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Biomedical subjects

L Larson

Publications and source records attributed to L Larson.

At least 91 records · Page 5Linked to original sources
PubMed1983

Human chromosome analysis: methodology and applications.

This issue focuses on the rapidly developing field of human cytogenetics. The first article discusses the methodology used in the study of human chromosomes as well as its application in the diagnosis of chromosomal disorders. The second article discusses the application of chromosome analysis to the diagnosis and prognosis of hematologic malignancies, and the final article illustrates clues found on a peripheral blood smear that lead to the diagnosis of a chromosomal disorder.

Chromosome Aberrations↗
PubMed1983

IgE antibody-mediated cutaneous basophil hypersensitivity reactions in guinea pigs.

Cutaneous basophil hypersensitivity (CBH) reactions are a heterogeneous group of delayed time course basophil-rich immune responses that can be mediated in the guinea pig by T cells, B cells, or IgG1 antibody. This study examined whether guinea pig IgE antibody could also mediate CBH reactions. IgE antibody to picryl or oxazolone determinants was induced by immunizing Hartley strain guinea pigs pretreated with cyclophosphamide. Hyperimmune serum from these animals was passed through a heavy chain-specific anti-IgG1 affinity column. The presence of IgE anti-hapten antibody in the filtrate fraction was verified by passive cutaneous anaphylaxis (PCA) testing with a 7-day period of local passive sensitization and by the heat lability (56 degrees C, 4 hr) of PCA activity. This IgE-rich fraction and the IgG1 fraction eluted from the column with base (0.2 M Na2CO3, pH 11.3) were transferred i.v. to separate groups of normal guinea pigs. Both fractions mediated delayed time course reactions that contained basophils. Macroscopic and microscopic reactions mediated by the IgE-rich fraction were abolished with heat (56 degrees C, 4 hr). Thus, two antigen-specific factors in guinea pig serum can mediate delayed time course basophil-containing reactions: IgG1 and IgE antibodies. IgE-mediated CBH reactions are similar to the late-phase reaction that follows IgE-dependent wheal-and-flare reactions in humans. The finding that guinea pig IgE can mediate a late reaction that contains basophils makes this a possible model for the human late-phase response, and suggests that some forms of CBH may play a role in human allergic disease.

Animals↗
PubMed1982

Growth in primary culture of mouse submandibular epithelial cells embedded in collagen gels.

Mouse submandibular glands were dissociated and the epithelial cells embedded in a collagen gel matrix. A characteristic and reproducible pattern of growth was seen resulting in three-dimensional outgrowths with ductlike structures projecting into the matrix. A sustained cell growth leading to a 5 to 10-fold increase in cell number was observed in less than 2 wk. The extent of this growth was found to be dependent on serum concentration. Of the three sera tested, swine serum was found to promote greater growth compared to fetal bovine serum or horse serum. Swine serum dose response studies have shown that a concentration of 2 to 5% in the medium elicited only a modest increase, if any, in cell number compared to the initial value within a period of 2 wk. Various hormones and growth factors were then added to this "maintenance" medium. Insulin was found to stimulate growth consistently and reproducibly in a dose-dependent manner. Ultrastructurally, the resulting outgrowths were comprised of polarized cells joined by apical tight junction and desmosomes. The outgrowths produced epidermal growth factor in response to dihydrotestosterone, triiodothyronine, and cortisol. The present system provides a method for sustaining growth and functional differentiation in primary culture of mouse submandibular gland epithelial cells.

Animals↗
PubMed1980

A clinically applicable high-pressure liquid chromatographic method for measurement of serum theophylline, with detailed evaluation of interferences.

A high-pressure liquid chromatographic method for the routine measurement of serum theophylline that is accurate, specific, and sensitive is presented. It is technically simple, requires only 50 microliter serum, and takes relatively little technician time. Values for theophylline in sera obtained by this method correlate well with those obtained by use of a gas-liquid chromatographic method (r = 0.980) and with values obtained by the commonly used spectrophotometric method (r = 0.939) when the latter is free of interference. The assay has been employed for two years in a routine clinical chemistry laboratory, with interassay coefficients of variation of 2.4-3.2%. Interferences have been identified at an incidence rate of 3.8% of all specimens, and interfering substances include cephazolin, chloramphenicol, sulfamethoxazole, and sulfisoxazole. A calculation technic that allows a reliable and clinically useful estimation of a range of concentrations of theophylline in the serum when these interferences are present is described. In contrast, the incidence of interferences with the spectrophotometric method is 4.9%, and in this method the interferences prevent the analysis of theophylline. Of 33 samples having interferences by use of the spectrophotometric method, the high-pressure liquid chromatographic technic yielded precise values for theophylline in 21 and reliable estimates of ranges of concentrations of theophylline in the remaining 12.

Cefazolin↗
PubMed1979

A high-pressure liquid chromatography method for serum quinidine and (3S)-3-hydroxyquinidine.

A bonded reversed phase, high pressure liquid chromatography (HPLC) method for serum quinidine and its major metabolite in serum, (3S)-3-hydroxyquinidine, is presented. The method employs toluene, rather than benzene for extraction of 100 microliter of serum, can utilize either absorbance or fluorescence detectors, and utilizes a column and equipment which is also suitable for theophylline analyses. Quinidine values in sera by the present method correlated well with fluorometric non-chromatographic methods using ethylene chloride (r = 0.932) or benzene-sulfuric acid (r = 0.950) for extraction of the quinidine. The comparison data suggest a therapeutic range for quinidine of 1.3--5.0 mg/liter when measured by HPLC. In over one year of routine use in a clinical chemistry laboratory, the method has proven to be rapid and precise with interassay coefficients of variation of 2.5--5.5%. No interferences with the HPLC method have yet been identified.

Chromatography, High Pressure Liquid↗
PubMed1979

Program evaluation research: an experimental cost-effectiveness analysis of an armed robbery intervention program.

An armed robbery alarm system was implemented in 48 different stores in two separate geographical areas for 6 months and 12 months, respectively. The alarms were placed in the two separate areas at different times and all alarms were eventually removed. Thus, multiple baseline and reversal strategies were used to evaluate program impact. A device planted in a cash drawer was triggered whenever "bait" money was removed from the drawer sending an alarm signal directly to police cars and headquarters. On-scene apprehensions of armed robbers within target stores were greatly increased even though the armed robbery systems did not deter robbery incidents nor influence the court disposition of the cases. There was also no crime deterrence, crime displacement, or increased apprehensions in either the immediate neighborhoods of target stores or on a city-wide basis. The cost effectiveness of the program was calculated to be poor even though the program is being maintained because of the absence of an alternative robbery apprehension technology.

Cost-Benefit Analysis↗