We investigated pancreatic gene expression in the rat in response to taurocholate-induced acute pancreatitis. Concentrations of transcripts encoding pancreatic protein showed noncoordinated alterations. Contents in amylase, trypsinogen I, chymotrypsinogen B, elastase 1, and procarboxypeptidase A mRNAs decreased by greater than 50% during the acute phase (days 0-2), whereas actin and lithostathine mRNAs increased 5 and 0.6 times, respectively, and pancreatitis-associated protein (PAP) mRNA increased greater than 200 times, indicating redirection of the pattern of gene expression. Synthesis of pancreatic proteins was also altered in a noncoordinated manner. During the acute phase, it decreased more for trypsinogen I and chymotrypsinogen B than for amylase and lipase, whereas synthesis of the PAP increased dramatically. For amylase and chymotrypsinogen B, we compared the patterns of changes in mRNA concentrations, rates of synthesis, and pancreatic contents. Changes in enzyme contents and synthetic rates were temporally correlated during the acute phase. On the contrary, changes in mRNA concentrations and enzyme synthesis were not coordinated, suggesting that control of synthesis partly occurred at the posttranscriptional level. It was concluded that induction of pancreatitis is accompanied by transcriptional and posttranscriptional modifications resulting in rapid and massive rearrangement of the pattern of pancreatic protein gene expression.

It has been shown that an increase in sensitivity and selectivity of detection of an analyte can be achieved by tuning the ablation laser wavelength to match that of a resonant gas-phase transition of that analyte. This has been termed resonant laser ablation (RLA). For a pulsed tunable nanosecond laser, the data presented here illustrate the resonant enhancement effect in pure copper and aluminum samples, chromium oxide thin films, and for trace molybdenum in stainless steel samples, and indicate two main characteristics of the RLA phenomenon. The first is that there is an increase in the number of atoms ablated from the surface. The second is that the bandwidth of the wavelength dependence of the ablation is on the order of 1 nm. The effect was found to be virtually identical whether the atoms were detected by use of a microwave-induced plasma with atomic emission detection, by an inductively coupled plasma with mass spectrometric detection, or by observation of the number of laser pulses required to penetrate through thin films. The data indicate that a distinct ablation laser wavelength dependence exists, probably initiated via resonant radiation trapping, and accompanied by collisional broadening. Desorption contributions through radiation trapping are substantiated by changes in crater morphology as a function of wavelength and by the relatively broad linewidth of the ablation laser wavelength scans, compared to gas-phase excitation spectra. Also, other experiments with thin films demonstrate the existence of a distinct laser-material interaction and suggest that a combination of desorption induced by electronic transition (DIET) with resonant radiation trapping could assist in the enhancement of desorption yields. These results were obtained by a detailed inspection of the effect of the wavelength of the ablation laser over a narrow range of energy densities that lie between the threshold of laser-induced desorption of species and the usual analytical ablation regime. Normal ablation employs high-power lasers in an attempt to create a vapor plume without selective vaporization, and with a stoichiometry that accurately represents the stoichiometry of species in the solid sample. RLA, as a method of selective vaporization, appears to provide an opportunity to exploit selective vaporization in new ways.

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Abstract. Risk factors for low urinary citrate excretion were assessed in 34 consecutive male recurrent idiopathic calcium stone formers (RCSF) who collected two 24-h urines while on free-choice diet. Overt hypocitraturia (hypo-cit) was denned as U C j t x V<1.70 mmol/day, and 'low' citraturia (lowcit) as U Clt xV between 1.70 and 2.11 mmol/day. Twenty-three RCSF had normocitraturia (normo-cit), six low-cit and five hypo-cit. U Cit x V positively correlated with urine volume (VOLUME, r = 0.44, P = 0.009), vegetable fibre intake (fibers, r = 0.46, P = 0.009) and Gl-alkali absorption (alkali, r = 0.47, P = 0.006), and volume, fibres and alkali tended to be lower among RCSF with low-/hypo-cit. A 3-day NH 4 C1 loading test (0.95 mEq/kg BW daily in 3 doses) was performed in RCSF as well as in 14 age-matched healthy male controls (C). On a plot of urine pH versus serum bicarbonate, 10 of 11 RCSF with low-/hypo-cit, but only six of 23 with normo-cit (P = 0.0004) fell off the normal range, indicating incomplete RTA. Two or more risk factors simultaneously occurred in only four of 23 RCSF with normo-cit, but in eight of 11 with low-/hypo-cit (P = 0.002). In conclusion, incomplete RTA is the most prevalent risk factor for low-/hypo-cit in RCSF, and decreases in vegetable fibres and urine volume emerge as two new risk factors for low urinary CIT.