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Biomedical subjects

W Jubiz

Publications and source records attributed to W Jubiz.

At least 19 recordsLinked to original sources
PubMed1990

Dietary fish oil and olive oil supplementation in patients with rheumatoid arthritis. Clinical and immunologic effects.

Forty-nine patients with active rheumatoid arthritis completed a 24-week, prospective, double-blind, randomized study of dietary supplementation with 2 different dosages of fish oil and 1 dosage of olive oil. Clinical evaluations were performed at baseline and every 6 weeks thereafter, and immunologic variables were measured at baseline and after 24 weeks of study. The 3 groups of patients were matched for age, sex, disease severity, and use of disease-modifying antirheumatic drugs (DMARDs). Subjects continued receiving DMARDs and other background medications without change during the study. Twenty patients consumed daily dietary supplements of n3 fatty acids containing 27 mg/kg eicosapentaenoic acid (EPA) and 18 mg/kg docosahexaenoic acid (DHA) (low dose), 17 patients ingested 54 mg/kg EPA and 36 mg/kg DHA (high dose), and 12 patients ingested olive oil capsules containing 6.8 gm of oleic acid. Significant improvements from baseline in the number of tender joints were noted in the low-dose group at week 24 (P = 0.05) and in the high-dose group at week 18 (P = 0.04) and 24 (P = 0.02). Significant decreases from baseline in the number of swollen joints were noted in the low-dose group at weeks 12 (P = 0.003), 18 (P = 0.002), and 24 (P = 0.001) and in the high-dose group at weeks 12 (P = 0.0001), 18 (P = 0.008), and 24 (P = 0.02). A total of 5 of 45 clinical measures were significantly changed from baseline in the olive oil group, 8 of 45 in the low-dose fish oil group, and 21 of 45 in the high-dose fish oil group during the study (P = 0.0002). Neutrophil leukotriene B4 production decreased by 19% from baseline in the low-dose fish oil group (P = 0.0003) and 20% in the high-dose group (P = 0.03), while macrophage interleukin-1 production decreased by 38.5% in the olive oil group (P not significant), 40.6% in the low-dose group (P = 0.06), and 54.7% in the high-dose group (P = 0.0005). Tritiated thymidine incorporation in peripheral blood mononuclear cells after stimulation with concanavalin A increased significantly in all 3 groups after 24 weeks, compared with baseline values. We conclude that the clinical benefits of dietary supplementation with omega-3 fatty acids are more commonly observed in patients consuming higher dosages of fish oil for time intervals that are longer than those previously studied. Dietary supplementation with olive oil is also associated with certain changes in immune function, which require further investigation.

Arthritis, Rheumatoid↗
PubMed1989

1,25-Dihydroxyvitamin D3-induced growth restriction of cultured epithelial cells derived from a murine hepatic tumor.

Recent evidence suggests that 1,25-dihydroxyvitamin D3 can accumulate in certain presumed non-target tissues, although the mechanism of action of the vitamin in such cells is not understood. Exposure of 77-1/3a mouse hepatic tumor cells, which derived from a non-target tissue of vitamin D action, to 1,25-dihydroxyvitamin D3 in chemically-defined serum-free medium resulted in a dose-dependent decline in cellular growth rate and maximal culture population density but did not adversely affect cell viability. Culture of 77-1/3a cells in defined medium containing 10(-7) or 10(-6) M 1,25-dihydroxyvitamin D3 for 150 hr reduced the growth rate to 64 and 50% of control values respectively. Albumin secretion was unaffected by 1,25-dihydroxyvitamin D3 exposure; in contrast, the cellular content of the proliferation-associated protein p35 was reduced by 39%, a decline similar in trend and degree to that observed in other tumor cells exposed to differentiation-inducing agents. It appears that 1,25-dihydroxyvitamin D3 regulates cellular p35 content (within a specific restricted range) as a consequence of proliferative perturbation, rather than differentiated status, of cultured hepatic tumor cells.

Animals↗
PubMed1989

Lipoxygenase products induce neutrophil activation and increase endothelial permeability after thrombin-induced pulmonary microembolism.

We examined the mechanism of the neutrophil (PMN)-dependent increase in pulmonary vascular permeability to protein after thrombin-induced pulmonary microembolism. Humoral factors that activate PMNs after thrombin-induced pulmonary microembolism were characterized in pulmonary lymph obtained from unanesthetized sheep challenged with intravenous infusion of alpha-thrombin. Time-dependent increases in PMN migration, aggregation, and superoxide anion (O2-) generation were induced by the pulmonary lymph obtained within 20 minutes after thrombin infusion. The pulmonary lymph neutrophil activating factors present in ether extracts of lymph had retention times of leukotriene B4 (LTB4) and monohydroxyeicosatetraenoic acids (HETEs) by high-performance liquid chromatography. The postthrombin lymph samples containing the LTB4 and HETEs increased PMN O2- generation and endothelial monolayer permeability to 125I-albumin in the presence of PMNs layered on the endothelial monolayers. Control lymph samples replete with LTB4, 5-HETE, and 15-HETE induced increases in PMN O2- generation and endothelial monolayer permeability to 125I-albumin in the presence of PMNs layered on the endothelial monolayers. Maximal increases in PMN O2- production and endothelial permeability occurred when LTB4, 5-HETE, and 15-HETE were coincubated with PMNs, indicating a synergistic action of these mediators in inducing PMN activation. Endothelial monolayer permeability to 125I-albumin did not increase with postthrombin lymph samples obtained after pretreatment with the 5-lipoxygenase inhibitor, L-651,392. The results indicate that lipoxygenase products generated in the lungs after thrombin-induced microembolism contribute to increased endothelial permeability secondary to PMN activation.

Animals↗
PubMed1988

Biosynthesis of 20,20,20-trifluoroleukotriene B4 from 20,20,20-trifluoroarachidonic acid: a metabolically stable analog of leukotriene B4 and its application to a study of stimulation of leukotriene B4 synthesis by immunoglobulin G1,2.

Leukotriene B4 is rapidly metabolized through omega-oxidation, preventing its detection when it is produced under certain biological conditions. To investigate leukotriene B4 production in various physiological conditions, analogs of arachidonic acid which are converted to metabolically stable analogs of leukotriene B4 would be useful. We have synthesized 20,20,20-trifluoroarachidonic acid by the cis-selective Wittig reaction of the C12-C20 fragment with phosphonium salt. 20,20,20-trifluoroarachidonic acid was transformed into 20,20,20-trifluoroleukotriene B4 when incubated with human neutrophils in the presence of the calcium ionophore A23187. The product was identified by uv absorption spectrophotometry, gas chromatography-mass spectrometry, and coelution on high-performance liquid chromatography with 20,20,20-trifluoroleukotriene B4, which was enantioselectively synthesized by the reaction of the fluorine-containing C11-C20 fragment with the C1-C10 phosphonate. The fluorinated leukotriene B4 demonstrated as much chemotactic activity on human neutrophils as natural leukotriene B4 and was metabolically stable when incubated with human neutrophils, probably by blocking omega-oxidation. Also, enzymes catalyzing the transformation of arachidonic acid (AA) into leukotriene B4 did not discriminate the fluorinated precursors from the natural, nonfluorinated AA, thus 20-F3-AA is a valid analog of AA to be used in the study of AA metabolism. When 50 microM of the fluorinated acid was incubated with neutrophils stimulated with heat-aggregated human immunoglobulin G, a significant amount of fluorinated leukotriene B4 (4.3 ng/10(6) cells/40 min, at most) was formed in a dose-dependent manner while little leukotriene B4 was detected with incubation with 50 microM arachidonic acid, probably due to omega-oxidation of the product, leukotriene B4. 20,20,20-Trifluoroarachidonic acid appears to be a useful tool for studying the capacity of leukotriene B4 synthesis in various biological systems while long-lasting 20,20,20-trifluoroleukotriene B4 would serve as an excellent analog of leukotriene B4 in pharmacological studies to understand functions of leukotrienes B4.

Arachidonic Acids↗
PubMed1988

In vivo effects of 1,25-dihydroxyvitamin D3 and minerals on synthesis of leukotriene B4 and 5-hydroxyeicosatetraenoic acid by rat peritoneal neutrophils.

We investigated the in vivo effects of 1,25-dihydroxyvitamin D3, and serum calcium and inorganic phosphorus concentrations on productions of leukotriene B4 and 5-hydroxyeicosatetraenoic acid by glycogen stimulated peritoneal neutrophils of the rat. Neutrophils were incubated with ionophore A23187 for 5 min and the incubation medium was subjected to a reverse-phase high performance liquid chromatography for quantitation. Productions of these lipoxygenase metabolites by neutrophils from vitamin D depleted rats were decreased compared to the vitamin D sufficient levels. This difference was not observed when arachidonic acid was added to the incubation medium. When serum calcium concentrations of rats were altered by dietary calcium levels but 1,25-dihydroxyvitamin D3 was administered to those rats, the difference in serum calcium concentration did not show any effect on the production of leukotriene B4. In contrast, neutrophils from 1,25-dihydroxyvitamin D3 sufficient but phosphorus deficient rats still demonstrated decreased leukotriene B4 production. This reduction was corrected by exogenous arachidonic acid. The data suggest that 1,25-dihydroxyvitamin D3 or cellular calcium translocation mediated by the hormone, and serum inorganic phosphorus independent of 1,25-dihydroxyvitamin D3 affect arachidonic acid release, thus productions of leukotriene B4 and 5-hydroxyeicosatetraenoic acid.

Animals↗
PubMed1988

Inflammatory events after fibrin microembolization. Alterations in alveolar macrophage and neutrophil function.

We performed bronchoalveolar lavage (BAL) 0.5 to 24 h after thrombin-induced pulmonary microembolization in spontaneously breathing sheep to examine the inflammatory events that occur after pulmonary intravascular coagulation. Neutrophil alveolitis was evident as early as 0.5 h after microembolization and was maximal at 4 h (4.9 +/- 1.5% neutrophils of total BAL cells at baseline versus 26.2 +/- 2.8% at 4 h post-thrombin). Neutrophils obtained both at baseline (isolated from peripheral blood) and at 0.5 to 24 h after thrombin (isolated from BAL) did not demonstrate significant basal production of superoxide anion (O2-) and produced similar amounts of O2- upon challenge with phorbol myristate acetate (PMA) 200 micrograms/ml. The basal O2- production by alveolar macrophages was also not increased. However, alveolar macrophages recovered after fibrin microembolization produced greater amounts of O2- (29.1 +/- 6.3 nm O2-/10(6) cells at 0.5 h) after challenge with PMA compared with alveolar macrophages recovered prior to embolization (10.6 +/- 1.6 nm O2-/10(6) cells baseline), suggesting that thrombin-induced microembolization primes alveolar macrophages and enhances their O2- generation. Neutrophil chemotactic activity was detected in BAL fluid at 0.5 h post-microembolization and reached a peak level at 2 h. Alveolar macrophages were a source of the chemotactic activity since conditioned medium obtained from 2-h post-thrombin macrophages induced neutrophil chemotaxis, whereas baseline cells did not. The addition of the thrombin to macrophages did not result in the generation of chemotactic activity from baseline macrophages, indicating that macrophages were activated during the process of intravascular coagulation rather than by thrombin per se. Post-thrombin BAL fluid also stimulated O2- generation from sheep neutrophils.(ABSTRACT TRUNCATED AT 250 WORDS)

Albumins↗
PubMed1987

Fish-oil fatty acid supplementation in active rheumatoid arthritis. A double-blinded, controlled, crossover study.

STUDY OBJECTIVE: to determine the efficacy of fish-oil dietary supplements in active rheumatoid arthritis and their effect on neutrophil leukotriene levels. DESIGN: nonrandomized, double-blinded, placebo-controlled, crossover trial with 14-week treatment periods and 4-week washout periods. SETTING: academic medical center, referral-based rheumatology clinic. PATIENTS: forty volunteers with active, definite, or classical rheumatoid arthritis. Five patients dropped out, and two were removed for noncompliance. INTERVENTIONS: treatment with nonsteroidal anti-inflammatory drugs, slow-acting antirheumatic drugs, and prednisone was continued. Twenty-one patients began with a daily dosage of 2.7 g of eicosapaentanic acid and 1.8 g of docosahexenoic acid given in 15 MAX-EPA capsules (R.P. Scherer, Clearwater, Florida), and 19 began with identical-appearing placebos. The background diet was unchanged. MEASUREMENTS AND MAIN RESULTS: the following results favored fish oil placebo after 14 weeks: mean time to onset of fatigue improved by 156 minutes (95% confidence interval, 1.2 to 311.0 minutes), and number of tender joints decreased by 3.5 (95% Cl, -6.0 to -1.0). Other clinical measures favored fish oil as well but did reach statistical significance. Neutrophil leukotriene B4 production was correlated with the decrease in number of tender joints (Spearman rank correlation r=0.53; p less than 0.05). There were no statistically significant differences in hemoglobin level, sedimentation rate, or presence of rheumatoid factor or in patient-reported adverse effects. An effect from the fish oil persisted beyond the 4-week washout period. CONCLUSIONS: fish-oil ingestion results in subjective alleviation of active rheumatoid arthritis and reduction in neutrophil leukotriene B4 production. Further studies are needed to elucidate mechanisms of action and optimal dose and duration of fish-oil supplementation.

Adult↗
PubMed1985

Quadruple injection of hypothalamic peptides to evaluate pituitary function in normal subjects.

A single intravenous injection of four hypothalamic releasing hormones-corticotropin-, growth hormone-, gonadotropin- and thyrotropin-releasing hormones-was administered to normal subjects. Except for the plasma adrenocorticotropic hormone (ACTH) level, a statistically significant increase in all anterior pituitary hormone levels occurred. Transient flushing was the only consistent side effect. In the same persons, results were compared with those obtained with insulin-induced hypoglycemia and a single-dose overnight metyrapone test. Growth hormone and cortisol responses to insulin-induced hypoglycemia were similar but prolactin increment was less than that obtained by the peptide injection. ACTH increments from both tests were substantially less than those obtained by the overnight metyrapone test. We conclude that pituitary function can be effectively studied in normal subjects by the combination of a metyrapone test with a triple bolus of growth hormone-, thytropin- and gonadotropin-releasing hormones, but not by a quadruple bolus of the hypothalamic peptides. Compared with insulin-induced hypoglycemia, this approach yields more information with fewer side effects.

Adult↗
PubMed1979

Metyrapone test with adrenocorticotrophic levels. Separating primary from secondary adrenal insufficiency.

Basal plasma adrenocorticotrophic hormone (ACTH) and cortisol concentrations as well as plasma ACTH and 11-deoxycortisol responses to the administration of a single dose of metyrapone were evaluated in 104 patients with intact pituitary-adrenal axis, in 20 patients with secondary adrenal insufficiency, and in seven patients with primary adrenal insufficiency. In patients with primary adrenal insufficiency, baseline ACTH levels were high. Following metyrapone administration, 11-deoxycortisol concentrations were low and ACTH levels did not change. In patients with secondary adrenal insufficiency, baseline plasma ACTH levels were normal, but neither 11-deoxycortisol nor ACTH levels increased in response to metyrapone. The metyrapone test is not only useful to screen for adrenal insufficiency, it is also useful to differentiate a primary from a secondary cause.

Adrenal Insufficiency↗
PubMed1979

Alterations of glucocorticoid actions by other drugs and disease states.

Glucocorticoids are used in physiological and pharmacological amounts in the management of a variety of clinical conditions. Concomitant utilisation of other drugs or the presence of some diseases may affect the physiological action of the steroid in the tissues. Phenytoin, phenobarbitone, ephedrine and rifampicin accelerate the metabolism of glucocorticoids thereby decreasing their biological activity. A similar phenomenon occurs in patients with hyperthyroidism. In contrast, glucocorticoid action is enhanced in hypothyroid patients and in those with hepatic damage as the result of a defect in the clearance of the hormone from blood. In turn, glucocorticoids antagonise the effects of cholinesterase inhibitors and ganglion blocking agents. The above mentioned effects should be kept in mind whenever glucocorticoids are utilised in the diagnosis and management of endocrine or non-endocrine conditions.

Anticonvulsants↗
PubMed1979

Inhibitory effect of prostaglandin F2 alpha on the growth of a hormone-dependent rat mammary tumor.

Growth of the rat hormone-dependent mammary adenocarcinoma MTW-9 was inhibited by prostaglandin F2alpha (PGF2alpha) This inhibition of tumor growth was associated with a marked reduction in serum progesterone concentrations. The inhibitory effect of PGF2alpha on tumor growth was abolished by concomitant injections of progesterone. The growth rates of coimplanted prolactin-secreting pituitary tumor MtTW-5 and plasma concentrations of prolactin and estradiol were not affected significantly by PGF2alpha. Our data imply that the effect of PGF2alpha on growth of rat mammary adenocarcinoma is mediated by progesterone.

Adenocarcinoma↗
PubMed1979

Serum C-peptide in renal failure patients following stimulation of pancreatic secretion.

We have demonstrated persistently elevated serum C-peptide concentrations in patients with chronic renal failure on chronic hemodialysis. A blunted serum C-peptide response to intravenous glucose, glucagon and tolbutamide was also found. However, the response to oral glucose stimulation was greater and more prolonged than in control subjects, probably related to the magnitude of hyperglycemia found in patients with chronic renal failure. These observations suggest the existence of a defect in the renal clearance of C-peptide although an abnormality in C-peptide secretion cannot be excluded.

Adult↗
PubMed1978

The effect of prednisone on serum thyrotropin, thyroxine and triiodothyronine concentrations in hypothyroid patients.

The effect of exogenous prednisone on serum thyrotropin (TSH), thyroxine (T4), and triiodothyronine (T3) concentrations was investigated in four patients with non-functioning thyroid glands receiving T4 replacement therapy. Orally administered prednisone, in a dose of 20 mg each day for nine days, resulted in a significant decrease in mean serum TSH levels (p less than 0.01) without significant changes in levels of serum T4, T3, and thyroxine binding globulin (TBG). These findings suggest an inhibitory action of relatively low pharmacologic doses of prednisone on TSH release without changes in circulating thyroid hormone concentrations or inhibition of the peripheral conversion of T4 to T3.

Adult↗
PubMed1978

A concept for the control of kidney production of erythropoietin involving prostaglandins and cyclic nucleotides.

Our hypothesis is that PGs released within the kidney play a role in the modulation of kidney production of Ep. PGs release probably at medullary and/or cortical sites following erythropoietic stimuli such as hypoxic hypoxia, anemic hypoxia, and ischemic hypoxia induced by renal artery constriction increase kidney production of Ep. PGs which are released probably activate a renal cortical adenylate cyclase thereby enhancing the production of intracellular cAMP. This initiates the cascade of events resulting in the production and/or secretion of Ep by the kidney. The endoperoxide analogs and PGE2 have been found to produce a dose-related and Ep-dependent increase in radioiron incorporation into newly formed red blood cells of exhypoxic polycythemic mice. Indomethacin, a potent PG cyclo-oxygenase inhibitior, attenuates Ep production and the appearance of PGE in the renal venous effluent of animals exposed to hypoxic hypoxia and renal artery constriction. Arachidonic acid (C20:4) and PGE2 infusion into the posthypoxic isolated perfused dog kidney produced a significant elevation in Ep titers in the perfusate. The increase in Ep production caused by arachidonate is blocked by indomethacin. It has been previously reported that PGs of the E series stimulate cAMP formation in several tissues. We have found that not only are renal cortical cAMP levels significantly elevated in rats following exposure to hypobaric hypoxia but that dibutyryl cAMP administration produces an increase in hematocrit and circulating red cell mass in normal mice. Our data thus far strongly support the hypothesis that the renal PGs and the cyclic nucleotides are intimately involved in the pharmacologic and/or pathophysiologic control of Ep production. Further work is necessary to determine whether the PGs and cyclic nucleotides are involved in the day-to-day control of Ep production by the mammalian kidney.

Animals↗
PubMed1978

Effect of indomethacin on the hypothalamic-pituitary-adrenal axis in man.

The effect of the cyclo-oxygenase inhibitor, indomethacin, on hypothalamic-pituitary-adrenal function was investigated in five normal males. Baseline 0800 and 1600 h plasma ACTH and cortisol, plasma ACTH and 11-deoxycortisol responses to metyrapone, and plasma cortisol responses to dexamethasone and exogenous ACTH were not affected by indomethacin. However, the area under the curve for plasma ACTH after iv injection of regular insulin (0.1 U/kg) was significantly decreased during indomethacin administration (control, 88.0 +/- 32.6 cm2, mean +/- sd; indomethacin, 47.6 +/- 23.1, P less than 0.01). Plasma cortisol levels were decreased only at 30 min. Our results support the hypothesis that prostaglandins or any of their precursors play a role in the hypothalamic control of ACTH secretion and indicate that evaluation of hypophyseal ACTH secretory capacity by means of insulin-induced hypoglycemia may yield abnormal results in patients receiving indomethacin.

Adrenal Glands↗
PubMed1978

N-Ethylmaleimide prevents destruction of corticotropin (ACTH) in plasma.

Addition of N-ethylmaleimide, an inhibitor of proteolytic enzymes, to samples for plasma corticotropin determinations prevents destruction of the hormone at room temperature for at least 72 h. A concentration of 125 mg per liter of blood is effective. N-Ethylmaleimide is not so effective in preventing corticotropin degradation in whole blood. Use of the inhibitor should make plasma corticotropin determinations more practical and reliable.

Adrenocorticotropic Hormone↗