the gelatin carrier could be inhibited in a dose-dependent fashion by addition of not only MMR vaccine but also gelatin from a variety of animal sources. Immunoblotting confirmed the presence of IgE antibodies to multiple gelatin components as well as to MMR vaccine components. CONCLUSIONS: We conclude that the patient has an anaphylactic sensitivity to gelatin, and that her anaphylaxis to MMR vaccine was caused by the gelatin component. This sensitivity may explain other cases of MMR anaphylaxis.
Adolescent↗
Drug refusal behavior: the relative efficacy of skills-based and information-based treatment.
Examined the impact of two treatment strategies on children's drug refusal skills and drug-related information. Fifty-seven third graders were randomly assigned to one of three groups: rehearsal-plus, general information, and control. Children in the rehearsal-plus group were taught drug knowledge, assertiveness skills, decision-making skills, rationale and specific drug refusal skills in the context of a skills-based strategy. At a more global level, the general information group targeted all of the same components with the exception of rationale. Results indicated that children in the skills-based strategy (rehearsal-plus) showed significant improvement in behavioral skills, decision-making, and rationale, while children in the information/education-based strategy (general information) improved most on the measure of general knowledge. At follow-up, gains were generally maintained.
Assertiveness↗
Prediction in drug abuse: cocaine interactions with alcohol and buprenorphine.
We describe the limitations on studying the interactions of drugs of abuse in humans. Two 'acute' studies were carried out. In the first study, the administration of alcohol/placebo with cocaine showed the possibility of identifying the euphoric effect of the drugs by the EEG power spectra analysis in terms of enhancement of alpha- and beta-wave activity. The results of the second study, in which cocaine and buprenorphine were administered, show the existence of low-dose interactions and the influence of buprenorphine on craving for cocaine.
Alpha Rhythm↗
Fluoxetine for cocaine dependence in methadone maintenance: quantitative plasma and urine cocaine/benzoylecgonine concentrations.
Cocaine abuse is a common clinical problem among opioid-dependent patients who are in methadone maintenance treatment. In an open prospective study, 16 DSM-III-R, cocaine-dependent, methadone maintenance treatment patients were treated with fluoxetine, at a mean dose of 45 mg/day for 9 weeks. Eleven subjects (69%) were infected with the human immunodeficiency virus. Cocaine use was significantly reduced by the end of treatment, although most subjects did not achieve abstinence. Comparison of intake to week 9 showed a significant decrease in self-reported cocaine use, craving, and quality of high. Actual cocaine use was measured by a quantitative analysis of cocaine and benzoylecgonine (BE) concentrations in plasma and urine. Median BE and cocaine concentrations in urine decreased significantly from intake to week 9 of fluoxetine treatment. This decrease would not have been detected if BE had been measured only qualitatively, as present or absent in the urine. Fluoxetine was well tolerated in combination with methadone and did not appear to alter methadone concentrations in plasma. Few adverse effects were noted. No subjects had to discontinue fluoxetine. Fluoxetine may be a promising treatment approach for cocaine abuse in methadone maintenance patients. Quantitative determination of exact cocaine and BE concentrations in biofluids may be a more accurate method of measuring cocaine use outcome than qualitative urinalysis.
Adult↗
Three-point cross-linking: potential red cell substitutes from the reaction of trimesoyl tris(methyl phosphate) with hemoglobin.
The symmetrical trifunctional cross-linking reagent trimesoyl tris(methyl phosphate) (3), reacts selectively with amino groups (beta 1Val and beta 82Lys) in the diphosphoglycerate binding site of human hemoglobin A, producing cross-linked tetrameric species in good yield. A major species is triply linked, alpha alpha beta 1(82) greater than B beta 82, where B symbolizes benzene-1,3,5-tricarbonyl. Both this triply linked species and the doubly linked species, alpha alpha beta 1B beta 82, produced from deoxyhemoglobin have a considerably lower oxygen affinity than does native hemoglobin while maintaining a high degree of cooperativity (n50 = 2.4), making them potentially useful as red cell substitutes, in principle delivering twice as much oxygen as whole blood between pO2 = 100 and = 40 Torr. The yield of products indicates that triply and doubly linked species form in parallel so that there are independent routes to each. It is proposed that differences in routes are due to stereoisomerism about the amide bonds which form from reaction of the reagent with the protein.
Amino Acid Sequence↗
Regulation of protein degradation in normal and transformed human bronchial epithelial cells in culture.
Protein degradation rates are decreased in some transformed cells of mesenchymal origin. We have tested the generality of this phenomenon and evaluated the role of the lysosomes in this down-regulation. To this end we have compared the induction of lysosomal protein degradation among normal, transformed (BEAS-2B), and transformed tumorigenic (BZR, Calu-1) human bronchial epithelial cells in culture. Serum and/or nutrient deprivation, cell confluency, and Ca2+ were used to modulate lysosomal protein degradation. Protein degradation and synthesis were determined by the release or incorporation of [14C]valine in the cells. Autophagic degradation of cytoplasm by lysosomes was evaluated by ultrastructural morphometry. Basal protein degradation was lower (27%) in two of the transformed cell lines (BEAS-2B and BZR). Incorporation of [14C]valine label was raised approximately 4-fold in the transformed cells. Nutrient deprivation stimulated protein degradation equally (2-fold) in transformed and normal cells. Postconfluency increased (1.5-fold) basal protein degradation in Calu-1 cells and a marked enhancement (4-fold) of degradation occurred during nutrient deprivation. Culture of normal human bronchial epithelial cells in high Ca2+ caused phenotypic changes and increased (30%) the degradation of protein induced by nutrient deprivation. In Calu-1, high Ca2+ caused only phenotypic changes. The volume density (Vd) of autophagic vacuoles and dense bodies in the transformed cells was lower under basal conditions but increased markedly during nutrient deprivation. A marked accumulation of lysosomes also occurred in transformed cells during postconfluency. We conclude that cell transformation lowers basal protein degradation in some human epithelial cells. Lysosomal proteolysis of transformed cells is not down-regulated and can be markedly enhanced during nutritional deprivation by the autophagic degradation pathway.
Analysis of Variance↗
Comparison of diagnostic procedures for porcine leptospirosis.
Kidneys and matched serum samples were obtained from 368 pigs slaughtered at three Victorian abattoirs, and originating from 42 farms. Macroscopic lesions (white spots) were observed on 102 of the kidneys. Serum samples were tested by the microscopic agglutination test (MAT) and by an IgM enzyme immunoassay (EIA). Kidneys were cultured for leptospires, examined histologically after Warthin-Starry silver staining and after immunogold silver staining (IGSS), and tested for leptospiral DNA by DNA hybridization. Forty-four infected pigs were identified by culture or immunogold silver staining of kidneys or by high MAT titres (greater than or equal to 1024). Infection was demonstrated in 7.5% of visibly normal kidneys, in 23.5% of kidneys with white spots, and in 48% of kidneys with large white spots, of 1 cm diameter or greater. The apparent (maximum) sensitivities of diagnostic procedures for detecting infection were as follows: MAT (at a titre of either 64 or 1024) 95%; IgM EIA 82%; culture 61%; presence of white spots 55%; IGSS 52%; presence of large white spots 30%; Warthin-Starry silver staining 20%. IGSS, Warthin-Starry staining and DNA hybridization all appeared to be highly specific. Of 22 kidney sections identified as positive by IGSS, 13 showed intact leptospires, and these kidneys were all culture-positive. Nine others showed leptospiral antigen in the kidney tubules but no intact leptospires. Only five of these kidneys were culture-positive.
Abattoirs↗