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Morris RC, Sebastian A, Forman A, Tanaka M, Schmidlin O. Normotensive salt sensitivity: effects of race and dietary potassium. Hypertension 1999; 33:18-23. [PMID: 9931076 DOI: 10.1161/01.hyp.33.1.18] [Citation(s) in RCA: 178] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
-Normotensive salt sensitivity, a putative precursor of hypertension, might be quite frequent in African Americans (blacks) and less frequent in Caucasian Americans (whites), but only when dietary potassium is deficient and not when maintained well within the normal range. We tested this hypothesis in 41 metabolically controlled studies of 38 healthy normotensive men (24 blacks, 14 whites) who ate a basal diet low in sodium (15 mmol/d) and marginally deficient in potassium (30 mmol/d) for 6 weeks. Throughout the last 4 weeks, NaCl was loaded (250 mmol/d); throughout the last 3, potassium was supplemented (as potassium bicarbonate) to either mid- or high-normal levels, 70 and 120 mmol/d. Salt sensitivity, defined as an increase in mean arterial blood pressure >/=3 mm Hg with salt loading, was deemed "moderate" if increasing </=10 mm Hg and "severe" if increasing more. When dietary potassium was 30 mmol/d, salt loading induced a mean increase in blood pressure only in blacks (P<0.001), and salt sensitivity occurred in most blacks but not whites (79% vs 36% (P<0.02). Supplementing potassium only to 70 mmol/d attenuated moderate salt sensitivity similarly in blacks and whites; 120 mmol/d abolished it, attenuated severe salt sensitivity, which occurred in a quarter of affected blacks, and suppressed the frequency and severity of salt sensitivity in blacks to levels similar to those observed in whites. These observations demonstrate that in most normotensive black men but not white men, salt sensitivity occurs when dietary potassium is even marginally deficient but is dose-dependently suppressed when dietary potassium is increased within its normal range. Such suppression might prevent or delay the occurrence of hypertension, particularly in the many blacks, in whom dietary potassium is deficient.
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Frassetto LA, Todd KM, Morris RC, Sebastian A. Estimation of net endogenous noncarbonic acid production in humans from diet potassium and protein contents. Am J Clin Nutr 1998; 68:576-83. [PMID: 9734733 DOI: 10.1093/ajcn/68.3.576] [Citation(s) in RCA: 374] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Normal adult humans eating Western diets have chronic, low-grade metabolic acidosis, the severity of which is determined in part by the net rate of endogenous noncarbonic acid production (NEAP), which varies with diet. To prevent or reverse age-related sequelae of such diet-dependent acidosis (eg, bone and muscle loss), methods are needed for estimating and regulating NEAP. Because NEAP is difficult to measure directly, we sought a simple method to estimate it from diet-composition data. We focused on protein and potassium contents because the production of sulfuric acid from protein metabolism and bicarbonate from dietary potassium salts of organic acids are the major variable components of NEAP. Using steady state renal net acid excretion (RNAE) as an index of NEAP in 141 normal subjects eating 20 different diets, we found by multiple linear regression analysis that RNAE [mEq/d x 10460 kJ diet (mEq/d 2500 kcal)] was predictable (R2 = 0.62) from protein [g/d x 10460 kJ diet (g/d 2500 kcal); positive regression coefficient, P < 0.001] and potassium [mEq/d x 10460 kJ diet (mEq/d x 2500 kcal): negative regression coefficient, P = 0.001] contents, which were not themselves correlated. Among diets, 71% of the variation in RNAE could be accounted for by the ratio of protein (Pro) to potassium (K) content: RNAE = 62Pro/K - 17.9 (r = 0.84, R2 = 0.71, P < 0.001). Thus, by considering both the acidifying effect of protein and the alkalinizing effect of potassium (organic anions), NEAP can be predicted with confidence from the readily available contents of only 2 nutrients in foods. Provisionally, these findings allow estimation and regulation of NEAP through diet modification.
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Sebastian A, Cuenca A, Li SF, Carlson J, Lancaster M, Cardello J, Nour B, Katz E. Pancreas transplant graft evaluation using the MIBI scan--a useful tool. Transplant Proc 1998; 30:257-60. [PMID: 9532022 DOI: 10.1016/s0041-1345(97)01251-7] [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: 02/07/2023]
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Katz E, Miller CM, Nour B, Schwartz ME, Sebastian A, Emre S. The first in situ split of a liver in the USA performed by two geographically distant transplant centers--enhancing, sharing, and expanding the cadaveric liver organ pool. THE JOURNAL OF THE OKLAHOMA STATE MEDICAL ASSOCIATION 1997; 90:442-3. [PMID: 9816390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
In situ split of the liver was performed in a heart-beating cadaveric organ donor for the first time in the U.S.A. by two geographically distant transplant centers. The procedure, initiated by a transplant team in Oklahoma City, was a joint project of the transplant teams from Oklahoma City and New York City. The in situ split resulted in two liver grafts. A left graft (left lateral segment) which was transplanted into a 7-year-old pediatric recipient in Oklahoma City and a right graft (right lobe and segment IV) which was transplanted into a 52-year-old adult recipient in New York City. Initial graft function was excellent in the two patients. The adult recipient was discharged home 10 days after the transplant and is doing well. The pediatric recipient died two and a half months later from multi-system organ failure. The recently introduced in situ split technique provides two excellent liver grafts from one donor and enhances sharing of liver grafts between transplant centers.
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Katz E, Sebastian A, Vanhooser D. Is it necessary to use venous-right atrial bypass in orthotopic liver transplantation? Transplantation 1997; 64:792. [PMID: 9311726 DOI: 10.1097/00007890-199709150-00027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Sudhir K, Forman A, Yi SL, Sorof J, Schmidlin O, Sebastian A, Morris RC. Reduced dietary potassium reversibly enhances vasopressor response to stress in African Americans. Hypertension 1997; 29:1083-90. [PMID: 9149670 DOI: 10.1161/01.hyp.29.5.1083] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Acute vasopressor responses to stress are adrenergically mediated and hence potentially subject to differential modulation by dietary potassium and sodium. The greater vasopressor responsiveness in blacks compared with whites might then be consequent not only to a high dietary salt intake but also to a marginally reduced dietary potassium intake. Under controlled metabolic conditions, we compared acute vasopressor responses to cold and mental stress in black and white normotensive men during three successive dietary periods: (1) while dietary potassium was reduced (30 mmol K+/70 kg per day) and salt was restricted (10 to 14 days); (2) while salt was loaded (15 to 250 mmol Na+/70 kg per day) (7 days); and (3) while salt loading was continued and potassium was either supplemented (70 mmol K+/70 kg per day) (7 to 21 days) in 9 blacks and 6 whites or continued reduced (30 mmol K+/70 kg per day) (28 days) in 4 blacks (time controls). At the lower potassium intake, cold-induced increase in forearm vascular resistance in blacks was twice that in whites during both salt restriction and salt loading. Normalization of dietary potassium attenuated cold-induced increases in both forearm vascular resistance and systolic and diastolic blood pressures in blacks but only in systolic pressure in whites. In blacks but not in whites, normalization of dietary potassium attenuated mental stress-induced increases in systolic and diastolic pressures. In normotensive blacks but not whites, a marginally reduced dietary intake of potassium reversibly enhances adrenergically mediated vasopressor responsiveness to stress. That responsiveness so enhanced over time might contribute to the pathogenesis of hypertension in blacks.
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Negita M, Nour B, Sebastian A, Griggs JR, Torres-Pinedo RB, Wright HI, Katz E. Living related liver transplantation in Oklahoma. THE JOURNAL OF THE OKLAHOMA STATE MEDICAL ASSOCIATION 1997; 90:89-93. [PMID: 9097497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Living related liver transplantation (LRLT) presents several advantages as compared to cadaveric liver transplantation, and it has become an increasingly popular option for children with end-stage liver diseases. Since 1995, five LRLT procedures have been performed at the authors' facility. Recipients were three boys and two girls, whose mean age was 2.6 years. Recipients' primary diagnoses were primary hyperoxaluria (PH) (n = 3), Alagille's syndrome (n = 1), and Byler's disease (n = 1). Left lateral segments harvested from their parents were used as the liver grafts on all patients. The donors included three mothers and two fathers, with a mean age of 29 years. Tacrolimus with steroids was used as immunosuppressive therapy. In all cases (mean follow-up time of 11 months), graft function was excellent and four children are doing very well. One boy died of post-transplant lymphoproliferative disorder (PTLD) 7 months after LRLT. All donors are doing very well with no postoperative complications. The authors believe that LRLT is a safe procedure for both the donor and the recipient, and provides, in children, an excellent alternative to cadaveric liver transplantation.
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McLaughlin JP, Sebastian A, Archer S, Bidlack JM. 14 beta-Chlorocinnamoylamino derivatives of metopon: long-term mu-opioid receptor antagonists. Eur J Pharmacol 1997; 320:121-9. [PMID: 9059844 DOI: 10.1016/s0014-2999(96)00904-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The affinity, selectivity and antinociceptive properties of 5 beta-methyl-14 beta-(p-chlorocinnamoylamino)-7,8-dihydromorphinone (MET-Cl-CAMO) and N-cyclopropyl-methyl-5 beta-methyl-14 beta-(p-chlorocinnamoylamino)-7, 8-dihydronormorphinone (N-CPM-MET-Cl-CAMO) for the multiple opioid receptors were characterized. In competition binding assays using bovine striatal membranes, both compounds inhibited the binding of 0.25 nM [3H][D-Ala2, (Me)-Phe4,Gly(ol)5]enkephalin (DAMGO) with IC 50 values of less than 2 nM. Preincubation of membranes with MET-CI-CAMO and N-CPM-MET-Cl-CAMO produced a concentration-dependent, wash-resistant inhibition of mu-opioid receptor binding. Saturation binding experiments with N-CPM-MET-Cl-CAMO showed a reduction in the number of mu-opioid binding sites without a change in affinity. In the mouse 55 degrees C warm-water tail-flick assay, neither MET-Cl-CAMO nor N-CPM-MET-Cl-CAMO at doses up to 100 nmol produced antinociception after intracerebroventricular administration, but morphine-induced antinociception was antagonized in a time- and dose-dependent manner by both compounds. The antagonism produced by 1 nmol of either MET-Cl-CAMO or N-CPM-MET-Cl-CAMO reached a maximal effect after 24 h, and lasted up to 48 h. Analgesia mediated by delta- or kappa-opioids was not altered by either compound. In summary, the data suggest that MET-Cl-CAMO and N-CPM-MET-Cl-CAMO are long-term, mu-opioid receptor antagonists, devoid of agonist properties in the mouse tail-flick assay, and that N-CPM-MET-Cl-CAMO may produce its antagonistic effects by binding irreversibly to the mu-opioid receptor.
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Frassetto L, Morris RC, Sebastian A. Potassium bicarbonate reduces urinary nitrogen excretion in postmenopausal women. J Clin Endocrinol Metab 1997; 82:254-9. [PMID: 8989270 DOI: 10.1210/jcem.82.1.3663] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Previously we demonstrated that low grade chronic metabolic acidosis exists normally in humans eating ordinary diets that yield normal net rates of endogenous acid production (EAP), and that the degree of acidosis increases with age. We hypothesize that such diet-dependent and age-amplifying low grade metabolic acidosis contributes to the decline in skeletal muscle mass that occurs normally with aging. This hypothesis is based on the reported finding that chronic metabolic acidosis induces muscle protein breakdown, and that correction of acidosis reverses the effect. Accordingly, in 14 healthy postmenopausal women residing in a General Clinical Research Center and eating a constant diet yielding a normal EAP rate, we tested whether correcting their "physiological" acidosis with orally administered potassium bicarbonate (KHCO3; 60-120 mmol/day for 18 days) reduces their urinary nitrogen loss. KHCO3 reduced EAP to nearly zero, significantly reduced the blood hydrogen ion concentration (P < 0.001), and increased the plasma bicarbonate concentration (P < 0.001), indicating that pre-KHCO3, diet-dependent EAP was significantly perturbing systemic acid-base equilibrium, causing a low grade metabolic acidosis. Urinary ammonia nitrogen, urea nitrogen, and total nitrogen levels significantly decreased. The cumulative reduction in nitrogen excretion was 14.1 +/- 12.3 g (P < 0.001). Renal creatinine clearance and urine volume remained unchanged. We conclude that in postmenopausal women, neutralization of diet-induced EAP with KHCO3 corrects their preexisting diet-dependent low grade metabolic acidosis and significantly reduces their urinary nitrogen wasting. The magnitude of the KHCO3-induced nitrogen-sparing effect is potentially sufficient to both prevent continuing age-related loss of muscle mass and restore previously accrued deficits.
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Frassetto LA, Morris RC, Sebastian A. Effect of age on blood acid-base composition in adult humans: role of age-related renal functional decline. THE AMERICAN JOURNAL OF PHYSIOLOGY 1996; 271:F1114-22. [PMID: 8997384 DOI: 10.1152/ajprenal.1996.271.6.f1114] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
In 64 apparently healthy adult humans (ages 17-74 yr) ingesting controlled diets, we investigated the separate and combined effects of age, glomerular filtration rate (GFR, index of age-related renal functional decline), renal net acid excretion [NAE, index of endogenous acid production (EAP)], and blood PCO2 (PbCO2, index of respiratory set point) on steady-state blood hydrogen ion ([H+]b) and plasma bicarbonate concentration ([HCO3-]p). Independent predictors of [H+]b and [HCO3-]p were PbCO2, NAE, and either age or GFR, but not both, because the two were highly correlated (inversely). [H+]b increased with increasing PbCO2, NAE, and age and with decreasing GFR. [HCO3-]p decreased with increasing NAE and age but increased with increasing PbCO2 and GFR. Age (or GFR) at constant NAE had greater effect on both [H+]b and [HCO3-]p than did NAE at constant age (or GFR). Neither PbCO2 nor NAE correlated with age or GFR. Thus two metabolic factors, diet-dependent EAP and age (or GFR), operate independently to determine blood acid-base composition in adult humans. Otherwise healthy adults manifest a low-grade diet-dependent metabolic acidosis, the severity of which increases with age at constant EAP, apparently due in part to the normal age-related decline of renal function.
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Emre S, Schwartz ME, Altaca G, Sethi P, Fiel MI, Guy SR, Kelly DM, Sebastian A, Fisher A, Eickmeyer D, Sheiner PA, Miller CM. Safe use of hepatic allografts from donors older than 70 years. Transplantation 1996; 62:62-5. [PMID: 8693547 DOI: 10.1097/00007890-199607150-00013] [Citation(s) in RCA: 143] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Between March 1991 and August 1995, 36 livers from donors >/=70 years old were transplanted. In donors, we recorded the following risk factors: alanine aminotransferase > 120 and rising, dopamine dose > 15 microg/kg/min, hypotension (systolic blood pressure <80) >1 hr, stay in the intensive care unit >5 days and body mass index >/=27. In 35 recipients, we recorded pretransplant United Network for Organ Sharing (UNOS) status, cold/warm ischemia time, intraoperative blood loss, and occurrence of poor early graft function or primary nonfunction. Mean recipient age was 55 years (range, 25-75 years). Four recipients were UNOS status 1, 19 were UNOS 2, and 12 were UNOS 3. Two livers were used as second grafts for primary graft nonfunction. Mean donor age was 73 years (range, 70-84 years). Intracranial bleeding was the cause of death in the majority of donors. The 36 donors had 40 risk factors; 10 donors had >1 risk factor. Mean cold and warm ischemia times were 9:08 +/- 2:57 hr and 51 +/- 9 min. Mean total operative time was 7.5 hr. Posttransplant mean peak alanine aminotransferase and aspartate aminotransferase levels were 937.3 +/- 703.1 IU/L and 923.3 +/- 708.5 IU/L, respectively. Mean prothrombin time on postoperative day 2 was 14.9 +/- 1.6 sec. Average total bilirubin on postoperative day 5 was 4.9 mg/dl. Median length of stay in the intensive care unit was 4 days. One recipient had poor early graft function; two recipients had primary nonfunction. Mean follow-up was 503 days (range, 110-1714 days). Three-month actual graft and patient survival rates were 85% and 91%, respectively. One-year actuarial graft and patient survival rates were also 85% and 91%, respectively. We conclude that older livers can be used safely. Advanced donor age should not be a contraindication to liver procurement.
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Schultz AG, Wang A, Alva C, Sebastian A, Glick SD, Deecher DC, Bidlack JM. Asymmetric syntheses, opioid receptor affinities, and antinociceptive effects of 8-amino-5,9-methanobenzocyclooctenes, a new class of structural analogues of the morphine alkaloids. J Med Chem 1996; 39:1956-66. [PMID: 8642554 DOI: 10.1021/jm950817g] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Several 8-amino-5,9-methanobenzocyclooctenes have been prepared by asymmetric organic synthesis techniques. Opioid receptor affinity studies have revealed the virtual absence of enantioselectivity for receptor binding, particularly at the mu-receptor, for the (+)-3a-f and the (-)-3a-f series. It is noteworthy that inversion of configuration at the nitrogen-bearing carbon atom [5S,8S,9S)-8-amino-3-hydroxy-5, 9-methano-9-(methoxymethyl)-5-methylbenzocyclooctene, (+)-3a vs (5S,8S,9R)-8-amino-3-hydroxy-5, 9-methano-9-(methoxymethyl)-5-methylbenzocyclooctene, (dl)-22] resulted in a > 10-fold increase in kappa-receptor affinity. Antinociceptive studies demonstrated that (dl)-22 was a full kappa-agonist while (+)-3a and (-)-3a did not possess kappa-activity. Although both (dl)-22 and (+)-3a/(-)-3a had high affinity for the mu-receptor, these compounds did not act as high-affinity agonists or antagonists at this receptor.
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Frassetto L, Sebastian A. Age and systemic acid-base equilibrium: analysis of published data. J Gerontol A Biol Sci Med Sci 1996; 51:B91-9. [PMID: 8548506 DOI: 10.1093/gerona/51a.1.b91] [Citation(s) in RCA: 80] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
To investigate whether systemic acid-base equilibrium changes with aging in normal adult humans, we reviewed published articles reporting the acid-base composition of arterial, arterialized venous, or capillary blood in age-identified healthy subjects. We extracted or calculated blood hydrogen ion concentration ([H+]), plasma bicarbonate concentration ([HCO3(-)]), blood PCO2, and age, and computed a total of 61 age-group means, distributed among eight 10-year intervals from age 20 to 100 years. Using linear regression analysis, we found that with increasing age, there is a significant increase in the steady-state blood [H+] (p < .001), and reduction in steady-state plasma [HCO3(-)] (p < .001), indicative of a progressively worsening low-level metabolic acidosis. Blood PCO2 decreased with age (p < .05), in keeping with the expected respiratory adaptation to metabolic acidosis. Such age-related increasing metabolic acidosis may reflect in part the normal decline of renal function with increasing age. The role of age-related metabolic acidosis in the pathogenesis of the degenerative diseases of aging warrants consideration.
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89
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McLaughlin JP, Nowak D, Sebastian A, Schultz AG, Archer S, Bidlack JM. Metopon and two unique derivatives: affinity and selectivity for the multiple opioid receptors. Eur J Pharmacol 1995; 294:201-6. [PMID: 8788432 DOI: 10.1016/0014-2999(95)00536-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
5 beta-Methyl-7,8-dihydromorphinone (metopon), an isomer [6aS-(6a alpha,9a alpha, 10 beta)13aS]-1,10-methano-4-hydroxy-11-methyl- 6,6a,8,9,10,11,12,13-octahydro-[1]-benzopyrano[4,3,e]isoquinoline- 7-(9aH)-one (compound 1) derived from a photochemical rearrangement of 5 beta-methylmorphinone, and [6aS-(6a alpha,9a alpha,10 beta)13aS]-1,10-methano-4-hydroxy-11-methyl- 6,6a,8,9, 10,11,12,13-octahydro-[1]-benzopyrano[4,3,e]-14 beta- (p-nitrocinnamoylamino) isoquinoline-7-(9aH)-one (compound 2) were characterized for opioid receptor affinity, selectivity and analgesic properties. In competition binding assays using bovine striatal membranes, the three compounds inhibited the binding of 0.25 nM [3H][D-Ala2,(Me)-Phe4,Gly(ol)5]enkephalin (DAMGO), a mu-selective peptide, with IC50 values less than 5 nM. All three compounds exhibited lower affinity for delta- and kappa-opioid receptors. In the mouse 55 degrees C warm-water tail-flick assay, both metopon and compound 1 displayed antinociception that lasted for 60 min after i.c.v. injection. Morphine sulfate, metopon and compound 1 produced 50% antinociception with i.c.v. doses of 0.83, 2.0 and 4.0 nmol, respectively. The mu-selective, irreversible opioid receptor antagonist beta-funaltrexamine blocked antinociception induced by metopon and compound 1, while delta- and kappa-opioid receptor selective antagonists did not effect antinociception. These findings demonstrate metopon and its isomer bound with high affinity to the mu-opioid receptor and produced antinociception through this receptor.
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MESH Headings
- Analgesics, Opioid/pharmacokinetics
- Analgesics, Opioid/pharmacology
- Animals
- Binding, Competitive/drug effects
- Cattle
- In Vitro Techniques
- Injections, Intraventricular
- Male
- Mice
- Mice, Inbred ICR
- Morphinans/administration & dosage
- Morphinans/pharmacokinetics
- Morphinans/pharmacology
- Morphine/pharmacokinetics
- Morphine/pharmacology
- Neostriatum/drug effects
- Neostriatum/metabolism
- Pain Measurement/drug effects
- Rats
- Rats, Sprague-Dawley
- Receptors, Opioid/drug effects
- Receptors, Opioid/metabolism
- Receptors, Opioid, delta/drug effects
- Receptors, Opioid, delta/metabolism
- Receptors, Opioid, kappa/drug effects
- Receptors, Opioid, kappa/metabolism
- Receptors, Opioid, mu/drug effects
- Receptors, Opioid, mu/metabolism
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90
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Kusumoto F, Venet T, Schiller NB, Sebastian A, Foster E. Measurement of aortic blood flow by Doppler echocardiography: temporal, technician, and reader variability in normal subjects and the application of generalizability theory in clinical research. J Am Soc Echocardiogr 1995; 8:647-53. [PMID: 9417207 DOI: 10.1016/s0894-7317(05)80378-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Although Doppler echocardiographic measurements of aortic flow have been found to correlate with stroke volume, the reliability of this technique is unknown. The purpose of this study was to measure the reliability of Doppler estimates of cardiac output by identifying and estimating the magnitude of different sources of error. We measured the reliability of Doppler estimates of cardiac output by identifying the magnitude of sources of error in 11 subjects with studies performed by two technicians and read by two readers. Analysis with generalizability theory demonstrated that the largest portion of the total variance was from differences among patients, with a smaller contribution due to day-to-day variability. Variability due to technician was low for continuous wave Doppler (2.0%), but high for pulsed wave (23.2%). Thus continuous wave, but not pulsed wave Doppler measurements, can be used to detect serial changes in cardiac output due to an intervention.
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91
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Jiang Q, Seyed-Mozaffari A, Sebastian A, Archer S, Bidlack JM. Preventing morphine antinociceptive tolerance by irreversible mu opioid antagonists before the onset of their antagonism. J Pharmacol Exp Ther 1995; 273:680-8. [PMID: 7752070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Irreversible opioid antagonists, when administered at small doses, require several hours to display their antagonism of antinociception mediated by opioid receptors. However, most opioid affinity ligands only need a few minutes to produce wash-resistant inhibition of opioid binding to brain membranes. Our study investigated whether the irreversible antagonists, beta-funaltrexamine (beta-FNA), 14 alpha, 14'beta-[dithiobis[(2-oxo-2,1-ethanediyl)imino]]-7,8-dihydro-N- (cyclopropylmethyl)normorphine (N-CPM-TAMO), and N-cyclopropylmethyl-5 beta-methyl- beta-(p-nitrocinnamoylamino)-7,8-dihydromorphinone (N-CPM-MET-CAMO) had any effect on morphine-induced antinociceptive tolerance before the appearance of their antagonism in the mouse tail-flick assay. All opioids were given by i.c.v. administration. The irreversible antagonists, beta-FNA (20 nmol), N-CPM-TAMO (0.5 nmol) and N-CPM-MET-CAMO (1 nmol) did not produce any antagonism of morphine-induced analgesia until at least 8 hr after administration. Pretreatment with morphine (3 nmol, -140 min) produced acute antinociceptive tolerance as demonstrated by a 45-fold rightward shift of the morphine dose-response curve. When coadministered with morphine, beta-FNA, N-CPM-TAMO and N-CPM-MET-CAMO completely prevented the development of morphine tolerance 140 min after administration in a dose-dependent manner. This preventive effect lasted for up to 420 min, during which time, morphine was given repeatedly up to four times. This antinociception produced by morphine after coadministration with irreversible antagonists was antagonized by naloxone, demonstrating that morphine-induced analgesia was still mediated by opioid receptors. The kappa- and delta-selective opioid antagonists, nor-binaltorphimine and ICI 174,864, respectively, did not block the preventive effect produced by the irreversible antagonists.(ABSTRACT TRUNCATED AT 250 WORDS)
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Jiang Q, Seyed-Mozaffari A, Sebastian A, Archer S, Bidlack JM. Preventing morphine antinociceptive tolerance by irreversible mu opioid antagonists before the onset of their antagonism. ACTA ACUST UNITED AC 1994. [DOI: 10.1016/0167-0115(94)90428-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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93
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Sebastian A, Morris RC. Improved mineral balance and skeletal metabolism in postmenopausal women treated with potassium bicarbonate. N Engl J Med 1994; 331:279. [PMID: 8015587 DOI: 10.1056/nejm199407283310421] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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94
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Sebastian A, Harris ST, Ottaway JH, Todd KM, Morris RC. Improved mineral balance and skeletal metabolism in postmenopausal women treated with potassium bicarbonate. N Engl J Med 1994; 330:1776-81. [PMID: 8190153 DOI: 10.1056/nejm199406233302502] [Citation(s) in RCA: 319] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
BACKGROUND In normal subjects, a low level of metabolic acidosis and positive acid balance (the production of more acid than is excreted) are typically present and correlate in degree with the amount of endogenous acid produced by the metabolism of foods in ordinary diets abundant in protein. Over a lifetime, the counteraction of retained endogenous acid by base mobilized from the skeleton may contribute to the decrease in bone mass that occurs normally with aging. METHODS To test that possibility, we administered potassium bicarbonate to 18 postmenopausal women who were given a constant diet (652 mg [16 mmol] of calcium and 96 g of protein per 60 kg of body weight). The potassium bicarbonate was given orally for 18 days in doses (60 to 120 mmol per day) that nearly completely neutralized the endogenous acid. RESULTS During the administration of potassium bicarbonate, the calcium and phosphorus balance became less negative or more positive--that is, less was excreted in comparison with the amount ingested (mean [+/- SD] change in calcium balance, +56 +/- 76 mg [1.4 +/- 1.9 mmol] per day per 60 kg; P = 0.009; change in phosphorus balance, +47 +/- 64 mg [1.5 +/- 2.1 mmol] per day per 60 kg; P = 0.007) because of reductions in urinary calcium and phosphorus excretion. The changes in calcium and phosphorus balance were positively correlated (P < 0.001). Serum osteocalcin concentrations increased from 5.5 +/- 2.8 to 6.1 +/- 2.8 ng per milliliter (P < 0.001), and urinary hydroxyproline excretion decreased from 28.9 +/- 12.3 to 26.7 +/- 10.8 mg per day (220 +/- 94 to 204 +/- 82 mumol per day; P = 0.05). Net renal acid excretion decreased from 70.9 +/- 10.1 to 12.8 +/- 21.8 mmol per day, indicating nearly complete neutralization of endogenous acid. CONCLUSIONS In postmenopausal women, the oral administration of potassium bicarbonate at a dose sufficient to neutralize endogenous acid improves calcium and phosphorus balance, reduces bone resorption, and increases the rate of bone formation.
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Jiang Q, Sebastian A, Archer S, Bidlack JM. 5 beta-Methyl-14 beta-(p-nitrocinnamoylamino)-7,8-dihydromorphinone and its corresponding N-cyclopropylmethyl analog, N-cyclopropylmethylnor-5 beta-methyl-14 beta-(p-nitrocinnamoylamino)- 7,8-dihydromorphinone: mu-selective irreversible opioid antagonists. J Pharmacol Exp Ther 1994; 268:1107-13. [PMID: 7511163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
5 beta-Methyl-14 beta-(p-nitrocinnamoylamino)-7,8-dihydromorphinone (MET-CAMO) and its corresponding N-cyclopropylmethyl analog, N-cyclopropylmethylnor-5 beta-methyl-14 beta-(p-nitrocinnamoylamino)- 7,8-dihydromorphinone (N-CPM-MET-CAMO) were tested in opioid receptor binding assays and in the mouse tail-flick test in order to characterize the affinity, selectivity and antinociceptive properties of these two compounds. Incubating bovine striatal membranes with either MET-CAMO or N-CPM-MET-CAMO produced a wash-resistant, concentration- and time-dependent inhibition of the binding of the mu-selective ligand, [3H]-[D-Ala2,MePhe4,Gly(ol)5]enkephalin, but with no change in delta or kappa binding. Preincubating membranes with N-CPM-MET-CAMO decreased the maximum binding value for [3H]-[D-Ala2,MePhe4,Gly(ol)5]enkephalin binding without changing the Kd value. In the mouse tail-flick assay, MET-CAMO and N-CPM-MET-CAMO did not produce any antinociception up to a dose of 100 nmol after i.c.v. administration. However, pretreatment of mice with either compound produced a time- and dose-dependent antagonism of morphine-induced antinociception. Analgesia mediated by delta or kappa opioids was not altered by either MET-CAMO or N-CPM-MET-CAMO at a dose of up to 100 nmol. The mu antagonistic effect of 1 nmol of MET-CAMO and N-CPM-MET-CAMO appeared at 8 hr and lasted up to 72 hr, with a maximal effect at 16 to 24 hr after i.c.v. administration. Pretreatment of mice with 1 nmol of MET-CAMO or N-CPM-MET-CAMO, given by i.c.v. administration at -24 hr, produced a rightward and downward shift of dose-response line of i.c.v. morphine.(ABSTRACT TRUNCATED AT 250 WORDS)
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96
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Sebastian A, Bidlack JM, Jiang Q, Deecher D, Teitler M, Glick SD, Archer S. 14 beta-[(p-nitrocinnamoyl)amino]morphinones, 14 beta-[(p-nitrocinnamoyl)amino]-7,8-dihydromorphinones, and their codeinone analogues: synthesis and receptor activity. J Med Chem 1993; 36:3154-60. [PMID: 7693944 DOI: 10.1021/jm00073a015] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A series of 14 beta-[(nitrocinnamoyl)amino]codeinones and morphinones, some of which contain a 5 beta-methyl group, were prepared from 14 beta-aminocodeinones and 14 beta-[N-(cyclopropylmethyl)-amino]norcodeinones. The affinities of the target compounds for the mu, delta, and kappa opioid receptors were determined by radiolabeled binding experiments using bovine brain membranes. An analogous series of 7,8-dihydrocodeinones and morphinones was prepared and assayed in the same systems. The 3-methoxy derivatives 3 and 4 were more selective than the corresponding morphinones for the mu receptor. The 5 beta-methylcodeinones 25 and 27 had lower affinity at all receptors than the corresponding morphinones, but the 5 beta-methylmorphinones had affinities similar to the morphinones 5 and 6. A similar pattern was observed in the 7,8-dihydro series. Two compounds, 5 beta-methyl-14 beta-[(p-nitrocinnamoyl)amino]-7,8-dihydromorphinone, 20 (MET-CAMO), and N-(cyclopropylmethyl)-14 beta-[(p-nitrocinnamoyl)amino]-7,8-dihydronormorphinone, 22 (N-CPM-MET- CAMO), acted as nonequilibrium ligands in antinociception and membrane binding studies. In mice after icv administration, neither ligand showed any agonist activity but 8-24 h after administration both compounds acted as potent mu antagonists. A Scatchard plot of the effect of N-CPM-MET-CAMO on [3H]DAMGO ([3H]D-Ala2, (Me)-Phe4, Gly(ol)5] enkephalin) binding to bovine striatal membranes showed that there was a significant decrease in the Bmax value and a marginal effect on the Kd value suggesting that the number of binding sites was reduced. When taken together, these results support the view that 20 and 22 bind covalently to the mu receptor. On the other hand, when N-acetylcysteine and 22 were allowed to react in a buffered solution, 22 was recovered unchanged. Under these conditions no Michael reaction was observed.
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Hagiwara S, Lane N, Engelke K, Sebastian A, Kimmel DB, Genant HK. Precision and accuracy for rat whole body and femur bone mineral determination with dual X-ray absorptiometry. BONE AND MINERAL 1993; 22:57-68. [PMID: 8219938 DOI: 10.1016/s0169-6009(08)80081-5] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Precision and accuracy for rat whole body and excised femur bone mineral density (BMD) measurements were evaluated with two dual X-ray absorptiometry (DXA) systems. The 'small subject' mode on the Norland XR-26 (XR), and the 'ultra high resolution mode' on the Hologic QDR-1000/W(QDR) were used for the analysis. The whole body mode was only available on the XR. The lowest precision error for the whole body was found using a scan resolution of 1.0 x 1.0 mm and a scan speed of 15 mm/s. The scan spatial resolution of the femur measurement was approximately eight times higher on the QDR than on the XR. However, the XR allowed analysis of an arbitrary region of interest within the femur, which was not easily done with the QDR. Precision for the total femur measurement on the QDR (0.5-0.9%) was approximately two to four times superior to that of the XR (1.5-4.3%). The difference may be due to the superior scan resolution of the QDR. Bone mineral content and BMD on the QDR significantly declined with an increase of water depth (P < 0.001). No significant change was observed on the XR. Both DXA systems demonstrated an excellent correlation (r > or = 0.98) with ash weight under the scan conditions examined. The optimal scan condition for the excised femur measurement on the XR was obtained with 1.5-2.5 cm of perspex or water and a scan speed of 10 mm/s. For the QDR, we recommend scanning the rat femur with approximately 2.5 cm of perspex or water in terms of precision and accuracy.
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Jiang Q, Sebastian A, Archer S, Bidlack JM. 5 beta-Methyl-14 beta-(p-nitrocinnamoylamino)-7,8-dihydromorphinone: a long-lasting mu-opioid receptor antagonist devoid of agonist properties. Eur J Pharmacol 1993; 230:129-30. [PMID: 7679076 DOI: 10.1016/0014-2999(93)90423-f] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
5 beta-Methyl-14 beta-(p-nitrocinnamoylamino)-7,8-dihydromorphinone (MET-CAMO) suppressed morphine-induced antinociception but had no effect on antinociception mediated by delta- or kappa-opioid receptors after a single i.c.v. 1-nmol injection from 8 to 72 h before testing. MET-CAMO had no agonist effects in the mouse tail-flick assay in doses up to 100 nmol. MET-CAMO is the first N-methylated morphine derivative which shows such long-lasting mu-selective opioid receptor antagonism with no agonistic properties.
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Siegel D, Hulley SB, Black DM, Cheitlin MD, Sebastian A, Seeley DG, Hearst N, Fine R. Diuretics, serum and intracellular electrolyte levels, and ventricular arrhythmias in hypertensive men. JAMA 1992; 267:1083-9. [PMID: 1735925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
OBJECTIVE To investigate the patterns of electrolyte abnormalities resulting from thiazide administration and whether they cause ventricular arrhythmias, and to help resolve the controversy over whether clinicians should routinely prescribe potassium-conserving therapy to all patients treated with thiazides. DESIGN Double-blind, randomized controlled trial. PARTICIPANTS A total of 233 hypertensive men aged 35 to 70 years. INTERVENTIONS Participants were withdrawn from prior diuretic treatment and were replenished with oral potassium chloride and magnesium oxide. They were then randomized to 2 months of treatment with (1) hydrochlorothiazide; (2) hydrochlorothiazide with oral potassium; (3) hydrochlorothiazide with oral potassium and magnesium; (4) hydrochlorothiazide and triamterene; (5) chlorthalidone; or (6) placebo. MAIN OUTCOME MEASURES Ventricular arrhythmias on 24-hour Holter monitoring and serum and intracellular potassium and magnesium levels. RESULTS Of the 233 participants, 212 (91%) completed the study. Serum potassium levels were 0.4 mmol/L lower in the hydrochlorothiazide group than in the placebo group (P less than 0.01), and this mean difference was not affected by supplementation with potassium, with potassium and magnesium, or with triamterene. However, the supplements did prevent the occasional occurrence of marked hypokalemia; all 12 of the men who developed serum potassium levels of 3.0 mmol/L or less were among the 90 who received diuretics without supplementation (P less than 0.01). Similarly, the overall proportion of men with ventricular arrhythmias was not affected by randomized treatment, but there was a twofold increase in the proportion with arrhythmias among the 12 men with serum potassium levels of 3.0 mmol/L or less (P = .02). Serum magnesium and intracellular potassium and magnesium levels were not reduced by hydrochlorothiazide, nor were they related to ventricular arrhythmias. CONCLUSIONS In the majority of hypertensive patients, treatment with 50 mg/d of hydrochlorothiazide does not cause marked hypokalemia or ventricular arrhythmias. However, because some individuals will develop hypokalemia after starting diuretic therapy, serum potassium levels should be monitored and potassium-sparing strategies should be used when indicated.
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Blankley CJ, Hodges JC, Klutchko SR, Himmelsbach RJ, Chucholowski A, Connolly CJ, Neergaard SJ, Van Nieuwenhze MS, Sebastian A, Quin J. Synthesis and structure-activity relationships of a novel series of non-peptide angiotensin II receptor binding inhibitors specific for the AT2 subtype. J Med Chem 1991; 34:3248-60. [PMID: 1956044 DOI: 10.1021/jm00115a014] [Citation(s) in RCA: 135] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Structure-activity relationships are reported for a novel class of 4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine-6-carboxylic acid derivatives that displace 125I-labeled angiotensin II from a specific subset of angiotensin II (Ang II) binding sites in rat adrenal preparations. This binding site is not the Ang II receptor mediating vascular contraction or aldosterone release, but, rather, is one whose function has not yet been fully elucidated. It has been identified in a number of tissues and has a similar affinity for Ang II and its peptide analogues as does the vascular receptor. The non-peptide compounds reported here are uniquely specific in displacing Ang II at this binding site and are inactive in antagonizing Ang II at the vascular receptor or in pharmacological assays measuring vascular effects. PD 123,319 (79), one of the most potent compounds, has an IC50 of 34 nM. Certain of these compounds may have utility in the definition and study of Ang II receptor subtypes.
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