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Biomedical subjects

R Carlson

Publications and source records attributed to R Carlson.

At least 73 records · Page 4Linked to original sources
PubMed1985

Narrow trachea in mucopolysaccharidoses.

Nine of 56 patients with mucopolysaccharidoses (MPS) showed small tracheal diameters on their frontal chest radiographs. Autopsy of an MPS I-H (Hurler disease) patient demonstrated that the small calibre was secondary to deposition of glycosaminoglycan (mucopolysaccharide). Autopsies of two patients with other storage diseases, one with geleophysic dysplasia and one with mucolipidosis II, also exhibited compromise of their airways because of storage material accumulation.

Adolescent↗
PubMed1984

The thermodynamics of flavin binding to the apoflavodoxin from Azotobacter vinelandii.

A thermodynamic study of the binding of flavins (FMN, FAD, 8-carboxylic acid-riboflavin) to the purified apoflavodoxin from Azotobacter vinelandii has been conducted. The binding of FMN was studied at a number of temperatures (10, 15, 20, 25, and 30 degrees C), pH's (6.0, 7.4, and 9.0), and buffer conditions. The binding of FAD was studied at pH 7.4 and 25 degrees C under a number of buffer conditions. The binding of 8-carboxylic acid-riboflavin to the apoflavodoxin and the binding of FMN to the dimeric form of the apoflavodoxin were investigated at pH 7.4 and 25 degrees C. Enthalpies of binding for FMN, FAD, and 8-carboxylic- acid-riboflavin were -28.3, -16.6, and -14.0 kcal mol-1, respectively. The enthalpy of binding of FMN to the dimeric form of the apoflavodoxin was -22.2 kcal mol of binding sites-1. Binding constants of about 10(8), 10(6), and 10(6) were obtained for the binding of FMN, FAD, and 8-carboxylic acid-riboflavin, respectively. Using established thermodynamic relationships free energy and entropy changes were calculated. The entropy data indicate that a large degree of ordering of the system occurs upon flavin binding. The pH data suggest that FMN may bind in both the mono- and dianion forms, and that binding doesn't change the pKa of any functional group in the system. It appears that the phosphate group is probably responsible for approximately half the binding enthalpy observed for the binding of FMN. The temperature-dependence data over the temperature range studied is biphasic, centered at 20 degrees C, indicating that flavin binding occurs to the protein in two thermodynamic states corresponding to the two heat capacities observed. These findings are used to discuss a model for flavin binding.

Apoproteins↗
PubMed1984

Studies of Jungian typology: III. Personality and marriage.

Jung's theory of psychological types provided the conceptual framework for a study of personality characteristics implicated in marital relationships. Partners in 20 couples completed the Myers-Briggs Type Indicator and a series of open-ended questions describing their marital relationships. As predicted, (a) type similarity was more characteristic than type dissimilarity, particularly on sensation-intuition and thinking-feeling preferences, (b) sensation-intuition preferences were reflected in perceptions of qualities valued in self and spouse, (c) thinking-feeling preferences were significantly related to reported satisfaction in marriage, and (d) intuitives were more open to changes in the relationship than were sensing types. Marital problems were highly diverse, and were not related in any clear way to type patterns in individuals or dyads.

Journal Article↗
PubMed1984

Mechanism of improvement in glucose metabolism after chronic glyburide therapy.

The effect of glyburide on glucose metabolism was examined in 10 non-insulin-dependent diabetic subjects (NIDDM) and 7 young, control subjects. After 3 mo of glyburide treatment in NIDDM, fasting plasma glucose declined from 198 to 141 mg/dl (P less than 0.01) without change in fasting insulin levels. Basal hepatic glucose production (HGP) was slightly elevated in NIDDM versus controls (2.35 versus 2.18 mg/kg X min, P = NS) and was positively correlated with the fasting glucose concentration (r = 0.93, P less than 0.001). With chronic glyburide therapy, HGP declined to 1.72 mg/kg X min (P less than 0.01 versus preglyburide) and remained highly correlated with the fasting glucose concentration (r = 0.85, P less than 0.005). Basal glucose clearance in NIDDM was reduced by 48% compared with age-matched controls (1.22 versus 2.32 ml/kg X min, P less than 0.001) and was unchanged after 3 mo of glyburide. Thus, the most important factor responsible for the decline in fasting plasma glucose concentration was an inhibition of hepatic glucose output. The decrease in basal hepatic glucose production and fasting plasma glucose concentration occurred without any change in fasting plasma insulin or C-peptide concentration. Insulin-mediated glucose metabolism (insulin clamp technique) was reduced by 55% in NIDDM (2.91 versus 6.39 mg/kg X min, P less than 0.001). After glyburide, insulin-mediated glucose metabolism increased by 26% to 3.67 mg/kg X min (P less than 0.01). This increase in tissue sensitivity to insulin was unassociated with any change in insulin binding to monocytes.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1983

An improved purification procedure and apoprotein preparation for the flavodoxin from Azotobacter vinelandii.

An improved method for the purification of the holoflavodoxin from Azotobacter vinelandii was developed, which resulted in improved yields and degree of homogeneity. The purity and homogeneity of this sample were established by polyacrylamide gel electrophoresis. An apoprotein preparation procedure is outlined, which results in a homogeneous preparation of the apoflavodoxin. The homogeneity of the apoflavodoxin sample was established by polyacrylamide gel electrophoresis.

Ammonium Sulfate↗
PubMed1983

In vitro and in vivo activity profile of RHC 2851: a new orally effective antiallergic agent.

RHC 2851 has been investigated for its antiallergic activity in three in vitro and two in vivo models of anaphylaxis. We have also compared its activity profile in these models with that of disodium cromoglycate (DSCG), doxantrazole, ketotifen and oxatomide. RHC 2851, given i.p., was 6 times more potent than DSCG, and given orally it was 3 times more potent than doxantrazole. As an inhibitor of mediator release, the activity profile of RHC 2851 was identical to that of DSCG in the following respects: inhibition of IgE-mediated in vitro release of histamine from rat mast cells (RMC) but not human basophils (HuB), possession of tachyphylactic properties and demonstration of rapid loss of inhibitory activity as a function of time before antigen challenge as well as inability to inhibit IgG1-mediated release of histamine, both in vitro and in vivo, and lack of mediator antagonist activity. Ketotifen and oxatomide did not inhibit either IgE or IgG1-mediated release of histamine in vitro or in vivo, and were potent mediator antagonists in vivo. We conclude that RHC 2851 is an orally effective inhibitor of mediator release with a mechanism of action similar to that of DSCG and different from that of ketotifen and oxatomide.

Anaphylaxis↗
PubMed1982

A closed-chest model for the study of electromechanical dissociation of the heart in dogs.

A closed chest model in mechanically ventilated dogs is presented for the study of electromechanical dissociation (EMD) after defibrillation for ventricular fibrillation (VF). In seven dogs VF was induced by internal application of an AC current in the right ventricle. Precordial compression was not performed. When VF was continued for either 30 s or 60 s defibrillation typically resulted in complete restoration of electrical and mechanical cardiac activity. Immediately after defibrillation, the mean arterial blood pressure, pulmonary artery pressure, right ventricular filling pressure and cardiac output were markedly elevated; these elevations were accompanied by a slight increase in lactate and a decline in pH of the arterial blood. When VF was continued for 120 s EMD was observed in each instance after defibrillation in association with a regular rhythm. After 5-20 min, the ventricular fibrillation reappeared. The constancy of EMD in this model provides an experimental basis for study of clinical options, by which EMD may be prevented and/or mechanical competence of the heart may be restored.

Animals↗
PubMed1982

Reduced hemoglobin as an inhibitor of human polymorphonuclear leukocyte bacterial killing. Role of hemoglobin--oxygen tension in polymorphonuclear function.

The effect of reduced hemoglobin (Hb) on in vitro human polymorphonuclear leukocyte (PMNL) bactericidal activity was investigated. Addition of Hb at physiologic concentrations and oxygen partial pressures (150 mg/ml, 35 torr) to PMNL bactericidal assays significantly inhibited the killing of blood culture isolates of Escherichia and Staphylococcus aureus. Raising the oxygen partial pressure above 35 torr greatly decreased this inhibition. Carboxy hemoglobin, produced by equilibrium of Hg with carbon monoxide, is unable to bind oxygen and did not inhibit PMNL bactericidal killing. We postulate that reduced Hb may scavenge oxygen near the surface of the PMNL therapy preventing utilization of oxygen by PMNL for maximal bactericidal activity.

Bacterial Physiological Phenomena↗
PubMed1981

Protein involvement in structural transition of erythrocyte ghosts. Use of thermal gel analysis to detect protein aggregation.

In this study, it is shown that systematic temperature-induced protein aggregation occurs on the erythrocyte membrane by intermolecular disulfide bond formation. Specific protein bands disappear from acrylamide gel profiles over rather narrow temperature regions. The aggregation appears to be the result of irreversible structural transitions of the membrane, which can be seen in a sensitive scanning calorimeter. When this method of thermal gel analysis is used, the results suggest that spectrin is a participant in the A transition, that bands 2.1, 4.1, and 4.2 and the cytoplasma portion of 3 are involved in the B transition, and that the transmembrane portion of band 3 may undergo changes in the C transition, previously shown to occur in the anion transport domain of the membrane. The aggregation of specific proteins in the narrow temperature region of these transitions persists as the transitions are moved around on the temperature axis by varying solution conditions. The assignment of particular proteins to specific transitions is reinforced by selective extraction of membrane proteins. Large variations in both the calorimetry and the aggregation pattern occur as salt concentration is increased from 77 mosm to 310 mosm, which is manifested in the splitting of the B transition into two separate transitions, B1 and B2. It is speculated that this occurs as the result of a structural change which may involve components of the cytoskeletal network.

Calorimetry↗
PubMed1981

A multi-language, portable text-to-speech system for the disabled.

Previous experience with speech output aids for blind and non-vocal persons has shown great promise. The need for individual adjustments and the relatively small market, makes flexible, programmable aids necessary. A modular microprocessor text-to-speech system has been developed that is portable and battery-operated. This prototype has been adjusted to several different users. Programs for different languages have been developed. Connection of text sources is simplified by standardized interfaces. One special attachment is a 500 symbol Blissymbol board and a related Bliss-to-speech program that transforms the symbol string to well formed sentences.

Blindness↗