Effects of carbon dioxide pneumoperitoneum, air pneumoperitoneum, and gasless laparoscopy on body weight and tumor growth

BACKGROUND: The oncologic consequences of intraperitoneal carbon dioxide (CO2) insufflation during the laparoscopic resection of cancer are under debate. The effect of other insufflating gases or gasless laparoscopy on cancer requires study. OBJECTIVE: To study body weight and tumor growth in rats after CO2 pneumoperitoneum, air pneumoperitoneum, and gasless laparoscopy. METHODS: On day 1, an 8-mg bolus of ROS-1 tumor was placed under the renal capsule of both kidneys in rats. In experiment A, rats had either CO2 insufflation (n=10) or a gasless laparoscopic bowel resection (n=10) on day 3 and were humanely killed after 7 days. In experiment B, rats had either a laparoscopic bowel resection with CO2 insufflation (n=11) or insufflation with air (n=11) on day 3 and were killed after 7 days. In both experiments, postoperative weight loss and tumor growth were measured, and the differences were tested with an analysis of covariance. RESULTS: Renal subcapsular tumor growth in the group having gasless laparoscopy was less than that in the group having CO2 pneumoperitoneum (P=.04). Postoperative weight loss in these groups showed no differences (P=.55). No differences in tumor growth or weight loss were found between rats having insufflation with CO2 and those having insufflation with air (P=.61 and P=.68, respectively). CONCLUSIONS: The restoration of body weight after a laparoscopic surgical procedure was similar with CO2, air, or gasless laparoscopy. Gasless laparoscopy was associated with less renal subcapsular tumor growth than was insufflation with CO2. Therefore, the application of gasless techniques in laparoscopic oncologic surgical treatment demands further study.     

Reaction paths of iron oxidation and hydrolysis in horse spleen and recombinant human ferritins

UV-visible spectroscopy, electrode oximetry, and pH stat were used to study Fe(II) oxidation and hydrolysis in horse spleen ferritin (HoSF) and recombinant human H-chain and L-chain ferritins (HuHF and HuLF). Appropriate test reactions and electrode responses were measured, establishing the reliability of oxygen electrode/pH stat for kinetics studies of iron uptake by ferritin. Stoichiometric ratios, Fe(II)/O2 and H+/Fe(II), and rates of oxygen uptake and proton production were simultaneously measured as a function of iron loading of the protein. The data show a clear distinction between the diiron ferroxidase site and mineral surface catalyzed oxidation of Fe(II). The oxidation/hydrolysis reaction attributed to the ferroxidase site has been determined for the first time and is given by 2Fe2+ + O2 + 3H2O --> [Fe2O(OH)2]2+ + H2O2 + 2H+ where [Fe2O(OH)2]2+ represents the hydrolyzed dinuclear iron(III) center postulated to be a mu-oxo-bridged species from UV spectrometric titration data and absorption band maxima. The transfer of iron from the ferroxidase site to the mineral core has been now established to be [Fe2O(OH)2]2+ + H2O --> 2FeOOH(core) + 2H+. Regeneration of protein ferroxidase activity with time is observed for both HoSF and HuHF, consistent with their having enzymatic properties, and is facilitated by higher pH (7.0) and temperature (37 degreesC) and by the presence of L-subunit and is complete within 10 min. In accord with previous studies, the mineral surface reaction is given by 4Fe2+ + O2 + 6H2O --> 4FeOOH(core) + 8H+. As the protein progressively acquires iron, oxidation/hydrolysis increasingly shifts from a ferroxidase site to a mineral surface based mechanism, decreasing the production of H2O2.     

Stage theories of health behavior: conceptual and methodological issues

Despite growing interest in stage theories of health behavior, there is considerable confusion in the literature concerning the essential characteristics of stage theories and the manner in which such theories should be tested. In this article, the 4 key characteristics of a stage theory-a category system, an ordering of categories, similar barriers to change within categories, and different barriers to change between categories--are discussed in detail. Examples of stage models of health behavior also are described. Four major types of research designs that might be used for testing stage theories are examined, including examples from the empirical literature. The most commonly used design, which involves cross-sectional comparisons of people believed to be in different stages, is shown to have only limited value for testing whether behavior change follows a stage process.     

Spontaneous and chemically induced proliferative lesions in Tg.AC transgenic and p53-heterozygous mice

The prevention of stroke in patients with carotid pathology has been traditionally carried out with either medications that prevent clot formation (i.e., warfarin or antiplatelet agents) or revascularization of stenotic segments of the artery by surgical means (i.e., carotid endarterectomy). Recently, the use of percutaneous endovascular techniques, to treat lesions of the carotid artery has become increasingly popular. The most important techniques being used for this purpose are balloon angioplasty and stenting. Although still under intense investigation, it is already clear that endovascular therapy of the carotid artery is effective in the correction of lesions not readily accessible by surgery, those due to recurrent stenosis after endarterectomy, those not of an atherosclerotic nature, and those with unusually high surgical morbidity and mortality. The role of endovascular therapy in the treatment of type A lesions, which are perfect for endarterectomy, awaits the completion of prospective randomized trials. However, care must be exercised in the planning of these trials to allow a fair testing of the endovascular procedures.     

Altered cortical blood flow in HIV-seropositive individuals with and without dementia: a single photon emission computed tomography study

OBJECTIVE: To quantitatively demonstrate the pattern of cerebral perfusion abnormalities in HIV-1-infected individuals described as 'patchiness' or inhomogeneity in previous qualitative emission tomographic imaging studies. DESIGN: We aimed to create a quantitative measure of inhomogeneity in HIV-infected individuals. High-frequency variance in cortical profiles is an indication of inhomogeneity in the distribution of radiotracer in the cerebral cortex. Therefore, the study analysis was designed to enable the estimation of variance frequencies in cortical profiles. METHODS: Regional cerebral blood flow was examined in nine mildly demented and 10 cognitively normal HIV-1-seropositive individuals and eight seronegative normal controls using single photon emission computed tomography with the radiotracer [I-123]-N-isopropyl-p-iodoamphetamine. Quantitative analysis was performed using circumferential profiles of cerebral cortical perfusion. Fourier transform power spectra of the profiles were examined as an index of patchiness in tracer distribution. RESULTS: Normal controls were characterized by strong middle frequency and weak high-frequency power. Both HIV-1-infected groups showed a significant power shift from middle to high frequencies. CONCLUSIONS: Increased high-frequency variations in both HIV-1-infected groups indicates diffuse cortical perfusion changes compared with normal controls. This study suggests that there are cerebral bloodflow abnormalities in HIV-1-infected individuals both with and without clinically severe dementia.     

Novel membrane bioreactor with gas/liquid two-phase flow for high-performance degradation of phenol

The use of a membrane bioreactor with cell retention to achieve high biomass concentrations has been examined for phenol degradation by the bacteria Alcaligenes eutrophus. This process is particularly interesting for toxic substrates as the hydraulic dilution rate and the growth rate are independently controlled. In the case of a transitory excess of phenol, this potentially toxic situation can be overcome by modifying the substrate concentration or the dilution rate without any loss of cells. The injection of a gas phase at the filter inlet increased both the permeate flow rate (by a factor of 1. 75) and the oxygen transfer capacity (by a factor of 1.5). This has enabled the cell concentration to reach a maximal value of 60 g L-1 with a hydraulic dilution rate of 0.5 h-1 and a phenol feed concentration of 8 g L-1. The volumetric productivity of this process corresponds to a phenol degradation rate approaching 100 kg m-3 day-1. The on-line measurement of the characteristic yellow color of 2-hydroxymuconate semialdehyde, a metabolic intermediate of the phenol degradation pathway, in the permeate provides an interesting basis for process control of phenol supply into the reactor since the color intensity correlates directly to the specific rate of phenol degradation.     

Long-term follow up of dorsal root entry zone lesions in brachial plexus avulsion

The long-term results of 44 patients who underwent dorsal route entry zone (DREZ) lesioning for pain secondary to brachial plexus avulsion are reported with a mean clinical follow up period of 63 months. The postoperative analgesic effect was judged by the patients as being good (greater than 75% pain reduction), fair (25-75% pain reduction), or poor (0-25% pain reduction). With these criteria 35 patients (77%) had continuing good (30 cases, 68%) or fair (five cases, 11%) pain relief at the time of final follow up. Eight cases (18%) had persisting neurological deficits, although these were generally mild. DREZ thermocoagulation is an effective procedure for relieving deafferentation pain. The analgesic effect which is produced in the early postoperative period seems to be maintained in the long-term.     

Distribution of inhibitory synapses on the somata of pyramidal neurons in cat motor cortex

The mechanisms by which cortical neurons perform spatial and temporal integration of synaptic inputs are dependent, in large part, on the numbers, types, and distributions of their synapses. To further our understanding of these integrative mechanisms, we examined the distribution of synapses on identified classes of cortical neurons. Pyramidal cells in the cat motor cortex projecting either to the ipsilateral somatosensory cortex or to the spinal cord were labeled by the retrograde transport of horseradish peroxidase. Entire soma of selected corticocortical and corticospinal cells were examined using serial-section electron microscopy. The profiles of these somata and the synapses formed with each of these profiles were reconstructed from each thin section with a computer-aided morphometry system. All somatic synapses were of the symmetrical, presumably inhibitory type. For both cell types, these synapses were not homogeneously distributed over the somatic membrane, but were clustered at several discrete zones. The number and density of synapses on the somata of different corticocortical and corticospinal neurons were not significantly different. However, the density of these synapses was inversely correlated with the size of their postsynaptic somata. We discuss the significance of these findings to the integrative properties of cortical neurons.     

Domino hepatic transplantation using the liver from a patient with familial amyloid polyneuropathy

BACKGROUND: In transplantation, novel methods are required to augment the supply of donor organs. We report the first domino liver transplant in which a patient with familial amyloid polyneuropathy (FAP) received an orthotopic split liver graft, and her explanted liver was donated to another patient. Three successful liver transplants were thus achieved from the one cadaver liver. PATIENTS AND METHODS: A cadaveric donor liver was split and the left lobe was grafted into a child with biliary atresia. The right lobe was transplanted into a woman with FAP associated with the transthyretin Met30 variant. Her own otherwise healthy liver was donated to a patient with cirrhosis and hepatocellular carcinoma. RESULTS: Fifteen months after transplantation, all three recipients are well with normal liver function. The domino recipient developed inferior vena cava stricturing at the level of anastomosis after surgery with resultant ascites, requiring dilatation and LeVeen shunt insertion. Serum amyloid P component scintigraphy showed amyloid regression in the domino donor and to date has not identified any amyloid deposits in the recipient, who also remains free of tumor recurrence. CONCLUSIONS: Domino transplantation using the livers from patients with FAP may be justified for patients whose disease condition precludes a long spell on the waiting list, including those with hepatic malignancies and those for whom palliation rather than long-term cure is the aim.