Gene/Protein Disease Symptom Drug Enzyme Compound
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 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In a controlled cross-over trial, we have compared a conventional 40-g protein diet (30 g animal and 10 g vegetable, diet A) with an 80-g vegetable-protein-supplemented diet (30 g animal and 50 g vegetable, diet B) in the treatment of six patients with chronic stable portal systemic encephalopathy, requiring dietary and lactulose therapy. Each diet was given, in random order, for 5 days in hospital. EEG, clinical indices of encephalopathy, and the plasma amino acid profile were assessed at the end of each treatment period. The increase in vegetable protein intake was associated with minor improvement in EEG and clinical performance in two patients, and no change in the others. Fasting plasma phenylalanine and tyrosine were higher on diet B [phenylalanine 108.6 +/- 9.3 (SEM) mumol/L versus 99.6 +/- 8.37, p less than 0.05 (paired t test); tyrosine 153 +/- 15.2 mumol/L versus 140 +/- 14, p less than 0.05). The plasma branched-chain amino acid levels did not change, and the branched chain/aromatic amino acid ratio (BCAA/AAA) was lower on diet B (p less than 0.02). Fecal weights were not significantly altered. These results indicate that patients with chronic portal systemic encephalopathy are tolerant of protein supplementation from vegetable sources. A minor improvement in parameters of encephalopathy was seen in some individuals, despite a lowering of BCAA/AAA which some investigators have thought important in the pathogenesis of encephalopathy.
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PMID:Dietary protein supplementation from vegetable sources in the management of chronic portal systemic encephalopathy. 639 Nov 54

A sensitive and specific radioimmunoassay for measuring urinary kinins was developed. Antibodies against bradykinin were induced in rabbits by injecting bradykinin coupled to bovine albumin. One of the antisera generated was used at a final dilution of 1:18,000 to obtain a 30% total binding of bradykinin-(8-tyrosine)-[125I]-triacetate. Synthetic bradykinin (5-1,000 pg) was used as standard in the curves. The sensitivity of the assay was 5 pg. The recovery of bradykinin added to urinary samples was 86.85 +/- 6%. The intraassay and interassay coefficients of variation were 3.3% (n = 12) and 4.4% (n = 5), respectively. The antiserum showed no cross-reactivity with oxytocin or low molecular weight kininogen and cross-reacted with kallidin (lys-bradykinin), met-kallidin, and angiotensin I, but cross-reaction with angiotensin I (2.5%) was low enough to be disregarded. The mean urinary levels of total kinins in 12 normal subjects were 23.2 +/- (SEM) 2.2 micrograms/day.
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PMID:A radioimmunoassay method for measurement of urinary kinins. 648 28

Clonal variants of PC12 cells with respect to catecholamine biosynthesis were isolated, and the catecholamine content was measured by high performance liquid chromatography with electrochemical detection. The dopamine content of 13 subclones, which were selected and isolated in tyrosine-free medium, was substantially higher than the control level: 0.91 +/- 0.10 nmol/mg protein (mean +/- SEM; n = 3). In contrast, the noradrenaline content showed a marked heterogeneity: only two subclones contained noradrenaline levels similar to or higher than the control level: 0.40 +/- 0.05 (n = 5). The rest of them contained below the level of 0.20, and only negligible amounts of noradrenaline were found in four subclones. Thus, the noradrenaline-to-dopamine ratio varied widely between 0.003:1 and 0.53:1. This divergence of the noradrenaline content appears to be related to differing levels of dopamine beta-monooxygenase activity. The administration of ascorbate to the medium alone, however, did not restore the level of noradrenaline to the normal level in a subclone. Heterogeneity of the response to applied glucocorticoid was also demonstrated.
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PMID:Clonal variability of PC12 pheochromocytoma cells with respect to catecholamine biosynthesis. 670 45

Previous in situ voltammetric microelectrode measurements of median eminence dopamine release during mammary nerve stimulation of anesthetized lactating rats revealed a transient (1-3 min) 70% decline of dopamine concentrations. This dopamine was believed to be destined for secretion into the hypophysial portal circulation, but direct experimental support for this supposition was lacking. Thus, in the present study, [3H]dopamine release into brief sequential samples of hypophysial portal blood was compared with dopamine release in the median eminence measured by voltammetry. Lactating female rats were urethane anesthetized, and the median eminence pituitary region was exposed. [3H]Tyrosine was injected into a jugular cannula (100 microCi) followed by continuous infusion (5 microCi/min). In a preliminary experiment, this regimen produced a steady state level of [3H]dopamine in the portal blood within 45 min. In subsequent experiments, portal blood was collected as sequential 3-min samples, and electrochemical sampling from a microelectrode placed in the median eminence occurred at 1-min intervals. Electrochemical current resulting from the oxidation of dopamine in the medial median eminence was unvarying throughout the 75-min experiment in control rats (n = 4) and during the 30-min control period preceding mammary nerve stimulation in the other group (n = 4). These results were parallel by [3H] dopamine levels in portal blood during the same periods of time. All animals showed simultaneous decreases in oxidation current and [3H]dopamine levels within 1-4 min after initiation of mammary nerve stimulation (respectively, 35 +/- 7% and 62.5 +/- 5.9%, mean +/- SEM). Significant increases in oxidation current, taking the form of brief 2- to 6-min pulses began within an average of 18.5 min after initiation of stimulation. Similar increases in [3H]dopamine levels in portal blood were also observed. These and earlier results demonstrate that mammary nerve stimulation (and by extension, suckling) induces a momentary, but profound, decrease in hypothalamic dopamine secretion which precedes or accompanies the rise in PRL secretion evoked by the same stimulus.
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PMID:The decrease in hypothalamic dopamine secretion induced by suckling: comparison of voltammetric and radioisotopic methods of measurement. 705 24

Abnormalities in plasma amino acid profiles have been reported in severe uraemia and dialysis patients and may be a consequence of altered protein metabolism in the presence of metabolic acidosis. We studied plasma amino acid profiles in 7 control subjects [GFR 92.7 +/- (SEM) 14.5 ml/min/1.73 m2] and 7 elderly patients with renal failure (GFR 16.5 +/- 1.3 ml/min/1.73 m2). Uraemic patients had significantly reduced plasma levels of valine, tyrosine, phenylalanine, tryptophan and elevated histidine compared to controls. There was no correlation between arterial pH or bicarbonate and plasma amino acid levels.
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PMID:Plasma amino acid profile in the elderly with increasing uraemia. 813 45

Two experiments were conducted in cyclic beef heifers to determine whether active immunization against bovine inhibin alpha 1-26 Gly-Tyr (bINH) affected follicular dynamics, hormone concentration or ovulation rate. In Expt 1, heifers (n = 9) were actively immunized against bINH conjugated to human alpha globulins (HAG) using bis-diazotized benzidine in non-ulcerative Freund's adjuvant (NUFA; primary on day 0; booster injections on days 53, 84 and 116 using conjugated bINH and on days 176 and 366 using unconjugated bINH; ten heifers were used as controls). Ovaries were examined daily using ultrasound scanning (days 70-155 and 384-391) and corresponding blood samples were collected for bINH antibody titre, luteinizing hormone (LH), follicle-stimulating hormone (FSH) and oestradiol determinations. Four treated and four control heifers were injected with 10 micrograms gonadotrophin-releasing hormone (GnRH) on day 386 (day 2 of the oestrous cycle). Although bINH-immunized heifers had variable antibody titres ranging from 4 to 50% I125-labelled bINH bound to serum diluted 1:2000, ovulation rate was unaffected. In oestrous cycles with three dominant follicles, the ovulatory follicles grew faster (2.5 +/- 0.2 versus 1.6 +/- 0.3 mm day-1; mean +/- SEM), had shorter durations of growth (5.7 +/- 0.8 versus 9.6 +/- 1.6 days) and duration of detection (7.5 +/- 0.8 versus 12.0 +/- 2.4 days) in immunized heifers. Mean concentrations of FSH, LH and oestradiol were unaltered in most cases during oestrous cycles in bINH-immunized compared with control heifers. There was no significant difference in the percentage increase in FSH or LH, after GnRH injection, between control and immunized heifers. As ovulation rate was unaltered in the first experiment, a second similar study was designed using a different immunization protocol. In Expt 2, heifers were immunized with bINH conjugated to human serum albumin using glutaraldehyde with the following doses: 0.0 (control; n = 7), 0.33 (n = 7), 1.0 (n = 8) and 3.0 (n = 7) mg. Three booster immunizations were given 33, 66 and 209 days after primary immunization. Immunization increased the number of oestrous cycles with multiple ovulations (42 of 132 (32%) oestrous cycles examined) compared with controls (1 of 30 (3.3%) oestrous cycles examined). Neither titre nor ovulation rate was affected by dose of bINH used. In summary, following bINH immunization, ovulation rate was not increased despite changes in follicular dynamics in Expt 1, but was increased in 32% of oestrous cycles in Expt 2.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Active immunization of heifers against a synthetic fragment of bovine inhibin. 846 14

During human pregnancy, plasma CRH immunoreactivity (CRH-IR) rises progressively, peaking during labor and falling after delivery. Among animal species, only higher primates have elevated CRH-IR during pregnancy. This study examines whether changes in plasma CRH-IR in the baboon (Papio hamadryas) are similar to those in the human. CRH-IR was determined by RIA in 16 baboons at different stages of gestation (44 samples) and in 3 males. Assays were performed on Vycor extracts of plasma and CRH-IR diluted in parallel to synthetic human (h) CRH-41 standard. Reverse phase high pressure liquid chromatography and size-exclusion chromatography with Sephadex G-50 showed that baboon CRH-IR eluted in a position similar to that of hCRH-41. Regression analysis revealed a cubic association between plasma CRH-IR and gestational age, with peak concentrations occurring at 60 days gestation (term = 182 days). Although greatly elevated concentrations persisted throughout pregnancy, concentrations in the first half (1-91 days) were significantly higher (mean +/- SEM, 1.9 +/- 0.3 nM/L; n = 27) than in the second half (92-182 days; 1.0 +/- 0.2 nM/L; n = 11; P < 0.003 by t test). CRH-IR fell to low levels by day 1 postpartum. The concentration of total cortisol in nonpregnant animals was 1370.9 +/- 134.9 nM/L (n = 5), which was similar to pregnancy levels (1346.3 +/- 356.1 nM/L; n = 28); there was no gestational age-related pattern evident. Plasma corticosteroid-binding globulin was estimated by RIA, and plasma free cortisol was calculated to be 73 +/- 14 nM/L in pregnant animals and showed no gestational age-related changes. The mean progesterone concentration in the pregnant baboon was 12.5 +/- 2.2 nM/L (7-169 days; n = 27). There was no significant change in progesterone levels during the period of gestation studied; however, they were higher than nonpregnant levels. Baboon and human plasma (0.1 mL each) were incubated with [125I]Tyr-hCRH in Tris-HCl buffer (pH 7.5) and chromatographed with Sephadex G-75, using the same buffer. The radioactivity of fractions was determined, and no CRH-binding protein was identified in baboon plasma. This study indicates that gestational changes in CRH-IR in the baboon are different from those observed in humans. There is a dissociation between maternal plasma CRH and cortisol. The apparent lack of bioactivity of baboon plasma CRH is not due to a circulating binding protein, which is absent in this species.
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PMID:Corticotropin-releasing hormone in baboon pregnancy. 847 82

A combination of arterio-venous difference, kinetic isotope transfer and blood flow rate techniques were used to measure tyrosine metabolism across hindlimb tissues of nine growing lambs (average live weight 36.5 kg) fed on a range of dry matter intakes. Muscle protein synthesis was measured using a continuous infusion technique and compared with simultaneous estimates of hindlimb protein turnover calculated from the values for tyrosine metabolism. When the specific radioactivity (SRA) of tyrosine in the arterial plasma free pool was assumed to be the same as the SRA of tyrosine in the direct precursor pool of protein synthesis, hindlimb protein synthesis (ksav; 3.66 (SEM 0.50) %/d) was significantly (P < 0.001) higher (68%) than muscle protein synthesis (ksp; 2.18 (SEM 0.31) %/d) but was similar to the value for muscle protein synthesis calculated using the homogenate free tyrosine SRA (ksh; 3.35 (SEM 0.42) %/d). Hindlimb and muscle protein synthesis (y) were both significantly related to dry matter intake (chi) (ksav, r2 0.667, P = 0.007; ksh, r2 0.968, P < 0.001) and there was no significant difference between the slopes (P = 0.532) and intercepts (P = 0.945) of the two regression lines. The results demonstrate that hindlimb protein turnover cannot be quantitatively compared with muscle protein synthesis, probably due to high protein metabolic activity in non-muscular tissues within the hindlimb, although similar responses in protein synthetic rate to the level of feed intake were observed between hindlimb and muscle tissues.
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PMID:Hindlimb protein turnover and muscle protein synthesis in lambs: a comparison of techniques. 848 93

Tyrosine is the endogenous substrate for melanin production within melanosomes, but the method of tyrosine transport into the melanosome has not been investigated. In the mouse, melanogenesis is disrupted by mutations in the p gene resulting in the pink-eyed dilution phenotype; it has been suggested that the p gene codes for a tyrosine transport protein. We determined that normal (melan-a) melanosome-rich granular fractions take up 10 microns [3H]tyrosine at 21.1 +/- 6.1 (SEM, standard error of the mean) pmol/min/mg protein (N = 7) compared with 21.3 +/- 5.8 SEM pmol/min/mg protein (N = 5) for pink-eyed dilution, whose plasma membrane tyrosine transport was also normal (Km 89 microM; Vmax 302 pmol/min/mg cell protein). We also demonstrated that pink-eyed dilution melanosomes are immature by virtue of their low density, high hexosaminidase activity, and lack of pigment. These data indicate that a tyrosine transport system exists in the melanosomal membrane and that the p gene does not encode a tyrosine transporter of critical importance.
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PMID:Melanosomal tyrosine transport in normal and pink-eyed dilution murine melanocytes. 878 96

This report extends previous investigations of endogenous catecholamine levels in patients with orthostatic hypotension due to familial dysautonomia (FD), to define better the neurochemical phenotype and elucidate possible pathophysiological mechanisms. Ten FD patients (age 26.1 +/- 2.6 (SEM) years) and eight control subjects (age 29.5 +/- 3.7 years) were studied. Heart rate, blood pressure and venous blood samples were obtained while supine and after 5 min in the upright position. Plasma levels of dihydroxyphenylalanine (DOPA), noradrenaline (NA), adrenaline (A), dopamine (DA), dihydroxyphenylglycol (DHPG) and dihydroxyphenylacetic acid (DOPAC) were measured. When supine, the FD group had greater NA and DOPA levels, and lower DHPG levels. Plasma NA did not increase with erect posture in FD patients. Individual FD mean blood pressures were correlated positively with plasma NA levels when supine and with plasma DA and DOPAC when upright. In FD, DOPA:DHPG ratios were above the range found in normal subjects or that reported in patients with acquired forms of dysautonomia regardless of posture, whereas DOPAC:DHPG ratios remained normal. Thus FD patients have a characteristic neurochemical pattern which probably reflects either decreased vesicular storage of catecholamines or limited oxidative deamination despite normal or increased tyrosine hydroxylation.
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PMID:Pattern of plasma levels of catecholamines in familial dysautonomia. 890 16


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