Characterization of Trichomonas vaginalis virus proteins in the pathogenic protozoan T. vaginalis

PURPOSE: Children who have brain tumors are at risk for a variety of treatment-related sequelae, including neuropsychological and cognitive impairment, neurologic deficits, and neuroendocrinologic disturbances. We sought to determine the value of proton MR spectroscopy in assessing brain tissue remote from the tumor site to ascertain the effects of chemotherapy and radiation treatment in these patients. METHODS: Single-voxel proton MR spectra from 70 patients (111 spectra) and 11 healthy volunteers (11 spectra) were analyzed. NAA/Cr, NAA/Cho, and Cho/Cr ratios based on peak areas were obtained from nonneoplastic regions of the frontal lobe. The relationship between MR spectroscopic ratios and treatment was determined. RESULTS: NAA-containing ratios were decreased in patients as compared with control subjects. The presence of gadolinium-based contrast material did not cause significant changes in the ratios as compared with precontrast data. When chemotherapy was a component of a child's treatment protocol, we found a significant decline in NAA/Cr ratios. Patients who underwent both chemotherapy and radiation therapy showed a trend toward lower NAA-containing ratios if the chemotherapy was administered before the radiation therapy. Patients receiving whole-brain radiation had a trend toward lower NAA-containing ratios than did those who had only focal tumor treatment. CONCLUSION: In children with brain tumors, MR spectroscopy of brain tissue remote from the tumor reveals treatment-related biochemical changes.     

Treatment of carbon monoxide poisoning with hyperbaric oxygen

This report describes differences in humoral immune response of acute and chronic phases of human Chagas disease. The reactivities of IgG, IgM, and IgA anti-Trypanosoma cruzi antibodies in serum samples from both groups of patients were compared by enzyme-linked immunosorbent assay (ELISA) employing either one of four antigenic fractions: mouse laminin (LAM), which reacts through Gal alpha 1-3Gal epitopes expressed on trypomastigote surface: whole intact trypomastigotes (TCT); trypomastigotes excreted/secreted antigens (TESA); and epimastigote alkaline extract (EAE). The selection of T. cruzi antigen preparations was based on their relative content of surface and internal antigens found in trypomastigote forms. The proportion of IgG reactive to carbohydrate epitopes was assessed through the decay of IgG reactivity from acute and chronic sera after m-periodate oxidation of solid-phase bound antigens. Trypomastigote and TESA antigens recognized by IgG from acute and chronic sera were also compared by immunoblotting. ELISA and immunoblotting data showed that: (1) the proportion of IgG directed to trypomastigote surface antigens was higher in acute than in chronic sera, whereas the opposite was found for internal antigens, (2) acute sera contained a higher percentage of IgG reactive to trypomastigote carbohydrate epitopes than chronic sera, and (3) anti-T. cruzi IgA was found exclusively in acute sera and led to 100% positivity when LAM, TCT, and TESA were employed as antigens. IgA ELISA with these antigens and IgG immunoblotting pattern with TESA could be useful as serological markers for the acute phase of human Chagas disease.     

The modulation of cellular responses to poly(2-hydroxyethyl methacrylate) hydrogel surfaces: phosphorylation decreases macrophage collagenase production in vitro

We examined the regulation of collagenase production by the monocyte/macrophage THP-1 cell line when these cells were exposed to poly(2-hydroxyethyl methacrylate) (PHEMA) hydrogel surfaces with different chemistries and morphologies. Tissue culture modified polystyrene (TCP), used as a control surface, induced the maximum collagenase response. Copolymer hydrogels containing 2-ethoxyethyl methacrylate (EMA) or methyl methacrylate (MMA) also induced a high response, while PHEMA hydrogels induced a low level response and the phosphorylated hydrogel induced no response. This pattern was altered when the morphology of the hydrogels was changed to that of a sponge. The overall enzyme response to the sponge hydrogels was lower than that to the homogeneous hydrogels. Sponges containing EMA and MMA produced low level response relative to the TCP control. PHEMA and phosphorylated sponges produced little and no response respectively. The dramatically reduced enzyme response to phosphorylated surfaces was not a consequence of cell death, and may be a phenomenon related to changes in cell surface charge.     

Lumbar spine magnetic resonance imaging: comparison between fast spin echo proton density and spin echo T1 axial scans

Spin echo (SE) T1 axial scans are routinely obtained in magnetic resonance imaging of the lumbar spine in many centres. This study directly compared matched SE T1 and fast SE (FSE) proton density (PD) axial scans. Both SE T1 and FSE PD axial scans of the lumbar spine were obtained in 116 consecutive patients. The imaging parameters (field-of-view, slice thickness, interslice gap, number of excitations and matrix size) and scan levels were identical for each pair of sequences. At two selected levels, L4/5 and L5/S1, various structures were independently graded by two observers. In 232 lumbar levels analysed, the bone marrow, epidural fat, disc, extradural nerve root and facet joint were equally well seen on both sequences by both observers (combined mean grades of 2.93-2.99). The thecal sac was marginally better depicted on FSE PD than on SE T1 images, with mean grades of 2.96 and 2.88, respectively. The psoas muscle was adequately visualized for diagnostic purposes on both sequences (mean grades of 2.30-2.32). The cauda equina were better seen on FSE PD (mean grade 1.92) than on SE T1 (mean grade 1.00) images. In conclusion, FSE PD scans are comparable to and may potentially replace SE T1 axial MR scans of the lumbar spine.     

Swelling detection for volume regulation in the primitive eukaryote Giardia intestinalis: a common feature of volume detection in present-day eukaryotes

Interleukin (IL)-12, a natural killer (NK) cell stimulatory factor, is a heterodimeric cytokine that is known to be a potent activator of non-major histocompatibility complex-restricted cytotoxicity by peripheral blood-derived NK cells. NK cells (CD3-CD16+/CD56+) represent approximately 15% of human umbilical cord blood mononuclear cells (HUCB MNCs) and are known to be highly sensitive to activation by IL-2. In the present study, we monitored the effect of IL-12 on the cytotoxic activity, proliferation, and phenotypic expression of HUCB-derived resting and IL-2-activated cytotoxic cells and compared these parameters with those of bone marrow (BM)-derived cells. Lymphocytes were separated from HUCB by 3% gelatin sedimentation and incubated with IL-12 and/or IL-2 for 18 hours. At effector:target ratios of 40:1 and 20:1, IL-12 (50 U/mL) significantly increased both resting and IL-2-activated NK cell-mediated cytotoxicity in a standard 51Cr-release assay against both NK-sensitive (K562) and NK-resistant (Colo-205) cell lines. In addition, resting and IL-2-activated cytotoxic cells derived from HUCB exhibited superior cytolytic ability compared with BM-derived cells. This increase was observed in resting cells as well as in those that were preincubated with IL-12. Moreover, HUCB-derived cells were found to be more sensitive to IL-12 activation than cytotoxic cells from BM. To evaluate the involvement of accessory cells, NK cells were purified from HUCB using immunomagnetic beads, and these cells were found to have a lower response to treatment with IL-12 than unpurified populations. HUCB MNCs exhibited a nonsignificant increase in proliferation after IL-12 treatment and were better able to respond to IL-12 activation than BM MNCs. Following an 18-hour incubation, IL-12 was able to cause upregulation of CD25 and CD69 activation antigens, whereas no significant change in expression of CD16 and CD56 NK cell surface antigens, CD3 on T cells, or IL-12 receptor was observed. Similarly, IL-12 did not affect NK cell:target cell conjugation as assessed by fluorescence-activated cell sorting. Our results indicate that HUCB-derived NK-mediated cytotoxic capabilities can be increased by IL-12, a finding that may have clinical relevance.     

Oxytocin acts at V1 receptors to excite sympathetic preganglionic neurones in neonate rat spinal cord in vitro

Intracellular recordings were made from sympathetic preganglionic neurones (SPNs) in transverse slices of thoraco-lumbar spinal cord of young rats (12-20 days old). A small group of SPNs generally having higher membrane potentials (-70 mV) compared to a remaining group (-66 mV) showed spontaneous oscillations of their membrane potential. Oxytocin superfused in concentrations of 0.1-30 microM had four effects on SPNs, inducing slow depolarisation, EPSPs, IPSPs and brief rhythmic oscillations. The slow depolarisation was unaffected by TTX whereas this abolished the other changes. The oxytocin-induced depolarisation was associated with a slow inward current and was not reversed at membrane potentials negative to EK, it increased at more positive potentials and was still present in low Ca2+ and high Mg2+ solutions. These features of the oxytocin induced current are similar to those of the TTX resistant voltage dependent Na+ current described in brainstem autonomic neurones. Vasopressin superfused at concentrations of 0.1 microM to 30 microM had similar effects on SPNs to those of oxytocin. A comparison of the effects of oxytocin and vasopressin on the same neurones revealed that oxytocin was almost 10 times less potent than vasopressin. The effects of oxytocin were not mimicked by a selective oxytocin agonist but were mimicked by a selective vasopressin V1a agonist and blocked by a selective V1a antagonist. Therefore it is concluded that the effects of oxytocin on SPNs are mediated by the vasopressin V1a receptor. It is suggested that oxytocin and vasopressin terminals in the lateral horn are part of a descending system controlling oscillating networks of SPNs in the spinal cord.