Common bile duct calculi: updated experience with dissolution with methyl tertiary butyl ether

The authors describe their experience with methyl tertiary butyl ether (MTBE) in a larger series of patients than previously reported in order to acquaint physicians with both its effectiveness for dissolution of common bile duct calculi and the limitations of its use. Ten patients with 13 biliary calculi underwent percutaneous stone dissolution treatment with the experimental cholesterol solvent, MTBE. Three stones completely dissolved within 30 minutes, seven were reduced in size, and three were visibly unaffected. All stones not completely dissolved were easily extracted by means of a stone basket except for one in a patient taken to surgery. Although MTBE perfusion is an effective technique for management of biliary calculi, practitioners should be aware that its use is quite time consuming and its odor difficult to control.     

Clinical MR imaging with a Helmholtz-type surface coil

Limited-field-of-view radio-frequency receiver antennas provide improved near-field sensitivity for magnetic resonance imaging by decreasing the antenna volume. The Helmholtz-type surface coil, consisting of two flat rings, is an organ-encompassing antenna that takes advantage of this principle to yield an improved signal-to-noise ratio (S/N). The coil was tested in a group of 50 patients and 16 healthy volunteers. Images obtained with the Helmholtz coil demonstrated quantitatively superior S/N of 2.2-fold or greater than that of comparison body coil images, as well as qualitatively superior anatomic resolution.     

Mild hypothermia during halothane-induced anesthesia decreases resistance to Staphylococcus aureus dermal infection in guinea pigs

Because various immune functions are impaired at temperatures only 1 degrees to 3 degrees C less than normal, we tested the hypothesis that mild hypothermia during anesthesia impairs resistance to dermal infections. Guinea pigs were anesthetized for 6 hours with 1% inspired halothane. Their core temperatures were maintained at either 39 degrees C (normal for guinea pigs, n = 12) or 36 degrees C (n = 12). Two hours after induction of anesthesia, three doses each of Staphylococcus aureus (10(8), 10(7), and 10(6) organisms) were injected intradermally at nine sites on each animal's back. Core temperatures were not controlled after recovery from the anesthetic, and animals in each group were maintained in the same environment. Four days after anesthesia, each injection site was excised to obtain a count of viable bacteria. Subcutaneous oxygen partial pressure values, averaged over time, were 53 +/- 3 mm Hg (mean +/- SEM) in the hypothermic group and 62 +/- 4 mm Hg in the normothermic group (p = 0.06). Capillary perfusion, as assessed by laser Doppler flowmetry, was comparable in the two groups. One day after injection of 10(8) bacteria, the area of induration was 89 +/- 11 mm(2) in the hypothermic group but only 61 +/- 6 mm(2) in the normothermic group (p < 0.05). On postanesthetic day 4, the area of induration was 72 +/- 6 and 59 +/- 6 mm(2) in the hypothermic and normothermic groups, respectively (p > 0.05). After inoculation with 10(8) bacteria, the fraction recovered was 1.0 +/- 0.2 in the hypothermic groups and 0.6 +/- 0.2 in the normothermic group (p < 0.05). After inoculation with 10(7) and 10(6) bacteria, the fraction recovered was less than 0.2, and no difference was found between the hypothermic and normothermic animals. Thus mild hypothermia during halothane-induced anesthesia slightly impairs resistance to dermal infection.     

Uroscopy in the 21st century: high-field NMR spectroscopy

From the experiments described, it can be seen that there are different research approaches that can be taken and these are summarized in Table 1. Whereas much scientific research is principally hypothesis led, there remains, nevertheless, an important place for exploratory research. High resolution NMR can measure, directly and simultaneously, a wide range of endogenous metabolites in biological fluids and has the unique capability of providing structural information on the metabolites detected. It has proved to be a powerful research tool with which to study inherited metabolic diseases, renal disease, drug metabolism, and toxicity, and can be used to monitor the effects of drug therapy. For instance, by using a library of experimental toxins one can map the metabolic profile of site-specific nephron injury. With this approach in man one could eventually take an unknown disease such as Balkan nephropathy and predict the initial site of tubular injury, the mode of injury and therefore the kind of toxin capable of producing that injury. NMR spectroscopic techniques are still advancing rapidly, with ever increasing sensitivity and sophistication of NMR pulse sequences to enhance structural elucidation in complex mixtures. Given the advances in directly coupled HPLC-NMR and even HPLC-NMR-mass spectroscopy it is likely that these technologies in conjunction with pattern recognition will make major contribution to our understanding of renal processes and provide new diagnostic insights in the 21st century.      

105Changes in Nitric Oxide Levels After Deep Dermal injury in the Female,Red Duroc Pig (FRDP)

Introduction : Hypertrophic scar is a devastating sequel to burns and other tangential skin injuries. It follows deep dermal injuries and does not occur after superficial injuries. Nitric oxide (NO) plays many important roles in wound healing from inflammation to scar remodeling. Studies have shown that expression of nitric oxide synthase and nitric oxide production are decreased in human hypertrophic scar. However little is known about NO involvement in the early stages of hypertrophic scarring, because of the lack of an animal model. It was recently reported that the female red Duroc pig (FRDP) makes thick scar, which is similar to human hypertrophic scar. We hypothesized that NO production in wounds on the female, red Duroc pig is similar to that of human hypertrophic scar and that NO involvement in deep wounds is different from that in superficial wounds. Methods : Superficial (0.015” to 0.030”) and deep (0.045” to 0.060”) wounds were created on the backs of four FRDPs. Biopsies were collected at weeks 1.5, 4, 8 and 21 post wounding including samples of uninjured skin. Nitric oxide levels were measured with the Griess reaction assay and normalized with tissue protein level. Results : Superficial wounds healed with an invisible scar whereas the deep wounds healed with scar resembling mild hypertrophic scar. The thickness of the scars from the deep wounds was significantly greater than uninjured skin and healed superficial wounds (p < 0.01). NO levels were increased at 1.5 weeks in deep wounds compared to superficial wounds and uninjured skin (p < 0.05). At 8 weeks, NO levels in deep wounds had returned to the level of uninjured tissue and superficial wounds. By 21 weeks, NO levels had decreased significantly when compared to superficial wounds (p < 0.01). There were no differences in NO levels between uninjured skin and superficial wounds at any time point (p > 0.05). Conclusions : NO production is similar in late, deep wounds on the female, red Duroc pig to that reported in the literature for human hypertrophic scar further validating this animal model. NO production is quite different after deep wounds as compared to superficial wounds in the FRDP. Early elevation in nitric oxide production might account for excessive inflammation in deep wounds that become thick scars in the FRDP. Nitric oxide regulators and effects at early stages of scar formation should be elucidated further and the FRDP appears to be a useful model.