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Conlin PR, Chow D, Miller ER, Svetkey LP, Lin PH, Harsha DW, Moore TJ, Sacks FM, Appel LJ. The effect of dietary patterns on blood pressure control in hypertensive patients: results from the Dietary Approaches to Stop Hypertension (DASH) trial. Am J Hypertens 2000; 13:949-55. [PMID: 10981543 DOI: 10.1016/s0895-7061(99)00284-8] [Citation(s) in RCA: 136] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
To determine the impact of dietary patterns on the control of hypertension we studied the subgroup of 133 participants with systolic blood pressure (BP) of 140 to 159 mm Hg and/or diastolic BP of 90 to 95 mm Hg enrolled in the Dietary Approaches to Stop Hypertension (DASH) study. Participants were fed a control diet for a 3-week period and were then randomized to receive for 8 weeks either the control diet; a diet rich in fruits and vegetables, but otherwise similar to control; or a combination diet rich in fruits, vegetables, and low-fat dairy products, including whole grains, fish, poultry, and nuts, and reduced in fats, red meats, sweets, and sugar-containing beverages. Sodium intake and body weight were held constant throughout the study. The combination diet significantly reduced systolic BP (-11.4 mm Hg, P < .001) and diastolic BP (-5.5 mm Hg, P < .001). The fruits-and-vegetables diet also significantly reduced systolic BP (-7.2 mm Hg, P < .001) and diastolic BP (-2.8 mm Hg, P = .013). The combination diet produced significantly greater BP effects (P < .05) than the fruits-and-vegetables diet. Blood pressure changes were evident within 2 weeks of starting the intervention feeding. After the 8-week intervention period, 70% of participants eating the combination diet had a normal BP (systolic BP < 140 and diastolic BP < 90 mm Hg) compared with 45% on the fruits-and-vegetables diet and 23% on the control diet. In patients with hypertension, the DASH combination diet effectively lowers BP and may be useful in achieving control of Stage 1 hypertension.
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Appel LJ, Miller ER, Jee SH, Stolzenberg-Solomon R, Lin PH, Erlinger T, Nadeau MR, Selhub J. Effect of dietary patterns on serum homocysteine: results of a randomized, controlled feeding study. Circulation 2000; 102:852-7. [PMID: 10952952 DOI: 10.1161/01.cir.102.8.852] [Citation(s) in RCA: 129] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Elevated blood levels of homocysteine are associated with an increased risk of atherosclerotic cardiovascular disease. Although numerous studies have assessed the impact of vitamin supplements on homocysteine, the effect of dietary patterns on homocysteine has not been well studied. METHODS AND RESULTS During a 3-week run-in, 118 participants were fed a control diet, low in fruits, vegetables, and dairy products, with a fat content typical of US consumption. During an 8-week intervention phase, participants were then fed 1 of 3 randomly assigned diets: the control diet, a diet rich in fruits and vegetables but otherwise similar to control, or a combination diet rich in fruits, vegetables, and low-fat dairy products and reduced in saturated and total fat. Between the end of run-in and intervention periods, mean change in homocysteine was +0.46 micromol/L in the control diet, +0.21 micromol/L in the fruits and vegetables diet (P=0.47 compared with control), and -0.34 micromol/L in the combination diet (P=0.03 compared with control, P=0.12 compared with the fruits and vegetables diet). In multivariable regression models, change in homocysteine was significantly and inversely associated with change in serum folate (P=0.03) but not with change in serum vitamin B(12) (P=0.64) or pyridoxal 5' phosphate, the coenzyme form of vitamin B(6) (P=0.83). CONCLUSIONS Modification of dietary patterns can have substantial effects on fasting levels of total serum homocysteine. These results provide additional insights into the mechanisms by which diet might influence the occurrence of atherosclerotic cardiovascular disease.
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Su TC, Lin PH, Chiu MJ, Chu TS, Chang MJ, Wang JD, Cheng TJ. Dimethylacetamide, ethylenediamine, and diphenylmethane diisocyanate poisoning manifest as acute psychosis and pulmonary edema: treatment with hemoperfusion. JOURNAL OF TOXICOLOGY. CLINICAL TOXICOLOGY 2000; 38:429-33. [PMID: 10930060 DOI: 10.1081/clt-100100953] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
CASE REPORT A 27-year-old man, employed by a synthetic fiber company, had been exposed to dimethylacetamide, ethylenediamine, and diphenylmethane diisocyanate in a confined space continuously for 4-6 hours per day for 3 days before admission. Hallucinations and delusions were noted at admission; pulmonary edema developed subsequently. The electroencephalogram showed diffuse moderate cortical dysfunction and slow waves at 4-7 Hz, 20-80 microV. Seizures, liver injury, and rhabdomyolysis were noted on the 4th hospital day. The patient was treated by hemoperfusion with a decrease in urine dimethylacetamide from 3,265 mg/g to 4 mg/g creatinine over 4 days. Serial urinary dimethylacetamide and electroencephalogram correlated with the clinical condition.
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Lin PH, Koffron AJ, Heilizer TJ, Lujan HJ. Right lower quadrant abdominal pain due to appendicitis and an incarcerated spigelian hernia. Am Surg 2000; 66:725-7. [PMID: 10966026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Spigelian hernias are uncommon and difficult to diagnose because of their location in the aponeurosis in the anterior abdominal wall. When they occur on the right side, the symptoms can include nonspecific abdominal pain mimicking appendicitis. We present an adult with right lower quadrant abdominal pain due to an incarcerated spigelian hernia and acute appendicitis. Early recognition and prompt surgical treatment were important to the successful treatment of our patient.
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Lin PH, Sangaiah R, Ranasinghe A, Upton PB, La DK, Gold A, Swenberg JA. Formation of quinonoid-derived protein adducts in the liver and brain of Sprague-Dawley rats treated with 2,2',5, 5'-tetrachlorobiphenyl. Chem Res Toxicol 2000; 13:710-8. [PMID: 10956058 DOI: 10.1021/tx000030f] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
A possible role for metabolic activation of 2,2',5, 5'-tetrachlorobiphenyl (TCB) to quinonoid metabolites was investigated in vitro in rat liver microsomes and in vivo in male Sprague-Dawley rats. Incubation of TCB with phenobarbital-induced rat liver microsomes resulted in metabolism of TCB to 3-hydroxy-TCB (3-OH-TCB) and 3,4-dihydroxy-TCB (3,4-diOH-TCB), which were further oxidized to form a reactive intermediate that bound to liver proteins. The predominant species observed in the Raney nickel assay for cysteinyl adducts was identified as 3,4-diOH-TCB, consistent with an adduct having the structure 5-cysteinyl-3,6-dichloro-4-(2', 5'-dichlorophenyl)-1,2-benzoquinone. This adduct may arise via the Michael addition of the sulfhydryl group of cysteine to 3, 6-dichloro-4-(2',5'-dichlorophenyl)-1,2-benzoquinone (Cl(4)PhBQ). Metabolism of 3-OH-TCB by phenobarbital-induced microsomes in the presence of either NADPH or cumene hydroperoxide as a cofactor resulted in the formation of adducts. Dose-dependent formation of cysteinyl adducts was observed in liver cytosolic protein from rats treated with a single dose of TCB (0-200 mg/kg) by gavage. By regression analysis, the TCB adducts decayed with a half-life of 2. 03 +/- 0.131 days (mean +/- SE), which is approximately 2.5-fold shorter than the endogenous half-life for liver cytosolic protein in rat liver, suggesting adduct instability. Saturable formation of TCB adducts was observed in liver cytosolic protein of rats receiving multiple doses of TCB over 5 days. The levels of Cl(4)PhBQ-derived adducts were 2.1-fold greater than the estimated steady-state levels predicted by the single-dose treatment [97.7 +/- 13.2 vs 45.7 +/- 3. 73 (pmol/g)/(mg/kg of body weight)], suggesting induction of metabolism. A single cysteinyl adduct, inferred to be 5-cysteinyl-3, 6-dichloro-4-(2',5'-dichlorophenyl)-1,2-benzoquinone, was detected in brain cytosolic protein of rats treated with multiple doses of TCB with levels of 15.2 (pmol/g)/(mg/kg of body weight). Implied involvement of a reactive quinone in the liver and brain of TCB-treated rats supports the idea that quinonoid metabolites may be important contributors to PCB-derived oxidative damage to genomic DNA.
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Conklin BS, Surowiec SM, Lin PH, Chen C. A simple physiologic pulsatile perfusion system for the study of intact vascular tissue. Med Eng Phys 2000; 22:441-9. [PMID: 11086256 DOI: 10.1016/s1350-4533(00)00052-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Perfusion vascular culture models may provide a useful link between cell culture models and animal culture models by allowing a high level of control over important parameters while maintaining physiologic structure. The purpose of this study was to develop and test a new vascular culture system for pulsatile perfusion culture of intact vascular tissue. The system generates a pulsatile component of flow by means of a cam-driven syringe and a peristaltic pump and compliance chamber. Cams were designed, constructed and tested to simulate canine femoral and common carotid artery flows. The mean pressure was adjusted between 60 and 200 mmHg without significantly affecting flow rate, flow waveform, or the pressure waveform. Porcine common carotid artery segments were cultured in this pulsatile perfusion system. The viability of vascular segments was tested after various culture times with a functional assay that demonstrated both smooth muscle cell and endothelial cell response to vasomotor challenge.
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Lin PH, Koffron AJ, Heilizer TJ, Theodoropoulus P, Pasikhov D, Lujan HJ. Gastric adenocarcinoma of Meckel's diverticulum as a cause of colonic obstruction. Am Surg 2000; 66:627-30. [PMID: 10917471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
A 45-year-old-female patient with no prior surgical history presented with bowel obstruction. At laparotomy, a bulky tumor arising from the ileum, which completely obstructed the sigmoid colon, was found. A left hemicolectomy followed by a transverse colostomy and a Hartman's pouch were performed. Pathological examination of the specimen revealed gastric adenocarcinoma arising from a Meckel's diverticulum in the ileum. Malignant transformation from a Meckel's diverticulum is an uncommon occurrence. This case illustrates that successful management of a symptomatic Meckel's diverticulum, even with malignant transformation, can be achieved by surgical resection.
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Lin PH, Surowiec SM, Conklin B, Chen C, Bush R, Weiss VJ, Lumsden AB. Evaluation of thrombolysis and angioplasty in a porcine iliac artery thrombosis model: application of endovascular stent-graft-induced thrombosis. J Vasc Interv Radiol 2000; 11:785-91. [PMID: 10877428 DOI: 10.1016/s1051-0443(07)61642-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
PURPOSE To develop a novel endovascular thrombosis model in the porcine iliac artery for the evaluation of thrombolysis and angioplasty. MATERIALS AND METHODS A stent-inversion-graft (SIG) model combining either a 3-mm or 5-mm tapered expandable polytetrafluoroethylene (ePTFE) graft attached within a self-expandable, 10-mm nitinol stent was placed in the left common iliac artery via an ipsilateral common femoral artery approach in 24 pigs. When the iliac artery was thrombosed, urokinase (250,000 IU) plus heparin (1,000 units) were pulse sprayed via a contralateral femoral approach (n = 12). Saline pulse-spray was used as a control group (n = 12). Balloon angioplasty was performed to eliminate the stenotic tapered graft within the stent after successful thrombolysis. The efficacy of the thrombolysis was assessed with use of intravascular ultrasound (IVUS) and arteriogram. RESULTS Both the 3-mm tapered and 5-mm tapered SIG models caused iliac artery occlusion in 22 +/- 5 and 41 +/- 9 minutes, respectively, after the deployment. Luminal patency was re-established successfully in all occluded arteries after urokinase infusion. Angioplasty was successful in eliminating the tapered stenosis and restoring the normal diameter in all iliac arteries treated with urokinase. Complete thrombolysis was achieved in both models treated with urokinase. CONCLUSION This novel endovascular approach of inducing arterial thrombosis is simple to perform and reliably produces arterial thrombosis. The intraluminal stenosis is also amenable to angioplasty. This model is useful for the evaluation of antithrombotic treatment modality and adjunctive endovascular interventions.
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Lin PH, Chen C, Surowiec SM, Conklin B, Bush RL, Chaikof EL, Lumsden AB, Weiss V. A porcine model of carotid artery thrombosis for thrombolytic therapy and angioplasty: application of PTFE graft-induced stenosis. J Endovasc Ther 2000; 7:227-35. [PMID: 10883961 DOI: 10.1177/152660280000700310] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE To develop a porcine carotid artery thrombosis model for the evaluation of thrombolytic therapy and adjunctive angioplasty procedures. METHODS Bilateral carotid thrombosis was induced in 16 pigs using endothelial crush injury followed by external polytetrafluoroethylene (PTFE, 5 x 2 cm2) wrap placement to create segmental carotid stenosis. Light microscopy was used to examine thrombus composition. Selective carotid catheterization was performed via a femoral approach. Two hours following carotid artery occlusion, a urokinase (250,000 IU) and heparin (1000 U) solution was pulse-sprayed in 1 carotid artery while the contralateral vessel received the control saline vehicle. The efficacy of thrombolytic therapy was assessed using carotid arteriography and intravascular ultrasound. The feasibility and technical efficacy of balloon angioplasty within the carotid stenosis model were also evaluated. RESULTS Carotid artery occlusion occurred in 30 +/- 6 minutes following endothelial injury plus PTFE wrap placement. Histological examination of carotid arteries showed endothelial irregularity with fibrin-rich and platelet-rich thrombus. Urokinase was effective in recanalizing all occluded arteries (100%), while the control saline vehicle showed no effective thrombolysis (p < 0.001). Angioplasty was successful in restoring normal diameter in all arteries (100%). CONCLUSIONS This carotid artery thrombosis model, which incorporates intimal injury with segmental stenosis, is simple to create and reproducible. It provides not only a model for the evaluation of thrombolytic therapy but also a practical training tool for adjunctive endovascular interventions.
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Sinha U, Ku P, Malinowski J, Zhu BY, Scarborough RM, Marlowe CK, Wong PW, Lin PH, Hollenbach SJ. Antithrombotic and hemostatic capacity of factor Xa versus thrombin inhibitors in models of venous and arteriovenous thrombosis. Eur J Pharmacol 2000; 395:51-9. [PMID: 10781674 DOI: 10.1016/s0014-2999(00)00219-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Thrombin plays a central role in venous and arterial thrombosis. We utilized two different rabbit models of in vivo thrombosis to investigate the effect of inhibitors of thrombin generation and thrombin activity. The agents tested were specific inhibitors of factor Xa (fXa) [N2-[(phenylmethyl)sulfonyl]-D-arginyl-N-[(1S)-4-[(aminoiminomethyl++ +)a mino]-1-(2-thiazolylcarbonyl)butyl]-glycinamide (C921-78)] and thrombin [D-phenylalanyl-N-[4-[(aminoiminomethyl)amino]-1-(chloroacetyl)but yl]-L-prolinamide (PPACK)], as well as drugs that affect both thrombin and fXa, unfractionated and low molecular weight (enoxaparin) heparin. The agents administered as constant intravenous infusion were evaluated for antithrombotic efficacy in anesthetized rabbits. All four agents were capable of dose dependent inhibition of thrombosis in venous and arteriovenous thrombosis models. However, due to the more aggressive nature of thrombotic stimulation in the arteriovenous shunt model, complete cessation of thrombus growth was not achieved for any of the agents at the doses tested. Comparison between the agents focused on the differences in extension of coagulation parameters (activated partial thromboplastin time, prothrombin time, thrombin clotting time), changes in hematological parameters, and extension of rabbit cuticle bleeding time at doses required to produce maximum inhibition in the thrombosis models. In the venous thrombosis model at the maximally effective dose, C921-78 had minimal extension of ex vivo clotting parameters, while enoxaparin and unfractionated heparin demonstrated a two to sevenfold increase in activated partial thromboplastin times, and PPACK had a threefold extension of thrombin clotting times. In addition, unlike the other three agents, which exhibited no significant changes in hematological parameters, PPACK demonstrated dose dependent thrombocytopenia. A standardized cuticle bleeding time was used as a measure of perturbation of hemostasis. The agents were evaluated for significant increases in bleeding time at doses up to eight times that needed to completely inhibit venous thrombus formation. Unfractionated heparin displayed a significant bleeding time effect at the dose required to inhibit venous thrombosis (100 u/kg+2 u/kg/min). Enoxaparin and PPACK caused significant bleeding time extensions at four times the fully efficacious venous dose (800 u/kg+8 u/kg/min and 30 microg/kg/min). By contrast, C921-78 did not significantly increase bleeding time even at eight times the maximally effective dose (240 microg/kg+7.2 microg/kg/min). Our results demonstrate that specific inhibition of fXa can be utilized to derive potent antithrombotic activity without disrupting extravascular hemostasis.
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Lin PH, Chaikof EL. Embryology, anatomy, and surgical exposure of the great abdominal vessels. Surg Clin North Am 2000; 80:417-33, xiv. [PMID: 10685160 DOI: 10.1016/s0039-6109(05)70413-8] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
This article describes the embryology of the abdominal aorta and the anatomic features of its major visceral branches, including the celiac, superior mesenteric, and inferior mesenteric arteries. The common anatomic variants of these visceral vessels also are reviewed. Various operative techniques to gain surgical exposure to these vessels are described.
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Surowiec SM, Conklin BS, Li JS, Lin PH, Weiss VJ, Lumsden AB, Chen C. A new perfusion culture system used to study human vein. J Surg Res 2000; 88:34-41. [PMID: 10644464 DOI: 10.1006/jsre.1999.5759] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
BACKGROUND Cell culture studies, ring studies, and indirect physiologic studies are the predominant models used to study human vascular tissue. Such studies are limited in their capacity to permit physiologic single-factor changes or to provide the proper mechanical stress or extracellular matrix present in normal tissues. We present a newly devised organ culture system that addresses these issues and permits survival of intact segments of human vascular tissue in a perfused environment. Our experience culturing human saphenous vein with this system is detailed. METHODS Perfusion culture chambers were designed and constructed in our laboratory. Excess saphenous vein segments were collected from coronary artery bypass graft cases at our hospital and then mounted into our perfusion culture system for 0, 24, 48, 72, or 96 h. Vasomotor assays, hematoxylin and eosin staining, bromodeoxyuridine staining, and factor VIII staining were performed to assess tissue survival. RESULTS A total of 24 veins were cultured. Average vessel length was 5 cm. The vessels contracted and relaxed the following amounts: time 0 (6.7% contraction, 5.0% relaxation), 24 h (5.7%, 5.3%), 48 h (5.2%, 2.8%), 72 h (4.8%, 5.3%), 96 h (4.8%, 3.8%). Hematoxylin and eosin staining, bromodeoxyuridine staining, and factor VIII staining support the viability of the tissue segments. CONCLUSION A new perfusion organ culture system has been devised that permits survival of intact human venous tissue for periods up to 96 h. Studies that permit physiologic single-factor changes along with precise control of the hemodynamic environment are possible with this system.
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Chen C, Halkos ME, Surowiec SM, Conklin BS, Lin PH, Lumsden AB. Effects of homocysteine on smooth muscle cell proliferation in both cell culture and artery perfusion culture models. J Surg Res 2000; 88:26-33. [PMID: 10644463 DOI: 10.1006/jsre.1999.5756] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
BACKGROUND Hyperhomocysteinemia is associated with increased risk for vascular disease. However, the pathogenic mechanisms of homocysteine are largely unknown. We evaluated the effects of homocysteine on smooth muscle cell (SMC) and endothelial cell proliferation in cell culture and on SMC proliferation of balloon angioplasty-injured arteries in a perfusion culture model. METHODS Human and pig SMCs and endothelial cells were cultured with variable amounts of homocysteine for 72 h and the total cells were counted using a hemocytometer. Fresh pig carotid arteries were harvested from a local slaughterhouse and cultured in a newly designed artery perfusion culture system. Five groups of arteries (six per group) were cultured for 48 h under different conditions: normal control, balloon angioplasty injury alone, and injury with three different doses of homocysteine. Vessel viability was evaluated. SMC proliferation was assayed by bromodeoxyuridine (BrdU) DNA labeling. RESULTS At concentrations equivalent to those in human hyperhomocysteinemia, homocysteine significantly stimulated both cultured human and pig SMC proliferation with a dose-dependent effect, while it inhibited cultured endothelial cell growth. Perfusion-cultured pig carotid arteries remained contractile in response to norepinephrine and relaxant to nitroglycerine, and viable cells were also isolated from the cultured arteries. SMC proliferation (BrdU index) showed significant differences among the groups. SMC proliferation was stimulated by vascular injury and further enhanced by homocysteine in a dose-dependent manner. The proliferative response occurred strongly on the luminal side of the vessel wall, with the effects tapering toward the adventitia. CONCLUSIONS Homocysteine had a mitogenic effect on vascular SMCs and a cytotoxic effect on endothelial cells. This differential effect of homocysteine on vascular cells may represent a pathogenic mechanism of vascular lesion formation in patients with hyperhomocysteinemia.
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Windhauser MM, Evans MA, McCullough ML, Swain JF, Lin PH, Hoben KP, Plaisted CS, Karanja NM, Vollmer WM. Dietary adherence in the Dietary Approaches to Stop Hypertension trial. DASH Collaborative Research Group. JOURNAL OF THE AMERICAN DIETETIC ASSOCIATION 1999; 99:S76-83. [PMID: 10450298 DOI: 10.1016/s0002-8223(99)00420-4] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Participants in controlled feeding studies must consume all study foods and abstain from all other foods. In outpatient studies in which adherence may be compromised by free-living conditions, promoting, documenting, and monitoring dietary adherence are necessary. In the Dietary Approaches to Stop Hypertension (DASH) trial, a thorough participant screening process, an orientation session, and a run-in feeding period before randomization aided in the selection of participants who would most likely adhere to the demands of the study protocol. Throughout the feeding period, various educational and motivational techniques were used to encourage DASH participants to adhere to the dietary protocol. Both objective and subjective methods documented excellent participant adherence. Daily monitoring of individual adherence was based on meal attendance, body weight measurements, and daily diaries. Urinary sodium, potassium, phosphorus, and urea nitrogen values and an anonymous poststudy survey were used to evaluate adherence at the end of the study. Most DASH participants adhered to the feeding regimen by consuming only study foods and no other foods. When adherence lapsed, participants generally cited the lack of menu variety as a reason. Successful participant adherence to the constraints of an outpatient controlled feeding study is possible with carefully selected participants and a variety of adherence-promoting strategies incorporated into the study protocol.
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Vogt TM, Appel LJ, Obarzanek E, Moore TJ, Vollmer WM, Svetkey LP, Sacks FM, Bray GA, Cutler JA, Windhauser MM, Lin PH, Karanja NM. Dietary Approaches to Stop Hypertension: rationale, design, and methods. DASH Collaborative Research Group. JOURNAL OF THE AMERICAN DIETETIC ASSOCIATION 1999; 99:S12-8. [PMID: 10450289 DOI: 10.1016/s0002-8223(99)00411-3] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Epidemiologic studies across societies have shown consistent differences in blood pressure that appear to be related to diet. Vegetarian diets are consistently associated with reduced blood pressure in observational and interventional studies, but clinical trials of individual nutrient supplements have had an inconsistent pattern of results. Dietary Approaches to Stop Hypertension (DASH) was a multicenter, randomized feeding study, designed to compare the impact on blood pressure of 3 dietary patterns. DASH was designed as a test of eating patterns rather than of individual nutrients in an effort to identify practical, palatable dietary approaches that might have a meaningful impact on reducing morbidity and mortality related to blood pressure in the general population. The objectives of this article are to present the scientific rationale for this trial, review the methods used, and discuss important design considerations and implications.
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Plaisted CS, Lin PH, Ard JD, McClure ML, Svetkey LP. The effects of dietary patterns on quality of life: a substudy of the Dietary Approaches to Stop Hypertension trial. JOURNAL OF THE AMERICAN DIETETIC ASSOCIATION 1999; 99:S84-9. [PMID: 10450299 DOI: 10.1016/s0002-8223(99)00421-6] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Few studies have examined the effects of dietary changes, particularly modifications of whole dietary patterns, on quality of life. The Dietary Approaches to Stop Hypertension (DASH) trial compared the effects of 3 dietary patterns on blood pressure. In this substudy, we examined the effect of these diets on health-related quality of life. All DASH participants ate a control diet for 3 weeks and then were randomly assigned to continue the control diet, to a fruits and vegetables diet or to a combination diet for 8 weeks. The combination diet emphasized fruits, vegetables, and low-fat dairy products. It included whole grains, poultry, fish, and nuts, and was reduced in fats, red meat, sweets, and sugar-containing beverages. The control diet was similar to typical American intake; the fruits and vegetables diet was rich in fruits and vegetables but was otherwise similar to the control diet. Both the fruits and vegetables diet (P < .001) and the combination diet (P < .001) significantly lowered blood pressure. At the Duke University Medical Center, Durham, NC, site, participants completed the Medical Outcomes Study Short Form-36 questionnaire to assess their health-related quality of life at baseline and at the end of the dietary intervention. Eighty-three participants completed the questionnaires at both time points. In general, health-related quality of life improved in all treatment groups except for the control group in perceptions of change in health, which diminished. In the combination diet group all the subscales were improved or unchanged compared with baseline values. However, only the change in health score improved significantly (P < .05) as compared with that of the control diet group. When all the subscales were summed into a total score, the control diet was associated with mean improvement of 4.0%, the fruits and vegetables diet with 5.0%, and the combination diet with 5.9% from baseline. These data suggest that the fruits and vegetables diet and particularly the combination diet cannot only lower blood pressure, but may also improve the perception of health-related quality of life.
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Harsha DW, Lin PH, Obarzanek E, Karanja NM, Moore TJ, Caballero B. Dietary Approaches to Stop Hypertension: a summary of study results. DASH Collaborative Research Group. JOURNAL OF THE AMERICAN DIETETIC ASSOCIATION 1999; 99:S35-9. [PMID: 10450292 DOI: 10.1016/s0002-8223(99)00414-9] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The Dietary Approaches to Stop Hypertension multicenter trial examined the impact of dietary patterns on blood pressure in 459 adults with blood pressure < 160 mm Hg systolic and 80 to 95 mm Hg diastolic. After a 3-week run-in period on a control diet low in fruits, vegetables, and dairy products, and with a fat content typical for Americans, participants were randomized for 8 weeks to either the control diet, a diet rich in fruits and vegetables, or a combination diet that emphasized fruits, vegetables, and low-fat dairy products. Body weight and sodium intake were held constant, and physical activity did not change during the intervention. Baseline mean +/- standard deviation systolic and diastolic blood pressures were 131.3 +/- 10.8 mm Hg and 84.7 +/- 4.7 mm Hg, respectively. Relative to the control diet, the combination diet reduced blood pressure by 5.5 mm Hg and diastolic blood pressure by 3.0 mm Hg (P < .001). For those on the fruits and vegetables diet, blood pressure reductions relative to control were 2.8 mm Hg systolic (P < .001) and 1.1 mm Hg diastolic (P < .07). In 133 participants with hypertension, the combination diet produced a net blood pressure reduction of 11.4 and 5.5 mm Hg systolic and diastolic, respectively (P < .001). In participants without hypertension (n = 326), the corresponding blood pressure reductions were 3.5 mm Hg systolic (P < .001) and 2.1 mm Hg diastolic (P < .003). In other subgroup analyses, minorities showed relatively larger reductions in blood pressure than nonminorities (P < .001). We conclude that the dietary pattern reflected in the combination diet can substantially reduce blood pressure, and, accordingly, provides an additional lifestyle approach to preventing and treating hypertension.
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Karanja NM, McCullough ML, Kumanyika SK, Pedula KL, Windhauser MM, Obarzanek E, Lin PH, Champagne CM, Swain JF. Pre-enrollment diets of Dietary Approaches to Stop Hypertension trial participants. DASH Collaborative Research Group. JOURNAL OF THE AMERICAN DIETETIC ASSOCIATION 1999; 99:S28-34. [PMID: 10450291 DOI: 10.1016/s0002-8223(99)00413-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
A large body of evidence suggests that several nutrients are related to blood pressure. Less is known about the eating patterns of special populations, such as those at risk for hypertension, or how demographic factors affect the diets of these populations. This article characterizes the usual diets of participants before they enrolled in the Dietary Approaches to Stop Hypertension (DASH) trial. During screening for DASH, 380 participants completed the National Cancer Institute food frequency questionnaire. Nutrient and food group intake, the Keys score (a measure of a diet's atherogenicity), and the Diet Quality Index were estimated from the food frequency questionnaire. The effects of age, sex, race, baseline weight, and education on these dietary factors were assessed among DASH participants and compared with similar data from the Third National Health and Nutrition Examination Survey and other published reports. Among DASH participants, African-Americans reported lower intakes of dairy products (P < .001), calcium (P < .001), and magnesium (P < .05) than did whites. Older women reported greater intakes of calcium, magnesium, and potassium (all P < .05) and less fat (P < .05) than did younger women. Older men consumed fewer servings of fruits (P < .03), less vitamin C (P < .05), and had a higher Keys score (P < .05) than did younger men. Heavier (body mass index > or = 25) participants reported lower intakes of protein and potassium, but higher fat and energy intakes (all P < .05). Taken together, these data show that younger, overweight African-American women have the least healthful diets, because they consume more atherogenic foods and fewer of the nutrients related to decreased blood pressure. Overall Diet Quality Index scores did not differ between African-American and white participants. Despite differences in dietary assessment methods between the population samples of DASH and the Third National Health and Nutrition Examination Survey, within each population sample patterns of micronutrient intake were similar between African-American and white participants.
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Svetkey LP, Sacks FM, Obarzanek E, Vollmer WM, Appel LJ, Lin PH, Karanja NM, Harsha DW, Bray GA, Aickin M, Proschan MA, Windhauser MM, Swain JF, McCarron PB, Rhodes DG, Laws RL. The DASH Diet, Sodium Intake and Blood Pressure Trial (DASH-sodium): rationale and design. DASH-Sodium Collaborative Research Group. JOURNAL OF THE AMERICAN DIETETIC ASSOCIATION 1999; 99:S96-104. [PMID: 10450301 DOI: 10.1016/s0002-8223(99)00423-x] [Citation(s) in RCA: 134] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The DASH Diet, Sodium Intake and Blood Pressure Trial (DASH-Sodium) is a multicenter, randomized trial comparing the effects of 3 levels of sodium intake and 2 dietary patterns on blood pressure among adults with higher than optimal blood pressure or with stage 1 hypertension (120-159/80-95 mm Hg). The 2 dietary patterns are a control diet typical of what many Americans eat, and the DASH diet, which, by comparison, emphasizes fruits, vegetables, and low-fat dairy foods, includes whole grains, poultry, fish, and nuts, and is reduced in fats, red meat, sweets, and sugar-containing beverages. The 3 sodium levels are defined as higher (typical of current US consumption), intermediate (reflecting the upper limit of current US recommendations), and lower (reflecting potentially optimal levels). Participants are randomly assigned to 1 of the 2 dietary patterns using a parallel group design and are fed each of the 3 sodium levels using a randomized crossover design. The study provides participants with all of their food during a 2-week run-in feeding period and three 30-day intervention feeding periods. Participants attend the clinic for 1 meal per day, 5 days per week, and take home food for other meals. Weight is monitored and individual energy intake adjusted to maintain baseline weight. The primary outcome is systolic blood pressure measured at the end of each intervention feeding period. Systolic blood pressure is compared across the 3 sodium levels within each diet and across the 2 diets within each sodium level. If effects previously observed in clinical trials are additive, sodium reduction and the DASH diet together may lower blood pressure to an extent not as yet demonstrated for nonpharmacologic treatment. The DASH-Sodium results will have important implications for the prevention and treatment of high blood pressure.
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Lin PH, Windhauser MM, Plaisted CS, Hoben KP, McCullough ML, Obarzanek E. The Linear Index Model for establishing nutrient goals in the Dietary Approaches to Stop Hypertension trial. DASH Collaborative Research Group. JOURNAL OF THE AMERICAN DIETETIC ASSOCIATION 1999; 99:S40-4. [PMID: 10450293 DOI: 10.1016/s0002-8223(99)00415-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Establishing target levels of nutrients in feeding studies presents a challenge to dietitians. Although researchers studying energy-containing nutrients, such as protein and fat, commonly establish target levels according to body weight or as a percentage of energy, it is less clear how to establish levels of micronutrients. Typically, a constant target level is used regardless of energy requirements. Alternatively, nutrients could be provided at a fixed level per 1,000 kcal. Such an approach, however, could result in absolute levels of nutrient intakes that are difficult to achieve through foods alone, particularly for persons with high energy requirements. This report describes the Linear Index Model, a new approach for establishing target levels of selected micronutrients in the Dietary Approaches to Stop Hypertension trial. This model indexes micronutrient levels to energy levels to achieve a linear range of targeted intake in proportion to the energy intake. The Linear Index Model has several benefits: it takes advantage of indexing nutrients according to energy requirements, thus providing levels of nutrient intakes that can be readily achieved by foods; it is based on population consumption data, thus providing a realistic range of intakes for the experimental conditions; and it ensures distinct contrasts in experimental conditions. The Linear Index Model is a feasible and practical approach for establishing target levels of nutrients in feeding studies.
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Phillips KM, Stewart KK, Karanja NM, Windhauser MM, Champagne CM, Swain JF, Lin PH, Evans MA. Validation of diet composition for the Dietary Approaches to Stop Hypertension trial. DASH Collaborative Research Group. JOURNAL OF THE AMERICAN DIETETIC ASSOCIATION 1999; 99:S60-8. [PMID: 10450296 DOI: 10.1016/s0002-8223(99)00418-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The Dietary Approaches to Stop Hypertension trial involved 4 clinical sites at which 459 participants (in 5 cohorts) were fed 3 dietary patterns over 11 weeks per cohort. The 3 patterns were a control diet, a fruits and vegetables diet, and a combination diet. Before the intervention, key nutrient levels in each diet were validated at 2 energy levels (2,100 and 3,100 kcal) by chemical analysis of the prepared menus. During intervention, diets were sampled across all cohorts, sites, and energy levels, and 7-day menu cycle composites were assayed. In general, sodium, potassium, calcium, and magnesium in the validated menus for each diet/energy level met the nutrient targets, though moderate variability was evident among individual menus, particularly for potassium, calcium, and magnesium. However, as intended, there was clear separation and no overlap in mineral levels in individual menus of diets that were designed to differ. During intervention, macronutrient contents met nutrient goals. Sodium, potassium, calcium, and magnesium in the diets generally met target levels, though potassium in the fruits and vegetables diet was 11% to 23% below target. There were no consistent differences in nutrient levels between sites. The mean nutrient levels in the validated menus and diets sampled during intervention were in excellent agreement with each other, though sodium was somewhat higher (approximately 6%) in the diets from intervention vs validation. These results indicate the success of the quality control measures implemented and suggested consistent overall diet composition throughout the 28 months during which the study was conducted.
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Karanja NM, Obarzanek E, Lin PH, McCullough ML, Phillips KM, Swain JF, Champagne CM, Hoben KP. Descriptive characteristics of the dietary patterns used in the Dietary Approaches to Stop Hypertension Trial. DASH Collaborative Research Group. JOURNAL OF THE AMERICAN DIETETIC ASSOCIATION 1999; 99:S19-27. [PMID: 10450290 DOI: 10.1016/s0002-8223(99)00412-5] [Citation(s) in RCA: 190] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The Dietary Approaches to Stop Hypertension trial was a randomized, multicenter, controlled feeding study to compare the effect on blood pressure of 3 dietary patterns: control, fruits and vegetables, and combination diets. The patterns differed in selected nutrients hypothesized to alter blood pressure. This article examines the food-group structure and nutrient composition of the study diets and reports participant nutrient consumption during intervention. Participants consumed the control dietary pattern during a 3-week run-in period. They were then randomized either to continue on the control diet or to change to the fruits and vegetables or the combination diet for 8 weeks. Sodium intake and body weight were constant during the entire feeding period. Analysis of variance models compared the nutrient content of the 3 diets. Targeting a few nutrients thought to influence blood pressure resulted in diets that were profoundly different in their food-group and nutrient composition. The control and fruits and vegetables diets contained more oils, table fats, salad dressings, and red meats and were higher in saturated fat, total fat, and cholesterol than was the combination diet. The fruits and vegetables and combination diets contained relatively more servings of fruits, juices, vegetables, and nuts/seeds, and were higher in magnesium, potassium, and fiber than was the control diet. Both the fruits and vegetables and combination diets were low in sweets and sugar-containing drinks. The combination diet contained a greater variety of fruits, and its high calcium content was obtained by increasing low-fat dairy products. In addition, the distinct food grouping pattern across the 3 diets resulted in substantial differences in the levels of vitamins A, C, E, folate, B-6, and zinc.
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McCullough ML, Karanja NM, Lin PH, Obarzanek E, Phillips KM, Laws RL, Vollmer WM, O'Connor EA, Champagne CM, Windhauser MM. Comparison of 4 nutrient databases with chemical composition data from the Dietary Approaches to Stop Hypertension trial. DASH Collaborative Research Group. JOURNAL OF THE AMERICAN DIETETIC ASSOCIATION 1999; 99:S45-53. [PMID: 10450294 DOI: 10.1016/s0002-8223(99)00416-2] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Accuracy of computerized nutrient databases is an important consideration in selecting a nutrient analysis system. We project compared the nutrient content of daily menus calculated from 4 microcomputer programs to chemical analysis of menus analyzed for the Dietary Approaches to Stop Hypertension (DASH) trial. Thirty-six menus were entered at 2 independent DASH sites using the ESHA Food Processor, Minnesota Nutrition Data System, Moore's Extended Nutrient Database, and Nutritionist IV databases. Food prepared according to these menus was chemically analyzed at the Food Analysis Laboratory Control Center at Virginia Polytechnic Institute and State University, Department of Biochemistry, Blacksburg. Estimates for 13 nutrients were compared: energy, total fat, saturated fat, monounsaturated fat, polyunsaturated fat, carbohydrate, protein, cholesterol, calcium, potassium, magnesium, iron, and sodium. The overall intraclass correlation between the 2 sites' data entry was 0.998; thus, values were averaged for analyses. Databases varied significantly in their mean deviations from chemical analyses values for saturated, monounsaturated, and polyunsaturated fatty acids, potassium, magnesium, and iron (P < .05); however, these differences were small (< 10%). Absolute deviations, which estimate the combined effect of bias and precision, were significantly different among databases for energy, saturated fatty acids, and polyunsaturated acids. Absolute differences from the laboratory values varied by < 15%, except for iron. All 4 databases were comparable in accuracy and precision and performed well. Criteria for database selection depends not only on overall database accuracy, especially for nutrients of interest, but also on the ease of use of the program, relevant features of the associated software; and cost.
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Sacks FM, Appel LJ, Moore TJ, Obarzanek E, Vollmer WM, Svetkey LP, Bray GA, Vogt TM, Cutler JA, Windhauser MM, Lin PH, Karanja N. A dietary approach to prevent hypertension: a review of the Dietary Approaches to Stop Hypertension (DASH) Study. Clin Cardiol 1999; 22:III6-10. [PMID: 10410299 PMCID: PMC6655731 DOI: 10.1002/clc.4960221503] [Citation(s) in RCA: 141] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND Populations eating mainly vegetarian diets have lower blood pressure levels than those eating omnivorous diets. Epidemiologic findings suggest that eating fruits and vegetables lowers blood pressure. HYPOTHESIS Two hypotheses were tested: (1) that high intake of fruits and vegetables lowers blood pressure, and (2) that an overall dietary pattern (known as the DASH diet, or DASH combination diet) that is high in fruits, vegetables, nuts, and low-fat dairy products, emphasizes fish and chicken rather than red meat, and is low in saturated fat, cholesterol, sugar, and refined carbohydrate lowers blood pressure. METHODS Participants were 459 adults with untreated systolic blood pressure < 160 mmHg and diastolic blood pressure 80-95 mmHg. After a 3-week run-in on a control diet typical of Americans, they were randomized to 8 weeks receiving either the control diet, or a diet rich in fruits and vegetables, or the DASH diet. The participants were given all of their foods to eat, and body weight and sodium intake were held constant. Blood pressure was measured at the clinic and by 24-h ambulatory monitoring. RESULTS The DASH diet lowered systolic blood pressure significantly in the total group by 5.5/3.0 mmHg, in African Americans by 6.9/3.7 mmHg, in Caucasians by 3.3/2.4 mmHg, in hypertensives by 11.6/5.3 mmHg, and in nonhypertensives by 3.5/2.2 mmHg. The fruits and vegetables diet also reduced blood pressure in the same subgroups, but to a lesser extent. The DASH diet lowered blood pressure similarly throughout the day and night. CONCLUSIONS The DASH diet may offer an alternative to drug therapy in hypertensives and, as a population approach, may prevent hypertension, particularly in African Americans.
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Lee TY, Lin PH, Lin CH, Sun YN, Lin XZ. Interactive 3-D virtual colonoscopy system. IEEE TRANSACTIONS ON INFORMATION TECHNOLOGY IN BIOMEDICINE : A PUBLICATION OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY 1999; 3:139-50. [PMID: 10719495 DOI: 10.1109/4233.767089] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We describe a low-cost three-dimensional (3-D) virtual colonoscopy system that is a noninvasive technique for examining the entire colon and can assist physicians in detecting polyps inside the colon. Using the helical CT data and proposed techniques, we can three-dimensionally reconstruct and visualize the inner surface of the colon. We generate high resolution of video views of the colon interior structures as if the viewer's eyes were inside the colon. The physicians can virtually navigate inside the colon in two different modes: interactive and automatic navigation, respectively. For automatic navigation, the flythrough path is determined a priori using the 3-D thinning and two-pass tracking schemes. The whole colon is spatially subdivided into several cells, and only potentially visible cells are taken into account during rendering. To further improve rendering efficiency, potentially visible cells are rendered at different levels of detail. Additionally, a chain of bounding volume in each cell is used to avoid penetrating through the colon during navigation. In comparison with previous work, the proposed system can efficiently accomplish required preprocessing tasks and afford adequate rendering speeds on a low-cost PC system.
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