Clinical intestinal transplantation at the University of Pittsburgh: an update

In order to determine the outcome and associated chromosomal and structural anomalies in fetuses diagnosed in utero as having a congenital diaphragmatic hernia, we reviewed 48 consecutive cases referred to our regional Fetal Diagnostic Unit between 1988 and 1995. All babies were delivered in units with appropriate neonatal resuscitation facilities. Thirteen babies [34 per cent of those tested, confidence interval (CI) 19-49 per cent] had karyotypic abnormalities. Three had trisomies but the other nine had more complex karyotypic abnormalities including translocations, deletions, and marker chromosomes. Twenty-one fetuses (44 per cent, CI 30-58 per cent) had additional ultrasound abnormalities which affected the heart in ten cases (21 per cent). Overall, 13 babies survived (27 per cent, CI 14-40 per cent). In babies with normal chromosomes and no additional structural abnormalities the survival rate was 50 per cent (CI 25-75 per cent). Poor outcome was not predicted by early gestation at diagnosis, the hernial contents, or the presence of polyhydramnios. We conclude that parents should be counselled about prognosis with information derived from series of prenatally diagnosed diaphragmatic hernias. The investigations offered should include a detailed ultrasound examination, particularly of the heart, and karyotyping by fetal blood sampling.     

Characteristics of quinolone-induced small colony variants in Staphylococcus aureus

Exposure of Staphylococcus aureus to 1 x MIC of the quinolone antibiotic pazufloxacin for 24 h, followed by plating on drug-free media, led to the emergence of small colony variants (SCVs) in addition to large colony variants (LCVs). However, following incubation with 0.25 or 4 x MIC of pazufloxacin, only LCVs were obtained. The SCVs were half as susceptible to pazufloxacin or ciprofloxacin as wild-type S. aureus, while the susceptibilities of LCVs were essentially unchanged. The reduced susceptibilities of SCVs did not result from mutations in the quinolone-resistance-determining regions of DNA gyrase and topoisomerase IV, since the sequences of these genes were identical to those of the wild-type. However, the SCVs accumulated pazufloxacin and ciprofloxacin to a lesser degree than did wild-type. Furthermore, their susceptibility to quinolones was almost unaffected by reserpine or verapamil, suggesting that the reduced uptake resulted from decreased permeability, rather than from an active efflux pump. The ability of various quinolones to induce emergence of SCVs in S. aureus, correlated with the presence of carbon-bonded substituents at the C-7 position of a quinoline or naphthyridine nucleus, or with the presence of a benzoxazine nucleus. In conclusion, pazufloxacin-induced SCVs represent a mutant that one might expect to be rapidly eliminated in vivo and, hence, not to survive as a quinolone-resistant pathogen. This finding suggests a novel approach for development of future quinolones.     

Protein synthesis and immunoreactivities of contraction-related proteins in smooth muscle cells of canine basilar artery after experimental subarachnoid hemorrhage

We examined time-dependent changes in protein synthesis and in the immunoreactivities of representative contraction-related structural proteins in smooth muscle cells of canine basilar arteries after experimental subarachnoid hemorrhage (SAH). Protein synthesis was assessed by the percentage of polyribosome-forming ribosomes to total ribosomes (aggregation rate), a morphological index of the activity of protein synthesis. The aggregation rates in prostaglandin F2 alpha-(PGF 2 alpha) and 12-O-tetradecanoyl-phorbol-13-acetate (TPA)-induced contracted basilar arteries were 70.0 +/- 7.0% and 71.4 +/- 8.7%, respectively, quite similar to the value in normal basilar artery (73.0 +/- 8.0%). In the single-SAH group with little delayed histological changes in the basilar arteries, the aggregation rate was significantly decreased to 30.5 +/- 6.4% by 24 h after the SAH, and recovered to 52.3 +/- 9.0% and 70.2 +/- 7.6% at 7 and 14 days postSAH, respectively, when the vasospasm was moderately and completely ameliorated. In contrast, in the double-SAH group in which the basilar arteries developed delayed smooth muscle cell death and long-lasting arterial contraction, a significant decrease in the aggregation rate (25.0 +/- 5.0% on day 4) persisted for 14 days. The in vitro incorporation of [3H]-leucine in the basilar arterial cells was also significantly suppressed 4 and 7 days after the initial SAH (1.2 +/- 0.4 and 1.4 +/- 0.3 x 10(3) dpm/mg protein) in the double-SAH group, as opposed to no significant decrease in the basilar artery at 7 days postSAH in the single-SAH group (1.9 +/- 0.6 x 10(3) dpm/mg protein). The immunoreactivity of alpha-smooth muscle actin, a contractile protein, demonstrated by immunohistochemistry and immunoblots, was not altered for up to 14 days even in the double-SAH group, but that of calponin and of h-caldesmon, contraction-inhibiting proteins, was markedly reduced 4-14 days after the initial SAH. Persistent impairment of protein synthesis and relative reduction of immunoreactivities of the contraction-inhibiting proteins were observed in arteries with severe vasospasm and loss of smooth muscle cells, as noted in the double-SAH subjects. These abnormalities may cooperate to cause cerebral arterial narrowing accompanied by degeneration of smooth muscle cells after SAH.     

A method for personal expertise-independent evaluation of image resolution in scanning electron microscopy

The two conventional methods currently employed for the evaluation of image resolution in scanning electron microscopy are the gap method and a fast Fourier transform (FFT) method. These can be highly dependent on personal expertise on the distinction between signal information and noise contained in a micrograph. Hence, the present paper proposes an alternative method (referred to as a contrast-to-gradient (CG) method) that can determine the image resolution of a micrograph without requiring personal expertise on the judgment of noise. The image resolution in the CG method is defined as a weighted harmonic mean of the local resolution, which is proportional to the quotient of the threshold contrast divided by the local gradient. The local gradient is calculated from the quadratic function that best fits the local pixel intensities over 5 x 5 pixels. It has been shown that the CG method, compared with the FFT method, has a broader range of applications for various types of images, such as low-contrast, noise-containing, filter-processed, highly directional, and quasi-periodic feature images.     

Hydrodesulfurization and hydrogenation of aromatic compounds catalyzed by Ni-Mo/γ-Al2O3: effects of nickel sulfide and vanadium sulfide deposits

A standard Ni-Mo/-Al₂O₃ catalyst containing 4 wt% Ni was modified by addition of nickel (2 wt%) and, alternatively, of vanadium (4 wt%) by contacting with a solution of the respective metal naphthenate. The catalysts were sulfided and tested in a batch reactor at 350°C and 165 bar for hydrogenation of naphthalene and for hydroprocessing of dibenzothiophene. Reaction networks were determined for each reactant, and the dependence of the pseudo firs-torder rate constants on the amount of nickel and of vanadium in the catalyst was used to determine the effects of nickel sulfide and of vanadium sulfide deposits on catalyst performance. For example, the nickel sulfide deposits only slightly affected the rate constants for hydrogenation in either network, but the vanadium sulfide deposits led to a decrease of at most 50% in the rate constants for hydrogenation reactions in the naphthalene network and to a doubling of the rate constants for hydrogenation reactions in the dibenzothiophene network. The nickel sulfide deposits led to almost no change in the rate constant for hydrogenolysis of dibenzothiophene (to give biphenyl), but the vanadium sulfide deposits led to a threefold decrease in the rate constant for this reaction. The nickel sulfide deposits have little activity for reactions giving lower-molecular-weight (cracking) products, but the vanadium sulfide deposits have a relatively high activity for cracking, which suggests that they are acidic. The effects of the deposits are complex, as they both block catalytic sites and form new ones. The results indicate a need for representing the nickel and sulfide deposits separately in process models for heavy oil hydroprocessing.     

Circulating ICAM-1, E-selectin, IL-2 receptor, and HLA class I in human small bowel, liver, and small bowel-plus-liver transplant recipients

Recently, soluble(s) circulating isoforms of intercellular adhesion molecule-1 (sICAM-1) and sE-selectin (formerly endothelial leukocyte adhesion molecule-1) have been described in normal human serum. Elevated levels have been reported in acute and chronic inflammatory disorders, including allograft rejection. In this study, plasma levels of sICAM-1 and sE-selectin were determined in groups of tacrolimus (FK 506)-treated adult patients following either isolated small bowel (SB), liver, or combined SB plus liver (SB/L) transplantation. Each molecule was measured at 1, 2, 4, 6, 8, and 12 weeks (all patients) and at 6, 9, and 12 months after transplantation (SB and SB/L only) by enzyme linked immunosorbent assay. Levels were compared with those of soluble interleukin-2 receptor (sIL-2R; a marker of lymphocyte activation) and soluble HLA class I (which has been reported to be elevated in liver transplant-related complications). Elevations above normal in mean plasma levels of sICAM-1 (2.4-fold), sE-selectin (1.8-fold), sIL-2R (10.6-fold), and sHLA class I (1.3-fold) were found in patients with stable isolated SB grafts during the first 12 weeks posttransplant. Except for sHLA class I, levels of each protein were subsequently reduced, up to 1 year posttransplant. However, further increases in sICAM-1 and in sIL-2R and sE-selectin levels were observed during episodes of SB rejection compared with stable grafts. Mean levels of all molecules were higher in patients with isolated SB grafts compared with those given liver or combined (SB/L) transplants, either during stable SB graft function (up to 12 weeks posttransplant) or rejection. The data demonstrate increased adhesion molecule production/shedding following SB transplantation and are suggestive of a reduced overall level of immune activation in liver and SB/L compared with isolated SB transplantation.     

Detection of Helicobacter pylori gene by means of immunomagnetic separation-based polymerase chain reaction in feces

BACKGROUND: Detection of Helicobacter pylori is usually performed by culture, polymerase chain reaction (PCR), histology, or urease test on gastric biopsy samples. Although methods based on feces are non-invasive, their sensitivity has been relatively low. In this study, to improve its sensitivity, immunomagnetic separation (IMS) was used as a pre-PCR step for direct detection of H. pylori in feces. METHODS: Fresh fecal samples were taken from 72 patients attending for endoscopy. Of these, 57 patients had a positive H. pylori status according to the results of culture, histology, and PCR on gastric biopsy samples. Anti-H. pylori antibody-sensitized immunomagnetic beads were used to concentrate the bacteria. PCR was then performed to detect the H. pylori urease A-encoding gene. RESULTS: Of the 57 H. pylori-positive patients, 35 (61.4%) had positive fecal samples by IMS-based PCR method. None of the 15 H. pylori-negative patients had positive fecal samples. The sensitivity of this method was 61.4%, and the specificity 100.0%. CONCLUSIONS: This study confirms that non-invasive diagnosis of H. pylori infection could be made from feces by using IMS-based PCR.     

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