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Biomedical subjects

M Gleason

Publications and source records attributed to M Gleason.

15 recordsLinked to original sources
PubMed2001

Solar simulated irradiation modulates gene expression and activity of antioxidant enzymes in cultured human dermal fibroblasts.

Exposure of skin to solar irradiation generates reactive oxygen species that damage DNA, membranes, mitochondria and proteins. To protect against such damage, skin cells have evolved antioxidant enzymes including glutathione peroxidase (GSH-Px), copper and zinc-dependent superoxide dismutase (SOD1), the mitochondrial manganese-dependent superoxide dismutase (SOD2), and catalase. This report examines the effect of a single low or moderate dose exposure to solar-simulating combined UVB and UVA irradiation on the gene expression and activities of these antioxidant enzymes in cultured normal human fibroblasts. We find that both doses initially decrease GSH-Px, SOD2 and catalase activities, but within 5 days after irradiation the activities of the enzymes return to pre-irradiation level (catalase) or are induced slightly (SOD1, GSH-Px) or substantially (SOD2) above the basal level. For SOD1, SOD2 and catalase, the higher dose also detectably modulates the mRNA level of these enzymes. Our results indicate that the effects of a single physiologic solar simulated irradiation dose persist for at least several days and suggest that skin cells prepare for subsequent exposure to damaging irradiation by upregulating this antioxidant defense system, in particular the mitochondrial SOD2. Our findings are consistent with the existence of a broad-based SOS-like response in irradiated human skin.

Catalase↗
PubMed2000

Membranous subpulmonic stenosis associated with ventricular septal defect and aortic insufficiency.

We present a case report of a patient with conal septal hypoplasia (supracristal) ventricular septal defect (VSD) complicated by aortic insufficiency (AI) and subpulmonic stenosis from a fibrous membrane. The development of AI with VSD is a well-recognized problem. However, the association of VSD, AI, and significant right ventricular outflow tract obstruction (RVOTO) is less common. Mechanisms of RVOTO include prolapse of an aortic valve cusp across the VSD, as well as infundibular hypertrophy or muscle bundles. Technical echocardiographic issues can make the diagnosis of VSD, AI, and RVOTO challenging. The presence of a discrete fibrous subpulmonary membrane is uncommon in this setting.

Abnormalities, Multiple↗
PubMed2000

An in-school CD-ROM asthma education program.

Computer-based education in schools is not novel. However, only a few computer games have been introduced into school-based health education programs. This study describes inclusion of an asthma education space adventure game into fourth-grade classrooms. Using the game improved asthma knowledge in the intervention classes. Children in the active participation classroom gained significantly more asthma knowledge over the observation period compared to the classroom that did not play the computer game. Knowledge gained was retained over a four-week period and the addition of physician-led talks appeared to add little to the knowledge gained. "Air Academy: The Quest for Airtopia" is an easy and successful tool for elementary grade asthma-related health education in schools.

Asthma↗
PubMed1999

Expression of the heterogenous nuclear ribonucleoprotein complex K protein and the prolyl-4-hydroxylase alpha-subunit in atherosclerotic arterial smooth muscle cells.

Smooth muscle cells (SMC) play a major role in the formation of atherosclerotic lesions found on major blood vessels. SMC proliferation, migration, and protein synthesis promote the progression of the early lesion, the fatty streak, into a complex myointimal fibrous plaque. To investigate altered gene expression in SMC during atherogenesis, we characterized differences between SMC from normal rabbits, rabbits fed a 2% cholesterol diet, and Watanabe Heritable Hyperlipidemic rabbits (WHHL). We detected and isolated a 501 bp cDNA fragment representing the A isoform of heterogenous nuclear ribonucleoprotein complex K (hnRNP-K) and a 281 bp cDNA fragment representing the prolyl-4-hydroxylase alpha-subunit (alphaPH) mRNAs. hn-RNP-K was upregulated in SMC from cholesterol-fed rabbits isolated in primary culture, as well as in SMC medial tissue from both the cholesterol-fed and WHHL rabbits. alphaPH was upregulated in SMC from the cholesterol-fed rabbits isolated in primary culture and in the tissue from WHHL rabbits. These data demonstrate genes consistent with increased proliferation and collagen production are upregulated in SMC during atherogenesis and may shed new light on gene expression changes and corresponding phenotype changes in SMC during atherogenesis.

Animals↗
PubMed1995

Enzyme inhibition during the conversion of squalene to cholesterol.

Two separate enzymatic assays were developed in order to test the selectivity of inhibitors in cholesterol biosynthesis. One assay detects inhibition of delta 5.7-sterol delta 7-reductase, the enzyme involved in the conversion of 7-dehydrocholesterol to cholesterol. Delta 5.7-Sterol delta 7-reductase was inhibited by both RPR 101821, a protonated cyclohexylamine, and BM 15.766, a piperazine derivative, with IC50 values of 1 microM. The second assay detects accumulation of any of five intermediates (squalene oxide, squalene dioxide, lanosterol, desmosterol, and 7-dehydrocholesterol) upon inhibition of enzymes catalyzing reactions in the conversion of squalene to cholesterol. In this assay, inhibition data were most accurate when control assays exhibited a conversion of squalene to cholesterol in the order of 50%. The time required to attain 50% conversion of squalene to cholesterol was 6 h. Given a high inhibitor to substrate concentration ratio and the possible values of Ki, kon, and koff for the reaction between enzymes and inhibitor to form enzyme-inhibitor complexes, it was predicted that in the presence of inhibitors, intermediate accumulation could still be observed after 6 h incubation. The experimental results were in agreement with this prediction.

Animals↗
PubMed1991

Cumulative versus rapid introduction of new information.

This study investigated the way new information is presented to students. Subjects were 60 elementary and middle school students, most with learning disabilities. Students used two versions of a specially designed computer-assisted instruction (CAI) program. One version rapidly presented students with seven pieces of information (rapid-introduction group); the other cumulatively presented smaller "chunks" of information (cumulative-introduction group). Both groups worked to mastery level successfully but students in the cumulative group spent one-third the time, required fewer responses, showed less frustration, and made fewer errors in the process. Results suggest that students with learning disabilities need much more practice than most commercial CAI programs supply.

Child↗
PubMed1990

Optimization of immunocytochemical P-glycoprotein assessment in multidrug-resistant plasma cell myeloma using three antibodies.

Seeking to optimize the immunocytochemical assay of P-glycoprotein, a 170-kilodalton (P-170) molecule associated with multidrug resistance, we experimented with a variety of antibodies (JSB-1, C219, and MRK-16), fixation conditions, and titers using both human myeloma cell lines and clinical myeloma specimens. Under optimized conditions, using all three antibodies and the cell lines as standards and controls, the ICC method proved sensitive, specific, reliable, rapid, and within the realm of everyday hospital laboratory expertise. The 3 anti-P-glycoprotein antibodies revealed different reactivities with P-170. Both C219 and JSB1 were optimized by fixation in cold acetone. With MRK-16 optimal results were obtained on unfixed or formalin fixed specimens. Under optimal fixation and titering conditions, low level (DOX 4) detection was possible. Given that the three antibodies differ in reactivity and recognize different P-170 epitopes, it follows that using the antibodies in a small panel is a useful strategy in increasing the likelihood of detecting true P-glycoprotein expression by the immunocytochemical method. In dilution experiments, the immunocytochemical method was as sensitive as RNase protection assay and more sensitive than Western blot detection. Immunocytochemistry coupled to computer-assisted single-cell densitometry, showed a strong correlation (R = 0.98) between cellular P-170 density and in vitro resistance to doxorubicin. Multidrug-resistant specific probes for RNA expression and Western blot assays confirmed the specificity of P-170 expression in both cell lines and clinical samples. Thus, a small panel of antibodies, under optimized immunocytochemical conditions, appears to have potential as a rapid, sensitive, clinically useful assay for multidrug resistance in myeloma.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1979

Purification of proline-rich proteins from parotid glands of isoproterenol-treated rats.

Prolonged isoproterenol treatment of rats is known to cause hypertrophy and hyperplasia of the parotid glands. Our results show that a dramatic increase in the synthesis or accumulation in the parotid glands of a series of proteins rich in proline also occurs with isoproterenol treatment. After 10 days of treatment (5 mg of isoproterenol/day) these proline-rich proteins (PRPs) comprise more than 50% of the total soluble proteins in parotid gland homogenates. The PRPs are rapidly labeled in vivo by a single intraperitoneal injection of [3H]proline with maximum incorporation occurring at about 3. More than 90% of the [3h]proline found in parotid gland homogenates is incorporated into PRPs with less than 1% of the radioactivity in alpha-amylase. Tritium incorporated into PRPs was isolated as [3H]proline after acid hydrolysis. One acidic and six basic 3H-labeled PRPs were isolated from the 100,000 x g supernatant fraction of parotid gland homogenates by Sephadex G-100 and ion exchange chromatography. The six basic proteins accounted for about 90% of the total PRPs isolated.

Animals↗
PubMed1974

Characterization of the end groups of RNA of Rous sarcoma virus.

The 3' terminus of the 30-35S RNA of Rous sarcoma virus is adenosine. Its amount indicates an average molecular weight for that RNA of about 3 x 10(6). The 5' terminus of 30-35S RNA of Rous sarcoma virus was not di- or triphosphorylated, whether isolated by the standard procedure or from virus collected within 3 min of its release from the cells.

Adenine Nucleotides↗