PubMed · 10218390
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1999-03-15. [Calculus].. https://pubmed.ncbi.nlm.nih.gov/10218390/
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The exact composition of calculi is clinically important, but many specimens are not examined, with resultant loss of important information. We describe the incidence and nature of false stones, peculiar calculi and crystals growing on surprising materials. We studied 3100 calculi (97% urinary, 2% digestive and 1% others). Fourier transform infrared spectroscopy was used to identify calculi by detailed comparison with libraries of reference spectra. We also used UV-visible spectroscopy, nuclear magnetic resonance and gas chromatography-mass spectrometry for specific situations. Among 3100 calculi, 154 (5%) had an unusual composition; 101 specimens (3.3%) were false calculi or artifacts, 31 (1%) contained drugs or metabolites and 22 (0.7%) corresponded to crystallizations around other materials. The findings contribute to immediate patient management and to advances in scientific and medical knowledge. We conclude that the analysis of all calculi must be carried out, to determine their composition, and an efficient strategy must be used.
BACKGROUND: To improve visualization of the pancreatic duct with a pancreatoscope, we have developed the smallest known electronic endoscope, that is, the peroral electronic pancreatoscope. METHODS: This instrument (2.1 mm, external diameter) was developed with a 50k-pixel interline charge coupled device. A peroral fiberoptic pancreatoscope was used as control, connected to a video converter. The visibility of both systems was studied with a test chart. The model pancreatic duct, the oral mucosa, and the pancreatic ducts of a healthy control subject and patients with chronic pancreatitis were examined with both systems. RESULTS: The smallest visible interval (with a 5 mm distance between the object and the distal end of the endoscope) was 0.07 mm with the peroral electronic pancreatoscope and 0.2 mm with the peroral fiberoptic pancreatoscope. The electronic instrument produced better images of the model pancreatic duct than the fiberoptic endoscope. A clear image of the small vessels of the oral mucosa was obtained with the electronic but not with the fiberoptic instrument. The fine vessel network of the pancreatic duct was visualized only with the electronic instrument; pancreatic duct stones and rough-surfaced pancreatic duct were shown more precisely with the electronic endoscope. CONCLUSIONS: The peroral electronic pancreatoscope provides images of the fine detail of the pancreatic duct and will contribute to the diagnosis of pancreatic diseases.
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