AP-1--glucocorticoid receptor crosstalk taken to a higher level

More than a decade ago our view of gene regulation by glucocorticoids (GC) and other steroid hormones underwent a dramatic change with the discovery of negative crosstalk (transcriptional interference) between the GC receptor (GCR) and transcription factor AP-1 (Jun:Fos). It was initially observed that induction of the collagenase type 1 gene, which is mediated through activation of AP-1 by growth factors and inflammatory cytokines, is repressed by GC. This repression was attributed to mutual negative interactions between AP-1 and GCR. Although the exact molecular mechanism underlying this particular case of transcriptional interference is yet to be determined, it has become clear that this and analogous interactions with other transcription factors (e.g. nuclear factor-kappaB) underlie the anti-inflammatory and immunosuppressive activity of GC. Recent studies conducted at the whole animal level indicate that the interactions between the AP-1 and GC signaling pathways are much more extensive. AP-1-related signaling via the Jun N-terminal kinases can lead to increased levels of circulating GC, which eventually down-modulate AP-1 activity via transcriptional interference. This negative feedback loop is likely to be of great importance for maintenance of homeostasis and regulation of stress responses, including acute and chronic inflammation.

Cerebral activation in patients with irritable bowel syndrome and control subjects during rectosigmoid stimulation

OBJECTIVE

Patients with irritable bowel syndrome (IBS) show evidence of altered perceptual responses to visceral stimuli, consistent with altered processing of visceral afferent information by the brain. In the current study, brain responses to anticipated and delivered rectal balloon distension were assessed.

METHODS

Changes in regional cerebral blood flow were measured using H2(15)O-water positron emission tomography in 12 nonconstipated IBS patients and 12 healthy control subjects. Regional cerebral blood flow responses to moderate rectal distension (45 mm Hg) and anticipated but undelivered distension were assessed before and after a series of repetitive noxious (60-mm Hg) sigmoid distensions.

RESULTS

Brain regions activated by actual and simulated distensions were similar in both groups. Compared with control subjects, patients with IBS showed lateralized activation of right prefrontal cortex; reduced activation of perigenual cortex, temporal lobe, and brain stem; but enhanced activation of rostral anterior cingulate and posterior cingulate cortices.

CONCLUSIONS

IBS patients show altered brain responses to rectal stimuli, regardless of whether these stimuli are actually delivered or simply anticipated. These alterations are consistent with reported alterations in autonomic and perceptual responses and may be related to altered central noradrenergic modulation.

[A randomized clinical study of preoperative chemotherapy for esophageal carcinoma]

OBJECTIVE

To evaluate the effect of preoperative chemotherapy on the prognosis of stage II or III patients with esophageal carcinoma.

METHODS

From February 1991 to June 1994, 50 patients with stage II, III esophageal carcinoma were treated with preoperative combination (CDDP) chemotherapy and compared with 50 patients received operation alone.

RESULTS

The 5-year survival rate of the operation group and preoperative chemotherapy group was 32% and 46%, respectively. The difference was statistically significant.

CONCLUSION

Preoperative chemotherapy improves survival of surgically treated esophageal cancer patients.

V. Stress and irritable bowel syndrome

Different types of stress play important roles in the onset and modulation of irritable bowel syndrome (IBS) symptoms. The physiological effects of psychological and physical stressors on gut function and brain-gut interactions are mediated by outputs of the emotional motor system in terms of autonomic, neuroendocrine, attentional, and pain modulatory responses. IBS patients show an enhanced responsiveness of this system manifesting in altered modulation of gastrointestinal motility and secretion and in alterations in the perception of visceral events. Functional brain imaging techniques are beginning to identify brain circuits involved in the perceptual alterations. Animal models have recently been proposed that mimic key features of the human syndrome.

Modulation of wound healing after glaucoma surgery

The healing process after glaucoma filtration is the main determinant of surgical failure and, even more important, the final intraocular pressure. The ability to fully control wound healing may ultimately give us the ability to set the intraocular pressure in the low teens for all patients undergoing glaucoma filtration surgery. The authors review the changes in how to use antimetabolites to improve safety, and many of the exciting new areas of progress, including growth factor neutralization and future molecular therapies to control wound healing.

HIV-2 infection with cerebral toxoplasmosis and lymphomatoid granulomatosis

A Nigerian man had acute onset of headache and vertigo due to a cerebellar mass. A brain biopsy of the mass revealed toxoplasmosis despite repeated negative HIV-1 serology. The presence of an opportunistic infection and his country of origin raised the suspicion for HIV-2; this was confirmed by positive HIV-2 serology. Despite his preliminary pathological diagnosis, results of physiological magnetic resonance imaging (MRI) (perfusion MRI and proton magnetic resonance spectroscopy) were not typical for toxoplasmosis. The lesion showed a biochemical and perfusion pattern that was intermediate for infectious and neoplastic processes. Further neuropathology confirmed a secondary diagnosis of lymphomatoid granulomatosis.

[Isolation, purification and identification of metallothionein from strain BD102 of Hansenula anomala]

Metallothionein (MTs) in Cu and Cd resistant strain BD102 of Hansenula anomala were induced by administration of Cu2+ and Cd2+. These proteins were isolated and purified by Sephadex G-50 and subsequent DEAE-Sepharose CL-6B, then Sephadex G-25 for desalation. There were two isoform MTs by Cu(Cu-MTs), one form induced by Cd (Cd-MT). The molecular weights of the Cu-MTs and the Cd-MT were about 7 kD and 7.5 kD respectively. Exposure of Hansenula anomala to copper salts stimulated formation of two isoform Cu-MTs with a cysteine content of 6.6-6.8% and had 60 amino acids. Exposure of Hansenula anomala to cadmium, stimulated formation of Cd-MT with a cystein content of 10% was synthesized and had 61 amino acids. 4 atom Cu or Cd/mole MTs.

Association of dopamine transporter reduction with psychomotor impairment in methamphetamine abusers

OBJECTIVE

Methamphetamine is a popular and highly addictive drug of abuse that has raised concerns because it has been shown in laboratory animals to be neurotoxic to dopamine terminals. The authors evaluated if similar changes occur in humans and assessed if they were functionally significant.

METHOD

Positron emission tomography scans following administration of [(11)C]d-threo-methylphenidate (a dopamine transporter ligand) measured dopamine transporter levels (a marker of dopamine cell terminals) in the brains of 15 detoxified methamphetamine abusers and 18 comparison subjects. Neuropsychological tests were also performed to assess motor and cognitive function.

RESULTS

Methamphetamine abusers showed significant dopamine transporter reduction in the striatum (mean differences of 27.8% in the caudate and 21.1% in the putamen) relative to the comparison subjects; this reduction was evident even in abusers who had been detoxified for at least 11 months. Dopamine transporter reduction was associated with motor slowing and memory impairment.

CONCLUSIONS

These results provide evidence that methamphetamine at dose levels taken by human abusers of the drug leads to dopamine transporter reduction that is associated with motor and cognitive impairment. These results emphasize the urgency of alerting clinicians and the public of the long-term changes that methamphetamine can induce in the human brain.

Mammalian MAP kinase signalling cascades

Mitogen-activated protein kinases (MAPKs) are important signal transducing enzymes, unique to eukaryotes, that are involved in many facets of cellular regulation. Initial research concentrated on defining the components and organization of MAPK signalling cascades, but recent studies have begun to shed light on the physiological functions of these cascades in the control of gene expression, cell proliferation and programmed cell death.

Mammalian MAP kinase signalling cascades

Mitogen-activated protein kinases (MAPKs) are important signal transducing enzymes, unique to eukaryotes, that are involved in many facets of cellular regulation. Initial research concentrated on defining the components and organization of MAPK signalling cascades, but recent studies have begun to shed light on the physiological functions of these cascades in the control of gene expression, cell proliferation and programmed cell death.

Automatic scan prescription for brain MRI

Diagnostic brain MRI scans are usually performed by trained medical technologists who manually prescribe the position and orientation of a scanning volume. In this study, a fully automatic computer algorithm is described which compensates for variable patient positioning and acquires brain MRI scans in a predefined reference orientation. The method involves acquiring a rapid water-only pilot scan, segmenting the brain surface, and matching it to a reference surface. The inverse matching transformation is then used to adapt a geometric description of the desired scanning volume, defined relative to the reference surface, to the current patient. Both pilot scan and processing are performed within 30 sec. The method was tested in 25 subjects, and consistently recovered orientation differences between the reference and each subject to within +/-5 degrees. Compared to manual prescription, automatic scan prescription promises many potential benefits, including reduced scan times, reproducible scan orientations along anatomically preferable orientations, and better reproducibility for longitudinal studies. Magn Reson Med 45:486-494, 2001.

Higher cortical and lower subcortical metabolism in detoxified methamphetamine abusers

OBJECTIVE

Methamphetamine has raised concerns because it may be neurotoxic to the human brain. Although prior work has focused primarily on the effects of methamphetamine on dopamine cells, there is evidence that other neuronal types are affected. The authors measured regional brain glucose metabolism, which serves as a marker of brain function, to assess if there is evidence of functional changes in methamphetamine abusers in regions other than those innervated by dopamine cells.

METHOD

Fifteen detoxified methamphetamine abusers and 21 comparison subjects underwent positron emission tomography following administration of [(18)F]fluorodeoxyglucose.

RESULTS

Whole brain metabolism in the methamphetamine abusers was 14% higher than that of comparison subjects; the differences were most accentuated in the parietal cortex (20%). After normalization for whole brain metabolism, methamphetamine abusers exhibited significantly lower metabolism in the thalamus (17% difference) and striatum (where the differences were larger for the caudate [12%] than for the putamen [6%]). Statistical parametric mapping analyses corroborated these findings, revealing higher metabolism in the parietal cortex and lower metabolism in the thalamus and striatum of methamphetamine abusers.

CONCLUSIONS

The fact that the parietal cortex is a region devoid of any significant dopaminergic innervation suggests that the higher metabolism seen in this region in the methamphetamine abusers is the result of methamphetamine effects in circuits other than those modulated by dopamine. In addition, the lower metabolism in the striatum and thalamus (major outputs of dopamine signals into the cortex) is likely to reflect the functional consequence of methamphetamine in dopaminergic circuits. These results provide evidence that, in humans, methamphetamine abuse results in changes in function of dopamine- and nondopamine-innervated brain regions.

Laparoscopic transverse hemicystectomy with ileocystoplasty in a porcine model

BACKGROUND AND PURPOSE

The ideal replacement for bladder tissue is yet to be described, although multiple alternatives have been studied. Currently, enterocystoplasty, despite its limitations, is considered the gold standard for bladder augmentation. This study evaluated the feasibility, safety, and morbidity of laparoscopic ileocystoplasty in a large-animal model.

MATERIALS AND METHODS

In eight minipigs, laparoscopy was performed using four ports. A segment of ileum was delivered through a 3-cm umbilical incision and detubularized and refashioned using standard open surgical technique. Laparoscopic hemicystectomy was then performed, followed by laparoscopic suturing of the ileal patch to the bladder. The bladder was drained with a Foley catheter, but no pelvic drain was placed. All animals were followed for for a minimum of 3 months. Preoperative and postoperative evaluation included measurement of bladder capacity, ultrasound imaging of the kidneys, blood counts, and serum electrolyte and creatinine measurements. Two of the animals were sacrificed at 3 months and one at 6 months, and the bladders were harvested.

RESULTS

Eight animals underwent ileocystoplasty without intraoperative or postoperative complications. The average operating and anastomosis time was 250 minutes and 96 minutes, respectively. All animals had normal preoperative blood values that remained normal during follow-up. Bladder capacity decreased initially to 71% of the baseline volume and then increased to 83% and 117% at 3 and 6 months. One of three animals sacrificed was noted to have a right midureteral stricture.

CONCLUSIONS

We developed a reliable laparoscopic technique for ileocystoplasty that may extend the advantages of laparoscopy, including better cosmesis and reduced risk of postoperative adhesions, to bladder augmentation.

Comparison of the 5' leader sequences of North American isolates of reference and field strains of porcine reproductive and respiratory syndrome virus (PRRSV)

The 5' leader is documented to be an important regulatory element in many (+) ssRNAvirus genome. To understand the significance of the 5' leader RNA of PRRSV, we determined the complete leader sequences of fifteen different North American strains of PRRSV and predicted their secondary structures. Viruses analysed included three reference strains and nine field strains originating from different geographic locations. To further examine the leader region, one of the field strains was adapted to grow in tissue culture, and three clones were isolated. We also predicted the secondary structures of two European strains based on their published sequences. The predicted RNA secondary structures of the leader sequences suggested the existence of three conserved domains formed by the 5' region of the leader among the North American strains, two of which were conserved in the European strains. A variable structural domain was predicted from the 3' region of the leader sequences of the North American strains, where all tissue culture-adapted isolates were characterized by a stem-loop while field isolates were characterized by an internal bulge within the stem-loop.

Brain proton magnetic resonance spectroscopy and imaging in children exposed to cocaine in utero

OBJECTIVE

The effects of prenatal cocaine exposure have been examined using neurobehavioral and brain structural evaluations; however, no study has examined the effects of prenatal cocaine on brain metabolism. Proton magnetic resonance spectroscopy ((1)H-MRS) is a noninvasive method to examine the biochemistry of various brain regions. The purpose of this study was to examine the possible neurotoxic effects of prenatal cocaine exposure on the developing brain using (1)H-MRS.

METHODS

Cocaine-exposed children (n = 14) and age-matched unexposed control participants (n = 12) were evaluated with MRI and localized (1)H-MRS. Metabolite concentrations of N-acetyl-containing compounds (NA), total creatine (Cr), choline-containing compounds, myoinositol, and glutamate + glutamine were measured in the frontal white matter and striatum.

RESULTS

Despite an absence of structural abnormalities in either group, children exposed to cocaine in utero had significantly higher Cr (+13%) in the frontal white matter. NA, primarily a measure of N-acetyl aspartate and neuronal content, was normal in both regions examined by (1)H-MRS. Normal NA suggests no significant neuronal loss or damage in the 2 brain regions examined in children exposed to cocaine prenatally.

CONCLUSIONS

Consistent with findings in abstinent adult cocaine users, we found increased Cr in the frontal white matter, with normal NA in children exposed to cocaine. These findings suggest the need to investigate further possible abnormalities of energy metabolism in the brain of children exposed to cocaine in utero. In addition, this study demonstrates the feasibility of using (1)H-MRS to investigate the effects of prenatal drug exposure on the developing brain.

Kinetic analyses of stability of simple and complex retroviral vectors

Simple and complex retroviral vectors derived from Moloney murine leukemia virus (MLV) and human immunodeficiency virus type 1 (HIV-1), respectively, are useful tools for gene transfer studies. However, factors affecting the stability of these vectors have not been carefully investigated. Here we studied the stability factors on vesicular stomatitis viral envelope glycoprotein (VSV-G)-pseudotyped MLV- and HIV-1-derived vectors. Analysis of the ratio of defective particles versus infectious units using electron microscopy and a functional transduction assay revealed that both vectors consisted of high numbers of defective particles ( approximately 100-350:1), which could be reduced ( approximately 10-20:1) by centrifugation. Frequent freeze-and-thaw rapidly decreased vector titer in the first three to five cycles and stabilized thereafter. Both viral vectors were sensitive to temperatures above 37 degrees C but more stable at temperatures below 37 degrees C, exhibiting a two-phase inactivation kinetic starting with a steep inactivation phase, followed by a more leveled phase. Interestingly, HIV-1-derived vectors were significantly more stable than MLV-derived vectors at higher temperatures (>37 degrees C). Both vectors were rapidly destabilized at pH either below or above 7.0. Incubation with human or mouse serum significantly inhibited VSV-G-pseudotyped vector activities. Preheated human serum still reduced vector half-lives to approximately 50% (150 min), suggesting that certain inactivation factors are not heat-labile. Analyses of these stability factors may improve future production and applications of retroviral and lentiviral vectors.

Four-dimensional dielectric property image obtained from electron spectroscopic imaging series

We have demonstrated a new quantitative method to characterize two-dimensional distributions of energy-dependent dielectric function of materials from low loss electron spectroscopic image (ESI) series. Two problems associated with extracted image-spectrum from the low-loss image series, under-sampling and loss of energy resolution, were overcome by using fast Fourier transformation (FFT) interpolation and maximum entropy deconvolution method. In this study, Black Diamond/Si3N4/SiO2/Si-substrate dielectric layer designed for copper metallization was used as the sample. We show that the reconstructed (FFT interpolated and maximum entropy deconvoluted) image-spectrum obtained from ESI series images can be quantified with the same accuracy as conventional electron energy-loss spectroscopy spectra. Since the analysis of the dielectric function is sensitive to the local thickness of the specimen using Kramers-Kronig analysis, we also developed a new method to quantitatively determine the dielectric constant for low-k materials. We have determined the thickness of the Black Diamond using the extrapolated thickness method from the materials of known dielectric constants. Using Kramers-Kronig formula, the dielectric function map can be deduced from two-dimensional reconstructed single scattering spectra with providing the information of thickness. We proposed a four-dimensional data presentation for revealing the uniformity of the energy dependent property. The accuracy of our methods depends on the thickness determination and on the quality of the reconstructed spectra from the image series.

[Isolation, purification and determination of polysaccharides X-C-3-III and X-C-3-IV from Angelica sinensis (Oliv) Diels]

Polysaccharides X-C-3-III and X-C-3-IV had been obtained from Angelica sinensis (Oliv) Diels. Their average MW were determined to be 85,000 and 65,765 by gel chromatography after the hydrolysates of X-C-3-III and X-C-3-IV, the compositions of them were identified by silanization method and capillary gas chromatography. X-C-3-III and X-C-3-IV are composed of galacose, arabinose, rhamnose, glucuronic acid and galacturonic acid. The molar ratio of those sugars were determined as 24.3:15.8:4.2:3.1:52.6 and 12.6:10.7:7.2:8.3:61.2, respectively.

Predicting soil-water partition coefficients for Hg(II) from soil properties

The metal adsorption characteristics for fifteen Taiwan soils by Hg(II), were evaluated using pH as the major variable. The soil samples were thoroughly characterized for their physical chemical properties and composition, particularly organic matter and metal oxides. The adsorption of Hg(II) increased with increasing pH between pH 2.5 and 5.5, whereas the adsorption significantly decreased above around pH 5.5. Below pH 5.5, greater adsorption was found for soils with a higher organic matter content at constant pH and metal concentration. To better understand the mechanism of adsorption, the experimental results for Hg (II) were tested in a partition coefficient model to relate the adsorption of the Hg(II) by the different soils with soil components: organic matter, iron oxide, aluminium oxide and manganese oxide. This model was not successful when applied to measurements at the differing natural soil pHs because of the importance of pH. At pH greater than 5.5 the model fails because of the complexation of Hg by the dissolved organic matter. However, partition coefficients obtained from experimental data were highly correlated with those calculated for a partition coefficient between mercury and organic matter alone at lower pH. Normalization of the partition coefficients, Kd, for the organic matter content of the soils, Kom, greatly improved the correlation between the partition coefficient and pH under pH 5.5 (R2 increased from 0.484 to 0.716). This suggests that the surficial adsorption sites are principally due to organic matter for pH less than 5.5. For the 24-hour equilibration period employed, diffusion of Hg through this superficial organic matter coating to underlying sorptive materials, including metal oxides, is not important in the partitioning of Hg. At pH above 5, a decrease of mercury adsorption with increasing solution pH was also found. This result may be explained in part by the complexation of mercury by soil dissolved organic matter whose concentration increased with increasing pH.

The role of nitric oxide in hyperoxic lung injury in premature rats

To investigate the role of nitric oxide (NO) in hyperoxic lung injury, the 3-day-old preterm rats were randomly assigned to four groups: group I (hyperoxia group), group II (hyperoxia + Nw-nitro-L-arginine methyl ester (L-NAME) group), group III (air group), and group IV (air + L-NAME) group. Group I and II were exposed to > or = 90% O2 for 3 or 7 days. Group II and IV received subcutaneous L-NAMEy on daily basis (20 mg/kg). After 3 day or 7 day exposure, the lung wet weight/dry weight ratio (W/D), total protein and malondialdehyde (MDA) in bronchoalveolar lavage fluid (BALF) and lung pathology were examined in all groups. NO content, expression of endothelial NOS (eNOS) and inducible NOS (iNOS) in lungs were measured in group I and III. Our results showed that after 3 day exposure, group I appeared acute lung injury characterized by the increase of MDA content (P < 0.01) and the presence of hyperaemia, red cell extravasation and inflammatory infiltration; after 7 day exposure, except MDA, total protein and W/D were also increased in comparison with group III (P < 0.01, 0.05), pathological changes were more severe than those after 3 day exposure. After 3 and 7 day exposure, total protein in group II was significantly increased as compared with group I (P < 0.01 for both). The pulmonary acute inflammatory changes were more obvious in group II than in group I. Occasionally, mild hemorrhage was detected in the lungs of group IV. BALF protein content in group IV was higher than that in group III after 7 day exposure (P < 0.01). After 3 and 7 day exposure, NO content in BALF were all significantly elevated in group I as compared with group III (P < 0.01 for all). In the lungs of group I, strong immunostaining for iNOS was observed in airway and alveolar epithelia, inflammatory cells, which were stronger than those in group III. Expression of iNOS in rats after 7 day hyperoxic exposure was stronger than that after 3 day exposure. Shortly after 7 day exposure, stronger immunostaining for eNOS in airway epithelia in group I than that in group III was seen. Our study suggested that treatment with L-NAME worsened acute hyperoxic lung injury in preterm rats and also had a deleterious effect on the rats exposed to air, indicating that endogenous nitric oxide may play a protective role in rats under both physiological and hyperoxic status. Hyperoxia can significantly upregulate the expression of iNOS and eNOS in inflammatory cells, epithelia in the lungs of preterm rats, promote NO generation, which suggests that endogenous NO may mediate the hyperoxic pulmonary damage. Over-stimulation of iNOS may contribute to the pathogenesis of hyperoxic lung injury. NO may have dual roles in pulmonary oxygen toxicity.

Extension of HRTEM resolution by semi-blind deconvolution method and Gerchberg-Saxton algorithm: application to grain boundary and interface

A generalized maximum entropy method coupled with Gerchberg-Saxton algorithm has been developed to extend the resolution from high-resolution TEM image(s) for weak objects. The Gerchberg-Saxton algorithm restores spatial resolution by operating real space and reciprocal space projections cyclically. In our methodology, a generalized maximum entropy method (Kullback-Leibler cross entropy) dealing with weak objects is used as a real space (P1) projection. After P1 projection, not only are the phases within the input spatial frequencies improved, but also the phases in the next higher frequencies are extrapolated. An example of semi-blind deconvolution (P1 project only) to improve the resolution in SiC twin boundary is shown. The nature of the bonding in this twin boundary is Si-C but it was rotated 180 degrees along the boundary normal. The optimum solution from P1 projection can be further improved by a P2 projection. The square roots of diffraction intensities from a diffraction pattern are then substituted to complete a cycle operation of the Gerchberg-Saxton algorithm. Application examples of Gerchberg-Saxton algorithm to solve the atomic structure of defects (2 x 1 interfacial reconstruction and dislocation) in NiSi2/Si interfaces will be shown also.

The effect of hydration on adsorption and desorption of heavy metals in soils

Cr, Ni, and Cd adsorption-desorption on five characterized Taiwan soils was studied. The potential for toxicity and the fate of metals in the soils is dependent upon the ability of the metals to desorb into the aqueous phase. To simulate field conditions, the soils were subjected to wet-dry cycles. The amount and rate of desorption was found to decrease with increasing number of cycles. The wet-dry cycle effect in the desorption of metals from soils is related to the soil composition, with desorption being easiest from sandy soil with low organic content. The desorption process is much slower than adsorption process. More than 95% of each metal adsorption takes place within one hour, and the amount of metal adsorbed from solution reached equilibrium in one day. In contrast, less than 20% metal desorption could be attained after 3 days each of four wet-dry cycles for Cr, Ni, and Cd.