PLASMA L-TRYPTOPHAN CONCENTRATIONS IN CHRONIC RHEUMATIC DISEASES AND THE EFFECTS OF SOME ANTIRHEUMATIC DRUGS ON THE BINDING OF THE AMINO-ACID TO PLASMA PROTEINS IN VIVO AND IN VITRO

L-TRYPTOPHAN may be used as a model endogenous molecule to studythe binding characteristics of the plasma proteins of patientswith connective-tissue diseases. A drug's ability to displaceL-tryptophan from binding to human serum albumin may also representa new in-vitro assay for screening drugs for potential anti-inflammatoryactivity. In patients with rheumatoid arthritis, ankylosingspondylitis, and psoriatic arthritis, antirheumatic drugs displaceL-tryptophan from plasma proteins in vivo, whereas withdrawalof such therapy is associated with excessive binding of theamino-acid to plasma proteins. In children with Still's disease,virtually all plasma tryptophan exists in the protein-boundform, and protein-bound tryptophan is less easily displacedfrom Still's disease plasma than from healthy children's plasmaby antirheumatic drugs in vitro. Results obtained with the novelin-vitro assay described indicate its greater sensitivity thanthe Mizushima test for screening antirheumatic agents. ^*Based on a paper presented at a combined meeting of the BritishAssociation for Rheumatology and Rehabilitation with the RoyalSociety of Medicine, Section of Rheumatology and Rehabilitation,Cardiff, September 1973.     

NIDDM患者红细胞膜脂质成分改变与血糖、血脂、血浆脂蛋白的关系

对75例NIDDM患者红细胞膜脂质成分,空腹血糖、血脂、血浆脂蛋白进行测定,以探讨红细胞膜脂质成分改变与高血糖、高血脂及血浆脂蛋白的关系。结果表明:NIDDM组红细胞膜胆固醇,胆固醇/磷脂比值、过氧化脂质明显高于正常对照组;膜磷脂低于正常对照组;血糖、血脂良好控制的NIDDM患者红细胞膜脂质成分与正常对照组差异无显著性;直线相关分析显示红细胞膜成分改变与高血糖,高血脂及血浆脂蛋白水平存在明显相关性。提示NIDDM患者严重代谢紊乱与红细胞膜脂质成分改变密切有关。     

SPIN-STATE CHANGES IN CYTOCHROME P-450cam ON BINDING OF SPECIFIC SUBSTRATES

The electron paramagnetic resonance signals of the soluble P-450 cytochrome from Pseudomonas putida were observed at temperatures from 4.2 to 80 degrees K. As isolated, P-450 has a signal typical of a low spin ferric-heme compound with sulfur as one of the axial ligands (g = 2.45, 2.26, 1.91(5)). We also detected a minor signal typical of high spin ferric heme (g = 8, 4, 1.8) equivalent to less than 7% of the heme at temperatures below 20 degrees K. On titration with the substrate, (+)-camphor, the low spin signal decreased and the high spin signal increased, maximally representing about 60% of the heme. For reasons not thus far understood, 40% of the heme is not converted to high spin by either (+) or (-)-camphor. The high spin signal has a rhombic character which is stronger than any previously observed with a heme compound (E = 0.33 cm(-1); D = 3.8 cm(-1); E/D = 0.087).We conclude that P-450(cam) as isolated is equal to or more than 95% in a low spin form probably having sulfur as one of the axial ligands. The binding of substrate displaces this ligand sufficiently to allow for conversion from a low to a high spin form.     

BINDING SITES FOR IMMUNE COMPONENTS IN HUMAN CHOROID PLEXUS

In immunologically mediated disorders such as systemic lupus erythematosus and experimental serum sickness, immunoglobulin and complement may be localized in the choroid plexus. This report demonstrates the presence of binding activity for the Fc fragment of IgG in 34 of 36 samples of human choroid plexus. We suggest that the number, distribution, and avidity of these Ig receptors may modulate the occurrence and/or severity of central nervous system symptoms in patients with immunologically mediated systemic diseases.     

ELEVATED LEVELS OF CORTICOTROPHIN-RELEASING FACTOR BINDING PROTEIN IN THE BLOOD OF PATIENTS SUFFERING FROM ARTHRITIS AND SEPTICAEMIA AND THE PRESENCE OF NOVEL LIGANDS IN SYNOVIAL FLUID

In view of the reported inflammatory effects of corticotrophin-releasingfactor (CRF) and the associated regulatory elements in the geneof its binding protein (BP), we postulate that both BP as wellas novel BP-ligands other than CRF may be involved in inflammatorydisease. We have investigated BP in the blood of patients witharthritis and septicaemia, and have attempted to identify CRFand other BP-ligands in synovial fluid. The BP was found tobe significantly elevated in the blood of patients with rheumatoidarthritis and septicaemia. There was less BP-ligand and CRFin synovial fluid from patients with rheumatoid arthritis thanfrom those with osteo- or psoriatic arthritis. There was atleast 10-fold more BP-ligand than CRF in the fluid of all threegroups of patients. A small amount of immunoreactive human (h)CRF,eluting in the expected position of CRF-41, was detected afterhigh-pressure liquid chromatography of arthritic synovial fluid;however, the bulk of material with BP-ligand binding activityeluted earlier, suggesting that synovial fluid contained novelpeptides that interacted with the BP. These results would suggestthat the BP and its ligands could play an endocrine immunomodulatoryrole in inflammatory disease. KEY WORDS: CRF, CRFBP, BP-ligand immunoreactivity, Blood, Synovial fluid, Arthritis, Septicaemia     

SPECIFIC BINDING OF LEUCYL TRANSFER RNA TO AN IMMATURE FORM OF L-THREONINE DEAMINASE: ITS IMPLICATIONS IN REPRESSION

The in vitro assembly of L-threonine deaminase from its constituent parts results in the formation of an inactive species of this enzyme which specifically and reversibly binds leucyl-tRNA. The native, catalytically active enzyme, which is derived from this species in the presence of maturation-inducing ligands, does not bind tRNA. The possible involvement of this protein-tRNA complex in the repression of the ilv (ADE) operon is discussed.     

THE MEASUREMENT OF TESTOSTERONE IN PLASMA

A simplified radioimmunoassay is described for routine determination of testosterone in plasma, using antiserum to a testosterone-3-conjugate, and ³H-testosterone as the sole radio-ligand. The method avoids chromatography by using the plasma sex-steroid binding globulins to effect a partial purification. The radioimmunological method is compared with a specific, chromatographic, competitive protein binding method. Testosterone concentrations in normal subjects are 7.84±2.38 (SD) ng/ml in men, and 0.81±0.17 (SD) ng/ml in women.     

THE MEASUREMENT OF SERUM THYROGLOBULIN IN THE PRESENCE OF THYROGLOBULIN ANTIBODIES

In a significant proportion of patients with thyroid disorders, thyroglobulin antibodies (TgAb) invalidate double-antibody radioimmunoassays (RIA) for thyroglobulin (Tg). A modified RIA procedure for determining serum Tg in the presence of TgAb, is described. Two measurements are made on each sample.

• a Ratio of immunoglobulin (Ig)-bound thyroglobulin to free thyroglobulin (bound:free ratio). This is measured by the distribution of a trace quantity of ¹²⁵I-Tg between bound and free fractions.
• b Concentration of free, i.e. unbound thyroglobulin. This is measured in the supernatant after precipitation of IgG-bound Tg.

Then, bound Tg = B:F x (free Tg) and total Tg = (bound Tg) + (free Tg). Critical factors examined in the validation of the modified method were: (1) use of immunologically intact ¹²⁵I-Tg (specific activity ± 5 mCi/mg); (2) equilibration of tracer Tg with endogenous serum Tg, and (3) clean separation of IgG-bound and free fractions of Tg with goat anti-human IgG. Recovery of added Tg in the presence of TgAb was 105% and interassay precision of total Tg assay was ≤ 9·3%. In euthyroid subjects without TgAb, the correlation between total Tg levels by the modified and standard double-antibody method was 0·931. The correlation was much poorer in the presence of TgAb (r = 0·752) reflecting their interference in the standard method. Reference ranges for serum total Tg levels by the modified method in euthyroid, hyper-and hypothyroid subjects with and without TgAb are detailed.     

高血压病患者红细胞膜结合钙测定的临床意义

高血压病(EH)患者有多种细胞膜钙运转异常。本研究用原子吸收法测定红细胞膜结合钙含量发现:(1)EH组(48例)值明显低于对照组(35例);分别为2.16±0.87和4.65±1.39μg/mg膜蛋白(P<0.01)。(2)不同期的高血压即Ⅰ期(12例)、Ⅱ期(26例)和Ⅲ期(10例),也显示膜结合量不同,分别力3.21±0.37、2.20±0.3和0.82±0.25μg/mg膜蛋白(P<0.01)。膜钙与收缩压、舒张压和平均压呈负相关,r分别为-0.795、-0.797和-0.883(P均<0.01)。(3)本研究所用膜钙测定方法简便、实用。因而。我们认为,膜钙降低不但对高血压发病膜缺陷机理探讨有益,而且对了解高血压病的程度有一定价值。     

RESPONSE OF PLASMA ALDOSTERONE TO FLUDROCORTISONE IN PRIMARY HYPERALDOSTERONISM AND OTHER FORMS OF HYPERTENSION

The response of plasma aldosterone to fludrocortisone administration (400 mug 12-hourly for 3 days) was studied in twenty-two patients with primary hyperaldosteronism. No difference was observed in the response between those patients with an adrenal adenoma and those with bilateral adrenocortical hyperplasia, there being no significant change in plasma aldosterone levels across the test period. No separation between the groups was seen when basal plasma renin concentration was related to the aldosterone level following fludrocortisone. It is concluded that the test is of little value in the pre-operative differentiation of these conditions. Twenty-three patients with no demonstrable cause for their hypertension and four with elevated levels of plasma deoxycorticosterone were similarly studied for comparison. These groups demonstrated a normal fall in plasma aldosterone levels following fludrocortisone.     

THYROID BINDING ANTIBODIES AND OTHER IMMUNOLOGICAL ABNORMALITIES IN PATIENTS WITH GRAVES''OPHTHALMOPATHY: EFFECT OF TREATMENT WITH CYCLOPHOSPHAMIDE

Patients with Graves' ophthalmopathy were studied for a possible role of thyroid binding antibodies (TBAb) as measured by a radioreceptor assay, and for in vitro evidence of immunoreactivity to orbital antigens. The effect of cyclophosphamide (CY) treatment on the immunological parameters and the clinical course of the eye disease was also studied. The mean TBAb index for all patients with eye disease was significantly less than that for the normal and for patients with Graves hyperthyroidism who lacked eye disease. The mean TBAb index for patients with ophthalmopathy and past or present hyperthyroidism was significantly less than for those patients with eye disease but no associated hyperthyroidism ('euthyroid Graves' disease'). TBAb levels did not correlate with the severity of duration of the eye disease and did not change during treatment with CY. Significant titres of serum antibodies against human eye muscle extract or subcellular fractions, or macrophage inhibitory factor (MIF) production in response to human orbital tissue extract were not detected in patients with eye disease. The congestive changes improved in all patients treated with CY, although the degree of proptosis and eye muscle involvement improved in only 3 of 24 and 11 of 20 patients respectively with these abnormalities. TBAb are unlikely to play a role in the pathogenesis of Graves' ophthalmopathy and the hyperthyroidism and eye disease should be considered separate autoimmune disorders. The apparently anomalous finding of a higher mean TBAb index in patients with eye disease and hyperthyroidism than in those with hyperthyroidiam alone may reflect a more severe defect of suppressor T cell function in the former group. Because evidence for specific immunoreactivity against orbital antigens was not found in this study other approaches to defining the underlying immunological mechanisms will have to be sought.