[Prenatal gene diagnosis of 200 fetuses at high risk of osteogenesis imperfect]

Objective: The authors aim to provide genetic counselling and prenatal gene diagnosis to the families with osteogenesis imperfecta(OI), based on the identification of pathogenetic mutations in large cohort genetic testing. Methods: DNA was extracted from the peripheral blood of parents of the fetuses, and from the villi tissue, amniotic fluid or cord blood of the fetuses using a standard sodium dodecyl sulfate-proteinase K-phenol/chloroform extraction method. PCR combined with Sanger DNA sequencing was performed to validate the pathogenic mutations of 200 fetuses at risk of OI and their parents from 158 families. Allelic analysis of microsatellite markers was applied to exclude the false positive caused by maternal DNA contamination, when both the fetus and the mother harbored the same pathogenic genotype. Results: A total of 83 affected fetuses (83/200, 41.5%) and 12 (12/200, 6.0%) recessive carriers were identified among the 200 fetuses. The 83 affected fetuses included 78 heterozygotes (45 of COL1A1, 32 of COL1A2, one of IFITM5), and 5 compound heterozygotes or homozygotes of recessive OI (two of FKBP10, one of SEC24D, one of WNT1 and one of CRTAP); The 12 recessive carriers included 7 of WNT1, 4 of SERPINF1 and one of SERPINH1. Maternal DNA contamination was excluded from the genomic DNA samples of OI fetuses when their mother with the same affected genotypes. Conclusion: In this study, the authors used an optimized gene diagnosis system of OI to perform prenatal genetic diagnosis to 200 fetuses at high risk of OI, and provided precisely genetic counselling to the OI families.

Giant anterior urethra stones combined with a diverticulum: a case report

Urethral diverticulum is a condition where the urethra or the periurethral glands push into the connective tissue layers that surround it. Patients of urethral diverticulum present with nonspecific symptoms such as incontinence, urinary frequency and urgency, and pain during sexual intercourse and urination. The incidence of this condition is low. We report a case of giant anterior urethra stones combined with a diverticulum with no lower urinary tract symptoms. We believe that this case is extremely rare, and the process of diagnosis and treatment is of great significance in clinical practice.

Effect of H2O on the NO emission characteristics of pulverized coal during oxy-fuel combustion

The NO emission characteristics of Datong bituminous coal and Yangquan anthracite in O₂/H₂O/CO₂ atmospheres were investigated by using a fixed-bed reactor system, and the emission characteristics were compared with the experimental results from O₂/N₂ and O₂/CO₂ atmospheres, especially at low O₂ concentrations and high temperatures. The results showed that NO emissions of pulverized coal in O₂/CO₂ environments were less than those in the O₂/N₂ environments, regardless of the O₂ concentration and the furnace temperature. Adding H₂O decreased the possibility of reactions between the reductive groups (NH) and the oxygen radical during devolatilization, which led to a decrease in NO emissions at 1000 °C. However, as the furnace temperature increased, "additional" nitrogen precursors (HCN and NH₃) generated by enhanced char-H₂O gasification were quickly oxidized to generate a large amount of NO during char oxidation that exceeded the amount of NO reduced by NH during devolatilization. Thus, the NO emissions in O₂/CO₂/H₂O atmosphere were higher than those in O₂/CO₂ atmosphere at a low O₂ concentration. However, as the O₂ concentration increased, the NO emissions in O₂/CO₂/H₂O atmosphere became lower than those in O₂/CO₂ atmosphere because the effect of H₂O gasification became weaker. The NO emissions of Yangquan anthracite (YQ) were higher than those of DT, but the changing trend of YQ was similar to that of DT.

Identification of a Panax ginseng fruit fingerprint by HPLC-ESI-MS

Over many years, parts of Panax ginseng (root and rhizome) have been identified and applied for medical purposes as traditional Chinese herbal medicine. Recently, research has indicated that ginseng fruit also contains similar compounds and is as rich as the other parts of the ginseng. This discovery may dramatically improve the efficient of outputs derived from ginseng products. Here, a new technique combining high-performance liquid chromatography (HPLC) with electrospray ionization tandem mass spectrometry (ESI-MS) was employed to identify the fingerprint of P. ginseng fruit. Using HPLC, compounds that are important for medical purposes were extracted and purified. Combined with ESI-MS, the characteristic peaks (nine common peaks) of those compounds were identified, and the accuracy was confirmed by analysis using the Chromatographic Fingerprint Similarity Evaluation System (2004A edition). Overall, 15 batches of ginseng fruit had a similarity of more than 0.80, 13 batches of samples had a similarity between 0.97 and 0.99, and two batches had a similarity less than 0.90. The test solution and mobile phase selection was discussed. The HPLC-ESI-MS method can produce repeatable and reliable results and can be applied in the quality control of P. ginseng fruit.

Production of succinic acid from sugarcane molasses supplemented with a mixture of corn steep liquor powder and peanut meal as nitrogen sources by Actinobacillus succinogenes

The potential of using corn steep liquor powder (CSLP), peanut meal (PM), soybean meal (SM), cotton meal (CM) and urea as the substitute of yeast extract (YE) as the nitrogen source was investigated for producing succinic acid (SA). Actinobacillus succinogenes GXAS137 was used as the fermenting bacterium and sugarcane molasses was used as the main substrate. None of these materials were able to produce SA as high as YE did. The CSLP could still be considered as a feasible and inexpensive alternate for YE as the yield of SA produced using CSLP was second only to the yield of SA obtained by YE. The use of CSLP-PM mixed formulation (CSLP to PM ratio = 2·6) as nitrogen source produced SA up to 59·2 g l(-1) with a productivity of 1·2 g l(-1) h(-1). A batch fermentation using a stirred bioreactor produced up to 60·7 g l(-1) of SA at the same formulation. Fed-batch fermentation that minimized the substrate inhibition produced 64·7 g l(-1) SA. These results suggest that sugarcane molasses supplemented with a mixture of CSLP and PM as the nitrogen source could be used to produce SA more economically using A. succinogenes. Significance and impact of the study: Succinic acid (SA) is commonly used as a platform chemical to produce a number of high value derivatives. Yeast extract (YE) is used as a nitrogen source to produce SA. The high cost of YE is currently the limiting factor for industrial production of SA. This study reports the use of a mixture of corn steep liquor powder (CSLP) and peanut meal (PM) as an inexpensive nitrogen source to substitute YE. The results showed that this CSLP-PM mixed formulation can be used as an effective and economic nitrogen source for the production of SA.

Cardiovascular risk assessment scoring system for the determination of cardiovascular mortality in renal transplant patients

It is well known that the greatest risk for mortality post-renal transplant is cardiovascular death. We compared a modified cardiac risk assessment system among renal transplant patients who subsequently died versus the group that survived. There was a good correlation between the low, medium, and high scores with survival. The deceased group had significantly greater cardiovascular scores than case controls.

Anti-vimentin Antibody Detection in Recipients of Heart-Beating and Non–Heart Beating Donor Kidneys

Alternative donor sources include non-heart-beating donors (NHBDs). There donors have been exposed to significant ischemia, so that it is common to utilize machine perfusion to either improve the organs or at least assess their viability. Both prolonged warm ischemia and machine perfusion can potentially damage the vascular endothelium, thereby exposing vimentin to antigenic recognition. The aim of this study was to determine whether anti-vimentin antibodies could be detected in the blood of renal transplant recipients at specific time points after transplant and whether they could be related to the donor source. Fifty-one recipients of NHBD kidneys were compared to 52 recipients of heart-beating donor (HBD) kidneys. All recipients had similar anti-vimentin levels pretransplant. However, at 1 month those kidneys from Maastricht category II NHB donors showed significantly higher levels. At 6 months both Maastricht category II and category III NHB donor recipients displayed significantly higher levels than recipients of HBD kidneys.

Do Recipients of Kidneys From Donors Treated With Streptokinase Develop Anti-streptokinase Antibodies?

Streptokinase is used for preflush for non-heart-beating donors (NHBDs) in our center. The aim of this study was to evaluate whether the use of thrombolytic streptokinase results in the production of anti-streptokinase antibodies in the recipients after renal transplantation. Recipient sera taken prior to and at 1 and 6 months posttransplant were tested for the presence of antibodies to streptokinase using an enzyme-linked immunosorbent assay assay. No differences were detected between a group of 18 recipients who had kidneys from thrombolytic-treated NHBDs and a further group of 18 who received NHBD kidneys without such treatment.

Effect of food reductones, 2,5-dimethyl-4-hydroxy-3(2H)-furanone (DMHF) and hydroxyhydroquinone (HHQ), on lipid peroxidation and type IV and I allergy responses of mouse

The effect of long-term supplementation of food reductones, 2,5-dimethyl-4-hydroxy-3(2H)-furanone (DMHF) (2%, w/w), detected in many foodstuffs including soy sauce, and hydroxyhydroquinone (1,2,4-benzenetriol) (HHQ) (1.2%, w/w), detected in coffee, on mouse lipid peroxidation and type IV and I allergy responses was investigated. The effect of supplementation of these reductones combined with NO(2) inhalation (5-6 ppm) was also investigated. Levels of thiobarbituric acid-reactive substances in lung were remarkably increased, and those in kidney and liver were slightly decreased by supplementation of DMHF or HHQ. The degree of 2,4-dinitrochlorobenzene (DNCB)-sensitized lymph node cell proliferation as assessed by lymph node assay was remarkably enhanced by supplementation of DMHF or HHQ. Both the DNCB-sensitized and the trimellitic anhydride-sensitized increases in IgE levels of mice were enhanced to greater extent by supplementation of DMHF or HHQ. In no cases were additive effects of NO(2) inhalation observable. Allergen-sensitized type IV and I allergy responses of mice may be enhanced by supplementation of food reductones, DMHF or HHQ.

Separation of six uremic middle molecular compounds by high performance liquid chromatography and analysis by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

BACKGROUND

Since the postulation of uremic middle molecule (UMM) hypothesis made by Babb et al. [Trans-Am Soc Artif Intern Organs 18 (1972) 98], there has been great interest in the separation and identification of the role of UMM. However, few of the compounds isolated from UMM fractions were demonstrated to play an important role in humans. Thus, the separation and identification of the real UMM is essential for UMM research.

METHODS

Urine and serum samples from uremic patients and healthy subjects were separated by gel permeation chromatography. Two presumed UMM fractions, A and B, were obtained from uremic sera and urine, normal urine, but not normal sera. Fraction A was further isolated by anion exchange chromatography and a series of sub-peaks were obtained. The sub-fraction A-3 obtained in the second step was desalted on a Sephadex G-15 column, and characterized by IR, UV and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Further separation of sub-fraction A-3 was performed by high performance liquid chromatography (HPLC).

RESULTS

By gel permeation chromatography, two UMM peaks (A and B) were detected at 206 nm in normal urine, uremic sera, but they were barely noticed in the profile of normal sera. In contrast, the absorption at 206 nm of fractions A and B from uremic serum and urine were smaller than that of fractions A and B from normal urine. Fractions A from different origins were resolved into eight to nine sub-peaks at 230 nm by anion exchange chromatography. One of these sub-peaks, A-3, was detected in uremic serum and normal urine, but is undetectable in uremic urine. After desalting, sub-fraction A-3 was separated into two parts designated as A-3-I and A-3-II. MALDI-TOF-MS revealed that fraction A-3-I and A-3-II from two origins were identical, respectively-fraction A-3-I contained three components with MW 839.69, 1007.94 and 2015.16 and fraction A-3-II consisted of another three components with MW 873.69, 1106.67 and 1680.28. Six middle molecular compounds in sub-fraction A-3 were thoroughly resolved by HPLC.

CONCLUSION

Our results demonstrated that the UMM sub-fraction A-3 contains the real UMM in the MW range of 800-2015 Da. By multi-step chromatographic isolation, six real middle molecular compounds were purified and characterized with MALDI-TOF-MS. It is likely that three of these UMM compounds are important, as they readily accumulated in sera of uremic patients, but are normally excreted in healthy subjects.

[Identification of red kojic from different habitats with clustering analysis by near-infrared diffuse reflectance spectrometry]

OBJECTIVE

To provide a new method for identifying Red kojic.

METHODS

Being controled with the Aspergillus terreus, near-infrared diffuse reflectance spectroscopy combining with clusering analysis was used in the identification of Red Kojic made by M. purpureus fermentation from 18 different habitats.

RESULTS

We can easily distinguish the Red Kojic from different habitats and the Aspergillus terreus. The results are consistent in some degree with that of morphologic study.

CONCLUSION

This method is a new, rapid, simple and low cost assay technique being able to be used in the quality control of Red Kojic.

Protein interactions of the MLL PHD fingers modulate MLL target gene regulation in human cells

The PHD fingers of the human MLL and Drosophila trx proteins have strong amino acid sequence conservation but their function is unknown. We have determined that these fingers mediate homodimerization and binding of MLL to Cyp33, a nuclear cyclophilin. These two proteins interact in vitro and in vivo in mammalian cells and colocalize at specific nuclear subdomains. Overexpression of the Cyp33 protein in leukemia cells results in altered expression of HOX genes that are targets for regulation by MLL. These alterations are suppressed by cyclosporine and are not observed in cell lines that express a mutant MLL protein without PHD fingers. These results suggest that binding of Cyp33 to MLL modulates its effects on the expression of target genes.

Induction of astrocyte differentiation by endothelial cells

Here we have investigated the mechanisms that control astrocyte differentiation within the developing rat optic nerve. Astrocytes are normally generated by astrocyte precursor cells within the embryonic optic nerve. We show that there is a close temporal and spatial correlation between endothelial and astrocyte differentiation. We tested the potential role of endothelial cells in inducing astrocyte differentiation by developing an immunopanning method to highly purify endothelial cells from developing optic nerves. We show that the purified endothelial cells, but not other embryonic optic nerve cell types, strongly induce the differentiation of purified astrocyte precursor cells into astrocytes in vitro. Leukemia inhibitory factor (LIF) and LIF receptors have been implicated previously in astrocyte differentiation in vivo. We show that purified endothelial cells express LIF mRNA and that their ability to induce astrocyte differentiation is prevented by a neutralizing anti-LIF, but not anti-ciliary neurotrophic factor, antiserum. These findings demonstrate a role for endothelial cells in inducing astrocyte differentiation. The induction of astrocyte differentiation by endothelial cells makes sense phylogenetically, anatomically, and functionally, because astrocytes evolved concurrently with brain vasculature and ensheathe capillaries throughout the brain. The ability to purify and culture astrocytes and endothelial cells should provide an excellent model system for future studies of blood-brain barrier development.

The sequence of the human genome

A 2.91-billion base pair (bp) consensus sequence of the euchromatic portion of the human genome was generated by the whole-genome shotgun sequencing method. The 14.8-billion bp DNA sequence was generated over 9 months from 27,271,853 high-quality sequence reads (5.11-fold coverage of the genome) from both ends of plasmid clones made from the DNA of five individuals. Two assembly strategies-a whole-genome assembly and a regional chromosome assembly-were used, each combining sequence data from Celera and the publicly funded genome effort. The public data were shredded into 550-bp segments to create a 2.9-fold coverage of those genome regions that had been sequenced, without including biases inherent in the cloning and assembly procedure used by the publicly funded group. This brought the effective coverage in the assemblies to eightfold, reducing the number and size of gaps in the final assembly over what would be obtained with 5.11-fold coverage. The two assembly strategies yielded very similar results that largely agree with independent mapping data. The assemblies effectively cover the euchromatic regions of the human chromosomes. More than 90% of the genome is in scaffold assemblies of 100,000 bp or more, and 25% of the genome is in scaffolds of 10 million bp or larger. Analysis of the genome sequence revealed 26,588 protein-encoding transcripts for which there was strong corroborating evidence and an additional approximately 12,000 computationally derived genes with mouse matches or other weak supporting evidence. Although gene-dense clusters are obvious, almost half the genes are dispersed in low G+C sequence separated by large tracts of apparently noncoding sequence. Only 1.1% of the genome is spanned by exons, whereas 24% is in introns, with 75% of the genome being intergenic DNA. Duplications of segmental blocks, ranging in size up to chromosomal lengths, are abundant throughout the genome and reveal a complex evolutionary history. Comparative genomic analysis indicates vertebrate expansions of genes associated with neuronal function, with tissue-specific developmental regulation, and with the hemostasis and immune systems. DNA sequence comparisons between the consensus sequence and publicly funded genome data provided locations of 2.1 million single-nucleotide polymorphisms (SNPs). A random pair of human haploid genomes differed at a rate of 1 bp per 1250 on average, but there was marked heterogeneity in the level of polymorphism across the genome. Less than 1% of all SNPs resulted in variation in proteins, but the task of determining which SNPs have functional consequences remains an open challenge.

Photo-induction of an NADPH dehydrogenase which functions as a mediator of electron transport to the intersystem chain in the cyanobacterium Synechocystis PCC6803

Illumination of the dark-incubated cells of Synechocystis PCC6803 caused recovery of both respiratory activity of oxygen uptake and PS I-cyclic electron flow, which was monitored by the dark reduction of P700(+) in the presence of DCMU after a 50 ms pulse light (MT) under background far-red light, but the effects were much smaller in those of the mutant M55, which has an ndh-B defective gene. Activity of an NADPH-NBT oxidoreductase with a higher molecular mass (around 380 kDa), which was only found in wild type but not in M55, became evident after the dark-incubated cells were exposed to the light. Immuno-blotting analysis indicated that the NADPH-NBT oxidoreductase contains the NdhB subunit of NDH. The expression of NdhB decreased in dark-incubated cells and increased upon transfer of the cells back to light. These results indicate that an NADPH-specific NDH participates in the light-regulated cyclic electron transport around Photosystem I as well as in respiratory electron transport to the intersystem chain in Synechocystis 6803.

Light-induced dynamic changes of NADPH fluorescence in Synechocystis PCC 6803 and its ndhB-defective mutant M55

Blue-green fluorescence emission of intact cells of Synechocystis PCC6803 and of its ndhB-defective mutant M55 was measured with a standard pulse-amplitude-modulation chlorophyll fluorometer equipped with a new type of emitter-detector unit featuring pulse-modulated UV-A measuring light and a photomultiplier detector. A special illumination program of repetitive saturating light pulses with intermittent dark periods (10 s light, 40 s dark) was applied to elicit dynamic fluorescence changes under conditions of quasi-stationary illumination. The observed effects of artificial electron acceptors and inhibitors on the responses of wild-type and mutant M55 cells lead to the conclusion that changes of NAD(P)H fluorescence are measured. In control samples, a rapid phase of light-driven NADP reduction is overlapped by a somewhat slower phase of NADPH oxidation which is suppressed by iodoacetic acid and, hence, appears to reflect NADPH oxidation by the Calvin cycle. Mercury chloride transforms the light-driven positive response into a negative one, suggesting that inhibition of NADP reduction at the acceptor side of PSI leads to reduction of molecular oxygen, with the hydrogen peroxide formed (via superoxide) causing rapid oxidation of NADPH. The new fluorescence approach opens the way for new insights into the complex interactions between photosynthetic and respiratory pathways in cyanobacteria.

PAH emission from the industrial boilers

Polycyclic aromatic hydrocarbons (PAHs) emitted from 25 industrial boilers were investigated. The fuels used for these 25 boilers included 21 heavy oil, two diesel, a co-combustion of heavy oil and natural gas (HO+NG) and a co-combustion of coke oven gas and blast furnace gas (COG+BFG) boilers. PAH samples from the stack flue gas (gas and particle phases) of these 25 boilers were collected by using a PAH stack sampling system. Twenty one individual PAHs were analyzed primarily by a gas chromatography/mass spectrometer (GC/MS). Total-PAH concentration in the flue gas of 83 measured data for these 25 boiler stacks ranged between 29.0 and 4250 microg/m(3) and averaged 488 microg/m(3). The average of PAH-homologue mass (F%) counted for the total-PAH mass was 54.7%, 9.47% and 15.3% for the 2-ring, 3-ring and 4-ring PAHs, respectively. The PAHs in the stack flue gas were dominant in the lower molecular weight PAHs. The emission factors (EFs) of total-PAHs were 13,300, 2920, 2880 and 208 microg/kg-fuel for the heavy oil, diesel, HO+NG and COG+BFG fueled-boiler, respectively. Nap was the most predominant PAH occurring in the stack flue gas. In addition, the EF of 21 individual PAHs in heavy-oil boiler were almost the highest among the four various fueled-boilers except for those of FL and BkF in the diesel boiler. Furthermore, the EF of total-PAHs or BaP for heavy oil were both one order of magnitude higher than that for the diesel-fueled boiler.

[Studies on gel electrophoresis of soluble protein and two kinds of isodynamic enzyme in hongqu from different producing areas]

OBJECTIVE

To investigate the consanguinity between 12 strains of Monascus(MS 01-12) separated and purified from different samples of Hongqu collected from 12 areas in China and the variant strain of Monascus(MS 18) mutated from M. purpureus.

METHOD

Gel electrophoresis of soluble protein, esterase and superoxide dismutase(SOD) was used to study the consanguinity between strains MS 01-12 and the variant strain MS 18.

RESULTS

The electrochromatophoreses of soluble protein, esterase and SOD in the 12 strains (MS 01-12) are identical, but in the variant strain MS 18 are remarkably different. The results are consistent with those of morphological studies.

CONCLUSION

Strains MS 01-12 are the identical species M. purpureus, but strain MS 18 is different from strains of MS 01-12, or a variant of M. purpureus.

[Studies on pharmacognostic identification and quality control standards for hongqu]

OBJECTIVE

To develop effective methods for quality control of the traditional Chinese drug Hongqu.

METHOD

TLC and microscopic identification were performed. HPLC was used to determine the content of lovastatin.

RESULT

A lot of hyphae and spores in Hongqu were observed under microscope. The spot of lovastatin was found on the TLC chromatogram. The standard curve of lovastatin by HPLC was linera in the range of 5 micrograms/ml-100 micrograms/ml. The average recovery of lovastatin was 96.4%, RSD 3.68%, n = 5.

CONCLUSION

The methods are simple, sensitive and accurate. These studies provide the scientific basis for quality evaluation and quality control of Hongqu.

Identification and localization of Ca(2+)-activated K+ channels in rat sciatic nerve

To understand the physiology of Schwann cells and myelinated nerve, we have been engaged in identifying K+ channels in sciatic nerve and determining their subcellular localization. In the present study, we examined the slo family of Ca(2+)-activated K+ channels, a class of channel that had not previously been identified in myelinated nerve. We have determined that these channels are indeed expressed in peripheral nerve, and have cloned rat homologues of slo that are more than 95% identical to the murine slo. We found that sciatic nerve RNA contained numerous alternatively spliced variants of the slo homologue, as has been seen in other tissues. We raised a polyclonal antibody against a peptide from the carboxyl terminal of the channels. Immunocytochemistry revealed that the channel proteins are in Schwann cells and are associated with canaliculi that run along the outer surface of the cells. They are also relatively concentrated near the node of Ranvier in the Schwann cell outer membrane. This staining pattern is quite similar to what we previously reported for the voltage-dependent K+ channel Kv 1.5. We did not observe staining of axons or connective tissue in the nerve and so it seems likely that most or all of the splicing variants are located in the Schwann cells. The localization of these channels also suggests that they may participate in maintaining the resting potential of the Schwann cells during K+ buffering.

Purification and characterization of astrocyte precursor cells in the developing rat optic nerve

The signaling interactions that control oligodendrocyte generation from their precursor cells have been studied intensively. Much less is known about how astrocyte generation is normally controlled. Here we report the purification and characterization of astrocyte precursor cells (APCs) from the developing rat optic nerve. APCs are antigenically distinct from astrocytes. Both cell types are Pax2(+) and vimentin+, whereas astrocytes are GFAP+ and S100beta+, and the precursor cells are A2B5(+). In contrast to purified astrocytes, purified APCs rapidly die in serum-free culture but can be saved by basic fibroblast growth factor (bFGF) and glial growth factor 2 (GGF2). Unlike oligodendrocyte precursor cells, APCs do not differentiate by default; their differentiation into GFAP+ cells is induced by ciliary neurotrophic factor (CNTF) or by leukemia inhibitory factor (LIF). Finally, the survival, proliferation, and differentiation of APCs were promoted by coculture with other embryonic optic nerve cell types but not with purified embryonic retinal ganglion cells, indicating that interactions with non-neuronal cells are likely to play an important role in controlling astrocyte generation in the developing optic nerve.

Ssp1, a site-specific parvulin homolog from Neurospora crassa active in protein folding

Peptidyl-prolyl cis-trans-isomerases (PPIases) are enzymes capable of isomerizing a Xaa-Pro peptide bond. Three families of PPIases are known: cyclophilins, FKBPs, and parvulins. The physiological functions of the PPIases are only poorly understood. Eucaryotic members of the parvulin family have recently been shown to be essential for regulation of mitosis. Here we describe the purification and characterization of Ssp1, an abundant parvulin homolog from Neurospora crassa, which is unique among the known eucaryotic parvulins in containing a polyglutamine stretch between the N-terminal WW domain and the C-terminal PPIase domain. Ssp1 is a site-specific PPIase with respect to the amino acid N-terminal to the proline residue. Peptides with glutamate, phosphoserine, or phosphothreonine in the -1-position proved to be the best substrates. Ssp1 is not only able to isomerize small peptides but is also active in protein folding, as shown with mouse dihydrofolate reductase. Using the substrate specificity of Ssp1, we could identify Glu81-Pro82 as a PPIase-sensitive site in folding of dihydrofolate reductase. These results demonstrate that Ssp1 is a potent mediator of protein folding and that parvulins can serve as tools to elucidate rate-limiting steps in protein folding reactions.

[Restoration of elbow joint and its function by transposition of latissimus dorsi myocutaneous flap following serious high-voltage injury in upper limb]

OBJECTIVE

This is to introduce a method for repairing and restoring the elbow joints and their function of the patients suffering from serious high-voltage electric burns in upper extremity.

METHODS

We designed the transposition of latissimus dorsi myocutaneous flap (MCF) to repair the wounds of elbow, as well as restore the joint's flexion function by the motor power of the muscle. This procedure salvaged the elbow joints, which would have to be amputated before.

RESULTS

8 cases, 10 limbs were involved. All flaps survived completely and 6 of them had primary healing while the other 4 flaps healed after dressing changing. The elbow joints and their functions were satisfactorily restored in 5 limbs and the functions were also regained through further elbow joint release procedures in 2 limbs. The other 3 limbs (2 cases) lost contact with us and so the results were not clear.

CONCLUSION

This method has evident advantages and satisfactory results.

Human T cell cyclophilin18 binds to thiol-specific antioxidant protein Aop1 and stimulates its activity

Cyclophilins (CyPs) define a family of proteins binding to the immunosuppressive drug cyclosporin A (CsA). They are evolutionary highly conserved proteins being present in both pro- and eukaryotes and in different subcellular locations. CyPs possess enzymatic activity, namely peptidyl-prolyl cis-trans isomerase (PPIase) activity and are involved in cellular protein folding and protein interactions. Here we describe a novel interaction of human T cell cyclophilin18 (hCyP18). Abundant cytosolic hCyP18 binds to the thiol-specific antioxidant protein Aop1 and stimulates its enzymatic activity. Aop1 belongs to a family of proteins thought to be involved in defense of oxidative stress. The interaction of both proteins seem to be specific, since other PPIases do not have any stimulatory effect on Aop1.

[One stage repair and reconstruction for severe deep burns with compound tissue defects of upper limb]

In order to solve the difficult problems of repair and reconstruction for severe deep burns with compound tissue defects of upper limb, 26 cases were treated with transplantation of compound tissue flap, vascularized by anastomosis of blood vessel or by vascular pedicle. Several kinds of reparative and reconstructive procedure could be performed simultaneously. Not only the tissue defect was repaired, but also the upper limb function was reconstructed in one stage operation. Owing to the presence of abundant vascular supply from the vascularized compound tissue and primarily closing the wounds, the anti-infection potency was high, then it was suitable for such conditions as fresh severe deep burn with infection and compound tissue defects. As a result, this technique provided the best chance to save upper limb from amputation. The duration required for treatment could be markedly shortened. All the cases successed. The long-term functional recovery was satisfactory. This method provided the possibility to solve effectively the difficult problem dealing with the severe deep burns with compound tissue defects of upper limb.

A nuclear RNA-binding cyclophilin in human T cells

Cyclophilins (CyPs) are binding proteins for the immunosuppressive drug cyclosporin A (CsA). CyPs are evolutionarily highly conserved proteins present in both pro- and eukaryotes as well as in different subcellular locations. CyPs possess enzymatic activity, namely peptidyl-prolyl cis-trans isomerase (PPIase) activity; CyPs are involved in cellular protein folding and protein interactions. To date, only cyclosporins and proteins are known to interact with CyPs. Here we describe a novel nuclear cyclophilin (hCyP33) from human T cells with an additional RNA-binding domain. This combines for the first time RNA binding and protein folding in one protein.

Inwardly rectifying K+ channels that may participate in K+ buffering are localized in microvilli of Schwann cells

The presence of K+ channels on the Schwann cell plasma membrane suggests that Schwann cells may participate actively during action potential propagation in the peripheral nervous system. One such role for Schwann cells may be to maintain a constant extracellular concentration of K+ in the face of K+ efflux from a repolarizing axon. This buffering is likely to involve the influx of K+ through inward rectifying K+ channels. The molecular cloning of these genes allowed us to examine their expression and localization in Schwann cells in detail. In this study, we demonstrate the expression of two inward rectifying K+ channels, IRK1 and IRK3, in adult rat sciatic nerve. Immunocytochemistry using a polyclonal antibody against these proteins showed that the channels were highly localized at nodes in sciatic nerve. By immunoelectron microscopy, the nodal staining was shown to be concentrated in the microvilli of Schwann cells (also called nodal processes). The large surface area of the microvilli and their presence in the nodal space suggest involvement with ionic buffering. Thus, IRK1 and IRK3 are well suited to K+ buffering by virtue of both their biophysical properties and their localization. The restricted distribution of the inward rectifying K+ channels also provides an example of the highly regulated localization of ion channels to their specialized membrane domains. In the Schwann cell, where the nodal processes are a minute fraction of the total cell membrane, a potent mechanism must be present to concentrate the channels in this structure.

Differential distribution of closely related potassium channels in rat Schwann cells

Closely related K+ channels can coassemble to form heteromultimers in expression systems, as well as in vivo. Whether in vivo this coassembly is random and inevitable or whether highly homologous channels can be segregated and targeted independently within a given cell has not been determined. In this study, we address these questions by characterizing and localizing voltage-dependent K+ channels in Schwann cells. Transcripts for three closely related members of the Shaker-like family of K+ channels are found in adult rat sciatic nerve: Kv1.1, Kv1.2, and Kv1.5. We have examined two of these and observed that both Kv1.1 and Kv1.5 proteins are expressed in Schwann cells but differ in their distributions. Kv1.5 is localized on the Schwann cell membrane at the nodes of Ranvier and in bands that run along the outer surface of the myelin. It is also seen intracellularly in the vicinity of the nucleus. Schwann cell staining for Kv1.1, on the other hand, was seen only in perinuclear, intracellular compartments. These results provide evidence that closely related channels from the same family need not coassemble and can be localized differentially in the same cell. In addition, Kv1.1 was highly concentrated in the axonal membrane at juxtaparanodal regions. The distributions of these K+ channels in myelinated nerve highlight the elaborate molecular specializations of these membranes.

Competition of rifampicin with binding of substrate and RNA to RNA polymerase

The rate of formation of dinucleoside tetraphosphate, pppApU, from ATP and UTP by RNA polymerase on the A1 promoter of the mutant D111 of bacteriophage T7 is distinctly and specifically reduced not only by the third template-directed nucleotide, CTP, but also by CMP. The inhibitory effect of CMP is not changed when the enzyme contains prebound rifampicin. The synthesis of pppApU is also strongly reduced after preincubation of the enzyme with RNA. This inhibitory effect of RNA is, however, distinctly diminished by rifampicin bound to the enzyme prior to the addition of RNA. On the other hand RNA can suppress the specific binding of the antibiotic to the RNA polymerase subassembly alpha 2 beta.