Photopolarimetric measurement of single, intact pulp fibers by mueller matrix imaging polarimetry

A method based on Mueller matrix polarimetry is developed and demonstrated for determining the fibril angle and relative phase retardation of single, intact pulp fibers. The method permits quantitative and nondestructive determination of these parameters from measurements at one wavelength without any fiber alignment. The Mueller matrix of a pulp fiber and its relationship with the fibril angle and phase retardation are described. A nonmodulation method for determining the Mueller matrix is then proposed that is based on a set of intensity data registered by a single detector. Measurements were carried out with single pulp fibers as samples to test the theoretical prediction. The test measurements and results are described and presented.

[Timing of vitrectomy for proliferative diabetic retinopathy in cases with type II diabetes mellitus]

OBJECTIVE

To determine the timing of vitrectomy for proliferative diabetic retinopathy with severe vitreous hemorrhage, retinal traction and even tractional detachment resulted from fibrovascular membranes in type II diabetes mellitus.

METHODS

According to the preoperative duration of vitreous hemorrhage and severity of diabetic retinopathy, 78 eyes of 64 cases having undergone vitrectomy were divided into 2 groups for the comparison of postoperative visual acuity.

RESULTS

After 9 months of follow-up, in the group with preoperative vitreous hemorrhage of <or= 6 months' duration 42.1% of cases had visual acuity of >or= 0.3, while in the group with preoperative vitreous hemorrhage of > 6 months' duration 5.3% of cases reached such a level (P < 0.01). After one year, in the group with preoperative vitreous hemorrhage of <or= 6 months 35.7% of cases had visual acuity of >or= 0.5, while in the group with preoperative vitreous hemorrhages of > 6 months' duration, 7.1% (P < 0.05). In the group of vitreous hemorrhage with or without local tractional retinal detachment, 35.7% had visual acuity of >or= 0.5, while in the group with large area of tractional retinal detachment, 16.7% (P < 0.05).

CONCLUSION

Earlier vitrectomy is preferable for type II diabetes mellitus with vitreous hemorrhage, and the operative treatment should not be abandoned for the patients with vitreous hemorrhage of longer duration and severe tractional retinal detachment.

Nontargeted stable integration of recombinant adeno-associated virus into human leukemia and lymphoma cell lines as evaluated by fluorescence in situ hybridization

A number of studies on human epithelial cells of varying origin have demonstrated integration of recombinant adeno-associated virus (AAV) vectors into a variety of chromosomes compared with the site-specific integration on chromosome 19 predominantly observed for wild-type (wt) AAV. We have constructed a recombinant AAV (rAAV) vector and tested the integration into hematopoietic cells, using the human acute myeloid leukemia cell line AML5 and the human non-Hodgkin's lymphoma cell line OCI-LY18 as targets. The integration sites were visualized by fluorescence in situ hybridization (FISH). Positive signals were observed for chromosomes 1, 2, 3, 8, 14, 15, 19, and Y. The majority of cells demonstrated integration into one specific site. A minority showed simultaneous integration into more than one chromosome. The frequency of observed integrations was not uniformly distributed among chromosomes; for instance, in AML5 chromosome 2 seemed to be favored. Colony-derived AML5 clones bore unique integration patterns indicating successful transduction of clonogenic progenitor cells with high proliferative potential. The integration was stable and observed for more than 12 months after transduction. FISH has been shown to be a powerful tool for detailed analyses of rAAV integration patterns and can be used to evaluate targets and transduction conditions.

Two Arabidopsis mutants that overproduce ethylene are affected in the posttranscriptional regulation of 1-aminocyclopropane-1-carboxylic acid synthase

The Arabidopsis mutants eto1 (ethylene overproducer) and eto3 produce elevated levels of ethylene as etiolated seedlings. Ethylene production in these seedlings peaks at 60 to 96 h, and then declines back to almost wild-type levels. Ethylene overproduction in eto1 and eto3 is limited mainly to etiolated seedlings; light-grown seedlings and various adult tissues produce close to wild-type amounts of ethylene. Several compounds that induce ethylene biosynthesis in wild-type, etiolated seedlings through distinct 1-aminocyclopropane-1-carboxylic acid (ACC) synthase (ACS) isoforms were found to act synergistically with eto1 and eto3, as did the ethylene-insensitive mutation etr1 (ethylene resistant), which blocks feedback inhibition of biosynthesis. ACS activity, the rate-limiting step of ethylene biosynthesis, was highly elevated in both eto1 and eto3 mutant seedlings, even though RNA gel-blot analysis demonstrated that the steady-state level of ACS mRNA was not increased, including that of a novel Arabidopsis ACS gene that was identified. Measurements of the conversion of ACC to ethylene by intact seedlings indicated that the mutations did not affect conjugation of ACC or the activity of ACC oxidase, the final step of ethylene biosynthesis. Taken together, these data suggest that the eto1 and eto3 mutations elevate ethylene biosynthesis by affecting the posttranscriptional regulation of ACS.

Expression of midkine in the early stage of carcinogenesis in human colorectal cancer

It has been suggested that a heparin-binding growth factor, midkine (MK), plays an important role in carcinogenesis because of its frequent overexpression in various malignant tumours. To clarify whether or not MK contributes to the early stage of carcinogenesis, we examined the status of MK mRNA in 20 adenomas with moderate- and severe-grade dysplasia, 28 carcinomas and 28 corresponding normal tissues, by means of Northern blotting. The MK expression level was significantly more elevated in adenomas than in normal tissues (P < 0.001, unpaired Student's t-test). A difference was also observed between carcinomas and the corresponding normal tissues (P < 0.04, paired Student's t-test). Moreover, MK immunostaining was positive in the adenomas with moderate- and severe-grade dysplasia and in the carcinomas, but not in mild-grade dysplasia or in normal tissues. These findings were in line with those on Western blotting. In three patients with both adenomas with moderate- or severe-grade dysplasia and carcinomas, elevated MK expression was observed in the neoplastic lesions. This is the first report of the association of elevated MK expression with the early stage of carcinogenesis in humans.

[Application of perfluorocarbon liquids in vitrectomy]

OBJECTIVE

To popularize the use of perfluorocarbon liquids in vitrectomy and increase the cure rate of complicated retinal detachment.

METHODS

The clinical application of perfluorocarbon liquids during vitrectomy for complicated retinal detachment of 76 eyes has been summarized. The postoperative retinal detachment rate and visual acuity of 54 eyes with retinal detachment complicated with severe proliferative vitreoretinopathy and 11 eyes with giant retinal tears were analyzed statistically.

RESULTS

The retina was reattached in 71 of 76 eyes (93.4%), in 50 of 54 eyes with severe PVR (92.6%) and in 9 of 11 eyes with giant retinal tears (81.8%). The postoperative visual acuity was above 0.02 in 69 eyes (90.8%) and > 0.1 in 29 eyes (38.2%) of 76 eyes, respectively in 50 (92.6%) and 18 (33.3%) of 54 eyes with severe PVR and 9 (81.8%) and 4 (36.4%) of 11 eyes with giant retinal tears. During surgery, perfluorocarbon entered through tears into subretinal space and was removed immediately in 6 of 76 eyes. Postoperatively, a small portion of residual perfluorocarbon liquid was observed in the anterior chamber of 17 of 76 eyes and in the vitreous cavity of 2 phakic eyes of 76 eyes, no complication was observed except one case with mild corneal opacification.

CONCLUSION

Perfluorocarbon liquids are the useful adjunct to the hydrokinetic manipulation in vitreous surgery.

Analysis of trace atrazine and simazine in environmental samples by liquid chromatography-fluorescence detection with pre-column derivatization reaction

Coupled with off-line extraction, a pre-column derivatization liquid chromatographic fluorescence detection (LC-FL) procedure was developed for the determination of atrazine and simazine in soil, crop and water samples. Concentrations in real samples were expected to be at or below the low ng/g level, which requires pre-concentration of analytes and improved detection. 4-(2-Phthalimidyl) benzoyl chloride (PIB-Cl) was used as a pre-column derivation reagent for high-performance liquid chromatography. The clean-up and second-time concentration procedures, which were indispensable in the conventional analytical methods for soil and crop analysis because of the complexity of the samples, were replaced by a derivatization reaction between PIB-Cl and the analytes. The fluorescent and ultraviolet characteristics of the derivatives were investigated. The derivatization reaction and chromatographic separation conditions were optimized systematically. Detection limits of 1.2 ng/g for atrazine and 1.1 ng/g for simazine were obtained with recoveries of 84-95% for environmental samples. On the basis of practical application to five soil and five crop samples, the LC-FL method was compared with the conventional GC-MS method.

[Surgical treatment of perplexing renal cell carcinoma]

OBJECTIVE

To summarize the experience of surgical treatment of perplexing renal cell carcinoma in order to increase survival rate.

METHODS

From 1987 through 1996, 20 patients with perplexing renal cell carcinoma were surgically treated. There were 3 patients in stage I, 9 in stage II, and 8 in stage III. The operative proceduce was described and the follow-up results were analysed.

RESULTS

Among 20 patients, 18 were evaluable. The 1-, 3-, 5-year survival rate was 100%, 91.7% and 75% for stage I-II; 87.5%, 62.5% and 37.5% for stage III, respectively.

CONCLUSION

Radical nephrectomy is still effective for the patients with perplexing renal cell carcinoma.

A genetic locus susceptible to the overt proteinuria in BUF/Mna rat

The BUF/Mna (BUF) strain is a high-proteinuria line of rats, and virtually all rats develop overt proteinuria by the age of 20 weeks. Genetic analysis revealed that proteinuria susceptibility was determined principally by two autosomal recessive genes. These findings prompted us to perform genetic mapping of the genes. (BUF/Mna x WKY/NCrj) F1 x BUF/Mna backcross rats were raised and maintained for 40-60 weeks to detect proteinuria. DNAs were extracted from ears of these rats and were examined by linkage study with polymerase chain reaction (PCR) with 132 microsatellite markers. Fifty-three out of 167 rats developed proteinuria. DNAs of 51 out of these 53 rats showed homozygous BUF/BUF genotype in the D13Mgh4 and D13N1 markers located on Chromosome (Chr) 13. The D13Rat1, D13Mgh2, D13Rat13, D13Mgh3, Syt2, Ren, D13Rat25, D13Mit2, D13Mgh5, and D13N2 markers located on the chromosome also showed statistically significant linkage to the development of proteinuria, whereas the other 110 markers showed no linkage. Here we report that a proteinuria-susceptible gene, Pur1, resides on a region flanked by the loci D13Mgh3 and D13Mgh4 on Chr 13.

Induction of immune tolerance in adult rabbits undergoing heterotopic cardiac transplantation

OBJECTIVE

To induce experimental immune tolerance in rabbits and observe its effects on heterotopic cardiac transplantation.

METHODS

Donor's splenic lymphocytes pretreated with platinum metal chelator were injected into the recipient's mesenteric-portal vein. Cyclosporin A was perfused through the donor's heart.

RESULTS

The injection of donor's splenic lymphocytes before transplantation could significantly prolong the survival time of the heterotopically transplanted heart. The effect of two injections was better than that of one. Radioactive tracer studies showed that the 99mTc-HMPAO tagged lymphocytes injected into the recipient rabbit were later concentrated in the liver, though initially they were distributed in multiple organs. The induced immune tolerance was antigen-specific, and it neither affect the other immune functions of the lymphatic system prominently nor exert any harmful effect on the recipient's liver and renal functions. The perfusion of cyclosporin A through the donor heart could block the glycosyl groups, such as D-glucose, D-mannose or N-acetyl-galactosamine on the surface of the myocardial cells, thus might change the antigenic expression, effectively preventing rejection of the graft by the host, and might be considered as a new method to block graft rejection in cardiac transplantation. The combined use of the above-mentioned two methods acted on both the host and the donor, thus reducing the exposed antigens on the donor organ as well as the immune reaction against the donor antigens, and resulting in synergistic effect in inducing immune tolerance in adult rabbits, and resulting in relatively long-term survival of transplanted hearts.

CONCLUSION

This report may provide the experimental basis for inducing immune tolerance in clinical transplantation.

[Sequencing of a beta-amylase gene from Bacillus firmus]

The gene encoding a beta-amylase from Bacillus firmus 725 was sequenced. The sequenced DNA of 2012 bp contains one open reading frame of 1406 nucleotides without a translation stop codon. The deduced amino acid sequence homology with those known bacterial and some plant beta-amylase was 98% for Bacillus polymyxa 72, 98% for Bacillus polymyxa ATCC8523, 82% for Bacillus circulans, 54% for Clostridium thermosulfurogenes, 49% for Bacillus cereus BQ10-S1, 50% for Bacillus cereus var. mycoides, 36% for barley, and 36% for soybean Eleven well-conserved regions were found among the amino acid sequences of the nine beta-amylases.

Improved free musculocutaneous flap survival with induction of heat shock protein

The cellular response to a wide variety of stresses results in the synthesis of a family of stress response proteins termed heat shock proteins. Recent studies have demonstrated that heat shock proteins produced in response to an initial stress seem to protect against subsequent unrelated stresses. Importantly, hyperthermia-induced heat shock proteins provided protection from ischemia/reperfusion injury in several organ transplantation models. We hypothesized that free musculocutaneous flap survival could be improved by enhancing the flap's tolerance to relative ischemia by the prior induction of heat shock proteins. Accordingly, we determined the heat shock protein response in skin and muscle after systemic or local heating and examined the effect on free musculocutaneous flap survival in a rat model. Free musculocutaneous flaps incorporating thigh adductor muscles and a 2 x 6-cm2 skin paddle were transplanted to the ipsilateral groin in three groups of male Wistar rats. Systemically heated rats (n = 6) were anesthetized and incubated for 30 minutes at 42 degrees C 6 hours before free musculocutaneous tissue transfer. Locally heated rats (n = 6) were anesthetized, and their donor site anterior thigh was placed for 30 minutes on a heating block set at 44 degrees C 6 hours before free tissue transfer. Control rats (n = 5) did not have heating pretreatment but underwent identical anesthesia. Animals were sacrificed on postoperative day 3, at which time skin loss (cm2) and muscle viability, quantified by nitroblue tetrazolium staining time, were assessed in a blinded fashion. The skin and muscle from the free flap were analyzed for HSP72 mRNA and protein using quantitative Northern and Western blot techniques. All free musculocutaneous flaps were viable. However, the locally and systemically heated rats demonstrated a marked improvement of skin survival, which correlated with increased skin levels of HSP72. There were no differences in nitroblue tetrazolium muscle staining times or muscle levels of HSP72 among the three groups. These findings suggest that prior heat-induced heat shock proteins result in improvement in musculocutaneous flap survival, which may have direct clinical applications, especially in high-risk patients.

1H/27Al TRAPDOR NMR studies on aluminum species in dealuminated zeolites

Aluminum species in several dealuminated zeolites (ultrastable HY, HZSM-5 and mordenite) were investigated in detail by means of the newly introduced 1H/27Al TRAPDOR method in combination with 27Al MAS NMR, and the quadrupole coupling constants (Q[CC]s) for aluminum atoms associated with these species were obtained. A signal at ca. 6.8 ppm, due to water molecules adsorbed on Lewis acid sites, was observed in the 1H MAS spectra for all the three zeolites. The TRAPDOR NMR provides direct evidence that there is a strong interaction between the adsorbed water molecules and the aluminum atoms of the Lewis-acid sites. The Q(CC) values for this aluminum species of 8.3, 6.7 and 11.3 MHz were determined from the TRAPDOR profiles for the ultrastable HY, HZSM-5 and mordenite zeolites, respectively. The Q(CC)s calculated from the TRAPDOR curves are usually larger than 10 MHz for both Bronsted-acid sites (SiOHAI) and non-framework aluminum species in the three zeolites. Three narrow peaks at 54, 30 and 0 ppm are separately superimposed on a broad hump in the 27Al MAS spectra of the three dehydrated zeolites, while the latter is associated with the 'NMR invisible' Al. The NMR experimental results suggest that the three kinds of aluminum species (non-framework aluminum species, Bronsted- and Lewis-acid sites) are all responsible for the resonance of the broad hump in dehydrated zeolites, which makes it difficult to explain the 27Al MAS spectra. Fortunately, the TRAPDOR NMR provides a direct method for individually studying different aluminum species with large Q(CC)s via their dipolar coupling to nearby proton nuclei.

Three-dimensional maximum-quantum correlation HMQC NMR spectroscopy (3D MAXY-HMQC)

The extension of two-dimensional maximum-quantum correlation spectroscopy (2D MAXY NMR), which can be used to simplify complex NMR spectra, to three dimensions (3D) is described. A new pulse sequence for 3D MAXY-HMQC is presented and exemplified using the steroid drug dexamethasone. The sensitivity and coherence transfer efficiency of the MAXY NMR approach has also been assessed in relation to other HMQC- and HSQC-based 3D methods. Copyright 1997 Academic Press. Copyright 1997Academic Press

High-field (9.4 T)(1)H magnetic resonance microscopy of mouse brain

The FLASH and STEAM pulse sequences were used to perform the microimaging and localized spectroscopy of brain of living and dead mice, respectively. The phase-shift presaturation approach was used to suppress water NMR signal. The experimental results show that the differences in localized spectra and MR images of brain between live and dead mice can be observed by means of magnetic resonance microscopy.

Targeted inactivation of alphai2 or alphai3 disrupts activation of the cardiac muscarinic K+ channel, IK+Ach, in intact cells

Cardiac muscarinic receptors activate an inwardly rectifying K+ channel, IK+Ach, via pertussis toxin (PT)-sensitive heterotrimeric G proteins (in heart Gi2, Gi3, or Go). We have used embryonic stem cell (ES cell)-derived cardiocytes with targeted inactivations of specific PT-sensitive alpha subunits to determine which G proteins are required for receptor-mediated regulation of IK+Ach in intact cells. The muscarinic agonist carbachol increased IK+Ach activity in ES cell-derived cardiocytes from wild-type cells, in cells lacking alphao, and in cells lacking the PT-insensitive G protein alphaq. In cells with targeted inactivation of alphai2 or alphai3, channel activation by both carbachol and adenosine was blocked. Carbachol-induced channel activation was restored in the alphai2- and alphai3-null cells by reexpressing the previously targeted gene and guanosine 5'-[gamma-thio] triphosphate was able to fully activate IK+Ach in excised membranes patches from these mutants. In contrast, negative chronotropic responses to both carbachol and adenosine were preserved in cells lacking alphai2 or alphai3. Our results show that expression of two specific PT-sensitive alpha subunits (alphai2 and alphai3 but not alphao) is required for normal agonist-dependent activation of IK+Ach and suggest that both alphai2- and alphai3-containing heterotrimeric G proteins may be involved in the signaling process. Also the generation of negative chronotropic responses to muscarinic or adenosine receptor agonists do not require activation of IK+Ach or the expression of alphai2 or alphai3.

Calcium-sensing receptor in the rat hippocampus: a developmental study

The extracellular Ca2+ (Ca2+(o))-sensing receptor (CaR) plays a key role in maintaining near constancy of Ca2+(o) in mammals through its presence in parathyroid gland and kidney. The CaR is also present in brain, and although its role(s) in the brain is not known, it is possible that small changes in Ca2+(o) modify essential physiological and pathological processes, since calcium is crucial for numerous neuronal functions. Northern analysis has revealed that the CaR mRNA is present in hippocampus and several other regions of the brain. The hippocampus is an important site for learning and memory, but the relevance of the CaR to these processes is unknown. Long-term potentiation (LTP), a putative in vitro analog of memory, can only be induced after 7-10 days postnatally in rat hippocampus. Therefore, in the present study we determined the time course for the developmental expression of the CaR in rat hippocampus to assess its relationship to the development of other important hippocampal functions, such as the capacity for induction of LTP. Northern and Western analyses showed that CaR mRNA and protein were expressed at low levels at 5 days postnatally but then increased markedly at 10 days. A high level of receptor expression, due primarily to an increase in a 7.5 kb transcript, persisted until 30 days, when it gradually decreased by 3-fold to reach the adult level of expression. In situ hybridization histochemistry and immunohistochemistry revealed CaR mRNA and protein in pyramidal cells of all the layers of hippocampus and in granule cells of the dentate gyrus. The results show that CaR expression rises at a time when LTP can first be induced in hippocampus and persists at high levels during the time when brain development is proceeding most rapidly. Further studies are needed to determine the role of the CaR in the development of important aspects of the function of hippocampus and other regions of brain, including LTP.

Expression of extracellular calcium-sensing receptor by human lens epithelial cells

The extracellular calcium-sensing receptor (CaR) confers the capacity to sense small changes in the extracellular Ca2+ concentration (Ca2+o) not only upon cells involved in maintaining systemic Ca2+ homeostasis but also upon those not directly involved in this process. Since high Ca2+o is known to affect various physiological processes in lens epithelium both in health and in disease states (e.g., the formation of cataracts in hypocalcemic states), we investigated the expression and function of the CaR in these cells. By RT-PCR and immunocytochemistry the CaR is expressed in human lens epithelial cells in culture. In addition, the open state probability of a Ca(2+)-activated potassium (K+) channel with a conductance of 82 +/- 3 pS is significantly increased by elevating Ca2+o to 3.0 mM or by application of 100 microM neomycin, both effective CaR agonists. Therefore, our data suggest that human lens-epithelial cells express the CaR, which may be functionally linked to Ca(2+)-activated K+ channels and, perhaps, to other ion channels involved in ionic homeostasis in the lens.

Cao-sensing receptor (CaR)-mediated activation of K+ channels is blunted in CaR gene-deficient mouse neurons

The extracellular Ca2+ (Cao)-sensing receptor (CaR) is expressed in hippocampus and other brain regions, suggesting that it could mediate some of the well recognized but poorly understood direct actions of Cao on neuronal function. This study presents evidence that the CaR is functionally coupled to Ca(2+)-activated K+ channels. The effects of CaR agonists on these channels in neurons from wild type (WT) and CaR-deficient (CaR -/-) mice were compared. Neomycin (100 mM) and elevation of Cao from 0.5 to 3 mM significantly increased the probability of channel opening (Po) in neurons from WT but not in those from CaR -/- mice. Thus the CaR activates neuronal K+ channels and could potentially inhibit neuronal excitability and neurotransmission via membrane repolarization.

Dynamic nuclear polarization of nitrogen-15 in benzamide

A 15N dynamic nuclear polarization (DNP) experiment is reported in which a 15N DNP enhancement factor of approximately 2.6 x 10(2) is obtained on free radical doped samples of 99% 15N labeled benzamide. The free radicals BDPA (1:1 complex of alpha, gamma-bisdiphenylene-beta-phenylallyl with benzene) and DPPH (2,2-Di(4-tert-octylphenyl)-1-picrylhydrazyl) are used as dopants and the spin relaxation effects of adding these dopants are studied by means of changes in proton and nitrogen T1 values of the samples. The combination in solids of a very low natural abundance, 0.37%, a small gyromagnetic ratio, and a long spin-lattice relaxation time for 15N nuclei create severe sensitivity problems that, in large part, are ameliorated by the signal enhancement observed in the 15N DNP experiment on samples containing free electrons.

[Changes of calcium transport in rat liver nuclei during sepsis]

Calcium transport changes in rat liver nuclei were observed on the model of early sepsis (9 h after operation of cecal ligation and puncture). Calcium content in hepatocytes and nuclei were significantly increased by 20% and 36% respectively (P < 0.05) during sepsis. The activity of Ca(2+)-ATPase in hepatocytic nuclei was increased by 94% (P < 0.01) and 45Ca2+ transport accelerated by 32% (P < 0.01). There was a positive correlation between nuclear 45Ca2+ transport and nuclear Ca(2+)-ATPase activity (r = 0.914, P < 0.01). Calmodulin stimulated the activity of nuclear Ca(2+)-ATPase and 45Ca2+ transport; while calmodulin inhibitor trifluoperazine exerted an opposite effect. The above results suggest that liver nuclear calcium transport is strengthened during early sepsis as a result of changes of Ca(2+)-ATPase activity.

Amyloid-beta proteins activate Ca(2+)-permeable channels through calcium-sensing receptors

The amyloid-beta peptides (A beta) are produced in excess in Alzheimer's disease (AD) and may contribute to neuronal dysfunction and degeneration. This study provides strong evidence for a novel cellular target for the actions of A beta, the phospholipase C-coupled, extracellular Ca(2+)-sensing receptor (CaR). We demonstrate that A beta(s) produce a CaR-mediated activation of a Ca(2+)-permeable, nonselective cation channel (NCC), probably via elevation in cytosolic Ca2+ (Cai), in cultured hippocampal pyramidal neurons from normal rats and from wild type mice but not those from mice with targeted disruption of the CaR gene (CaR -/-). A beta(s) also activate NCC in CaR-transfected but not in nontransfected human embryonic kidney (HEK293) cells. Thus aggregates of A beta deposited on hippocampal neurons in AD could appropriately activate the CaR, stimulating Ca(2+)-permeable channels and causing sustained elevation of Cai with resultant neuronal dysfunction.

1H MAS and 1H[23Na] double resonance NMR studies on the modification of surface hydroxyl groups of gamma-alumina by sodium

The modification of surface hydroxyl groups with sodium in a series of Na2CO3-gamma-Al2O3 catalysts was investigated as a function of both the Na2CO3 loading and the calcination temperature by means of 1H magic angle spinning (MAS) and 1H(23Na) spin-echo double resonance NMR techniques. The 1H NMR experiments revealed that sodium ions are homogeneously distributed over the alumina surface and closely coordinated with the surface hydroxyl groups. In the catalysts calcined at 250 degrees C, the acidic hydroxyl groups (with a chemical shift of 2.0 ppm) are preferentially associated with sodium ions at low Na2CO3 coverages (5 and 10%), while both the acidic and the basic (0 ppm) hydroxyl groups are accessible for sodium ions at high coverages (15 and 20%). The coordination causes a low-field shift of about 2 ppm in the 1H MAS spectra, and a broad signal at 4.5 ppm appears. It is interesting that the 4.5 ppm signal is completely suppressed in the 1H(23Na) MAS experiments, providing direct evidence that a strong interaction exists between adsorbed sodium ions and the surface hydroxyl groups. Increasing the calcination temperature to 450 degrees C results in preferential removal of the acidic hydroxyl groups, and only the most basic hydroxyl groups remain when the calcination temperature is raised to 600 degrees C. This is attributed to the formation of the coordinated species. [formula: see text] which enhances the acidity of the surface hydroxyl groups and prompts their dehydroxylation, especially at high calcination temperature. Correlation of the 1H MAS NMR results and catalytic activity measurements indicates that the basic hydroxyl groups are essential for the carbonyl sulfide hydrolysis reaction.

[Metallothionein involvement in the delayed protection after ischemic or anoxic preconditioning in myocardium or cultured cardiomyocytes]

OBJECTIVE

To study whether metallothionein (MT) is an OH scavenger and plays a protective role in cardiac ischemic/reperfusion injury. MT involves in the delayed protection 24 hr after preconditioning (PC).

METHODS

MT contents in myocardium or cultured cardiomyocytes are assayed at the 0 hr, 12 hr, and 24 hr after PC on the model of rabbit heart in situ or that of the cultured cardiomyocytes. The myocardial infarct size, LDH release, cell viability, and the content of cellular MDA were measured with or without the intervention of PD098059, the inhibitor of mitogen-activated protein kinase in the models before PC and different time intervals after PC.

RESULTS

The MT contents were increased significantly at 2 hr (1406.2 +/- 112.2 vs 129.9 +/- 10.4 pmol/mg Pr., P < 0.01, in cardiomyocytes) and 24 hr (1032.7 +/- 199.1 vs 129.9 +/- 10.4 pmol/mg Pr., P < 0.01, in cardiomyocytes; 62.1 +/- 12.6 vs 27.2 +/- 3.7 pmol/mg Pr., P < 0.01, in myocardium) after PC compared with those in normal group. The infarct sizes (13.2 +/- 3.6% vs 32.3 +/- 5.7%, P < 0.05) and the rise of LDH release in plasma (1944 +/- 256 vs 2826 +/- 239 IU/L, P < 0.05) were greatly decreased in preconditioned myocardium after a long time ischemia-reperfusion than those in the unpreconditioned. Compared with the cardiomyocytes unconditioned, the number of viable cell (71.0 +/- 1.6 vs 48.2 +/- 2.2%, P < 0.01) was greatly increased, the cellular MDA contents (33.5 +/- 12.8 vs 103.5 +/- 15.0 nmol/mg Pr., P < 0.01) and the LDH release (850.0 +/- 139.1 vs 1552.0 +/- 102.6 IU/L, P < 0.01) were dramatically decreased in preconditioned ones. All the delayed protection at 24 hr after PC were completely disappeared with the inhibition of MT's production with PD098059 (P > 0.05).

CONCLUSION

The myocardium or cardiomyocytes at 24 hr after PC are offered more capacity to tolerate the I/R damage, and MT involves in the delayed protection.

Measurement of spin-lattice relaxation times of 13C in organic solids

A transient nuclear Overhauser effect (NOE) makes measurements of the 13C spin-lattice relaxation times in organic solids complicated. Extended Solomon equations are applied in order to describe 13C spin-lattice relaxation with 1H r.f. field irradiation. Spin-lattice relaxation under r.f. irradiation is shown to be generally a triple-exponential process, but it can be reduced to be single-exponential under stronger r.f. field irradiation as well as in the absence of 1H initial magnetizations. Based on numerical calculations, the difference between spin-lattice relaxation curves obeying T1C < T1H and those obeying T1C > T1H is clearly indicated. The methyl group resonances in solid-state L-valine are examined, and the experimental results agree well with the theoretical results.

A flickery block of a K+ channel mediated by extracellular Ca2+ and other agonists of the Ca2+-sensing receptors in dispersed bovine parathyroid cells

Single K+ channel activities in parathyroid cells were studied using the patch-clamp technique. A K+ channel modulated by external Ca2+ (Ca2+o) was identified. This channel had a unitary conductance of 109pS at 150 mM K+o in the pipette solution. An increase in Ca2+o from 0.5-0.75 to 2-3 mM induced a flickery partial block of the channel over a wide voltage range. The mechanism of channel blockade included a significant increase in the number of closings per burst and a reduction of the mean open times. Addition of other divalent and polyvalent agonists of the Ca2+-sensing receptor (CaR) induced a similar channel blockade. With its typical characteristics and flickery block by CaR agonists, this channel differs from previously described types of K+ channels. It is probably strongly coupled to the CaR and may contribute to the depolarization of parathyroid cells which is known to occur at elevated levels of Ca2+o.

[Clinical analysis of 120 patients with fibromyalgia]

The clinical characteristics of 120 patients with fibromyalgia is reported. Most of the patients were 21-50 years old. More than 56% patients had three chief symptoms: generalized myalgia, abnormal sensations and easily fatigue. 49.2% of the patients complained multiple arthralgia; 29% with sleep disorder and 23% with local myospasm of lower limbs. The trigger point was regarded as an important physical sign. The etiology and differential diagnosis for fibromyalgia were discussed.

Deficient cation channel regulation in neurons from mice with targeted disruption of the extracellular Ca2+-sensing receptor gene

This study presents evidence that a receptor sensitive to the concentration of extracellular Ca2+ (Ca[2+]o) (CaR) is functionally coupled to ion channels involved in modulation of neuronal excitability. This receptor is expressed in hippocampus and other brain regions, suggesting that it could mediate some of the well-recognized but poorly understood direct actions of extracellular Ca2+ (Ca[2+]o) on neuronal function. The effects of polycationic CaR agonists on the activity of a nonselective cation channel (NCC) in cultured hippocampal neurons from wild-type mice and from mice homozygous for targeted disruption of the CaR gene (CaR -/-) were compared in this study. The CaR agonists, neomycin (100 microM), spermine (300 microM), and elevation of Ca(2+)o from 0.75 to 3 mM, significantly increased the probability of channel opening (Po) in wild-type neurons. None of these agents, however, produced any effect on Po in neurons from mice lacking the CaR. The same NCC, however, could be activated by thapsigargin in neurons from both wild-type mice and CaR-deficient mice, most likely through an associated increase in the cytosolic free calcium concentration (Ca[i]). Thus the CaR regulates the activity of Ca2+-permeable NCC in hippocampal neurons and could potentially modulate key neuronal functions, including neurotransmission and neuronal excitability, via membrane depolarization.

Causes of rectal incontinence after sphincter-preserving operations for rectal cancer

PURPOSE

Low anterior resection (LAR) is the treatment of choice for middle and high rectal tumors. Even though the rectal sphincter is preserved, some patients show a postoperative loss of rectal continence that may be recovered during follow-up. The purpose of this study was to collect clinical and manometric data before and after LAR to find possible explanations for incontinence.

METHODS

Seventeen continent patients with rectal tumors located 10 cm above the anal verge were selected. Manometry was performed before and three months after surgery and when stable frequency of bowel movement was achieved (mean, 7 months).

RESULTS

Immediately after the operations, 14 of 17 patients showed a certain degree of incontinence but recovered during follow-up; at the end of the study, only two patients reported minor soiling. Resting and squeeze pressures were moderately reduced after surgery and increased during the following six months without regaining preoperative levels. Rectoanal inhibitory reflex was present in 94.4 percent of patients before the operations and in 25 percent of them after surgery, but it was not associated with incontinence. Rectal sensation was significantly reduced, and its recovery was well correlated with decrease in the frequency of bowel movements.

CONCLUSIONS

After LAR, there is a reduction in rectal pressures, suggesting damage to sphincter muscle fibers or innervation. There is also a reduction in rectal sensation related to loss in reservoir capacity, all of which may contribute to incontinence.

Agonists of the Ca(2+)-sensing receptor (CaR) activate nonselective cation channels in HEK293 cells stably transfected with the human CaR

Calcium (Ca2+) ions serve multiple roles both intra- and extracellularly. We recently cloned a cell surface, Cao(2+)-sensing receptor (CaR) that plays a central role in Cao2+ homeostasis by enabling direct regulation by Cao2+ of parathyroid hormone (PTH) secretion and the function of other tissues involved in mineral ion homeostasis. In parathyroid cells, the CaR activates phospholipase C, thereby raising the levels of inositol trisphosphate (IP3) and releasing Ca2+ from intracellular stores. High Cao2+ also activates Ca2+ influx into parathyroid cells through poorly defined mechanisms that may involve Ca(2+)-permeable, nonselective cation channels (NCC). We now show that human embryonic kidney (HEK293) cells also have NCC and, furthermore, that these channels are regulated by the CaR. We have utilized the cell-attached configuration of the patch clamp technique to characterize the properties of these channels as well as their regulation by various CaR agonists added to the external bath solution. The polycationic CaR agonist, neomycin (100 microM), as well as an elevated concentration of Cao2+ (3 mM), both of which activate the cloned CaR, significantly increased the probability of channel opening (Po) in HEK cells stably transfected with the CaR but not in nontransfected HEK cells which do not contain the receptor. Thus, the activation of the CaR enhances the activity of Ca(2+)-permeable NCC in these cells, which could contribute to the sustained increase in Cai2+ in parathyroid cells which is observed in response to elevated Cao2+. The CaR may also regulate the membrane functions of other CaR-expressing cells (e.g., those in the brain), at least in part, by modulating similar channels.

Modulation by polycationic Ca(2+)-sensing receptor agonists of nonselective cation channels in rat hippocampal neurons

We recently cloned an extracellular calcium (Ca2+0)-sensing receptor (CaR) from bovine parathyroid. The CaR is also expressed in various regions of brain, suggesting that it could potentially mediate some of the well-known but poorly understood effects of Ca2+0 on neuronal function. We have now examined the effects of polycationic CaR agonists on the activity of nonselective cation channels (NCC) in cultured rat hippocampal neurons, using the cell-attached configuration of the patch clamp technique and applying CaR active agents to the external bath solution. The polycationic CaR agonist, neomycin (100 microM), as well as an elevated concentration of Ca2+0 (3 mM), which is known to activate the cloned CaR, significantly increased the probability of channel opening (Po). The polyamine, spermine (300 microM), which also mimics the actions of Ca2+0 on the cloned CaR, produced similar changes in Po in rat hippocampal neurons. Elevation of Ca2+0 also increased Po for a similar NCC in HEK293 cells transfected with the cloned human CaR but not in nontransfected HEK cells. Thus the CaR can regulate the activity of Ca(2+)-permeable NCC in hippocampal neurons and could potentially modulate key functions of these cells, including neurotransmission and neuronal excitability.

Investigation of a naphthalene pitch by high-resolution solid-state dynamic nuclear polarization

The possibility of applying the dynamic nuclear polarization (DNP) technique to a study of char is explored with a naphthalene-derived pitch. It is shown that a 13C DNP enhancement factor of about 10(2) is obtained when the polarization is directly transferred from the unpaired electrons to the 13C nuclei. An undistorted spectrum with an enhancement factor of 8 is obtained by the DNP cross-polarization magic-angle spinning nuclear magnetic resonance (DNP-CP-MAS NMR) method. With such a high increase in S/N, it is possible to measure the 13C polarization time (Tp) and the spin-lattice relaxation time (T1) of the system in a reasonable experimental time. The resultant values are Tp = 19 s and T1 = 38 s, respectively. Based on the DNP enhancement as a function of the microwave frequency, it is found that the predominant DNP mechanism in the pitch is the solid-state effect.

Spectral editing in 13C CP/MAS experiments at high magnetic field

We show that the spinning side-bands of protonated and non-protonated carbon atoms can be well separated by means of the standard SCP and LCPD experiments at a relatively slow sample spinning rate or at high magnetic field. These experiments offer a promising way of measuring the principal values of chemical shift anisotropies via spinning side-band analysis in a moderately complex system. General spectral editing in 13C cross-polarization magic-angle spinning (CP/MAS) experiments at high field is achieved by incorporating the total side-band suppression (TOSS) pulse sequence into the standard series of spectral editing pulse sequences. It is confirmed that the relative signal intensity for a certain kind of functional group obtained at different polarization, polarization-inversion and depolarization times is about the same as that obtained at low magnetic field, and that the signal intensity distortion introduced by the TOSS sequence for resonances having different chemical shift anisotropies does not interfere with the spectral editing process. However, quantitative results can only be expected in those cases where full restoration of the intensity of the central band can be achieved by the TOSS sequence. This new strategy at high field is demonstrated by using fumaric acid monoethyl ester as a model compound. A typical application to a Chinese resin is presented, where the relative ratio of each functional group in the aliphatic portion to the total number of aliphatic carbon atoms is determined from only three experimental spectra.

High resolution 1H spectra of powdered solids observed by Hahn echo pulse sequence with magic-angle spinning

The 1H magic-angle spinning (MAS) spectrum for a typical powdered solid is composed of a high resolution component and a broadline component. The high resolution component can be well isolated from the broadline component by the Hahn echo sequence with a long echo time. Compared with CRAMPS experiment, which measures the proton system as a whole, the high resolution echo-MAS method measures only a fraction of the solid, which is usually small at room temperature and quite different from the majority of the solid in both molecular motion and chemical environment. It is shown that for a sample of fumaric acid monoethyl ester, the chemical shifts of the high resolution component are apparently distinguishable from the isotropic chemical shifts of the broadline component in the CRAMPS spectrum as the temperature approaches the melting point. In addition, for a sample of malonic acid, the echo-MAS spectrum is sensitive to moisture and temperature, while its corresponding CRAMPS spectrum is not. It is suggested that the molecules which produce the high resolution component are related to the lattice defects in a solid, including the surface disorder of the polycrystallites, while the molecules that generate the broadline component are located on the rigid lattice of the solid.

The use of differential transverse relaxation to detect mobile species in solids

Delayed acquisition of the proton NMR in selected organic molecular solids (L-alanine, durene, ethyl fumarate, and p-hydroxybenzoic acid) is shown to allow the observation of mobile species in the presence of relatively rigid bulk molecules. The mobility is found to be thermally activated. The combination of the thermally activated motion and magic-angle spinning leads to a fraction of these species moving nearly isotropically on the time scale of the inverse of the homonuclear dipolar splitting. In the case of ethyl fumarate and alanine, there exist populations with differing values of T1 and T1 row. This indicates the co-existence of relatively rigid and relatively mobile molecules in the same sample. The intensities under delayed acquisition cannot always be trusted to yield quantitative information. Comparison of spectra taken under delayed acquisition and under the CRAMPS (B.C. Gerstein, R.G. Pembleton, R.C. Wilson and L.M. Ryan, J. Chem. Phys., 66 (1977)361) technique is made.

Long-term survival of heterotopic heart transplants in allogenic rats without using anti-rejection drugs after inducing immune tolerance

Graft rejection is a baffling problem in organ transplantation which has so far no successful resolution. Present antirejection therapy is expensive, toxic, susceptible to infection, oncogenesis and atherosclerosis. With the use of 2 extremely histoincompatible strains of rats as model, it was found that when six donor splenocytes preconditioned by an extract from the culture medium of streptomyces caespitosus were injected into the host, after 2 weeks immune tolerance heterotopic transplanted donor hearts could survive normally more than 100 days without using any anti-rejection drug. Their mean survival time was 141.4 +/- 2.56 days, while that in the control group was only 11.7 +/- 3.48 days (P < 0.005). Thus, the present research offers some bright prospects in the area of organ transplantation.

A novel disentangling technique for the propagator describing cross-polarization dynamics

The heteronuclear cross-polarization dynamics is described by the rotation operator approach proposed recently. The established theory is suitable for an isolated two-spin system. It is shown that the propagator can be disentangled into a cascade of six exponential operators and the polarization transfer concerned can be evaluated by the usual procedure.

Off-resonance effects on 2D NMR nutation spectra of I = 3/2 quadrupolar nuclei in static samples

The off-resonance effects on 2D NMR nutation of I = 3/2 quadrupolar nuclei are demonstrated with perturbation theory and numerical calculation in static samples. The off-resonant (delta omega) rf field (omega 1) enlarges a nutation frequency and consequently increases the measurement range of nuclear quadrupolar interaction parameters. When omega e > omega Qmax, and arctg(omega 1/delta omega) = +/- 54.7 degrees (magic angle), the satellite lines (produced by coherence transfers) in a nutation spectrum are superimposed with the line of central transition, and hence the nutation spectrum is simplified and its sensitivity is enhanced. The nuclear quadrupolar interaction parameters of 23Na nuclei in Na omega molecular sieve are obtained using 2D NMR nutation.

[E-selectin expression in serum and tissue correlates with distant metastasis of colorectal cancer]

E-selectin is an adhesion molecule of endothelial cells that binds to cancer cells mediated by sialyl Lewis A (sLea) or sialyl Lewis X (sLex). It is suspected to be involved in hematogenous metastasis of tumors. Therefore, it is worth examining E-selectin expression in human colorectal cancer and its hepatic metastasis. In the present study, E-selectin was clearly revealed on the endothelial cells of small vessels adjacent to cancer nests in both primary and metastatic nests in immunohistochemistry. In these tissues, E-selectin was observed on the endothelial cells lining the lumen of small vessels. Its expression adjacent to cancer nests appears to be induced through some stimuli by cancer cells, since its degree of expression is inversely correlated to the distance of the blood vessels from the cancer nests (P < 0.001). Endothelial cells adjacent to the metastatic lesion expressed E-selectin more extensively than those adjacent to the primary foci. This is also in line with the finding on serum E-selectin levels which were significantly elevated in the metastatic group compared to the non-metastatic group. The serum E-selectin level may provide useful information in the diagnosis for hepatic metastasis of colorectal cancer, although the results are still very preliminary.

Expression of E-selectin on endothelial cells of small veins in human colorectal cancer

E-selectin is an adhesion molecule of endothelial cells that binds to cancer cells mediated by sialyl Lewis A (sLea) or sialyl Lewis X (sLe(x)). It is suspected to be involved in hematogenous metastasis of tumors. Therefore, it is worth examining E-selectin expression in human colorectal cancer and its hepatic metastasis. In the present study, E-selectin was clearly revealed on the endothelial cells of small vessels adjacent to cancer nests both in primary and in metastatic nests in immunohistochemistry. In these tissues, E-selectin was observed on the endothelial cells lining the lumen of small vessels. Its expression adjacent to cancer nests appears to be induced through some stimuli by cancer cells, since its degree of expression is inversely correlated to the distance of the blood vessels from the cancer nests (p < 0.001). Endothelial cells adjacent to the metastatic lesion expressed E-selectin more extensively than those adjacent to the primary foci. This is also in line with the finding on serum E-selectin levels which were significantly elevated in the metastatic group as compared with the non-metastatic group. The serum E-selectin level may provide useful information in the diagnosis for hepatic metastasis of colorectal cancer, although the results are still tentative.

Study of natural diamonds by dynamic nuclear polarization-enhanced 13C nuclear magnetic resonance spectroscopy

The results of a study of two types of natural-diamond crystals by dynamic nuclear polarization (DNP)-enhanced high-resolution solid-state 13C nuclear magnetic resonance (NMR) are reported. The home-built DNP magic-angle spinning (MAS) 13C NMR spectrometer operates at 54 GHz for electrons and 20.2 MHz for carbons. The power of the microwave source was about 30 W and the highest DNP enhancement factor came near to 10(3). It was shown that in the MAS spectra the 13C NMR linewidths of the Ib-type diamond were broader than those of IaB3-type diamond. From the hyperfine structure of the DNP enhancement as a function of frequency, four kinds of nitrogen-centred and one kind of carbon-centred free radicals could be identified in the Ib-type diamond. The hyperfine structures of the DNP enhancement curve that originated from the anisotropic hyperfine interaction between electron and nuclei could be partially averaged out by MAS. The 13C polarization time of DNP was rather long, i.e. 1500 s, and the spin-lattice relaxation time (without microwave irradiation) was about 300 s, which was somewhat shorter than anticipated. Discussions on these experimental results have been made in this report.

Microscopic transmission ellipsometry: measurement of the fibril angle and the relative phase retardation of single, intact wood pulp fibers

A new technique based on transmission intensity-quotient ellipsometry has been developed for determining the fibril angle and the relative phase retardation of single, intact pulp fibers. The method uses a polarizing microscope in conjunction with a microscope video camera or CCD camera. Requiring no sample pretreatment, the new method is simple, fast, more accurate than existing methods, and nondestructive of the fiber material. To test the new method, we employed the multiwavelength measurement principle. It is based on the fact that the fibril angle is independent of wavelength, while the relative retardation is inversely proportional to the wavelength used. Measurements were carried out with single pulp fibers as samples under the illumination of different light wavelengths. The measurements and some results are described and presented.

Density operator formalism for the description of coherence evolution of a homonuclear two-spin system in rotating solids

Based on a simple disentangling technique of the propagator, a density operator formalism is developed to describe the behavior of a homonuclear two-spin system in rotating solids. It is shown that the coherence evolutions can be characterized in terms of quaternions or a rotation matrix in a three-dimensional space; the coherence transfers between two different spins can thus be analysed well.

The endogenous vascular elastase that governs development and progression of monocrotaline-induced pulmonary hypertension in rats is a novel enzyme related to the serine proteinase adipsin

We showed previously a cause and effect relationship between increased activity of an endogenous vascular elastase (EVE) and experimentally induced pulmonary hypertension in rats. We now report the isolation and characterization of EVE. Degenerate oligonucleotides synthesized to homologous sequences in serine elastases were used in a PCR with rat pulmonary artery (PA) cDNA. The PCR product hybridized to a 1.2-kb mRNA and the intensity of hybridization was threefold increased in RNA from rat hypertensive PA at a timepoint when EVE activity was increased. The PCR product was used to screen a cDNA library and sequences obtained encoded rat adipsin. We then used immunoaffinity to purify EVE. An antibody to the elastin-binding protein was used to remove this competitor of elastase from the PA extract and the elastolytic activity increased 100-fold. The enzyme was purified using an antibody that recognizes NH2-terminal sequences of serine proteinases and the eluate was further purified using an antibody raised against recombinant adipsin. A single band at 20 kD immunoreactive with the adipsin antibody was resolved as an active enzyme on an elastin substrate gel. Immunogold labeling with an antibody to an adipsin peptide sequence localized EVE to PA smooth muscle cells. This is the first isolation of EVE; it appears to be a novel enzyme related to the serine proteinase adipsin originally found in adipose tissue.

Measurement of 13C chemical shift tensor principal values with a magic-angle turning experiment

The magic-angle turning (MAT) experiment introduced by Gan is developed into a powerful and routine method for measuring the principal values of 13C chemical shift tensors in powdered solids. A large-volume MAT probe with stable rotation frequencies down to 22 Hz is described. A triple-echo MAT pulse sequence is introduced to improve the quality of the two-dimensional baseplane. It is shown that measurements of the principal values of chemical shift tensors in complex compounds can be enhanced by using either short contact times or dipolar dephasing pulse sequences to isolate the powder patterns from protonated or non-protonated carbons, respectively. A model compound, 1,2,3-trimethoxybenzene, is used to demonstrate these techniques, and the 13C principal values in 2,3-dimethylnaphthalene and Pocahontas coal are reported as typical examples.