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Ginzinger DG, Clee SM, Dallongeville J, Lewis ME, Henderson HE, Bauje E, Rogers QR, Jensen DR, Eckel RH, Dyer R, Innis S, Jones B, Fruchart JC, Hayden MR. Lipid and lipoprotein analysis of cats with lipoprotein lipase deficiency. Eur J Clin Invest 1999; 29:17-26. [PMID: 10092984 DOI: 10.1046/j.1365-2362.1999.00435.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND We have previously described a colony of domestic cats with a naturally occurring mutation in the lipoprotein lipase (LPL) gene. We have now further characterized cats homozygous for LPL deficiency (LPL -/-, homozygotes), and have contrasted these with heterozygotes (LPL +/-) and normal cats (LPL +/+). MATERIALS AND METHODS Density gradient ultracentrifugation with subsequent lipid analysis, agarose and polyacrylamide gel electrophoresis was used to examine detailed liproprotein differences between the genotypes. Oral fat loading studies and breast milk fatty acid analysis were also performed to further characterize the phenotypic expression of LPL deficiency in this model system. RESULTS Several lipid abnormalities associated with homozygosity for LPL deficiency were evident. Triglyceride-rich lipoprotein-triglycerides (TRL-TG) and cholesterol (TRL-C) were higher (TRL-TG 2.09 +/- 1.14 vs. 0.15 +/- 0.04 mmol L-1, P < 0.001; TRL-C 0.42 +/- 0.30 vs. 0.11 +/- 0.16 mmol L-1, P < 0.05) in male -/- than in male +/+ cats, as was HDL-cholesterol (HDL-C, 1.75 +/- 0.24 vs. 1.41 +/- 0.14 mmol L-1, P < 0.05). LDL-C levels were lower in homozygous cats than in control cats, similar to what is seen in human LPL deficiency. Oral fat loading studies revealed that homozygous cats have a marked reduced ability to clear plasma TGs in terms of peak time (7 h vs. 3 h), peak height (9.36 vs. 1.1 mmol L-1), area under the TG clearance curve (AUC, 280.3 vs. 2.2 h mmol L-1) and time to return to baseline. Fasting lipid and lipoprotein levels were not significantly different between heterozygous and normal cats. However, oral fat loading in heterozygotes revealed an intermediate phenotype (peak of 2.35 mmol L-1 at 5 h, AUC 13.1 h mmol L-1), highlighting the impaired TG clearance in these animals. CONCLUSION Thus, LPL deficiency in the cat results in a lipid and lipoprotein phenotype that predominantly parallels human LPL deficiency, further validating the use of these animals in studies on the pathobiology of LPL.
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Abstract
Matrix metalloproteinases are a family of highly regulated peptidases that are collectively responsible for the degradation of extracellular matrix during tissue remodeling. Dysregulated activity has long been implicated in the pathologies of cancer and arthritis, and the number of diseases more recently associated with these enzymes has been increasing. In the past year, new transgenic models of matrix metalloproteinase knockouts have been described, allowing the direct assessment of specific enzyme activity in particular disease models. In addition, more selective inhibitors with improved pharmacokinetic profiles have entered clinical trials, allowing the assessment of the safety and efficacy of this strategy.
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Djuric S, Dyer R, Glaser KB. Therapeutic regulation of allergic and inflammatory diseases, Fifth Annual Midwest Meeting, Chicago, IL, USA, 11 April 1997. Inflamm Res 1997; 46:482-5. [PMID: 9459077 DOI: 10.1007/s000110050229] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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Fuhrmann M, Zhou H, Neiheisel J, Schoonen MA, Dyer R. Sorption/desorption of radioactive contaminants by sediment from the Kara Sea. THE SCIENCE OF THE TOTAL ENVIRONMENT 1997; 202:5-24. [PMID: 9241875 DOI: 10.1016/s0048-9697(97)00101-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
To understand the long term impact of the disposal of radioactive waste on the Kara Sea, partition coefficients (Kd) for several important radionuclides, the mineralogy of the sediment, and the relationship of Kd to liquid-to-solid ratio were quantified. Sediment was obtained from four locations in the Kara Sea area. Slow sorption kinetics were observed for 85Sr, 232U, 125I and 99Tc, whilst sorption was rapid (less than 50 h to steady-state) for 137Cs, 210Pb, and 241Am. Partition coefficients (Kd) were determined using batch type experiments and sorption isotherms which were developed for 85Sr, 99Tc, 125I, U and 137Cs. Partition coefficients for 137Cs were approx. 350 ml/g for sediment from the Trough and 180 ml/g for Stepovogo Fjord. This difference may be caused by the lower fraction of expandable clay in sediment from the fjord. Uptake of 85Sr, 99Tc, 125I, and U were all similar for both locations, with Kd values averaging 4, 3, 17 and 60 ml/g, respectively. The Kd for 137 Cs varied non-linearly from 40 to 3800 ml/g as the liquid-to-solid ratio varied from 3.4 to 6500, but only when the sorption capacity was high compared to the mass of 137Cs in the closed system of the experiment. Under identical conditions, sediment with lower Kd values showed no effect. Oxidation of sediment effectively desorbed 99Tc from the solid phase, whilst it caused increased uptake of 85Sr and U. In sequential rinses with fresh seawater, desorption was limited to 60% of 137Cs and 85Sr, and 35% of uranium.
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Innis SM, Dyer R. Dietary triacylglycerols with palmitic acid (16:0) in the 2-position increase 16:0 in the 2-position of plasma and chylomicron triacylglycerols, but reduce phospholipid arachidonic and docosahexaenoic acids, and alter cholesteryl ester metabolism in formula-Fed piglets. J Nutr 1997; 127:1311-9. [PMID: 9202085 DOI: 10.1093/jn/127.7.1311] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Milk triacylglycerols have an unusual fatty acid distribution, with palmitic acid (16:0) esterified predominately at the center (sn-2) position. Other dietary triacylglycerols contain 16:0 predominantly at the sn-1,3 positions. This study was designed to evaluate the effect of formula triacylglycerol fatty acid distribution on the composition and distribution of plasma lipoprotein fatty acids in piglets fed formula containing synthesized triacylglycerols or palm olein oil with about 32 or 4.2% 16:0, respectively, in fatty acids at the sn-2 position, with comparison to piglets fed sow's milk. Feeding formula with 16:0 at the triglyceride sn-2 position or sow's milk resulted in higher chylomicron triacylglycerol sn-2 16:0 than when palm olein was fed. This suggests that dietary triacylglycerol sn-2 position fatty acids are conserved during digestion, absorption and reassembly to chylomicron triacylglycerols. The increased chylomicron triacylglycerol sn-2 position 16:0 in piglets fed synthesized triacylglycerols was accompanied by lower chylomicron triacylglycerol arachidonic and docosahexaenoic acid than in piglets fed formula with palm olein, suggesting an interaction between dietary triacylglycerol saturated fatty acid distribution and (n-6) and (n-3) fatty acid transport.
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Rioux FM, Innis SM, Dyer R, MacKinnon M. Diet-induced changes in liver and bile but not brain fatty acids can be predicted from differences in plasma phospholipid fatty acids in formula- and milk-fed piglets. J Nutr 1997; 127:370-7. [PMID: 9039842 DOI: 10.1093/jn/127.2.370] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The fatty acid composition of plasma phospholipids differs between infants fed formula and infants fed human milk, but the extent to which this is accompanied by differences in tissue phospholipid fatty acids is unclear. This paper describes analysis of plasma, liver and brain fatty acids from piglets fed one of seven formulas, varying in saturated, monounsaturated, (n-6) and (n-3) fatty acids or sow milk from birth for 18 d. Bile fatty acids were analyzed because they are secreted from liver and may be an important source of fatty acids for intestinal lipoprotein synthesis. The results were used to determine the relation between diet-related differences in plasma phospholipid fatty acids and those in brain, liver and bile. Where significant associations were found, prediction limits were constructed to assess the usefulness of analysis of plasma phospholipid fatty acids to predict diet-induced changes in tissue fatty acids. The proportions (g/100 g fatty acids) of 16:0, 18:0, 18:1, 18:2(n-6) and 20:4(n-6) in plasma phospholipids were significantly associated with the proportions of the same fatty acids in liver and bile, but not brain. The results show a reasonably precise, predictable association between plasma and liver, and plasma and bile fatty acids. Brain 20:4(n-6) and 22:6(n-3), in contrast, were not reliably associated with plasma phospholipid 20:4(n-6) and 22:6(n-3) for piglets fed milk or formula providing about 1.5% energy as 18:3(n-3).
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Innis SM, Dyer R, Quinlan PT, Diersen-Schade D. Dietary triacylglycerol structure and saturated fat alter plasma and tissue fatty acids in piglets. Lipids 1996; 31:497-505. [PMID: 8727642 DOI: 10.1007/bf02522643] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Human and pig milk triacylglycerols contain a large proportion of palmitic acid (16:0) which is predominately esterified in the 2-position. Other dietary fats contain variable amounts of 16:0, with unsaturated fatty acids predominantly esterified in the 2-position. These studies determined if the amount or position of 16:0 in dietary fat influences the composition or distribution of liver, adipose tissue, lung, or plasma fatty acids in developing piglets. Piglets were fed to 18 d with sow milk or formula with saturated fat from medium-chain triglyceride (MCT), coconut or palm oil, or synthesized triacylglycerols (synthesized to specifically direct 16:0 to the 2-position) with, in total fatty acids, 30.7, 4.3, 6.5, 27.0, and 29.6% 16:0, and in 2-position fatty acids, 55.3, 0.4, 1.3, 4.4, and 69.9% 16:0, respectively. The percentage of 16:0 in the 2-position of adipose fat from piglets fed sow milk, palm oil, and synthesized triacylglycerols were similar and higher than in piglets fed MCT or coconut oil. Thus, the amount, not the position, of dietary 16:0 determines piglet adipose tissue 16:0 content. The effects of the diets on the plasma and liver triacylglycerols were similar, with significantly lower 16:0 in total and 2-position fatty acids of the MCT and coconut oil groups, and significantly higher 16:0 in the plasma and liver triacylglycerol 2-position of piglets fed the synthesized triacylglycerols rather than sow milk or palm oil. The lung phospholipid total and 2-position 16:0 was significantly lower in the MCT, coconut, and palm oil groups, but similar in the synthesized triacylglycerol group and sow milk group. The lung phospholipid total and 2-position percentage of arachidonic acid (20:4n-6) was significantly lower in all of the formula-fed piglets than in milk-fed piglets. The physiological significance of this is not known.
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Bandy WD, Strong L, Roberts T, Dyer R. False aneurysm--a complication following an inversion ankle sprain: a case report. J Orthop Sports Phys Ther 1996; 23:272-9. [PMID: 8775373 DOI: 10.2519/jospt.1996.23.4.272] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Sprains of the lateral ligamentous structures of the ankle joint as a result of inversion are common and frequently result in pain. In most cases, the pain is related to soft-tissue injury and the associated hemorrhage and swelling. This case report describes the complication of posttraumatic false aneurysm of the peroneal artery following an inversion ankle sprain in a 22-year-old athlete, a complication which should be added to the differential diagnosis as a rare, but important possibility. Emphasis of the case report is placed on the rehabilitation of the patient following medical intervention.
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Santos C, Galdos R, Alvarez M, Velarde C, Barriga O, Dyer R, Estrada H, Almonte M. One-session management of cervical intraepithelial neoplasia: a solution for developing countries. Gynecol Oncol 1996; 61:11-5. [PMID: 8626096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Six hundred thirty-nine patients with CIN on referral Pap were evaluated cytocolposcopically at the first visit and decided whether to be treated the same day or not. One hundred ninety-two patients (30%) were considered negative. Follow-up evidenced later appearance of CIN in five of them. One hundred fifty-three (24%) were candidates for delayed treatment due to conditions contraindicating same-day treatment. Two hundred ninety-four patients (46%) were randomly allocated in LEEP (149) or excisional laser (145) arms, and treated the same day under local anesthesia. Both arms were comparable. There were three microinvasive carcinomas diagnosed in the surgical specimen. LEEP was faster and produced less bleeding than laser, although required a mean of four slices to remove the lesion. Arterial hypertension after anesthetic infiltration was detected in 26% of cases. Two intraoperative and two delayed bleeders required surgery. The size of lesion and surgical defect were larger than those reported in the literature. Margins were involved in 8 patients (2.7%). Only 4.7% (7/149) of patients randomized to LEEP and 3.4% (5/145) with excisional laser had persistent or recurrent CIN on follow-up. Factors predisposing to failure included depth of surgical defect, grade of lesion, and operator's expertise. With this approach, 69% of patients referred for cytology of CIN were adequately managed in the first visit, which contrasts to classical management that reaches the state of treatment in 30% of patients. LEEP appears to be faster, less costly, and requires less expertise. Its use in conjunction with adequate screening is recommended for developing countries.
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Dyer R, Cohan RH. What is the risk of reaction on repeat exposure to contrast material, and how should the patients be premedicated? AJR Am J Roentgenol 1995; 165:1543. [PMID: 7484603 DOI: 10.2214/ajr.165.6.7484603] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Pow-Sang M, Orihuela E, Motamedi M, Pow-Sang JE, Cowan DF, Dyer R, Warren MM. Thermocoagulation effect of diode laser radiation in the human prostate: acute and chronic study. Urology 1995; 45:790-4. [PMID: 7747372 DOI: 10.1016/s0090-4295(99)80085-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
OBJECTIVES To evaluate the safety and efficacy of low-power slow-heating diode laser-induced photocoagulation of prostatic tissue for treatment of benign prostatic hyperplasia, we conducted a series of acute and chronic studies using a diode laser (810 nm) to irradiate human prostate. METHODS The study included 6 patients undergoing radical prostatectomy because of malignancy. Laser radiation to the prostate was given transurethrally, in a noncontact mode, at the time of the procedure in 2 patients (acute group): 10 W for 300 seconds on the right side of the prostate and 15 W for 180 seconds on the left. In the remaining 4 patients (chronic group), laser radiation was given at 1, 7, 10, and 12 weeks prior to the prostatectomy. RESULTS In the acute group the average depth of coagulation was 8.5 and 9.0 mm for the laser regimens of 15 W for 180 seconds and the 10 W for 300 seconds, respectively. In the chronic group, the average depth of coagulation was 8.9 mm for both laser regimens studied. In the acute group, there was an ill-defined hemorrhagic ring at the periphery of the lesion. At 1 week, an intact necrotic coagulum was present. At 7 weeks, some of the coagulated tissue had already sloughed off. Longer follow-up at 10 and 12 weeks demonstrated formation of a well-defined cavity with mostly re-epithelialized surface. CONCLUSIONS Our findings suggest that noncontact diode laser (810 nm) irradiation can induce in the human prostate significant coagulation necrosis followed by sloughing of tissue and cavitation of the prostatic urethra.
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Innis SM, Dyer R, Quinlan P, Diersen-Schade D. Palmitic acid is absorbed as sn-2 monopalmitin from milk and formula with rearranged triacylglycerols and results in increased plasma triglyceride sn-2 and cholesteryl ester palmitate in piglets. J Nutr 1995; 125:73-81. [PMID: 7815179 DOI: 10.1093/jn/125.1.73] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Milk fatty acids contain 20-30% palmitic acid (16:0), with approximately 70% of the 16:0 esterified to the sn-2 position of the milk triacylglycerol. Formulae containing vegetable and oleo oils contain different amounts of 16:0, but all have unsaturated fatty acids esterified to the triacylglycerol sn-2 position. Intraluminal triacylglycerol hydrolysis by endogenous lipases produces sn-2 monoacylglycerols and free fatty acids, which are absorbed and re-esterified in the enterocyte for secretion to plasma. The extent of absorption and re-esterification of sn-2 monoacylglycerols from milk or formula fats in infants is unknown. This was studied by feeding piglets sow milk or formulae containing similar total saturated fat, 18:1, 18:2(n-6) and 18:3(n-3) with unsaturated fatty acids at the sn-2 position or with rearranged triacylglycerols containing approximately 30% 16:0, with 70% 16:0 in fatty acids at the sn-2 position. Feeding milk or 16:0 on the sn-2 position of formula with rearranged triacylglycerols resulted in higher 16:0 esterified to the plasma triacylglycerol sn-2 position and in cholesteryl esters than feeding formulae with 0.4 to 4.4% 16:0 in the sn-2 position fatty acids. The absorption of 16:0 as monopalmitin from milk and any metabolic importance in human infants has yet to be determined.
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Innis SM, Dyer R, Nelson CM. Evidence that palmitic acid is absorbed as sn-2 monoacylglycerol from human milk by breast-fed infants. Lipids 1994; 29:541-5. [PMID: 7990660 DOI: 10.1007/bf02536625] [Citation(s) in RCA: 119] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Milk fatty acids consist of about 20-25% palmitic acid (16:0), with about 70% of 16:0 esterified to the sn-2 position of the milk triacylglycerols. Hydrolysis of dietary triacylglycerols by endogeneous lipases produces sn-2 monoacylglycerols and free fatty acids, which are absorbed, reesterified, and then secreted into plasma. Unesterified 16:0 is not well absorbed and readily forms soaps with calcium in the intestine. The positioning of 16:0 at the sn-2 position of milk triacylglycerols could explain the high coefficient of absorption of milk fat. However, the milk lipase, bile salt-stimulated lipase, has been suggested to complete the hydrolysis of milk fat to free fatty acids and glycerol. These studies determined whether 16:0 is absorbed from human milk as sn-2 monopalmitin by comparison of the plasma triacylglycerol total and sn-2 position fatty acid composition between breast-fed and formula-fed term gestation infants. The human milk and formula had 21.0 and 22.3% of 16:0, respectively, with 54.2 and 4.8% 16:0 in the fatty acids esterified to the 2 position. The plasma triacylglycerol total fatty acids had 26.0 +/- 0.6 and 26.2 +/- 0.6% of 16:0, and the sn-2 position fatty acids had 23.3 +/- 3.3 and 7.4 +/- 0.7% of 16:0 in the three-month-old exclusively breast-fed (n = 17) and formula-fed (n = 18) infants, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
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Innis SM, Dyer R, Wadsworth L, Quinlan P, Diersen-Schade D. Dietary saturated, monounsaturated, n-6 and n-3 fatty acids, and cholesterol influence platelet fatty acids in the exclusively formula-fed piglet. Lipids 1993; 28:645-50. [PMID: 8355594 DOI: 10.1007/bf02536060] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Platelet lipid composition is important to normal platelet morphology and function, and is influenced by dietary fatty acids and cholesterol. The fatty acid composition and cholesterol content of infant formulas differs from those of human milk, but the possible effects on platelet lipids in young infants is not known. This was studied in piglets fed from birth to 18 d of age with one of eight formulas differing in saturated fatty acid chain length, or content of 18:1, 20:5n-3 plus 22:6n-3, or cholesterol. A reference group of piglets fed sow milk was also studied. Sow milk has a fatty acid composition and cholesterol content similar to that of human milk. Piglets fed formulas high in 18:1 (34.9-40.8% wt fatty acids) and low in 16.0 (< or = 6.5% wt fatty acids) had lower platelet counts and greater platelet size than piglets fed sow milk (40.4% 18:1, 30.7% 16:0). Piglets fed formulas high in 16:0 (27-29.6%) and 18:1 (40-40.6%), or low in both 16:0 (5.9-6.1%) and 18:1 (10.8-11.2%), had similar platelet counts and size to piglets fed sow milk. Platelet phospholipid % 20:4n-6 was lower in all the groups of piglets fed formula than in the group fed sow milk. Addition of fish oil with 20:5n-3 plus 22:6n-3 to the formula further decreased platelet phospholipid 20:4n-6. Addition of cholesterol to the formula increased the platelet phospholipid % 20:4n-6 and platelet volume.
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Becque MD, Katch V, Marks C, Dyer R. Reliability and within subject variability of VE, VO2, heart rate and blood pressure during submaximum cycle ergometry. Int J Sports Med 1993; 14:220-3. [PMID: 8325722 DOI: 10.1055/s-2007-1021167] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
To assess the reliability and within subject variability of steady-rate ventilation (VE), oxygen uptake (VO2), heart rate, systolic and diastolic blood pressure, 4 subjects exercised for 10 minutes at 3 work rates on a bicycle ergometer: 50 W, 125 W and 55% of maximum work rate (55% max). Each testing session included two work rates and only 2 testing sessions were scheduled per week. The order of the work rates was counterbalanced. In 8 to 10 weeks, 3 of the subjects completed 20 trials at 50 W while the fourth subject completed 11 trials, and all the subjects completed 10 trials at 125 W and 55% max. The within subject variability (S2w) was expressed as a percent of the mean steady-rate response. VO2 ranged from 21.2% to 27.5% of VO2max at 50 W, from 37.7% to 49.7% at 125 W and from 42.9% to 63.7% at 55% max. The S2w averaged 6.8% for VE, 4.3% for VO2, 3.2% for heart rate, 7.3% for systolic blood pressure and 10.5% for diastolic blood pressure. Reliability coefficients were calculated for the steady-rate scores by dividing the between subject variation by the total variation. The reliability was similar for VE, VO2 and heart rate and ranged from r = 0.69 to r = 0.97. Systolic and diastolic blood pressure reliabilities were lower and ranged from r = 0.27 and r = 0.80. In summary, the steady-rate ventilation, oxygen uptake and heart rate responses were reliable and consistent. The reliability of blood pressure was low. It is possible that this low reliability may result from variability in stroke volume or total peripheral resistance.
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Marshall LZ, Gilliam JH, Dyer R, Meredith JH. Dormia basket entanglement with a T tube: management with interventional radiologic techniques. Gastrointest Endosc 1993; 39:196-8. [PMID: 8495848 DOI: 10.1016/s0016-5107(93)70071-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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Carter GW, Young PR, Albert DH, Bouska J, Dyer R, Bell RL, Summers JB, Brooks DW. 5-lipoxygenase inhibitory activity of zileuton. J Pharmacol Exp Ther 1991; 256:929-37. [PMID: 1848634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Zileuton [N-(1-benzo[b]thien-2-ylethyl)-N-hydroxyure] inhibited 5-hydroxyeicosatetraenoic acid synthesis by rat basophilic leukemia cell 20,000 x g supernatant and rat polymorphonuclear leukocytes (PMNL) (IC50 = 0.5 and 0.3 microM) respectively. It also inhibited leukotriene (LT)B4 biosynthesis by rat PMNL (IC50 = 0.4 microM), human PMNL (IC50 = 0.4 microM) and human whole blood (IC50 = 0.9 microM). Inhibition of human PMNL LTB4 biosynthesis was removed readily by a simple wash procedure. At concentrations up to 100 microM, the compound produced little or no inhibition of several related enzymes, such as platelet 12-lipoxygenase, soybean and rabbit reticulocyte 15-lipoxygenase and sheep seminal vesicle cyclooxygenase. At p.o. doses from 0.5 to 5 mg/kg in the dog, zileuton produced a rapid and sustained inhibition of ex vivo blood LTB4 biosynthesis which correlated with the pharmacokinetic behavior of the compound. In a similar ex vivo study in the rat, the compound displayed an p.o. ED50 of 2 mg/kg. Zileuton was highly effective in preventing 6-sulfidopeptide LT formation in the rat peritoneal cavity triggered by an antigen-antibody reaction with an ED50 of 3 mg/kg. In experimental models of inflammation, zileuton significantly reduced arachidonic-acid induced mouse ear edema (ED50 = 31 mg/kg) and also attenuated inflammatory cell accumulation in the rat pleural Arthus reaction. The effectiveness of this compound for preventing LT formation in vitro, ex vivo and in vivo suggests its utility for preventing the pathophysiological effects of the LTs and other 5-lipoxygenase products in animals and in humans.
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Perks AM, Dore JJ, Dyer R, Thom J, Marshall JK, Ruiz T, Woods BA, Vanderhorst E, Ziabakhsh S. Fluid production by in vitro lungs from fetal guinea pigs. Can J Physiol Pharmacol 1990; 68:505-13. [PMID: 2328453 DOI: 10.1139/y90-072] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Lungs from fetal guinea pigs (54-67 days of gestation) were supported in vitro, and lung liquid secretion rates were measured by a dye-dilution technique. The average secretion rate in the first hour was 2.14 +/- 0.08 (SE) mL x kg-1 body weight.h-1 (0.21 +/- 0.01 mL/h) (n = 450); this was comparable to intact preparations. In an independent study of 30 lungs, secretion continued unchanged for 3 h, with no significant change in fluid composition. Between 54 days and term, production appeared to fall in terms of millilitres per kilogram per hour. The following agents were placed in the supporting saline during the middle hour of incubation. (i) Sodium iodoacetate: at 10(-4) M this produced a fall in secretion (fall, succeeding hours; 55.4 +/- 23.0 and 64.9 +/- 17.5%; n = 6); at 10(-3) M it stopped secretion (fall, succeeding hours; 87.2 +/- 10.3 and 100%, n = 6). (ii) Ouabain: at 10(-5) M there was no change in production (n = 6); at 10(-4) M, four preparations were unaffected, two reduced production. (iii) Epinephrine (10(-7) M) produced a significant fall in production in all cases (n = 6); in four preparations secretion reduced (average fall, 64.4 +/- 10.8%); in two preparations there was reabsorption (average rate, -1.03 mL.kg-1.h-1). This extends the effect of epinephrine to the guinea pig, and suggests that the in vitro preparation is a useful model for studies of the fetal lung.
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Koup JR, Tucker E, Thomas DJ, Kinkel AW, Sedman AJ, Dyer R, Sharoky M. A single and multiple dose pharmacokinetic and metabolism study of meclofenamate sodium. Biopharm Drug Dispos 1990; 11:1-15. [PMID: 2322633 DOI: 10.1002/bdd.2510110102] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A single and multiple oral dose administration study of meclofenamate sodium (Meclomen) was conducted in ten healthy male volunteers. An initial 300 mg oral dose on day 1 was followed by a 100 mg every 8 h dosage regimen on study days 4 through 18. Intensive plasma and urine sample collection was carried out over the first three study days, and for 120 h following administration of the final dose on day 18. Plasma and urine specimens were analyzed by a specific HPLC assay for unconjugated meclofenamic acid and metabolites I and II of meclofenamic acid before and after sample incubation with beta-glucuronidase. Meclofenamic acid was rapidly absorbed following oral dose administration. Concentrations of meclofenamic acid existed primarily as unconjugated drug in plasma, with only a small amount present in the conjugated form. Meclofenamic acid was rapidly eliminated, with an elimination half-life of approximately 1.3 h. This resulted in no detectable accumulation upon multiple dose administration. Metabolite I, which is one-fifth as active as meclofenamic acid in in vitro inhibition of cyclooxygenase, was present in unconjugated form at steady state in concentrations approximately 50 per cent of those of meclofenamic acid, as unconjugated drug. The majority of metabolite I in plasma existed as glucuronide conjugate. Metabolite II, which is inactive, was present in very significant concentrations in unconjugated form. Plasma protein binding determinations conducted on meclofenamic acid and metabolite I indicated that the free fraction of metabolite I was 8.7 to 10.9 times higher than that of meclofenamic acid. When the lower activity and lower steady state concentrations, but higher free fraction, are considered, it would appear that metabolite I may contribute significantly to the in vivo inhibition of cyclooxygenase activity seen after administration of meclofenamic acid.
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Otto D, Hudnell K, Boyes W, Janssen R, Dyer R. Electrophysiological measures of visual and auditory function as indices of neurotoxicity. Toxicology 1988; 49:205-18. [PMID: 3287694 DOI: 10.1016/0300-483x(88)90001-7] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The application of auditory and visual evoked potentials (VEP) to neurotoxicity testing of humans and animals is reviewed. VEPs elicited by flash, reversing-checkerboard patterns, and sine wave grating are described. The flask evoked potential in rats is altered by exposure to many heavy metals, pesticides and solvents. The brainstem auditory evoked potential also appears to be sensitive to neurotoxic chemicals, but the evidence available is limited. The homology of auditory and visual evoked potentials in rats and humans is useful for cross-species extrapolation in neurotoxicology research.
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48
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Van Swearingen FL, McCullough DL, Dyer R, Appel B. Radiation exposure to patients during extracorporeal shock wave lithotripsy. J Urol 1987; 138:18-20. [PMID: 3599209 DOI: 10.1016/s0022-5347(17)42972-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Extracorporeal shock wave lithotripsy is rapidly becoming an accepted treatment of renal calculi. Since fluoroscopy is involved to image the stones it is important to know how much radiation the patient receives during this proCedure. Surface radiation exposure to the patient was measured in more than 300 fluoroscopic and radiographic procedures using thermoluminescent dosimeters. Initial results showed an average skin exposure of 10.1 rad per procedure for each x-ray unit, comparing favorably with exposure rates for percutaneous nephrostolithotomy and other routine radiological procedures. Factors influencing exposure levels include stone characteristics (location, size and opacity), physician experience and number of shocks required. Suggestions are given that may result in a 50 per cent reduction of radiation exposure.
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49
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Tilson HA, Harry GJ, Nanry K, Rogers B, Peterson J, Jensen K, Dyer R. Experiential factors in the expression of hypermotility produced by intradentate colchicine: lack of effect of GM1 ganglioside on colchicine-induced loss of granule cells and mossy fibers. J Neurosci Res 1987; 17:410-6. [PMID: 3625805 DOI: 10.1002/jnr.490170412] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Adult male Fischer-344 rats were given bilateral injections of 2.5 micrograms colchicine or artificial cerebrospinal fluid into caudal and rostral sites of the dentate gyrus of the hippocampus. One group of rats received 21 consecutive daily injections of 20 mg/kg GM1 gangliosides, i.p., beginning the day prior to surgery. Another group received saline. Colchicine-induced hypermotility was not seen in animals repeatedly handled 21 d after surgery, in spite of significant decreases in granule cell number and decreases in the volume of hippocampal mossy fibers. Pretreatment with GM1 had no effect on behavior and it did not protect against the hippocampal damage produced by colchicine. Rats given colchicine, but not handled for 21 d, showed significant hypermotility, which was associated with decreases in hippocampal granule cells. These data underscore the importance of handling in postlesion functional recovery.
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50
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Seedat YK, Cassim B, Dyer R. Acute pernicious or fulminating beriberi with severe lactic acidosis. A case report. S Afr Med J 1985; 68:817-8. [PMID: 4071332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
This report describes a case of severe acidosis with cardiac failure due to alcohol in a black man. Treatment with parenteral thiamine produced a prompt response. Thiamine deficiency should be recognized as an important cause of lactic acidosis.
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