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Biomedical subjects

M Daudon

Publications and source records attributed to M Daudon.

At least 109 records · Page 6Linked to original sources
PubMed1987

Diffuse reflectance technique for infrared analysis of urinary calculi.

We investigated the application of diffuse reflectance infrared Fourier transform spectroscopy to analysis of urinary calculi and compared its operation with that of older sampling techniques (pellet, mull, and attenuated total reflectance). The new method requires shorter sample preparation time and less sample (30 micrograms). Quantitative measurements are easier. Because of the additivity of the Kubelka-Munk functions, a quasi-exhaustive collection of infrared spectra of mixtures of possible components of stones can be compiled, facilitating a computerized intrepretation of infrared spectra of urinary calculi.

Computers↗
PubMed1987

Identification of flumequine in a urinary calculus.

Various analytical methods are available to help identify the presence of drugs in urinary calculi. Using infrared spectrophotometric analysis, nonmetabolized flumequine was identified in a protein calculus from a patient who had taken the drug for a urinary tract infection. Free flumequine can precipitate in an acidic environment.

Aged↗
PubMed1987

[Study of spontaneous crystalluria in patients with calcium oxalate calculi].

We studied crystalluria in healthy subjects and in calcium oxalate stone formers using polarization microscopy and infrared spectroscopy, in freshly voided urine and after 48 h urine storage at +4 degrees C. 412 urine specimens from 39 normal subjects and from 172 stone formers were examined. In the latter, 90 voidings were obtained while on free diet, 61 on moderately calcium restricted diet, 34 in the fasting state and 136 while on thiazide therapy. In the normal subjects, all 91 voidings were obtained while on free diet. Crystalluria was more frequent in urine specimens collected on free diet in stone formers (48.9%) than in normal subjects (13.9%, p less than 0.001) and slightly decreased in patients on thiazide therapy (41.2%). Crystalluria increased following +4 degrees C urine storage in all groups. The most frequent crystalline phase was weddellite. Comparison of crystalline phases of calcium oxalate observed before and after +4 degrees C storage showed that crystallization spontaneously progressed to weddellite whatever the calcium oxalate phase initially present. On thiazide therapy we observed, in addition to lower calcium content, a decreased frequency of urate crystallization especially in +4 degrees C stored urine, in parallel with a decrease in urate concentration.

Calcium Oxalate↗
PubMed1987

Computer-aided infrared analysis of urinary calculi.

We have created a library of 497 digitized infrared spectra of 58 components of urinary calculi and of their usual binary and ternary mixtures. We tested the operation of the "Birsy" search program (Bruker Analytische Messtechnik) with this library for the interpretation of infrared spectra of 50 urinary calculi, selected from both classical and difficult cases. This program correctly identifies the two first components 98% of the time and the third (minor) component 70% of the time. Using this program, those without training or experience in infrared analysis can routinely use the infrared method of analysis of urinary calculi.

Humans↗
PubMed1986

[Drug-induced crystalluria: myths and realities].

Medicinal crystalluria is often difficult to recognize and identify. Whether due to therapeutic overdoses or individual susceptibility, the diagnosis is always important. 70% of the drugs involved in crystalluria can induce kidney stones or promote their growth. In addition, approximately one medicinal crystalluria out of ten is clinically or biologically accompanied by kidney failure. On the basis of 59 cases of medicinal crystalluria, the means of identification, the molecules involved and the frequency of these iatrogenic crystalluria is discusses.

Crystallization↗
PubMed1985

[Metabolism of antipyrine in man].

Antipyrine is widely used as a model compound to assess the hepatic metabolism in man. This drug is extensively metabolized by the hepatic microsomal drug-oxidizing system, into three main metabolites and six minor compounds of the phase I. The metabolite fate of this drug is not fully understood. A new metabolite pathway including a ring opening seems possible.

Antipyrine↗
PubMed1985

[Morphological typing of calcium oxalate calculi and etiopathogenic findings].

The occurrence of different hydrate forms derived from a single chemical compound results from the selective conditions of crystallization. Identification of the crystalline phases and the structural types of stones may provide the physician with important data concerning the etiopathogenesis of the complaint. The authors have studied the crystallization of calcium oxalate in an aqueous solution and the process of spontaneous crystalluria. They noted that whewellite resulted, in many cases, from a concentration of oxalate, and weddellite from a concentration of calcium. This article discusses the correlations between morphological types of oxalate stones, the localization of the stones in the urinary tract, the biological disorders noted, and the sex of the patients.

Calcium Oxalate↗
PubMed1984

[Whewellite and weddellite: toward a different etiopathogenesis. The significance of morphological typing of calculi].

From 3000 urinary calculi analysis, a morphological classification allowed us to appoint 7 structural types of oxalate stones, dependent on whewellite or/and weddellite. We observed evidence for correlations between biological data and these structural types, mainly between types I and hyperoxaluria, types II and hypercalciuria, types II + IV or IV and hyperparathyroïdism, as well as between whewellite and hyperuricuria. We determined in vitro calcium and oxalate concentrations ranges to crystallize various hydrate forms of calcium oxalate and we observed that whewellite form is almost the only one fitted for crystallizing in renal papilla. From this various data, it results that, in vivo, whewellite is dependent on oxalate concentration whereas weddellite is rather dependent on calcium concentration. Otherwise, differences in occurrence of morphological types of oxalate calculi were observed as a function of the patient' sex, the urinary tract localisation of calculi, or the crystalluria.

Calcium↗
PubMed1983

[Drug-induced urinary lithiasis].

All urinary calculi should be thoroughly examined. Among 2 000 calculi analyzed by infra-red spectrophotometry, some were found to contain rare constituants and drugs which might be held responsible for urinary stone formation. These included glafenine, triamterene, co-trimoxazole, sulphaguanidine, allopurinol, phenazopyridine, flumequine and anti-acid powders containing aluminium, calcium and magnesium trisilicates and/or carbonates or bicarbonates. Considering that these drugs are widely used, the incidence of drug-induced urinary calculi appears to be very low.

Allopurinol↗
PubMed1983

Infrared spectrometry and Raman microprobe in the analysis of urinary calculi.

Infrared spectrophotometry and Raman spectroscopy, thanks to the laser molecular microsond (MOLE), are two analytical techniques particularly well suited to a precise analysis of the composition and structure of urinary calculi. They both showed noteworthy efficiency in their ability to recognize the various crystalline or amorphous mineral and organic species. The MOLE permits analysis of crystals 1 mu in size, demonstrating its usefulness in the study of calculi nuclei as well as in the study of urinary crystals. These analyses are a very important source of information about conditions of crystalline nucleation and growth as well as about ions and molecules which can take place in the formation and the evolution of the diverse crystalline phases. On the clinical level, these data can contribute to a better comprehension of the formation of every stone.

Apatites↗
PubMed1983

[Renal toxicity of glafenine in man: renal stones and acute renal failure].

The role of glafenine in certain cases of acute renal failure was described several years ago, but very little work has been done on the intratubular precipitates generally responsible for these manifestations. We have been able to study 6 cases of acute poisoning and 5 cases of glafenine renal stones which have shown that several mechanisms are likely to be involved. In 4 cases, the acute poisoning resulted in reversible oliguria which resolved after several days. In 3 of the 5 cases of renal stones, variable amounts of glafenine were found in the zone of nucleation. Infrared spectrophotometric and chromatographic examination of the first urine after the return of diuresis in the oliguric subjects and in the patients with renal stones, revealed that several metabolites of glafenine could be implicated in the development of these renal precipitates. In the different cases, free metabolites and conjugated derivatives were found to be responsible. The authors discuss the relationship between the products detected and the clinical manifestations observed.

Acute Kidney Injury↗