[A computational spectral analysis method for multi-component drugs based on wavelet transform]

A novel computational spectral analysis method for multi-component drugs is proposed. The method applies the wavelet denoise processing technique to principle component regression(PCR). Since noise in the original spectral data is effectively filtered, the performance of PCR is obviously improved. A typical example in multi-component drug analysis has been used to verify the effectiveness of the novel algorithm. Compared with that obtained by PCR, the average of mean relative error which obtained by PCRW decreases to 0.46% from 1.48%.

Upregulation of COX-2 during cardiac allograft rejection

BACKGROUND

The hypothesis that cyclooxygenase-2 (COX-2) is involved in the myocardial inflammatory response during cardiac allograft rejection was investigated using a rat heterotopic abdominal cardiac transplantation model.

METHODS AND RESULTS

COX-2 mRNA and protein in the myocardium of rejecting cardiac allografts were significantly elevated 3 to 5 days after transplantation compared with syngeneic controls (n=3, P<0.05). COX-2 upregulation paralleled in time and extent the upregulation of iNOS mRNA, protein, and enzyme activity in this model. COX-2 immunostaining was prominent in macrophages infiltrating the rejecting allografts and in damaged cardiac myocytes. Prostaglandin (PG) levels in rejecting allografts were also higher than in native hearts. Because NO has been reported to modulate PG synthesis by COX-2, additional transplants were performed using animals treated with a selective COX-2 inhibitor (SC-58125) and a selective inhibitor of the inducible nitric oxide synthase (iNOS) N-aminomethyl-L-lysine. At posttransplant day 5, inhibitor administration resulted in a significant reduction of COX-2 mRNA expression (3764+/-337 versus 5110+/-141 arbitrary units, n=3, P<0.05) and iNOS enzymatic activity (1.7+/-0.4 versus 22.8+/-14. 4 nmol/mg protein, n=3, P<0.01) compared with vehicle-treated allogeneic transplants. Allograft survival in treated animals was increased modestly from 5.4 to 6.4 days (P<0.05). However, apoptosis of cardiac myocytes (TUNNEL method) was only marginally reduced relative to vehicle controls in treated graft recipients. The intensity of allograft rejection was also similar in the treated and untreated allografts.

CONCLUSIONS

The data indicates that COX-2 expression is enhanced in parallel with iNOS in the myocardium during cardiac allograft rejection.

[The pathogenic mechanism and prevention and treatment of muscle contracture after replantation of severed palm or wrist]

OBJECTIVE

To explore the pathogenic mechanism of intrinsic muscle contracture after replantation of severed palm or wrist, and put forward the prevention and treatment methods.

METHODS

From 1985 to 1997, 48 cases were received replantation of severed palm or wrist, among them, 9 cases with thumb adductor contracture and 6 cases with intrinsic muscle contracture were occurred in different degree. Two cases with mild thumb adductor contracture were received conservative treatment, and 7 cases with moderate thumb adductor contracture and 6 cases with intrinsic muscle contracture were received operative treatment. The pathogenic mechanism, clinical results, and prevention methods were studied in those 15 cases.

RESULTS

The postoperative function recovery was better in 4 cases, moderate in 5 cases with thumb adductor contracture, and better in 3 cases, moderate in 1 case with intrinsic muscle contracture, and moderate in 1 case, poor in 1 case with intrinsic muscle contracture of cord-like induration. Followed up 1 to 10 years, no recurrence was observed in all of 15 cases. The incidence and degree of thumb adductor contracture and intrinsic muscle contracture were closely related to the ischemia time of replanting graft.

CONCLUSION

Prevention of thumb adductor contracture and intrinsic muscle contracture is most important in severed palm or wrist replantation. When the ischemia time of replanting graft is longer than 12 hours, the effective decompression in myofascial compartment is performed in time to reach satisfactory result.

Determination of CKMB activity and protein concentration and their application in the diagnosis of AMI

The activity and protein concentration of CKMB in 19 patients with AMI, 17 non-AMI patients and 26 normal persons. It was found that both peak times in patients with AMI and non-AMI patients were similar but the peak values were different. At peak values the F value of CKMB (5.3) was much lower than that of CKMB protein concentration (50.1). We are led to conclude that the measurement of CKMB protein level can identify AMI much earlier than that of CKMB activity.

Sequence and analysis of chromosome 4 of the plant Arabidopsis thaliana

The higher plant Arabidopsis thaliana (Arabidopsis) is an important model for identifying plant genes and determining their function. To assist biological investigations and to define chromosome structure, a coordinated effort to sequence the Arabidopsis genome was initiated in late 1996. Here we report one of the first milestones of this project, the sequence of chromosome 4. Analysis of 17.38 megabases of unique sequence, representing about 17% of the genome, reveals 3,744 protein coding genes, 81 transfer RNAs and numerous repeat elements. Heterochromatic regions surrounding the putative centromere, which has not yet been completely sequenced, are characterized by an increased frequency of a variety of repeats, new repeats, reduced recombination, lowered gene density and lowered gene expression. Roughly 60% of the predicted protein-coding genes have been functionally characterized on the basis of their homology to known genes. Many genes encode predicted proteins that are homologous to human and Caenorhabditis elegans proteins.

The effects of tetrandrine on the contractile function and microvascular permeability in the stunned myocardium of rats

The effects of tetrandrine (Tet) on the contractile function and microvascular permeability in stunned rat myocardium in vivo were studied. Stunned myocardium was induced by 15 (MS(15) group) or 20 (MS(20) group) min of myocardial ischemia plus 60 min of reperfusion. The following was shown. (1) FITC-BSA concentration was 166.0 +/- 7. 9 microg/g myocardium in the control group. The concentrations in ischemic myocardium increased by 35.4 and 45.6% in MS(15) and MS(20) groups respectively (p<0.05). (2) Administration of Tet (64.2 and 96. 3 micromol/kg, I.P.) 20 min before ischemia not only ameliorated the contractile function, but also reduced the FITC-BSA concentrations in ischemic myocardium. At 60 min after reperfusion, the contractile function parameters in Tet-treated groups were significantly superior to those in corresponding stunning groups. FITC-BSA concentrations in Tet-treated groups were lower than those in stunning groups. Then, there was already no significant difference in FITC-BSA concentrations between Tet-treated groups and the control group. The FITC-BSA concentrations at the end of experiments were correlated negatively with dp/dt(max) (r = -0.83, p<0.01). (3) Tet inhibited KCl-induced calcium influx in isolated cardiomyocytes. The results suggest that Tet given before ischemia may be involved in the reduction of microvascular permeability in stunned myocardium, which might be associated with its calcium channel blocking effect.

[Identification of Panax quinquefolius, P. ginseng and P. notoginseng by protein fingerprints]

Establish the way of protein fingerprints to identify P. quinquefolius, P. ginseng and P. notoginseng of genus Panax by SDS-PAGE, Tris-tricine and Western blot. The fingerprints of Panax species from 28 KD to 58 KD and 55 KD are in common. Very different fingerprints of P. quinquefolius are found below 28 KD. The fingerprints above 58 KD seemed to be peculiar for P. ginseng. Hence the approach may be used as a means to authenticate the concerned Panax species, especially for identification of P. quinquefolius.

Ratio of remnant-like particle-cholesterol to serum total triglycerides is an effective alternative to ultracentrifugal and electrophoretic methods in the diagnosis of familial type III hyperlipoproteinemia

BACKGROUND

Familial type III hyperlipoproteinemia (HLP) is characterized by the presence of beta-migrating VLDL (beta-VLDL) and increased risk of cardiovascular disease. Assessment of plasma beta-VLDL is achieved by measuring the ratio of VLDL-cholesterol (VLDL-C) to total plasma triglycerides (TGs) or by detecting beta-VLDL in total VLDL. The objective of this study was to compare the clinical utility of the ratio of remnant-like particle-cholesterol (RLP-C) to total TGs with that of the current methods for diagnosing type III HLP.

METHODS

Detection of beta-VLDL by electrophoresis of VLDL was used to define type III HLP. Twenty-eight patients with type III HLP and 43 subjects lacking beta-VLDL were investigated. Fasting TG concentrations were >2.26 mmol/L in all subjects. Subjects were separated into three groups: group 1, serum total cholesterol </=5.18 mmol/L (n = 11); group 2, total cholesterol >5.18 mmol/L and TGs between 2.26 and 9.04 mmol/L (n = 51); and group 3, TGs >9.04 mmol/L (n = 9).

RESULTS

In group 2, a RLP-C-to-total TG molar ratio >/=0.23 (>/=0.10 when using mg/dL) and a VLDL-C-to-total TG molar ratio >/=0.69 (>/=0.30 when using mg/dL) correctly classified 94% and 90% of the subjects, respectively. The utility of the RLP-C-to-total TG ratio in diagnosing type III HLP decreased in patients in the other two groups.

CONCLUSION

When used in an appropriate target population, the RLP-C-to-total TG ratio is a convenient and effective alternative to ultracentrifugal and electrophoretic methods for diagnosing type III HLP.

[Experimental study on the effect of nourishing yin and tranquilizing of yangyin anshen koufuye]

Yangyin Anshen Koufuye could obviously decrease the spontaneous activity of rats, effectively shorten the process of falling into sleep of normal rats which were injected pentobarbital sodium and prolong the sleeping time. The effect of sedation and hypnotism were the same as Zhaoren Anshen Koufuye. Yangyin Anshen Koufuye also could markedly reduce the serum tensity of T3, T4 of hyperthyroid rats, which equaled to TCM's deficiency of yin. It also could prevent the glycogen content of liver from decreasing, decrease heart rate, resist weight losing, thus to show the effect of nourishing Yin and tranquilizing.

Anchoring protein is required for cAMP-dependent stimulation of L-type Ca(2+) channels in rabbit portal vein

Stimulation of cardiac L-type Ca(2+) channels by cAMP-dependent protein kinase (PKA) requires anchoring of PKA to a specific subcellular environment by A-kinase anchoring proteins (AKAP). This study evaluated the possible requirement of AKAP in PKA-dependent regulation of L-type Ca(2+) channels in vascular smooth muscle cells using the conventional whole cell patch-clamp technique. Peak Ba(2+) current in freshly isolated rabbit portal vein myocytes was significantly increased by superfusion with either 0.5 microM isoproterenol (131 +/- 3% of the control value, n = 11) or 10 microM 8-bromoadenosine 3',5'-cyclic monophosphate (8-BrcAMP; 114 +/- 1%, n = 8). The PKA-induced stimulatory effects of both isoproterenol and 8-BrcAMP were completely abolished by a specific PKA inhibitor KT-5720 (0.2 microM) or by dialyzing cells with Ht 31 (100 microM), a peptide that inhibits the binding of PKA to AKAP. In contrast, Ht 31 did not block the excitatory effect of the catalytic subunit of PKA when dialyzed into the cells. These data suggest that stimulation of Ca(2+) channels in vascular myocytes by endogenous PKA requires localization of PKA through binding to AKAP.

Anergy, IFN-gamma production, and apoptosis in terminal infection of mice with Mycobacterium avium

We have followed the course of experimental infection of mice with Mycobacterium avium over an extended period, assessing bacterial numbers and T cell responsiveness. When mice were infected intranasally, bacteria spread to the spleen and liver, but remained in highest numbers in the lungs. Both CD4+ and CD8+ T cells, assayed at any time from 6-28 wk after infection, produced IFN-gamma. After initial rapid growth, bacterial numbers slowly increased from approximately 107 at 6 wk to more than 5 x 108 at 28 wk, indicating that the resistance mechanisms so generated were not adequate to contain the infection. During infection, apoptosis of both CD4+ and CD8+ T cells, measured immediately ex vivo by staining with Annexin V, increased steadily. With some individual exceptions, there was a close correlation between apoptosis of CD4+ cells and level of IFN-gamma production by cultured spleen cells. By 34 wk postinfection, there was an abrupt cessation of IFN-gamma production. No IL-4 was detected, ruling out a switch to Th2 profile. Subsequently, bacterial numbers increased still further to >5 x 109 per lung, and the mice lost body weight and would have died if not killed for experimental or humane reasons. The possibility that T cells exposed over this prolonged period to extremely high doses of Ag may become tolerant by a process of terminal differentiation is discussed.

In vivo imaging of spin-trapped nitric oxide in rats with septic shock: MRI spin trapping

This paper reports the first in vivo NMR image of the distribution of NO using the "MRI spin-trapping" technique. NO was complexed with the Fe(II)-chelate spin trap, N-methyl-D-glucamine dithiocarbamate (MGD), verified as (MGD)(2)-Fe(II)-NO by EPR, and the radical distribution was "visualized" by MR images. In rats, the (MGD)(2)-Fe(II)-NO complex was concentrated in the liver displaying significantly enhanced contrast in the vascular structure such as hepatic vein and inferior vena cava. Nitric oxide synthase was verified as the source of NO in rats with septic shock by pre-administration of the competitive inhibitor N-monomethyl-L-arginine, resulting in reduced enhancement. The NO complex was more stable in vivo and a more effective MRI contrast agent than other stable nitrogen containing radicals, such as nitroxides. The MRI spin-trapping method should be a powerful tool for visualizing spatial distributions of free radicals in pathologic organs and tissues when combined with the appropriate radical complexing agent, such as (MGD)(2)-Fe(II) used in these studies. Magn Reson Med 42:235-239, 1999.

[Effect of decompression or transplantation of the facial nerve on serious advanced facial paralysis]

OBJECTIVE

To investigate operative effect on serious advanced facial paralysis.

METHOD

28 cases (28 sides) with serious facial paralysis underwent decompression or transplantation of facial nerve.

RESULT

After following up 0.5-2 years postoperatively, the total, most or partial and no recovery were 14 cases (50%), 12 cases (42%) and 2 cases (7.1%) respectively.

CONCLUSION

The operation performed as early as possible can be an effective procedure for correcting serious advanced facial paralysis if conservative treatment could be confirmed to be helpless.

Hyperphosphorylated tau in SY5Y cells: similarities and dissimilarities to abnormally hyperphosphorylated tau from Alzheimer disease brain

Unlike normal tau, abnormally hyperphosphorylated tau (AD P-tau) from Alzheimer disease (AD) does not promote but instead inhibits microtubule assembly and disrupts already formed microtubules. Tau in the human neuroblastoma cell line SH-SY5Y is hyperphosphorylated at several of the same sites as AD P-tau, and accumulates in the cell body without any association to the cellular microtubule network. The aim of the present study was to elucidate why the SY5Y tau does not affect the viability of the cells. We found that, like AD P-tau, SY5Y tau because of hyperphosphorylation does not bind to microtubules and inhibits the tau-promoted assembly of microtubules. However, the tau/HMW MAP ratio is about 10 times less in SY5Y cells than in AD brain. These findings suggest that the hyperphosphorylated tau from SY5Y cells has similar biological characteristics as AD P-tau from AD brain, but is not lethal to the SY5Y cells because of its low tau/HMW MAP ratio.

Functional MRI study of auditory and visual oddball tasks

To seek neural sources of endogenous event-related potentials, brain activations related to rare target stimuli detection in auditory and visual oddball tasks were imaged using a high temporal resolution functional MRI technique. There were multiple modality specific and modality non-specific activations. Auditory specific activations were seen in the bilateral transverse temporal gyri and posterior superior temporal planes while visual specific activations were seen in the bilateral occipital lobes and their junctions with the temporal lobes. Modality non-specific activations were seen in multiple areas including the bilateral parietal and temporal association areas, bilateral prefrontal cortex, bilateral premotor areas, bilateral supplementary motor areas and anterior cingulate gyrus. Results were consistent with previous intracranial evoked potential recording studies, and supported the multiple generator theory of the endogenous event-related potentials.

A double-stranded RNA binding protein required for activation of repressed messages in mammalian germ cells

Chromatin packaging in mammalian spermatozoa requires an ordered replacement of the somatic histones by two classes of spermatid-specific basic proteins, the transition proteins and the protamines. Temporal expression of transition proteins and protamines during spermatid differentiation is under translational control, and premature translation of protamine 1 leads to precocious nuclear condensation and sterility. We have previously suggested that the double-stranded (ds) RNA binding protein Prbp (encoded by the gene Tarbp2) functions as a translational regulator during mouse spermatogenesis. Here we show that Prbp is required for proper translational activation of the mRNAs encoding the protamines. We generated mice that carry a targeted disruption of Tarbp2 and determined that they were sterile and severely oligospermic. Using immunohistological analysis, we determined that the endogenous Prm2 mRNA and a reporter mRNA carrying protamine 1 translational-control elements were translated in a mosaic pattern. We showed that failure to synthesize the protamines resulted in delayed replacement of the transition proteins and subsequent failure of spermiation. The timing of Prbp expression suggests that it may function as a chaperone in the assembly of specific translationally regulated ribonucleoprotein particles.

Sensory impairments and delayed regeneration of sensory axons in interleukin-6-deficient mice

Interleukin-6 (IL-6) is a multifunctional cytokine mediating inflammatory or immune reactions. Here we investigated the possible role of IL-6 in the intact or lesioned peripheral nervous system using adult IL-6 gene knockout (IL-6(-/-)) mice. Various sensory functions were tested by applying electrophysiological, morphological, biochemical, and behavioral methods. There was a 60% reduction of the compound action potential of the sensory branch of IL-6(-/-) mice as compared with the motor branch in the intact sciatic nerve. Cross sections of L5 DRG of IL-6(-/-) mice showed a shift in the relative size distribution of the neurons. The temperature sensitivity of IL-6(-/-) mice was also significantly reduced. After crush lesion of the sciatic nerve, its functional recovery was delayed in IL-6(-/-) mice as analyzed from a behavioral footprint assay. Measurements of compound action potentials 20 d after crush lesion showed that there was a very low level of recovery of the sensory but not of the motor branch of IL-6(-/-) mice. Similar results of sensory impairments were obtained with mice showing slow Wallerian degeneration (Wlds) and a delayed lesion-induced recruitment of macrophages. However, in contrast to WldS mice, in IL-6(-/-) mice we observed the characteristic lesion-induced invasion of macrophages and the upregulation of low-affinity neurotrophin receptor p75 (p75LNTR) mRNA levels identical to those of IL-6(+/+) mice. Thus, the mechanisms leading to the common sensory deficiencies were different between IL-6(-/-) and WldS mice. Altogether, the results suggest that interleukin-6 is essential to modulate sensory functions in vivo.

Regulation of L-type Ca2+ channels in rabbit portal vein by G protein alphas and betagamma subunits

1. The effect of purified G protein subunits alphas and betagamma on L-type Ca2+ channels in vascular smooth muscle and the possible pathways involved were investigated using freshly isolated smooth muscle cells from rabbit portal vein and the whole-cell patch clamp technique. 2. Cells dialysed with either Galphas or Gbetagamma exhibited significant increases in peak Ba2+ current (IBa) density (148 % and 131 %, respectively) compared with control cells. The combination of Galphas and Gbetagamma further increased peak IBa density (181 %). Inactive Galphas and Gbetagamma did not have any effect on Ca2+ channels. 3. The stimulatory effect of Galphas on peak IBa was entirely abolished by the protein kinase A inhibitor Rp-8-Br-cAMPS, or the adenylyl cyclase inhibitor SQ 22536. On the other hand, the stimulatory response of Ca2+ channels to Gbetagamma was not affected by the protein kinase A inhibitors Rp-8-Br-cAMPS and KT 5720, or by the Ca2+-dependent protein kinase C inhibitor bisindolylmaleimide 1, but was completely blocked by the protein kinase C inhibitor calphostin C. Pretreatment of cells with phorbol 12-myristate 13-acetate for over 18 h prevented the stimulatory effect of Gbetagamma on peak IBa. In addition, acute application of phorbol 12,13-dibutyrate enhanced peak IBa density in control cells, which could be entirely blocked by calphostin C. 4. These data indicate that enhancement of Ba2+ currents by Galphas and Gbetagamma can be attributed to increased activity of protein kinase A and protein kinase C, respectively. No direct membrane-delimited pathway for Ca2+ channel regulation by activated Gs proteins could be detected in vascular smooth muscle cells.

High-performance liquid chromatography separation and quantitation of ofloxacin enantiomers in rat microsomes

A sensitive, simple and accurate method for determination of enantiomers of ofloxacin in microsomal incubates was developed by chiral ligand-exchange RP-HPLC with fluorescence detection to examine stereoselective metabolism of ofloxacin in the glucuronidation process. The C18 stationary phase was used as analytical column. The solution of chiral mobile phase additive was made up of 6 mM L-phenylalamine mixed with 3 mM CuSO4 in water. Mobile phase consisted of the solution of chiral mobile phase additive-methanol (86:14). The fluorescence detector was operated at lambda(ex) 330 nm and lambda(em) 505 nm. The flow-rate of mobile phase was set at 1.0 ml/min. The achiral ODS column offers good separation of the two enantiomers in less than 25 min. The recovery of the assay was 97.9+/-6.1% (n=10) for S-ofloxacin and 99.6+/-6.0% (n = 10) for R-ofloxacin. The method provides a high sensitivity and good precision (RSD<10%). The LOD was 0.6 microM for both enantiomers and the LOQ was 5.70+/-0.45 microM (n=8) for S-ofloxacin and 5.66+/-0.47 microM (n=8) for R-ofloxacin. The standard curves showed excellent linearity over the concentration range 5.5-2078 microM for S-(-)-ofloxacin and R-(+)-ofloxacin. The enantioselective method developed has been applied to determine the stereoselectivity of glucuronidation metabolism of ofloxacin optical isomers in rat liver microsomes.

In vivo measurement of ADC change due to intravascular susceptibility variation

The apparent diffusion coefficient (ADC) of extravascular tissue water in rat brains was measured in response to step-wise injections of the superparamagnetic intravascular contrast agent AMI-227. These data were normalized and compared with measured changes in R2* and blood magnetic susceptibility. Linear regression showed that ADC changes 33%/ppm shift of intravascular susceptibility and 0.43% s(-1) change in R2*. These changes correspond to a predicted ADC change of approximately 6% for a change between fully oxygenated and fully deoxygenated blood. The source of these ADC changes was confirmed to be background gradients within the sample by the use of diffusion weighting with bipolar gradients of odd symmetry designed to cancel such background gradient effects on ADC. The results suggest that diffusion-weighted imaging is sensitive to blood-oxygenation and may provide a means of measuring changes in blood oxygen. They also provide estimates of the potential contribution of susceptibility changes to changes in ADC that occur, for example, in stroke and seizure.

A baculovirus enhancin alters the permeability of a mucosal midgut peritrophic matrix from lepidopteran larvae

The peritrophic matrix (PM) in lepidopterous larvae may function as a defensive barrier against ingested viral pathogens. PMs isolated from Trichoplusia ni and Pseudaletia unipuncta larvae, were treated with a baculovirus-encoded metalloprotease (enhancin) from Trichoplusia ni granulosis virus (TnGV) and their in vitro permeability to blue dextran and fluorescent-labelled Autographa californica nuclear polyhedrosis virus (AcMNPV) was determined using a dual chamber permeability apparatus. Incubation of T. ni PMs with 0.0, 0.5, 1.0, and 2.0mg/ml enhancin resulted in a blue dextran 2000 flux of 4.4, 6.3, 9.9, and 15.6&mgr;g/mm(2)/h, respectively. In addition, T. ni PMs treated with enhancin were found to be significantly more permeable to fluorescent-labelled AcMNPV than non-treated control PMs. The permeability of T. ni PMs treated with 3.0mg/ml enhancin was 0.017 cumulative percent crossing/mm(2)/h, whereas the permeability of the control PM was below the detectable limit. Similarly, enhancin treatment greatly increased the permeability of P. unipuncta PMs to AcMNPV. These results provide evidence that the PM from two lepidopteran species can block the passage of baculovirions across this matrix thus reducing the probability of larval infection. Furthermore, these results support the hypothesis that enhancin facilitates NPV infection of larvae by altering the permeability of the PM.

Evaluation of an immunoseparation method for quantitative measurement of remnant-like particle-cholesterol in serum and plasma

Substantial evidence indicates that triglyceride-rich lipoprotein remnants are atherogenic. Additional research has, however, been limited by available methods for separation and quantification of remnants. We have evaluated an immunoseparation assay developed to measure cholesterol in remnant-like particles (RLP-C). This method uses monoclonal antibodies to human apolipoproteins B-100 and A-I to remove most of the apolipoprotein B-100-containing lipoproteins (namely LDL and nascent VLDL) and apolipoprotein A-I-containing lipoproteins (namely chylomicrons and HDL), leaving behind a fraction of triglyceride-rich lipoproteins, including chylomicron and VLDL remnants, both of which are enriched in apolipoprotein E. Cholesterol in the unbound fraction is measured with a sensitive enzymatic assay. The RLP-C concentration was highly correlated with total triglyceride-rich lipoproteins (sum of VLDL-cholesterol and IDL-cholesterol) separated by ultracentrifugation and by polyacrylamide gel electrophoresis (r = 0.86 and 0.76, respectively). The within-run and run-to-run imprecision (CV) of the assay was approximately 6% and 10%, respectively. The assay was not affected by hemoglobin up to 5000 mg/L (500 mg/dL), bilirubin up to 342 mmol/L (20 mg/dL), glucose up to 67 mmol/L (1200 mg/dL), or ascorbic acid up to 170 mmol/L (3.0 mg/dL). In 726 subjects (men, n = 364; women, n = 362) in the US, the 75th percentiles of RLP-C concentration were 0.17 mmol/L (6.6 mg/dL) and 0.23 mmol/L (8.8 mg/dL) in sera obtained after overnight fasting or randomly, respectively. A group of 151 patients from nine US centers and one Canadian center with coronary artery atherosclerosis established by angiography had higher median RLP-C concentrations than 302 gender- and age-matched controls (P <0.05). We conclude that the RLP-C assay compares favorably to ultracentrifugation and electrophoresis and provides a convenient and economical approach to measure triglyceride-rich lipoprotein remnants in routine clinical laboratories.

Quantification of intravascular and extravascular contributions to BOLD effects induced by alteration in oxygenation or intravascular contrast agents

A simple model is presented that allows quantitative separation of the contributions of signals from water in blood and extravascular parenchyma due to changes in blood oxygenation, induced either by brain activation or by alteration of inspired oxygen. The separation is based on the progressive attenuation of the signals in the vasculature of different levels when bipolar field gradient pulses are applied. Diffusion-weighted spin-echo echo-planar imaging sequences were used to measure signal changes under various conditions in both animals and human volunteers. Normoxic-hyperoxic episodes were induced in rats before and after injection of a superparamagnetic iron oxide contrast agent. Signal changes produced by visual stimulation were measured in human volunteers, and in volunteers subject to alternating normoxic-hyperoxic episodes, and with administration of Gd-DTPA. Analysis of the results with our simple model suggests that the apparent diffusion coefficient increases and R2 (= 1/T2) decreases upon brain activation, with a large component from extravascular water related to the decrease in the blood deoxyhemoglobin concentration. Furthermore, this study suggests that apparent diffusion coefficient of the extravascular component alone may provide localization of neuronal activation.

Ectopic expression of a chimeric colony-stimulating factor-1/TrkB-receptor promotes CSF-1-dependent survival of cultured sympathetic neurons

The regulation of the density of innervation and the promotion of survival of neurons are the original effects depending on neurotrophins. Here we analyse such effects evoked by trkB tyrosine kinase in transfected PC12 cells and transfected sympathetic neurons. In order to exclude the previously described modulation of trk kinase activity by the extracellular activation of the low-affinity p75 neurotrophin receptor, we applied a chimeric receptor approach: The extracellular domain of colony-stimulating factor-1 (CSF-1) receptor was fused to the transmembrane and cytoplasmic domain of the trkB tyrosine kinase receptor, allowing its selective activation by the heterologous ligand. Protein expression and CSF-1-induced tyrosine phosphorylation of the chimeric receptor protein was demonstrated in transfected COS cells. After stable transfection into nerve growth factor (NGF)-responsive PC12 cells, CSF-1 mediated the K252a-sensitive induction of fiber outgrowth. Furthermore, we were able to show by heterologous expression of the chimeric receptor, that activation of trkB tyrosine kinase activity is sufficient to promote survival of neurotrophin deprived sympathetic neurons.

[A fluorescence photometry study on the suberinite in the shallow burial peat]

A detailed study of the suberinite in the shallow burial peat from Zhenan basin, western Yunnan, has been carried out. The study has revealed that the suberinite is the most unstable maceral among all the stable macerals. It may be oxidized and/or decomposed, resulting in changes in the structure and, especially optical feature. The fluorescence light of the suberinite that has not been oxidized and decomposed is green with I546 ranging from 1.5 to 2.0; and the fluorescence spectrum has one peak: lambda(max) ranging from 480 to 510nm; Q500/650 ranging from 0.12 to 0.26; semi-wave width averaging 150nm. Nevertheless, those suberinites that are oxidized and/or decomposed give off yellow or yellowish brown fluorescent light and the I546 reduces to less than 1, even to 0.05 lambda(max) increases from 580 to 610nm; Q500/560 from 2.75 to 3.31. With illuminating time going by, the fluorescence feature of the suberinite could be changed, mainly in the fluorescence intensity and fluorescence spectrum. The suberinite that has been not oxidized and/or decomposed changes negetively in fluorescence intensity and its fluorescence spectrum moves towards red light wavelength. Nevertheless those suberinites that have been oxidized and/or decomposed change positively in fluorescence intensity and the fluorescent spectrum moves towards blue light wavelength.

The regulation of phosphorylation of tau in SY5Y neuroblastoma cells: the role of protein phosphatases

In Alzheimer disease brain the microtubule associated protein (MAP) tau is abnormally hyperphosphorylated. The role of protein phosphatases (PP) in the regulation of phosphorylation of tau was studied in undifferentiated SY5Y cells. In cells treated with 10 nM okadaic acid (OA), a PP-2A/PP-1 inhibitor, the PP-1 and -2A activities decreased by 60% and 100% respectively and the activities of MAPKs, cdc2 kinase and cdk5, but not of GSK-3, increased. OA increased the phosphorylation of tau at Thr-231/Ser-235 and Ser-3961404, but not at Ser-262/356 or Ser-199/202. An increase in tyrosinated/detyrosinated tubulin ratio, a decrease in the microtubule binding activities of tau, MAP1b and MAP2, and cell death were observed. Treatment with 1 microm taxol partially inhibited the cell death. These data suggest (1) that OA induced hyperphosphorylation of tau is probably the result of activated MAPK and cdks in addition to decreased PP-2A and PP-1 activities and (2) that in SY5Y cells the OA induced cell death is associated with a decrease in stable microtubules.

A note on the compartmental analysis and related issues in laser Doppler flowmetry

Compartmental analysis (CA) in laser Doppler flowmetry (LDF) means deciphering the nutritional and thermoregulating flows from the measured perfusion flux. Based on the new theories proposed in [1] and [2], the CA is formulated here as an optimal approximation without directly involving the geometric information of the vessel network. It is seen that this approximation approach could also solve the biological zero (BZ) problem simultaneously, therefore, it actually provides a systematic solution to the BZ problem without estimating the BZ flux experimentally. In addition, the BZ problem with compartmental differences is reformulated, and the condition under which multiple compartments can be treated as a single one is investigated. The result, together with some computer simulations, showed that the theory in [2] is still an easy and useful approximation in practice. This note serves as an useful supplement to [1] and [2] and may help to solve and clarify some critical problems in LDF.

Modulation of Ca2+ channels by cyclic nucleotide cross activation of opposing protein kinases in rabbit portal vein

Cyclic nucleotides are known to modify voltage-gated (L-type) Ca2+ channel activity in vascular smooth muscle cells, but the exact mechanism(s) underlying these effects is not well defined. The purpose of the present study was to investigate the modulatory role of the cAMP- and cGMP-dependent protein kinase (PKA and PKG, respectively) pathways in Ca2+ channel function by using both conventional and perforated-patch-clamp techniques in rabbit portal vein myocytes. The membrane-permeable cAMP derivative, 8-bromo cAMP (0.1 to 10 micromol/L), significantly increased (14% to 16%) peak Ba2+ currents, whereas higher concentrations (0.05 to 0.1 mmol/L) decreased Ba2+ currents (23% to 31%). In contrast, 8-bromo cGMP inhibited Ba2+ currents at all concentrations tested (0.01 to 1 mmol/L). Basal Ca2+ channel currents were significantly inhibited by the PKA blocker 8-Bromo-2'-O-monobutyryladenosine-3',5'-monophosphorothioate, Rp-isomer (Rp 8-Br-MP cAMPS, 30 micromol/L) and enhanced by the PKG inhibitor beta-Phenyl-1,N2-etheno-8-bromoguanosine-3',5'-monophosphorothioate, Rp-isomer (Rp-8-Br PET cGMPS, 10 nmol/L). In the presence of Rp 8-bromo PET cGMPS (10 to 100 nmol/L), both 8-bromo cAMP (0.1 mmol/L) and 8-bromo cGMP (0.1 mmol/L) enhanced Ba2+ currents (13% to 39%). The excitatory effect of 8-bromo cGMP was blocked by Rp 8-bromo MB-cAMPS. Both 8-bromo cAMP (0.05 mmol/L) and forskolin (10 micromol/L) elicited time-dependent effects, including an initial enhancement followed by suppression of Ba2+ currents. Ba2+ currents were also enhanced when cells were dialyzed with the catalytic subunit of PKA. This effect was reversed by the PKA blocker KT 5720 (200 nmol/L). Our results suggest that cAMP/PKA stimulation enhances and cGMP/PKG stimulation inhibits L-type Ca2+ channel activity in rabbit portal vein myocytes. Our results further suggest that both cAMP and cGMP have a primary action mediated by their own kinase as well as a secondary action mediated by the opposing kinase.

A mathematical analysis on the biological zero problem in laser Doppler flowmetry

The biological zero (BZ) problem is a critical issue inherent in laser Doppler flowmetry (LDF). It causes confusion when measuring low tissue blood flows. Many experimental studies have been done on the question of whether the BZ flux should be subtracted from the normally measured flux in various situations. However this problem can only be solved after a proper mathematical analysis. Only then can we clearly define and formulate what flux is truly meaningful in blood perfusion measurement and what movement generates the BZ flux and how can we correctly remove it. Following this motivation, the movement of moving blood cells (MBC's) is decomposed into a net translation and a random wondering based on in vivo observations. This important step leads to a clear definition of the BZ and net perfusion flux and reveals that subtraction of BZ flux from the normal flux will certainly cause an underestimation of the net flux. Using this decomposition, the relationship between the net, BZ and normal flux is established which leads to the correct formula to recover the net flux from the BZ and normal fluxes. This recovered net flux is shown to be bounded by the normal flux and the normal flux minus the BZ flux. Numerical studies, preliminary phantom model and clinical evaluations manifest that the new approach is more accurate and reasonable at measuring low net fluxes. In contrast, subtracting BZ flux causes a systematic underestimation of perfusion and is apparently inappropriate even from a methodological point of view. In addition to the novel BZ solution, a general density function of the speed of MBC's is given which is more faithful than the Maxwell density used in [4]. This general density function offers new possibilities for further theoretical developments in LDF.

Detection of clonal T-cell receptor gamma chain gene rearrangements by polymerase chain reaction and denaturing gradient gel electrophoresis (PCR/DGGE) in archival specimens from patients with early cutaneous T-cell lymphoma: correlation of histologic findings with PCR/DGGE

BACKGROUND

Early stages of cutaneous T-cell lymphoma (CTCL) may be difficult to distinguish from benign inflammatory dermatoses by routine histologic examination.

OBJECTIVE

Our purpose was to determine whether clonal rearrangements of the T-cell receptor (TCR) gamma gene by polymerase chain reaction and denaturing gradient gel electrophoresis (PCR/DGGE) could be detected in the early stages of CTCL and to correlate these findings with conventional histopathology.

METHODS

A total of 39 specimens from 12 patients with CTCL were obtained. The slides were evaluated independently by three dermatopathologists, and categorized into three groups: nondiagnostic, suggestive of CTCL, and diagnostic of CTCL. Of the 39 specimens, 33 were tested by PCR/DGGE by means of GC-clamped primers for clonal rearrangement of the TCR gamma gene.

RESULTS

The histologic evaluation of the 12 cases showed a significant variation among the three dermatopathologists. The correlation of PCR/DGGE with routine histology was as follows: Clonal TCR gamma gene rearrangements were demonstrated in 73% of the specimens nondiagnostic for CTCL, 71% of those suggestive of CTCL, and 74% of those diagnostic of CTCL.

CONCLUSION

Clonal TCR gamma gene rearrangements may be detected in patients with early CTCL, even when the histologic findings are not unequivocally diagnostic. In patients with multiple biopsy specimens, identical clones were demonstrated in all rearranged samples, indicating the same neoplastic clone was present in the earliest stages of disease.

Endotoxemia-induced myocardial dysfunction is not associated with changes in myofilament Ca2+ responsiveness

Myocardial contractile function is depressed after onset of endotoxemia and is intrinsic to the ventricular myocyte. We tested the hypothesis that decreased Ca2+ responsiveness of the contractile myofilaments underlies this inotropic depression. Specifically, we evaluated the relationship between Ca2+ and unloaded cell shortening and isometric tension development of skinned guinea pig ventricular myocytes. Myocytes were isolated 4 h after intraperitoneal injection of 4 mg/kg Escherichia coli lipopolysaccharide (LPS) or saline (control; Ctl). Myofilament Ca2+ responsiveness assessed by image analysis of shortening of skinned myocytes at pH 7.0 was not different between Ctl[pCa value that resulted in half-maximal shortening (pCa50): 5.78 +/- 0.04] and LPS (pCa50: 5.72 +/- 0.02). Similarly, myofilament Ca2+ responsiveness measured by isometric tension of skinned myocytes was not different between Ctl (pCa50: 5.73 +/- 0.02) and LPS (pCa50: 5.76 +/- 0.02). Maximal tension generated by LPS myocytes (2.89 +/- 0.23 g/mm2) was significantly less (P < 0.05) than Ctl (3.75 +/- 0.34 g/mm2). However, when myocytes were isolated and skinned in the presence of protease inhibitors, maximal tension generated by LPS myocytes (3.53 +/- 0.98 g/mm2) was similar to Ctl (3.01 +/- 0.80 g/mm2). We conclude that in vivo administration of LPS resulting in endotoxemia without shock does not alter myofilament Ca2+ responsiveness of ventricular myocytes. Rather, reduced contractility is more likely a result of decreased Ca2+ availability because systolic Ca2+ transients of fura 2-loaded LPS myocytes were significantly decreased (P < 0.05) compared with Ctl myocytes.

[The comprehensive treatment of varicosis of lower extremity with chronic ulcer of leg]

From Oct. 1993 to Dec. 1995, nineteen refractory cases with varicosis and chronic ulcer of lower limb were treated. The average age of these patients was sixty-eight, the disease history was more than 20 years. The size of the ulcer of the leg ranged from the minimum of 10 cm x 8 cm to the maximum of 30 cm x 15 cm. All of them had once received saphenectomy and split skin graft without ulcer healing before they were admitted in our department. Both venography and ultrasonography showed superficial venous valve incompetence. The following comprehensive treatment was adopted. Firstly, myoplasty around popliteal vein was done. Secondly, phlebexairesis and phleborrhaphy were done for the variciform veins through minor incision. Then through debridement of the ulcer was performed. Delayed split skin graft was exerted one week later. The result showed that all the cases were successful: the ulcer was healed and there was no recurrence of varicosis.

[Resources and geographical distribution of Ganodermataceae in Guizhou province]

This paper reports the geographical distribution and medicinal value of 30 species of Ganodermataceae produced in Guizhou Province. Of these 30 species one is newly discovered and 18 are expounded in respect to their geographical distribution.

Reduced L-type calcium current in ventricular myocytes from endotoxemic guinea pigs

The circulatory response to gram-negative sepsis and its experimental counterpart, endotoxemia, includes a profound dysfunction in myocardial contractility that is resident to the myocyte and associated with reduced systolic free intracellular Ca2+ concentration ([Ca2+]i). We explored the possibility that decreased systolic [Ca2+]i in endotoxemic myocytes is correlated with reduced L-type Ca2+ current (ICa,L). Ventricular myocytes were isolated from guinea pigs 4 h after an intraperitoneal injection of Escherichia coli lipopolysaccharide (LPS; 4 mg/kg). Membrane potentials and Ca2+ currents were measured using whole cell patch-clamp methods. The action potential duration of endotoxemic myocytes was significantly shorter than control values (time to 50% repolarization: LPS, 314 +/- 23 ms; control, 519 +/- 36 ms, P < 0.05). Correspondingly, endotoxemic myocytes demonstrated significantly reduced peak ICa,L density (3.5 +/- 0.2 pA/pF) and Ba2+ current (IBa) density (7.3 +/- 0.5 pA/pF) compared with respective values of control myocytes (ICa,L) density 6.1 +/- 0.3 pA/pF, IBa density 11.3 +/- 0.8 pA/pF; P < 0.05). Endotoxemia-induced reduction in peak ICa,L could not be attributed to alterations in current-voltage relationships, steady-state activation and inactivation, or recovery from inactivation. The beta-adrenoceptor agonist isoproterenol, but not the Ca2+ channel activator BAY K 8644, reversed the LPS-induced reduction in peak ICa,L, cell contraction, and systolic [Ca2+]i. These data demonstrate that part of the host response to endotoxemia involves diminished sarcolemmal ICa,L of ventricular myocytes.

[Fluorescence spectroscopic analysis of huminite of the peat and soft brown coal]

The huminite of the peat and soft brown coal in the Zhenan basin, western Yunnan, has been studied by means of fluorescence microscopy. The study reveals that the fluorescent features of the huminite are considerabably complicated: some huminite, like liptinites, can give out dark yellow to yellow fluorescent light, I546 ranging from 8.13 to 13.17; and the fluorescent spectrum having one peak or two peaks, lambdamax ranging from 555 to 585nm and Q650/500 from 0.60 to 2.93. Most of huminites do not give out fluorescent light or give out dark brown fluorescent light, I546 ranging from 0 to 5.38. Because of having extraordinarily weak fluorescent light, it is very difficult to obtain their fluorescent spectrum. Nevertherless, after being stimulated for several minutes, some huminites that do not give out fluorescent light or give out dark brown fluorescent light may give out yellowish brown to dark orange fluorescent light, I546 ranging from 6.12 to 12.17, lambdamax. from 590 to 615nm and Q650/600 from 3.49 to 4.31. With the stimulating time becoming longer (10 to 20min), some huminites,may give out sharper yellow fluorescent light, I546 ranging from 12.18 to 20.01, lambdamax from 555 to 595nm and Q650/500 from 0.87 to 1.60.

The pattern of p53 and p21WAF1/CIP1 immunoreactivity in non-Hodgkin's lymphomas predicts p53 gene status

P53 and p21WAF1/CIP1 (p21) immunostaining was performed on 92 non-Hodgkin's lymphomas (NHLs), and the staining pattern correlated with the presence or absence of p53 hot spot mutations as detected by PCR-SSCP of exons 5-8 and direct sequencing. Twenty-nine of 92 lymphomas overexpressed p53, and 17 overexpressed p21. Of the p53 overexpressing lymphomas, 14 also overexpressed p21, and none of these 14 harbored a detectable hot spot mutation. However, mutations were detected in 13 (87%) of 15 p53 overexpressing, p21 negative lymphomas. One of the 63 p53-negative lymphomas harbored a detectable hot spot mutation, and it was also negative for p21. These results demonstrate that among NHLs that overexpress p53 protein, those which also show p21 overexpression do not harbor p53 hot spot mutations, and furthermore, provide evidence that the transactivating function of p53 is retained. On the other hand, p53 overexpression in NHLs that lack p21 expression is usually indicative of p53 gene mutation.

[Preliminary analysis of healthy life expectancy in some urban residents]

Healthy life expectancy in some urban residents was analyzed with fundamental principles of Sullivan's method and mortality data in our residents and some data from national health service survey conducted in 1993 to assess their quality of life. Results showed that proportion of healthy to total life expectancy accounted for more in males than in females and in medium-sized and small cities than in large ones, and decreased with increase of age. It suggests that quality of life in some of our urban residents lowered with increase of age, was worse in women than in men and lower in large cities than in mediumsized and small ones.

[Influence of extraction on fluorescence of the subrenite in the peat]

Comparative study on the subrenite in the peat and extracted remain has been made. The study reveals that extraction has considerable influence on the fluorescence of the subrenite. Before extracted, the subrenite in the peat gives out violently fresh yellowish green to green fluorescent light ,and the lambda(max), ranges from 470 to 520nm and the Q650/500 from 0.10 to 0.65, but after extracted, the subrenite in the extrated remain gives out weakly dark yellow to orange-yellow fluorescent light and the lambda(max) ranges from 605 to 660nm and the Q650/500 from 1.85 to 4.09. The extraction has made the fluorescent intensity of the subrenite weak.

Cytosolic Ca2+ concentration and contraction-relaxation properties of ventricular myocytes from Escherichia coli endotoxemic guinea pigs: effect of fluid resuscitation

Hearts isolated from a guinea pig model of Escherichia coli endotoxemia exhibit decreased systolic contractile function and reduced diastolic compliance of the left ventricle within 4 h after injection of endotoxin. Fluid resuscitation prevented the endotoxin-induced decrease in diastolic compliance without affecting systolic contractile depression. Because intrinsic myocardial dysfunction after endotoxemia may result from alterations in intracellular Ca2+ handling, we tested the hypothesis that in vivo fluid resuscitation improved diastolic function by altering Ca2+ handling of the myocardium. We tested this hypothesis by measuring cell shortening and intracellular Ca2+ of ventricular myocytes isolated from endotoxemic guinea pigs. E. coli endotoxin (LPS, 1 mg/kg)-injected guinea pigs were divided into resuscitated and nonresuscitated groups. Fluid resuscitated animals received a Ringer's infusion (8 mL.kg-1.h-1) intravenously (i.v.) beginning immediately after endotoxin injection. Four hours later, ventricular myocytes were isolated enzymatically and loaded with fura-2/AM. When myocytes were field stimulated at .8 Hz, peak systolic Ca2+ transients of LPS-resuscitated (619 +/- 75 nM) and LPS-nonresuscitated (599 +/- 60 nM) myocytes were not significantly different from each other, but both were significantly less than values from control myocytes (1187 +/- 118 nM, p < .05). The percentage of cell shortening of LPS-resuscitated (6.2 +/- .9%) and LPS-nonresuscitated (6.2 +/- .3%) myocytes were also less than control (11.8 +/- .5%, p < .05). In contrast to improved diastolic compliance of fluid-resuscitated hearts, diastolic [Ca2+]i of myocytes (at .8 Hz) from LPS-resuscitated animals (138 +/- 47 nM) was not statistically different from LPS-nonresuscitated animals (129 +/- 19 nM). Diastolic values of both LPS groups were consistently lower than control value (251 +/- 38 nM, p < .05). These data suggest that improved diastolic compliance of LPS hearts following fluid resuscitation is not associated with improved myocyte contractility or myoplasmic Ca2+ handling.

Reversible, reproducible reduction of brain water apparent diffusion coefficient by cortical electroshocks

Rat brains were imaged after cortical electroshock pulse trains (1 ms pulses at 100 Hz) of varying durations (0.1-10 s), with diffusion-weighted echo planar imaging sequences at 2.0 T. The apparent water diffusion coefficient (ADC) decreased after either single or repeat electroshock trains. ADC reductions were observed within 6 s after the first shock. The size of the affected area of the brain increased in subsequent images during the 1st min after a 10-pulse (0.1 s) train, and also increased with the duration of electroshock trains. ADC reduction was reproducible in extent and time course after single 10-shock trains and was reversible. In the affected pixels the mean ADC reduction was 4% for a single shock train (0.1 s), and 7-8% for trains repeated once a minute, independent of electroshock train duration. The results indicate that neuronal activity associated with electrostimulation may be monitored with water diffusion measurements, and they may be useful for measuring the severity of seizure activity in patients with medically intractable epilepsy.

Use of subunit-specific antisense oligodeoxynucleotides to define developmental changes in the properties of N-methyl-D-aspartate receptors

Antisense oligodeoxynucleotides were used to determine whether alterations in the expression of N-methyl-D-aspartate (NMDA) receptor subunit mRNA are responsible for developmental changes in the sensitivity of receptors to agonists and antagonists. Xenopus laevis oocytes were injected with mRNA prepared from neonatal and adult rat cerebral cortex, and the effects of agonists and antagonists were determined under voltage-clamp conditions. Glycine-site antagonists like 7-chlorokynurenate and glutamate-site antagonists like CGP-39653 were more potent at NMDA receptors expressed from mRNA from adult rat cerebral cortex than those expressed from mRNA from 1-day-old rat. NMDA receptors from 1-day-old rat cerebral cortex were more sensitive to activation by glycine than were receptors from adult rat cerebral cortex. 7-Chlorokynurenate and CGP-39653 were more potent inhibitors of responses seen with heteromeric NR1/NR2A receptors than with NR1/ NR2B receptors. Conversely, heteromeric NR1/NR2B receptors were more sensitive to activation by glycine than were NR1/NR2A receptors. We previously described a delay in the expression of the NR2A subunit in developing rat brain. Anti-sense oligodeoxynucleotides were used to determine whether the delayed expression of the NR2A subunit underlies changes in pharmacological properties observed during development. The properties of receptors seen when adult brain mRNA was coinjected with antisense oligodeoxynucleotides against the NR2A subunit were similar to those found in receptors from 1-day-old rat brain. These data suggest that changes in the sensitivity of NMDA receptors to antagonists and to glycine seen during development are a result of alterations in the expression of different species of NR2 subunit mRNA.

Effects of channel modulators on cloned large-conductance calcium-activated potassium channels

Through expression of the cloned mouse (mSlo) or human (hSlo) large-conductance (BK) Ca(2+)-activated K+ channel in Xenopus laevis oocytes and HEK 293 cells, we characterized the effects of reported blockers and openers of BK channels to initiate the study of the molecular determinants of BK channel modulation. In oocytes, iberiotoxin and charybdotoxin, peptidyl scorpion toxins, were both equally effective blockers of BK current, although iberiotoxin was significantly more potent than charybdotoxin. The structurally related peptide kaliotoxin was not a potent blocker of BK current. Paxilline, a fungal tremorgenic alkaloid, was an effective but complex blocker of BK current. Tetrandrine, a putative blocker of type II BK channels, and ketamine were relatively ineffective. The putative BK openers NS004 and NS1619, phloretin, niflumic acid, flufenamic acid, and 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB) increased BK current in oocytes at microM concentrations; many of these produced biphasic concentration-response relationships. Coapplication of representative blockers and openers revealed several patterns of interaction, including competitive and noncompetitive antagonism. NS1619, niflumic acid, and phloretin were tested by using excised inside-out membrane patches from HEK 293 cells and were found to increase the activity of hSlo BK channels and produce a leftward shift in the G/Gmax-versus-voltage relationship of these channels. These results represent the first comprehensive examination of the molecular pharmacology of BK channels.

[Angioscopic in-situ arterial bypass for lower extremity revascularization]

The authors' initial experience of angioscopic in-situ arterial bypass of 37 extremities reveals that angioscopy can be used to assist complete valvular ablation and precise location and ligation of tributaries of saphenous vein grafts, avoiding postoperative arterial-venous fistula and warm ischemic injury to grafts. Angioscopy is also used to perform intraoperative completion inspection of the grafts and anastomoses. The designed biocomposite graft and common ostium technique promotes the usage rate of the limited autogenous vein grafts and enlarges the diameter of grafts and blood flow through the distal anastomosis. Because of the above new series of procedures, the extremity salvage rate in this study was 34/37 limbs. During the follow-up period of 2-18 months, all anastomoses were patent. The preoperative ankle and toe pressure of 3.5 +/- 0.2 kPa and 2.0 +/- 0.1 kPa respectively rose to 5.4 +/- 0.1 kPa and 3.8 +/- 0.2 kPa postoperatively. We conclude that angioscopic in-situ arterial bypass surgery is of practical value and specially advantageous in lower extremity revascularization.

The effects of cross-link density and chemical exchange on magnetization transfer in polyacrylamide gels

The effects of polymer structure and water-macromolecule interactions on proton relaxation in an aqueous model polymer have been investigated using quantitative measurements of magnetization transfer. Polyacrylamide gels composed of 95% water, 5% comonomers acrylamide and N,N'-methylene-bis-acrylamide were studied. The structure and rigidity were varied by changing the cross-linking density of the polymer. The polymer showed a biphasic change in transverse relaxation with increasing cross-linking density which was accompanied by a sudden increase in magnetization transfer above 40% cross linking. This change may be attributed to the formation of rigid domains in the polymer which exhibit solid-like behavior with a short T2 (11 microseconds) and a Gaussian lineshape. Water-macromolecule interactions were controlled by varying the pH of the gel. At high pH (> 8), there was an increase in magnetization transfer and transverse relaxivity consistent with a chemical-exchange-mediated interaction between water protons and the polymer. By analyzing the system as two proton reservoirs coupled by magnetization exchange, the proton populations, intrinsic relaxation rates, and exchange rates were estimated, for different degrees of cross linking and pH. This model affords useful insights into the relevance of both supramolecular structure and chemical exchange on relaxation in tissues.

Effects of osmotically driven cell volume changes on diffusion-weighted imaging of the rat optic nerve

The apparent diffusion coefficient (ADC) of the rat optic nerve was measured in vitro, using magnetic resonance imaging, to determine the effects of changes in cellular volume fraction on the diffusion of tissue water. Nerve ADC was determined under conditions of cell membrane depolarization and (i) increased intracellular volume, (ii) decreased intracellular volume, and (iii) negligible volume change. Depolarization alone had little affect on ADC, whereas volume changes produced strong, reversible effects. Increased cell volume decreased ADC and vice versa. These results are consistent with the view that changes in the extracellular space are the major source of ADC changes in brain tissue.