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Biomedical subjects

R Zender

Publications and source records attributed to R Zender.

At least 19 recordsLinked to original sources
PubMed1996

Citrate in synovial fluid and its relation to inflammation and crystal presence.

OBJECTIVE: To investigate the role of citrate in the pathophysiology of arthritides with calcium pyrophosphate dihydrate (CPPD) crystals and/or apatite-like material. METHODS: We measured citrate concentrations in the plasma and synovial fluid (SF) of 23 joints whose SF contained these crystals and 33 joints without crystals. The SF originated from 25 joints each of patients with rheumatoid arthritis (RA) and primary osteoarthritis (OA) and 10 patients with various other inflammatory joint diseases. RESULTS: There was significant correlation between citrate concentrations in the SF and plasma with values globally twice as high in the SF as in the plasma. Citrate concentrations in the SF of patients whose SF contained CPPD crystals and/or apatite-like material were not significantly lower than those without crystals. On the other hand, citrate concentrations were significantly lower in the SF of patients with RA and other inflammatory joint diseases versus those with OA. CONCLUSION: We have no evidence that lower amounts of citrate in SF favor the presence of CPPD crystals or apatite-like material. Our results, however, do suggest a complex regulation of the citrate concentration in SF where cellular metabolic processes and citrates arising from the plasma and neighboring tissues probably interact to produce the levels recorded.

Adult↗
PubMed1993

Between-country comparability of clinical chemistry results: an international quality assessment survey of 17 analytes in six European countries through existing national schemes.

Two lyophilized control sera were distributed through seven national external quality assessment schemes in six European countries--Belgium, Switzerland, France, The Netherlands, Sweden and the United Kingdom--participated in the study. The results for 17 routine analytes were obtained from almost 5000 laboratories for the two sera. The organizers of the schemes were asked to process the results according to a common outlier removal procedure, and submit method-related data if available. The two sera were also distributed through the external/internal scheme of The Netherlands, and the within-laboratory standard deviations calculated in this scheme have been used in a scaling procedure for the external mean values and between-laboratory standard deviations of the participating countries. The results show remarkable agreement in the national mean values for practically all analytes, but considerable differences in the between-laboratory variation. Data from comparable method groups was obtained for 12 analytes from Belgium, France, The Netherlands and the UK. Though revealing some specific differences between methods and countries, the method-related data are generally in agreement with the all-method data. In this study reference method values were only available for cholesterol. The high degree of agreement found suggests, however, that mutual recognition of all-method mean values in national schemes could be acceptable, especially for analytes for which reliable reference methods are not available. The major element of variation is between-laboratory rather than between-country.

Animals↗
PubMed1983

Salivary electrolytes and digitalis.

The hypothesis that an increase in salivary concentration of certain electrolytes (Ca X K) is a sign of digitalis intoxication was tested in 16 untreated health volunteers, 29 digitalized heart failure patients and four further healthy volunteers given digoxin. Salivary electrolyte levels were raised in only about half the digitalized patients and blood levels of digoxin were not always higher in these patients than in those with normal electrolyte concentrations. The salivary electrolyte levels of the healthy volunteers given digoxin remained normal. These findings would seem to rule out the possibility that digitalis is responsible for the changes in salivary electrolytes observed in certain cases of heart failure. A very marked correlation (P less than 0.00002 by Fisher's exact probability test) was found, however, between an increase in the product of salivary calcium and potassium (Casal X Ksal) and the presence of clinical signs of poorly compensated heart failure. It is suggested that this might be a result of adrenergic stimulation, which is known to occur in heart failure, affecting the salivary glands.

Adult↗
PubMed1979

International Union of Pure and Applied Chemistry and International Federation of Clinical Chemistry: IUPAC Section on Clinical Chemistry, Commission on Quantities and Units in Clinical Chemistry and IFCC Committee on Standards, Expert Panel on Quantities and Units. Provisional recommendation (1978) on quantities and units in clinical chemistry: optical spectroscopy. Part 1. Theoretical outline and general quantities.

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Chemical Phenomena↗
PubMed1978

[Salivary electrolytes, digitalis glycosides and cardiac insufficiency].

In a group of 29 patients treated with digoxin for cardiac failure, only 16 showed increased calcium and potassium concentrations in saliva. There was no correlation in the 29 patients between serum digoxin levels and concentrations of salivary electrolytes. On the other hand, in 4 normal subjects treated with digoxin no change in salivary electrolytes was noted. It is concluded that modifications in salivary electrolytes seen in patients with cardiac failure treated with digitalis are not due to this drug. However, a retrospective clinical study showed a good correlation between clinical signs of cardiac failure and increased levels of salivary calcium, potassium and CaX Kproduct. It is suggested that this phenomenon is due to the well-known adrenergic stimulation in patients with cardiac failure.

Adult↗
PubMed1977

[Study of critical values of plasma concentration of cholesterol in hospitalized patients by an enzymatic method].

The concentration of plasma cholesterol was measured in 794 women and 832 men by a method of enzyme analysis. The populations studied were composed of patients in hospital. The critical values were drawn up using parametric and nonparametric statistical methods. The serum cholesterol varied in these populations between 3.0 and 8.5 mmol/l and neither age nor sex modified seriously these values.

Adult↗