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Biomedical subjects

M E Cook

Publications and source records attributed to M E Cook.

At least 37 records · Page 2Linked to original sources
PubMed1999

Antihypertensive effect of the combination of fosinopril and HCTZ is resistant to interference by nonsteroidal antiinflammatory drugs.

Nonsteroidal antiinflammatory drugs (NSAID) are frequently reported to interfere with the blood pressure lowering actions of various antihypertensive medications. We studied 17 women with arthritis and hypertension who were receiving fosinopril and HCTZ, and administered sequentially in random order ibuprofen, sulindac, and nabumetone for 1 month each, with an intervening 2-week washout period between each treatment period. During the washout period, subjects received acetaminophen. Blood pressure at the end of 2 weeks of acetaminophen was compared with blood pressure after 1 month of treatment with each of the NSAID. Mean blood pressure was unchanged before and after all NSAID: 108 +/- 7 v 107 +/- 9 for nabumetone, 108 +/-9 v 108 +/- 9 for sulindac, and 108 +/- 8 v 107 +/- 9 for ibuprofen. The 24-h urinary sodium excretion was not significantly different. We conclude that the three NSAID did not neutralize the antihypertensive effect of the combination of fosinopril and HCTZ, and hence the blood pressure lowering action of the combination may not be prostaglandin dependent.

Acetaminophen↗
PubMed1999

Conjugated linoleic acid and the control of cancer and obesity.

The effects of conjugated linoleic acid (CLA) in animals are reviewed. In most of the CLA preparations that have been investigated to date for biological activity, two CLA isomers are present in about equal concentrations: cis-9,trans-11 CLA, and trans-10,cis-12 CLA. The occurrence of these isomers in foods and their production by rumen microorganisms are discussed. Potential mechanisms of action as regards the effects of CLA on cancer and body composition are reviewed, including recent evidence that body composition changes are produced by the trans-10,cis-12 CLA isomer. Evidence is presented indicating that CLA may modulate cellular response to tumor necrosis factor-alpha (TNF-alpha). The mechanistic implications of this finding are considered.

Animals↗
PubMed1998

Regulation of beta 1-integrin-mediated cell adhesion by the Cbl adaptor protein.

BACKGROUND: Leukocyte activation results in a rapid increase in adhesion to the extracellular matrix due to the activation of beta 1 integrin receptors. A role for phosphatidylinositol (PI) 3-kinase in integrin activation has been proposed, as activation of integrins by many receptors can be blocked by PI 3-kinase inhibitors. One receptor that regulates integrins is the CD28 surface antigen; here, we investigated the mechanisms responsible for CD28-mediated integrin activation. RESULTS: CD28-mediated integrin activation was blocked by mutation of the binding site for the p85 catalytic subunit of PI 3-kinase in the CD28 cytoplasmic domain, and by expression of a dominant-negative form of the p85 subunit. Substitution of the Src homology 2 (SH2)-binding motif in the CD28 cytoplasmic domain for the corresponding motif in the CD28-related CTLA-4 surface antigen also blocked integrin activation but did not affect the recruitment and activation of PI 3-kinase. Mutations of the CD28 cytoplasmic domain that blocked integrin activation also impaired the tyrosine phosphorylation of the Cbl adaptor protein and the activation of the PI 3-kinase that was associated with Cbl. This Cbl-associated PI 3-kinase was distinct from the PI 3-kinase that coprecipitated with the CD28 cytoplasmic domain. CD28-mediated activation of beta 1 integrins was inhibited by expression of a mutant Cbl protein that shows reduced association with PI 3-kinase. CONCLUSIONS: Cbl is required for PI-3-kinase-dependent regulation of integrin receptors by CD28. Furthermore, CD28 is coupled to two distinct pools of PI 3-kinase, one directly associated with the CD28 cytoplasmic tail and the other associated with Cbl.

Amino Acid Substitution↗
PubMed1998

Development and growth of potato tubers in microgravity.

A potato explant consisting of a leaf, its axillary bud, and a small segment of stem will develop a tuber in 10-14 days when grown on earth. The tubers develop from the axillary buds and accumulate starch derived from sugars produced through photosynthesis and/or mobilized from leaf tissue. Potato explants were harvested and maintained in the Astroculture (TM) unit, a plant growth chamber designed for spaceflight. The unit provides an environment with controlled temperature, humidity, CO2 level, light intensity, and a nutrient delivery system. The hardware was loaded onto the space shuttle Columbia 24 hours prior to the launch of the STS-73 mission. Explant leaf tissue appeared turgid and green for the first 11 days of flight, but then became chlorotic and eventually necrotic by the end of the mission. The same events occurred to ground control explants with approximately the same timing. At the end of the 16-day mission, tubers were present on each explant. The size and shape of the space-grown tubers were similar to the ground-control tubers. The arrangement of cells in the tuber interior and at the exterior in the periderm was similar in both environments. Starch and protein were present in the tubers grown in space and on the ground. The range in starch grain size was similar in tubers from both environments, but the distribution of grains into size classes differed somewhat, with the space-grown tubers having more small grains than the ground control tubers. Proteinaceous crystals were found in tubers formed in each condition.

Environment, Controlled↗
PubMed1998

Kidney transplantation in children younger than 1 year using cyclosporine immunosuppression.

OBJECTIVE: The optimal age for transplantation in children with end-stage renal disease remains controversial. Supported by national data, many centers recommend dialysis until the child reaches a certain minimum age. The authors' policy, however, has been to encourage living donor (LD) transplants for young children, with no minimum age restriction. METHODS: Between January 1, 1984, and December 31, 1996, the authors performed 248 kidney transplants in children younger than age 13 years, using cyclosporine as the primary immunosuppressive agent. Recipients were analyzed in three age groups: group 1, younger than age 1 year (n = 26); group 2, age 1 through 4 (n = 92); and group 3, age 5 through 13 (n = 130). Almost all recipients in group 1 underwent a primary LD transplant. Therefore, to compare results more meaningfully among the three age groups, only primary LD transplants were analyzed (group 1, n = 25; group 2, n = 59; group 3, n = 58). RESULTS: In primary LD transplants, no significant difference was noted among the age groups in 1-and 5-year patient or graft survival rates. To date, all 25 recipients from group 1 are alive and well; 19 still have a functional original graft. Causes of graft loss in the remaining six recipients were chronic rejection (n = 3), vascular thrombosis (n = 2), and recurrent disease (n = 1). The incidence of acute rejection in group 1 recipients was lower than in the two older groups. However, the incidence of delayed graft function was slightly higher in the youngest group than in the two older groups. For recipients in group 1, growth (as measured by weight) improved significantly posttransplant: the mean standard deviation score rose from -2.8 pretransplant to -0.2 by age 5 and to +1.8 by age 10. The improvement in height was not as dramatic: the mean standard deviation score rose from -3.2 pretransplant to -1.6 by age 5 and to -1.4 by age 10. CONCLUSIONS: Kidney transplantation in young children, including those younger than 1 year old, can achieve results comparable to those in older children. As long as an adult LD is available, the timing of the transplant should be based on renal function rather than age.

Adolescent↗
PubMed1997

Case study of bovine dermatitis caused by oat straw infected with Fusarium sporotrichioides.

A dermatitis characterised by discrete, raised, plaque-like and cracked skin lesions of variable sizes on the udder, the hind quarters, the lips and muzzle of all the cows in a herd was suspected of being caused by the oat straw used in bedding, after initial feed analysis and skin culture were negative for toxins and dermatophytes. Mycological analysis indicated an extensive infestation of the oat straw by Fusarium sporotrichioides, a toxic mould, and an immunochemical assay indicated dermatotoxic trichothecenes in the straw (0.22 microgram/g dried straw). An ethyl acetate extract of the straw induced a necrotic response on shaved rat skin. Ingestion of the toxic bedding straw and inhalation of toxic straw dust probably also caused the internal haemorrhage and lung emphysema observed in the two cows that died. The regression of the dermatitis and the recovery of general herd health after the withdrawal of the oat straw further supported the diagnosis.

Animals↗
PubMed1997

Effect of conjugated linoleic acid on body composition in mice.

The effects of conjugated linoleic acid (CLA) on body composition were investigated. ICR mice were fed a control diet containing 5.5% corn oil or a CLA-supplemented diet (5.0% corn oil plus 0.5% CLA). Mice fed CLA-supplemented diet exhibited 57% and 60% lower body fat and 5% and 14% increased lean body mass relative to controls (P < 0.05). Total carnitine palmitoyltransferase activity was increased by dietary CLA supplementation in both fat pad and skeletal muscle; the differences were significant for fat pad of fed mice and skeletal muscle of fasted mice. In cultured 3T3-L1 adipocytes CLA treatment (1 x 10(-4)M) significantly reduced heparin-releasable lipoprotein lipase activity (-66%) and the intracellular concentrations of triacylglyceride (-8%) and glycerol (-15%), but significantly increased free glycerol in the culture medium (+22%) compared to control (P < 0.05). The effects of CLA on body composition appear to be due in part to reduced fat deposition and increased lipolysis in adipocytes, possibly coupled with enhanced fatty acid oxidation in both muscle cells and adipocytes.

3T3 Cells↗
PubMed1997

Is kidney length a good predictor of kidney volume?

Kidney length is commonly used to determine kidney size; however, its relationship to kidney volume is not well established. This study evaluated the association between kidney length and kidney volume. Eighteen healthy adults (9 men and 9 women) consented to take part in this prospective study; all 18 underwent spiral computerized tomography (CT) of the kidneys, 14 of 18 also underwent kidney ultrasound. Kidney volume was measured by totaling the areas of the CT scan cuts, and kidney length was measured both on the kidney ultrasound and on the CT scan. Each independent variable, CT length (CTL) and ultrasound length (USL), was regressed against the dependent variable, kidney volume. Kidney length explained only 10% of the variability of the volume, although length x width was a better predictor of kidney volume (r = 0.72, P < 0.001). It was concluded that kidney length does not reliably predict kidney volume and that other methods, both clinical and radiologic, should be considered when a more exact determination of renal volume is clinically relevant.

Adult↗
PubMed1997

CYP2J subfamily cytochrome P450s in the gastrointestinal tract: expression, localization, and potential functional significance.

Our laboratory recently described a new human cytochrome P450 arachidonic acid epoxygenase (CYP2J2) and the corresponding rat homologue (CYP2J3), both of which were expressed in extrahepatic tissues. Northern analysis of RNA prepared from the human and rat intestine demonstrated that CYP2J2 and CYP2J3 mRNAs were expressed primarily in the small intestine and colon. In contrast, immunoblotting studies using a polyclonal antibody raised against recombinant CYP2J2 showed that CYP2J proteins were expressed throughout the gastrointestinal tract. Immunohistochemical staining of formalin-fixed, paraffin-embedded intestinal sections using anti-CYP2J2 IgG and avidin-biotin-peroxidase detection revealed that CYP2J proteins were present at high levels in nerve cells of autonomic ganglia, epithelial cells, intestinal smooth muscle cells, and vascular endothelium. The distribution of this immunoreactivity was confirmed by in situ hybridization using a CYP2J2-specific antisense RNA probe. Microsomal fractions prepared from human jejunum catalyzed the NADPH-dependent metabolism of arachidonic acid to epoxyeicosatrienoic acids as the principal reaction products. Direct evidence for the in vivo epoxidation of arachidonic acid by intestinal cytochrome P450 was provided by documenting, for the first time, the presence of epoxyeicosatrienoic acids in human jejunum by gas chromatography/mass spectrometry. We conclude that human and rat intestine contain an arachidonic acid epoxygenase belonging to the CYP2J subfamily that is localized to autonomic ganglion cells, epithelial cells, smooth muscle cells, and vascular endothelium. In addition to the known effects on intestinal vascular tone, we speculate that CYP2J products may be involved in the release of intestinal neuropeptides, control of intestinal motility, and/or modulation of intestinal fluid/electrolyte transport.

8,11,14-Eicosatrienoic Acid↗
PubMed1997

Comparative effects of nabumetone, sulindac, and ibuprofen on renal function.

OBJECTIVE: Nonsteroidal antiinflammatory drugs (NSAID) have been associated with hemodynamically mediated acute renal failure. There appear to be differences among NSAID in producing this effect. We compare renal effects of ibuprofen, sulindac, and nabumetone. METHODS: Seventeen women over age 56 receiving hydrochlorothiazide and fosinopril for hypertension who had osteoarthritis requiring NSAID received 3 different NSAID to evaluate potential varying renal effects. In an investigator blinded randomized study, patients received nabumetone, sulindac, or ibuprofen for 1 month with intervening 2 week control periods. After each period renal function was assessed by inulin and para-aminohippurate clearances and urinary prostaglandins were measured. RESULTS: No overall statistical differences among the NSAID were observed. However, there were clinically meaningful differences during ibuprofen therapy: 4 patients developed a clinically significant decrease in renal function; during sulindac therapy one of these also developed a clinically significant decrease in renal function. During nabumetone there were 0 episodes of clinically significant decrease in renal function. Using Gomez equations, glomerular hydrostatic pressure and afferent and efferent arteriolar resistances were estimated. None changed overall during any intervention. However, the 4 patients who developed decreased renal function while taking ibuprofen were analyzed separately. Glomerular hydrostatic pressure decreased 15%; afferent arteriolar resistance increased 85%. These changes were associated with marked decreases in vasodilatory prostaglandins compared to patients receiving ibuprofen who did not develop decreases in renal function. CONCLUSION: There are differences in effect on renal function among NSAID. These can be correlated with specific alterations in suppression of the cyclooxygenase system cascade and related to changes in the hemodynamic control of glomerular filtration.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1997

Grandparent donors in a living related renal transplant program.

Clinical renal transplantation is limited by the number of cadaver and living related donors. The use of kidneys from older donors and non-first-degree relatives, including grandparents, has increased the supply of organs for transplantation. The purpose of this study was to assess donor and recipient outcomes after living related renal transplants between grandparent donors and grandchild recipients. Fifteen living related renal transplants using grandparent donors were performed at the University of Minnesota from 1971 to 1995. All medical records from donors and recipients were retrospectively reviewed. In addition, all grandparents or, in one case, a surviving family member were contacted to obtain current information on medical health and feedback about the donation process. A current serum creatinine (Cr) level was obtained from 14 donors and 15 recipients. Statistical calculations were performed using the SAS system. Eleven grandmothers and four grandfathers, 34-70 yr old (mean, 55 yr) at the time of transplantation, donated a kidney to 15 grandchildren with end-stage renal disease. There were no major surgical complications in either group. One donor died from unrelated causes; the other 14 donors are alive with stable renal function (1.3 +/- 0.3 mg/dL). Of 15 transplanted kidneys, 10 remain functional (Cr 1.3 +/- 0.7 mg/dL) with 2- and 5-yr graft survival rates of 76% and 63%, respectively. Our results indicate that healthy grandparents provide an excellent population for living related kidney donation.

Adolescent↗
PubMed1996

Reduction of ferricyanide by thiamine or thiamine pyrophosphate.

The colorimetric assay for the activity of pyruvate dehydrogenase (EC 1.2.4.1) developed by Itokawa is based on a coupled reduction of ferricyanide and the formation of Prussian blue (Brian Research 94, 475-484). In this assay system, we found that the coenzyme, thiamine pyrophosphate, itself reduced ferricyanide independent of both the enzyme and the substrate. Similar effect was also observed with thiamine, but not with thiochrome. The reduction of ferricyanide by thiamine or thiamine pyrophosphate was blocked by trichloroacetic acid. Measurement of the activity of purified pyruvate dehydrogenase based on monitoring the reduction of ferricyanide as described by Schwartz et al (Biochem. Biophys. Res. Commun. 31, 495-500) has been widely used. Our findings clearly disprove the assumption that reduction of ferricyanide is dependent on pyruvate dehydrogenase and invalidate assays for thiamine-dependent dehydrogenases based on the reduction of ferricyanide.

Animals↗
PubMed1996

Case reports: cocaine-associated accelerated hypertension and renal failure.

These are two cases of cocaine abuse with the following previously unreported cocaine-associated features: 1) biopsy-proven accelerated/malignant hypertension, 2) association of cocaine with persistent hypertension, and 3) renal failure with rapid progression to end-stage renal disease that did not reverse following blood pressure control.

Adult↗
PubMed1995

Early detection of catabolic state via change in 13C/12C ratios of blood proteins.

We find that induction of catabolic state changes the ratios of carbon 13 to carbon 12 in blood proteins. Diet can be inferred in growing chicks by feather carbon isotope ratios. This suggests an approach for early detection of catabolic state induced in patients with HIV, cancers that induce catabolism, infection onset, sepsis, kidney and liver disease, malnutrition and dietary problems. The technique would also be useful in animal husbandry.

Animals↗
PubMed1994

Feeding conjugated linoleic acid to animals partially overcomes catabolic responses due to endotoxin injection.

The ability of conjugated linoleic acid to prevent endotoxin-induced growth suppression was examined. Mice fed a basal diet or diet with 0.5% fish oil lost twice as much body weight after endotoxin injection than mice fed conjugated linoleic acid. By 72 hours post injection, mice fed conjugated linoleic acid had body weights similar to vehicle injected controls; however, body weights of basal and fish oil fed mice injected with endotoxin were reduced. Conjugated linoleic acid prevented anorexia from endotoxin injection. Splenocyte blastogenesis was increased by conjugated linoleic acid.

Animals↗
PubMed1994

Conjugated linoleic acid is a growth factor for rats as shown by enhanced weight gain and improved feed efficiency.

We studied the effect of conjugated linoleic acid (CLA) on rat development and growth. Primigravid female Fischer rats were fed control or CLA-supplemented (0.25% or 0.5% CLA) diets during gestation and/or lactation. Conjugated linoleic acid was incorporated into milk fat and tissue lipids proportional to the level of CLA fed and the duration of CLA feeding. Conjugated linoleic acid was incorporated into fetal and neonatal tissues; it did not affect litter size nor induce apparent abnormalities. To the contrary, feeding CLA to the dams during gestation and lactation improved the postnatal body weight gain of pups (P < 0.05), measured on d 10 of lactation. Pups that continued to receive the CLA-supplemented diet after weaning had significantly greater body weight gain and improved feed efficiency relative to control animals (P < 0.05).

Animals↗
PubMed1994

Molybdenum but not copper counteracts cysteine-induced tibial dyschondroplasia in broiler chicks.

Studies were conducted to evaluate the ability of copper and molybdenum to prevent cysteine-induced tibial dyschondroplasia in broiler chicks. Experiment 1 was a 3 x 3 factorial arrangement of treatments used to investigate the interaction between Cu (0, 150 or 300 mg/kg diet) and Mo (0, 10, or 100 mg/kg diet) on cysteine-induced tibial dyschondroplasia. Molybdenum at both supplemental levels, but not Cu, prevented cysteine-induced tibial dyschondroplasia. In Experiment 2 (a 3 x 3 factorial arrangement of treatments with 0, 5 or 10 g/kg diet of cysteine and 0, 10 or 100 mg/kg diet of Mo), Mo prevented cysteine-induced but not spontaneous tibial dyschondroplasia. Cysteine and Mo did not affect the mechanical properties of the tibiotarsus. In Experiment 3, cysteine (0 or 10 g/kg diet) and Mo (0 or 100 mg/kg diet) were used to study the tissue concentrations of mineral and hepatic sulfite oxidase activity. Supplemental Mo increased Mo concentrations in the plasma and liver. Cysteine prevented these increases; however, cysteine, in the absence of supplemental Mo, did not affect concentrations of Mo in these tissues. Dietary cysteine and/or Mo did not affect tissue levels of Cu. We conclude that Mo prevents cysteine-induced tibial dyschondroplasia and that the induction of tibial dyschondroplasia by cysteine is not related to the Mo and Cu deficiency.

Animals↗